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标题: WPF 笔迹算法 从点集转笔迹轮廓 [打印本页]

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作者: 金歌    时间: 2023-10-27 23:04
标题: WPF 笔迹算法 从点集转笔迹轮廓
本文将告诉大家一些笔迹算法，从用户输入的点集，即鼠标轨迹点或触摸轨迹点等，转换为一个可在界面绘制显示笔迹画面的基础数学算法。尽管本文标记的是 WPF 的笔迹算法，然而实际上本文更侧重基础数学计算，理论上可以适用于任何能够支持几何绘制的 UI 框架上，包括 UWP 或 WinUI 或 UNO 或 MAUI 或 Eto 等框架
我将从简单到复杂的顺序描述笔迹算法，本文属于比较偏算法底层，阅读之前请先确保初中的数学知识还没忘了
本文适合于想要了解笔迹绘制更多细节的伙伴，以及期望自己设计出更好看的笔迹的伙伴，以及没事干摸鱼看博客的伙伴
最简单的笔迹轨迹算法

大家都知道，无论是鼠标还是触摸还是笔，所产生的数据基本都是点数据。根据点集创建一条笔迹轨迹的一个实现方式是创建一条几何图形，将几何图形绘制到界面上。在 UI 框架的底层里，是不存在笔迹的概念的，只有画图、画文本、画几何图形等基础绘制原语而已。从点集构建出一条几何轨迹最简单的方法是构建一条折线，代码也非常简单，只是将所有的输入点当成折线即可
也就是创建一个 Polyline 对象，不断将输出的点集加入到折线里面。以下是例子代码，先新建一个空 WPF 项目，在 MainWindow.xaml 里添加事件监听，如以下代码

1. <Window x:
2.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
3.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
4.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
5.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
6.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
7.         mc:Ignorable="d"
8.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
9.     <Canvas x:Name="InkCanvas">
11.     </Canvas>
12. </Window>

复制代码

在后台代码里面，实现事件，以下的代码很简单，相信大家一看就明白

1. public partial class MainWindow : Window{    public MainWindow()    {<Window x:
2.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
3.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
4.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
5.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
6.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
7.         mc:Ignorable="d"
8.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
9.     <Canvas x:Name="InkCanvas">
11.     </Canvas>
12. </Window>InitializeComponent();    }    private void MainWindow_OnStylusDown(object sender, StylusDownEventArgs e)    {<Window x:
13.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
14.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
15.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
16.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
17.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
18.         mc:Ignorable="d"
19.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
20.     <Canvas x:Name="InkCanvas">
22.     </Canvas>
23. </Window>var polyline = new Polyline()<Window x:
24.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
25.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
26.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
27.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
28.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
29.         mc:Ignorable="d"
30.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
31.     <Canvas x:Name="InkCanvas">
33.     </Canvas>
34. </Window>{<Window x:
35.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
36.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
37.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
38.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
39.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
40.         mc:Ignorable="d"
41.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
42.     <Canvas x:Name="InkCanvas">
44.     </Canvas>
45. </Window>    Stroke = Brushes.Black,<Window x:
46.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
47.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
48.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
49.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
50.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
51.         mc:Ignorable="d"
52.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
53.     <Canvas x:Name="InkCanvas">
55.     </Canvas>
56. </Window>    StrokeThickness = 5<Window x:
57.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
58.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
59.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
60.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
61.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
62.         mc:Ignorable="d"
63.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
64.     <Canvas x:Name="InkCanvas">
66.     </Canvas>
67. </Window>};<Window x:
68.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
69.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
70.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
71.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
72.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
73.         mc:Ignorable="d"
74.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
75.     <Canvas x:Name="InkCanvas">
77.     </Canvas>
78. </Window>InkCanvas.Children.Add(polyline);<Window x:
79.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
80.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
81.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
82.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
83.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
84.         mc:Ignorable="d"
85.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
86.     <Canvas x:Name="InkCanvas">
88.     </Canvas>
89. </Window>_pointCache[e.StylusDevice.Id] = polyline;<Window x:
90.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
91.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
92.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
93.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
94.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
95.         mc:Ignorable="d"
96.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
97.     <Canvas x:Name="InkCanvas">
99.     </Canvas>
100. </Window>foreach (var stylusPoint in e.GetStylusPoints(this))<Window x:
101.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
102.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
103.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
104.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
105.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
106.         mc:Ignorable="d"
107.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
108.     <Canvas x:Name="InkCanvas">
110.     </Canvas>
111. </Window>{<Window x:
112.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
113.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
114.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
115.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
116.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
117.         mc:Ignorable="d"
118.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
119.     <Canvas x:Name="InkCanvas">
121.     </Canvas>
122. </Window>    polyline.Points.Add(stylusPoint.ToPoint());<Window x:
123.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
124.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
125.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
126.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
127.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
128.         mc:Ignorable="d"
129.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
130.     <Canvas x:Name="InkCanvas">
132.     </Canvas>
133. </Window>}    }    private void MainWindow_OnStylusMove(object sender, StylusEventArgs e)    {<Window x:
134.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
135.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
136.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
137.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
138.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
139.         mc:Ignorable="d"
140.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
141.     <Canvas x:Name="InkCanvas">
143.     </Canvas>
144. </Window>if (_pointCache.TryGetValue(e.StylusDevice.Id,out var polyline))<Window x:
145.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
146.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
147.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
148.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
149.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
150.         mc:Ignorable="d"
151.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
152.     <Canvas x:Name="InkCanvas">
154.     </Canvas>
155. </Window>{<Window x:
156.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
157.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
158.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
159.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
160.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
161.         mc:Ignorable="d"
162.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
163.     <Canvas x:Name="InkCanvas">
165.     </Canvas>
166. </Window>    foreach (var stylusPoint in e.GetStylusPoints(this))<Window x:
167.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
168.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
169.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
170.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
171.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
172.         mc:Ignorable="d"
173.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
174.     <Canvas x:Name="InkCanvas">
176.     </Canvas>
177. </Window>    {<Window x:
178.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
179.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
180.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
181.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
182.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
183.         mc:Ignorable="d"
184.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
185.     <Canvas x:Name="InkCanvas">
187.     </Canvas>
188. </Window><Window x:
189.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
190.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
191.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
192.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
193.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
194.         mc:Ignorable="d"
195.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
196.     <Canvas x:Name="InkCanvas">
198.     </Canvas>
199. </Window>polyline.Points.Add(stylusPoint.ToPoint());<Window x:
200.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
201.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
202.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
203.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
204.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
205.         mc:Ignorable="d"
206.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
207.     <Canvas x:Name="InkCanvas">
209.     </Canvas>
210. </Window>    }<Window x:
211.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
212.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
213.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
214.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
215.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
216.         mc:Ignorable="d"
217.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
218.     <Canvas x:Name="InkCanvas">
220.     </Canvas>
221. </Window>}    }    private void MainWindow_OnStylusUp(object sender, StylusEventArgs e)    {<Window x:
222.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
223.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
224.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
225.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
226.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
227.         mc:Ignorable="d"
228.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
229.     <Canvas x:Name="InkCanvas">
231.     </Canvas>
232. </Window>if (_pointCache.Remove(e.StylusDevice.Id, out var polyline))<Window x:
233.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
234.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
235.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
236.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
237.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
238.         mc:Ignorable="d"
239.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
240.     <Canvas x:Name="InkCanvas">
242.     </Canvas>
243. </Window>{<Window x:
244.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
245.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
246.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
247.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
248.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
249.         mc:Ignorable="d"
250.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
251.     <Canvas x:Name="InkCanvas">
253.     </Canvas>
254. </Window>    foreach (var stylusPoint in e.GetStylusPoints(this))<Window x:
255.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
256.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
257.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
258.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
259.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
260.         mc:Ignorable="d"
261.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
262.     <Canvas x:Name="InkCanvas">
264.     </Canvas>
265. </Window>    {<Window x:
266.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
267.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
268.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
269.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
270.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
271.         mc:Ignorable="d"
272.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
273.     <Canvas x:Name="InkCanvas">
275.     </Canvas>
276. </Window><Window x:
277.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
278.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
279.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
280.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
281.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
282.         mc:Ignorable="d"
283.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
284.     <Canvas x:Name="InkCanvas">
286.     </Canvas>
287. </Window>polyline.Points.Add(stylusPoint.ToPoint());<Window x:
288.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
289.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
290.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
291.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
292.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
293.         mc:Ignorable="d"
294.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
295.     <Canvas x:Name="InkCanvas">
297.     </Canvas>
298. </Window>    }<Window x:
299.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
300.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
301.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
302.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
303.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
304.         mc:Ignorable="d"
305.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
306.     <Canvas x:Name="InkCanvas">
308.     </Canvas>
309. </Window>}    }    private readonly Dictionary _pointCache=new Dictionary();}

复制代码

以上的代码放在github 和 gitee 欢迎访问
可以通过如下方式获取本文的源代码，先创建一个空文件夹，接着使用命令行 cd 命令进入此空文件夹，在命令行里面输入以下代码，即可获取到本文的代码

1. git init
2. git remote add origin https://gitee.com/lindexi/lindexi_gd.git
3. git pull origin d76fffd214ed5b3aeb99f3593c441b7a12f10d55

复制代码

以上使用的是 gitee 的源，如果 gitee 不能访问，请替换为 github 的源。请在命令行继续输入以下代码

1. git remote remove origin
2. git remote add origin https://github.com/lindexi/lindexi_gd.git
3. git pull origin d76fffd214ed5b3aeb99f3593c441b7a12f10d55

复制代码

获取代码之后，进入 HallgaiwhiyiwaLejucona\YegeenurcairwheBeahealelbewe 文件夹
尽管以上的代码很简单，但是大家将会发现笔迹不够顺滑，至少比 WPF 最简逻辑实现多指顺滑的笔迹书写 调用 WPF 自带的笔迹绘制的方法不顺滑好多，而且绘制速度也差好多

先忘掉 WPF 的上层调用，假如现在咱想要自己编写算法来画一条比 WPF 不会差太多的笔迹轨迹，可以如何做呢。接下来我将继续从简单到复杂的顺序告诉大家不同的算法
用两条折线绘制笔迹

上文使用折线的方式可以很简单绘制出笔迹，但是无法实现一条粗细变化的笔迹轨迹。笔迹的粗细变更一般来说和触摸压感相关，换句话说，想要实现跟随触摸压感变更而变更粗细的笔迹轨迹轮廓就需要用到至少比折线更加复杂的方式
接下来介绍的方式是用两条线段绘制笔迹，可以将笔迹元素理解为一个由两条折线构成的闭合 Path 几何形状。如下图所示，笔迹轨迹就是一个 Path 几何形状的填充

这里如果看完还没理解的话，推荐先暂停下来，先想一想。因为这里有点难描述哈
在这个的基础上，咱的问题就转换为根据输入的点集转换为 Path 几何形状
接下来我将介绍根据输入的点集转换为 Path 几何形状的最简单方法之一，期望以下的方法能够给大家带来一些启示。我将快速给出一些图和文字描述给到大家，方便快速理解整体的思想。然后再给出具体的实现
下图的蓝色的点表示的是当前所输入收到的点集

接下来求每个点与下一个点相连的射线向量，再算出射线向量的法线方向，在此法线方向上以触摸点的中心向法线两端延伸线段，延伸的线段长度由笔迹粗细配置以及当前触摸点的压感系数决定，如下图，蓝色的线就是射线向量，黄色的线是射线向量的法线方向延伸的线段

再获取线段的两个端点，如下图，红色的圆点就是延伸的线段的两个端点

接着将各个线段的端点按照如下图的方式连接起来，各个线段的两个端点分别按照两边连接成两条折线，再将这两条折线和起始点和结束点连接到一起，构成闭合的 Path 几何形状，红色的折线就可以被当成笔迹轨迹的 Path 几何形状

最后将红色的折线组成的笔迹轨迹的 Path 几何形状填充，填充之后看起来的效果还行

相信大家看到这里就理解了用两条折线绘制笔迹的方法
接下来我将告诉大家如何使用具体的代码实现用两条折线绘制笔迹
原本我是想继续采用 WPF 项目完成此步骤的演示，但刚好我打开了一个 UNO 框架的项目，于是我就使用 UNO 框架项目作为演示。这里需要说明的是 UNO 和 WPF 之间的关系不是重复的存在，而是相互引用的关系，如下图可以看到 UNO 可以处于 WPF 的上层，换句话说就是使用 UNO 框架时可以将 WPF 当成底层，从这个方面来说，最后构建输出的也依然是一个 WPF 应用

新建一个 UNO 项目，在 MainPage.xaml 里面监听事件，制作一些准备辅助笔迹绘制的界面逻辑，简单的代码如下

1. [/code]在 MainPage.xaml.cs 后台代码里面，根据输入事件的监听，获取到当前的输入点集。这部分代码预计大家一看就明白，我这里就快速跳过
2. [code]    private void InkCanvas_OnPointerPressed(object sender, PointerRoutedEventArgs e)    {<Window x:
3.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
4.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
5.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
6.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
7.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
8.         mc:Ignorable="d"
9.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
10.     <Canvas x:Name="InkCanvas">
12.     </Canvas>
13. </Window>var pointerPoint = e.GetCurrentPoint(InkCanvas);<Window x:
14.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
15.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
16.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
17.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
18.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
19.         mc:Ignorable="d"
20.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
21.     <Canvas x:Name="InkCanvas">
23.     </Canvas>
24. </Window>Point position = pointerPoint.Position;<Window x:
25.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
26.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
27.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
28.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
29.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
30.         mc:Ignorable="d"
31.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
32.     <Canvas x:Name="InkCanvas">
34.     </Canvas>
35. </Window>var inkInfo = new InkInfo();<Window x:
36.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
37.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
38.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
39.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
40.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
41.         mc:Ignorable="d"
42.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
43.     <Canvas x:Name="InkCanvas">
45.     </Canvas>
46. </Window>_inkInfoCache[e.Pointer.PointerId] = inkInfo;<Window x:
47.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
48.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
49.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
50.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
51.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
52.         mc:Ignorable="d"
53.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
54.     <Canvas x:Name="InkCanvas">
56.     </Canvas>
57. </Window>inkInfo.PointList.Add(position);<Window x:
58.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
59.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
60.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
61.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
62.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
63.         mc:Ignorable="d"
64.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
65.     <Canvas x:Name="InkCanvas">
67.     </Canvas>
68. </Window>DrawStroke(inkInfo);    }    private void InkCanvas_OnPointerMoved(object sender, PointerRoutedEventArgs e)    {<Window x:
69.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
70.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
71.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
72.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
73.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
74.         mc:Ignorable="d"
75.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
76.     <Canvas x:Name="InkCanvas">
78.     </Canvas>
79. </Window>if (_inkInfoCache.TryGetValue(e.Pointer.PointerId, out var inkInfo))<Window x:
80.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
81.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
82.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
83.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
84.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
85.         mc:Ignorable="d"
86.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
87.     <Canvas x:Name="InkCanvas">
89.     </Canvas>
90. </Window>{<Window x:
91.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
92.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
93.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
94.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
95.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
96.         mc:Ignorable="d"
97.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
98.     <Canvas x:Name="InkCanvas">
100.     </Canvas>
101. </Window>    var pointerPoint = e.GetCurrentPoint(InkCanvas);<Window x:
102.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
103.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
104.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
105.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
106.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
107.         mc:Ignorable="d"
108.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
109.     <Canvas x:Name="InkCanvas">
111.     </Canvas>
112. </Window>    Point position = pointerPoint.Position;<Window x:
113.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
114.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
115.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
116.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
117.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
118.         mc:Ignorable="d"
119.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
120.     <Canvas x:Name="InkCanvas">
122.     </Canvas>
123. </Window>    inkInfo.PointList.Add(position);<Window x:
124.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
125.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
126.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
127.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
128.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
129.         mc:Ignorable="d"
130.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
131.     <Canvas x:Name="InkCanvas">
133.     </Canvas>
134. </Window>    DrawStroke(inkInfo);<Window x:
135.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
136.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
137.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
138.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
139.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
140.         mc:Ignorable="d"
141.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
142.     <Canvas x:Name="InkCanvas">
144.     </Canvas>
145. </Window>}    }    private void InkCanvas_OnPointerReleased(object sender, PointerRoutedEventArgs e)    {<Window x:
146.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
147.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
148.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
149.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
150.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
151.         mc:Ignorable="d"
152.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
153.     <Canvas x:Name="InkCanvas">
155.     </Canvas>
156. </Window>if (_inkInfoCache.Remove(e.Pointer.PointerId, out var inkInfo))<Window x:
157.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
158.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
159.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
160.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
161.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
162.         mc:Ignorable="d"
163.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
164.     <Canvas x:Name="InkCanvas">
166.     </Canvas>
167. </Window>{<Window x:
168.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
169.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
170.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
171.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
172.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
173.         mc:Ignorable="d"
174.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
175.     <Canvas x:Name="InkCanvas">
177.     </Canvas>
178. </Window>    var pointerPoint = e.GetCurrentPoint(InkCanvas);<Window x:
179.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
180.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
181.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
182.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
183.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
184.         mc:Ignorable="d"
185.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
186.     <Canvas x:Name="InkCanvas">
188.     </Canvas>
189. </Window>    Point position = pointerPoint.Position;<Window x:
190.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
191.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
192.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
193.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
194.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
195.         mc:Ignorable="d"
196.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
197.     <Canvas x:Name="InkCanvas">
199.     </Canvas>
200. </Window>    inkInfo.PointList.Add(position);<Window x:
201.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
202.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
203.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
204.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
205.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
206.         mc:Ignorable="d"
207.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
208.     <Canvas x:Name="InkCanvas">
210.     </Canvas>
211. </Window>    DrawStroke(inkInfo);<Window x:
212.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
213.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
214.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
215.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
216.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
217.         mc:Ignorable="d"
218.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
219.     <Canvas x:Name="InkCanvas">
221.     </Canvas>
222. </Window>}    }    private void InkCanvas_OnPointerCanceled(object sender, PointerRoutedEventArgs e)    {<Window x:
223.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
224.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
225.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
226.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
227.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
228.         mc:Ignorable="d"
229.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
230.     <Canvas x:Name="InkCanvas">
232.     </Canvas>
233. </Window>if (_inkInfoCache.Remove(e.Pointer.PointerId, out var inkInfo))<Window x:
234.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
235.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
236.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
237.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
238.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
239.         mc:Ignorable="d"
240.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
241.     <Canvas x:Name="InkCanvas">
243.     </Canvas>
244. </Window>{<Window x:
245.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
246.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
247.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
248.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
249.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
250.         mc:Ignorable="d"
251.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
252.     <Canvas x:Name="InkCanvas">
254.     </Canvas>
255. </Window>    RemoveInkElement(inkInfo.InkElement);<Window x:
256.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
257.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
258.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
259.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
260.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
261.         mc:Ignorable="d"
262.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
263.     <Canvas x:Name="InkCanvas">
265.     </Canvas>
266. </Window>}    }    private void RemoveInkElement(FrameworkElement? inkElement)    {<Window x:
267.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
268.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
269.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
270.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
271.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
272.         mc:Ignorable="d"
273.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
274.     <Canvas x:Name="InkCanvas">
276.     </Canvas>
277. </Window>if (inkElement != null)<Window x:
278.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
279.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
280.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
281.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
282.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
283.         mc:Ignorable="d"
284.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
285.     <Canvas x:Name="InkCanvas">
287.     </Canvas>
288. </Window>{<Window x:
289.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
290.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
291.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
292.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
293.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
294.         mc:Ignorable="d"
295.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
296.     <Canvas x:Name="InkCanvas">
298.     </Canvas>
299. </Window>    InkCanvas.Children.Remove(inkElement);<Window x:
300.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
301.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
302.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
303.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
304.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
305.         mc:Ignorable="d"
306.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
307.     <Canvas x:Name="InkCanvas">
309.     </Canvas>
310. </Window>}    }    private readonly Dictionary _inkInfoCache = new Dictionary();public class InkInfo{    public FrameworkElement? InkElement { set; get; }    public List PointList { get; } = new List();}public readonly record struct StrokePoint(Point Point, float Pressure = 0.5f){    public static implicit operator StrokePoint(Point point) => new StrokePoint(point);}

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以上代码没给出的 DrawStroke 则是核心算法，在 InkInfo 里面存放了 PointList 点集。在 DrawStroke 需要根据此点集信息构建出一个 FrameworkElement 类型的对象，这个对象就是笔迹元素对象。按照本文以上的算法原理描述，这个笔迹对象就是在数学上由两段折线组合而成的闭合 Path 几何形状。这里为了简单使用，就使用了内建的 Microsoft.UI.Xaml.Shapes.Polygon 类型
使用 Polygon 类型时，最重要的就是获取按照预期顺序的笔迹轮廓点，也就是上文的各个线段的两个端点，也就是如下图里黄色的点

为了计算笔迹轮廓点集，以下代码封装了 GetOutlinePointList 方法，这个方法需要传入 InkInfo 的 PointList 点集，也就是输入的点集，以及笔迹的大小

1.     public static Point[] GetOutlinePointList(List pointList, int inkSize)    {<Window x:
2.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
3.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
4.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
5.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
6.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
7.         mc:Ignorable="d"
8.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
9.     <Canvas x:Name="InkCanvas">
11.     </Canvas>
12. </Window>... // 忽略代码    }

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由于咱需要计算射线向量方向，这就意味着至少需要两个点才能计算，于是先加上如下判断逻辑

1.     public static Point[] GetOutlinePointList(List pointList, int inkSize)    {<Window x:
2.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
3.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
4.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
5.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
6.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
7.         mc:Ignorable="d"
8.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
9.     <Canvas x:Name="InkCanvas">
11.     </Canvas>
12. </Window>if (pointList.Count < 2)<Window x:
13.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
14.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
15.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
16.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
17.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
18.         mc:Ignorable="d"
19.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
20.     <Canvas x:Name="InkCanvas">
22.     </Canvas>
23. </Window>{<Window x:
24.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
25.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
26.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
27.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
28.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
29.         mc:Ignorable="d"
30.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
31.     <Canvas x:Name="InkCanvas">
33.     </Canvas>
34. </Window>    throw new ArgumentException("小于两个点的无法应用算法");<Window x:
35.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
36.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
37.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
38.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
39.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
40.         mc:Ignorable="d"
41.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
42.     <Canvas x:Name="InkCanvas">
44.     </Canvas>
45. </Window>}<Window x:
46.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
47.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
48.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
49.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
50.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
51.         mc:Ignorable="d"
52.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
53.     <Canvas x:Name="InkCanvas">
55.     </Canvas>
56. </Window>... // 忽略代码    }

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如上文的算法，可以看到输出的笔迹轮廓点集，也就是 GetOutlinePointList 的返回值，的元素个数将会是 pointList 点集的两倍加二。为什么会是 pointList 点集的两倍加二的值？因为如上文的算法，每个原始输入点都可以算出两个端点，再加上最后将首末两个点一共就是两倍加二的值

1. <Window x:
2.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
3.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
4.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
5.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
6.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
7.         mc:Ignorable="d"
8.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
9.     <Canvas x:Name="InkCanvas">
11.     </Canvas>
12. </Window>var pointCount = pointList.Count * 2 /*两边的笔迹轨迹*/ + 1 /*首点重复*/ + 1 /*末重复*/;<Window x:
13.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
14.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
15.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
16.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
17.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
18.         mc:Ignorable="d"
19.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
20.     <Canvas x:Name="InkCanvas">
22.     </Canvas>
23. </Window>var outlinePointList = new Point[pointCount];

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接着进行输入的原始点集的循环，计算每个点的射线向量

1. <Window x:
2.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
3.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
4.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
5.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
6.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
7.         mc:Ignorable="d"
8.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
9.     <Canvas x:Name="InkCanvas">
11.     </Canvas>
12. </Window>for (var i = 0; i < pointList.Count; i++)<Window x:
13.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
14.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
15.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
16.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
17.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
18.         mc:Ignorable="d"
19.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
20.     <Canvas x:Name="InkCanvas">
22.     </Canvas>
23. </Window>{<Window x:
24.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
25.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
26.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
27.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
28.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
29.         mc:Ignorable="d"
30.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
31.     <Canvas x:Name="InkCanvas">
33.     </Canvas>
34. </Window>    var currentPoint = pointList[i];<Window x:
35.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
36.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
37.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
38.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
39.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
40.         mc:Ignorable="d"
41.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
42.     <Canvas x:Name="InkCanvas">
44.     </Canvas>
45. </Window>    var nextPoint = pointList[i + 1]; // 先忽略最后一个点的错误计算<Window x:
46.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
47.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
48.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
49.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
50.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
51.         mc:Ignorable="d"
52.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
53.     <Canvas x:Name="InkCanvas">
55.     </Canvas>
56. </Window>    var x = nextPoint.Point.X - currentPoint.Point.X;<Window x:
57.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
58.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
59.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
60.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
61.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
62.         mc:Ignorable="d"
63.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
64.     <Canvas x:Name="InkCanvas">
66.     </Canvas>
67. </Window>    var y = nextPoint.Point.Y - currentPoint.Point.Y;<Window x:
68.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
69.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
70.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
71.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
72.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
73.         mc:Ignorable="d"
74.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
75.     <Canvas x:Name="InkCanvas">
77.     </Canvas>
78. </Window>    // 拿着纸笔自己画一下吧，这个是简单的数学计算<Window x:
79.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
80.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
81.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
82.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
83.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
84.         mc:Ignorable="d"
85.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
86.     <Canvas x:Name="InkCanvas">
88.     </Canvas>
89. </Window>    double angle = Math.Atan2(y, x) - Math.PI / 2;<Window x:
90.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
91.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
92.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
93.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
94.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
95.         mc:Ignorable="d"
96.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
97.     <Canvas x:Name="InkCanvas">
99.     </Canvas>
100. </Window>}

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以上代码的 angle 就是向量角度，于是再计算端点距离输入原始点的距离，即可算出端点坐标

1. <Window x:
2.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
3.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
4.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
5.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
6.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
7.         mc:Ignorable="d"
8.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
9.     <Canvas x:Name="InkCanvas">
11.     </Canvas>
12. </Window>    // 笔迹粗细的一半，一边用一半，合起来就是笔迹粗细了<Window x:
13.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
14.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
15.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
16.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
17.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
18.         mc:Ignorable="d"
19.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
20.     <Canvas x:Name="InkCanvas">
22.     </Canvas>
23. </Window>    var halfThickness = inkSize / 2d;<Window x:
24.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
25.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
26.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
27.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
28.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
29.         mc:Ignorable="d"
30.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
31.     <Canvas x:Name="InkCanvas">
33.     </Canvas>
34. </Window>    // 压感这里是直接乘法而已<Window x:
35.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
36.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
37.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
38.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
39.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
40.         mc:Ignorable="d"
41.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
42.     <Canvas x:Name="InkCanvas">
44.     </Canvas>
45. </Window>    halfThickness *= currentPoint.Pressure;<Window x:
46.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
47.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
48.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
49.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
50.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
51.         mc:Ignorable="d"
52.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
53.     <Canvas x:Name="InkCanvas">
55.     </Canvas>
56. </Window>    // 不能让笔迹粗细太小<Window x:
57.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
58.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
59.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
60.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
61.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
62.         mc:Ignorable="d"
63.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
64.     <Canvas x:Name="InkCanvas">
66.     </Canvas>
67. </Window>    halfThickness = Math.Max(0.01, halfThickness);<Window x:
68.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
69.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
70.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
71.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
72.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
73.         mc:Ignorable="d"
74.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
75.     <Canvas x:Name="InkCanvas">
77.     </Canvas>
78. </Window>    var leftX = currentPoint.Point.X + (Math.Cos(angle) * halfThickness);<Window x:
79.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
80.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
81.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
82.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
83.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
84.         mc:Ignorable="d"
85.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
86.     <Canvas x:Name="InkCanvas">
88.     </Canvas>
89. </Window>    var leftY = currentPoint.Point.Y + (Math.Sin(angle) * halfThickness);<Window x:
90.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
91.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
92.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
93.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
94.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
95.         mc:Ignorable="d"
96.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
97.     <Canvas x:Name="InkCanvas">
99.     </Canvas>
100. </Window>    var rightX = currentPoint.Point.X - (Math.Cos(angle) * halfThickness);<Window x:
101.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
102.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
103.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
104.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
105.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
106.         mc:Ignorable="d"
107.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
108.     <Canvas x:Name="InkCanvas">
110.     </Canvas>
111. </Window>    var rightY = currentPoint.Point.Y - (Math.Sin(angle) * halfThickness);<Window x:
112.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
113.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
114.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
115.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
116.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
117.         mc:Ignorable="d"
118.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
119.     <Canvas x:Name="InkCanvas">
121.     </Canvas>
122. </Window>    outlinePointList[i + 1] = new Point(leftX, leftY);<Window x:
123.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
124.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
125.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
126.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
127.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
128.         mc:Ignorable="d"
129.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
130.     <Canvas x:Name="InkCanvas">
132.     </Canvas>
133. </Window>    outlinePointList[pointCount - i - 1] = new Point(rightX, rightY);

复制代码

以上代码只是简单的初中函数计算，相信大家一看就知道
以上的代码实际上是不能运行的，因为最后一个点的计算还没有加上。这里就简单将最后一个点的向量方向记录为前一个点的方向，修改之后的代码如下

1. <Window x:
2.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
3.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
4.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
5.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
6.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
7.         mc:Ignorable="d"
8.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
9.     <Canvas x:Name="InkCanvas">
11.     </Canvas>
12. </Window>double angle = 0.0;<Window x:
13.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
14.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
15.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
16.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
17.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
18.         mc:Ignorable="d"
19.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
20.     <Canvas x:Name="InkCanvas">
22.     </Canvas>
23. </Window>for (var i = 0; i < pointList.Count; i++)<Window x:
24.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
25.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
26.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
27.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
28.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
29.         mc:Ignorable="d"
30.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
31.     <Canvas x:Name="InkCanvas">
33.     </Canvas>
34. </Window>{<Window x:
35.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
36.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
37.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
38.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
39.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
40.         mc:Ignorable="d"
41.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
42.     <Canvas x:Name="InkCanvas">
44.     </Canvas>
45. </Window>    var currentPoint = pointList[i];<Window x:
46.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
47.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
48.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
49.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
50.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
51.         mc:Ignorable="d"
52.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
53.     <Canvas x:Name="InkCanvas">
55.     </Canvas>
56. </Window>    // 如果不是最后一点，那就可以和笔迹当前轨迹点的下一点进行计算向量角度<Window x:
57.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
58.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
59.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
60.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
61.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
62.         mc:Ignorable="d"
63.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
64.     <Canvas x:Name="InkCanvas">
66.     </Canvas>
67. </Window>    if (i < pointList.Count - 1)<Window x:
68.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
69.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
70.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
71.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
72.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
73.         mc:Ignorable="d"
74.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
75.     <Canvas x:Name="InkCanvas">
77.     </Canvas>
78. </Window>    {<Window x:
79.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
80.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
81.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
82.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
83.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
84.         mc:Ignorable="d"
85.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
86.     <Canvas x:Name="InkCanvas">
88.     </Canvas>
89. </Window><Window x:
90.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
91.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
92.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
93.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
94.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
95.         mc:Ignorable="d"
96.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
97.     <Canvas x:Name="InkCanvas">
99.     </Canvas>
100. </Window>var nextPoint = pointList[i + 1];<Window x:
101.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
102.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
103.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
104.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
105.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
106.         mc:Ignorable="d"
107.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
108.     <Canvas x:Name="InkCanvas">
110.     </Canvas>
111. </Window><Window x:
112.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
113.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
114.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
115.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
116.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
117.         mc:Ignorable="d"
118.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
119.     <Canvas x:Name="InkCanvas">
121.     </Canvas>
122. </Window>var x = nextPoint.Point.X - currentPoint.Point.X;<Window x:
123.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
124.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
125.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
126.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
127.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
128.         mc:Ignorable="d"
129.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
130.     <Canvas x:Name="InkCanvas">
132.     </Canvas>
133. </Window><Window x:
134.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
135.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
136.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
137.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
138.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
139.         mc:Ignorable="d"
140.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
141.     <Canvas x:Name="InkCanvas">
143.     </Canvas>
144. </Window>var y = nextPoint.Point.Y - currentPoint.Point.Y;<Window x:
145.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
146.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
147.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
148.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
149.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
150.         mc:Ignorable="d"
151.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
152.     <Canvas x:Name="InkCanvas">
154.     </Canvas>
155. </Window><Window x:
156.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
157.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
158.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
159.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
160.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
161.         mc:Ignorable="d"
162.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
163.     <Canvas x:Name="InkCanvas">
165.     </Canvas>
166. </Window>// 拿着纸笔自己画一下吧，这个是简单的数学计算<Window x:
167.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
168.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
169.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
170.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
171.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
172.         mc:Ignorable="d"
173.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
174.     <Canvas x:Name="InkCanvas">
176.     </Canvas>
177. </Window><Window x:
178.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
179.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
180.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
181.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
182.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
183.         mc:Ignorable="d"
184.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
185.     <Canvas x:Name="InkCanvas">
187.     </Canvas>
188. </Window>angle = Math.Atan2(y, x) - Math.PI / 2;<Window x:
189.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
190.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
191.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
192.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
193.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
194.         mc:Ignorable="d"
195.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
196.     <Canvas x:Name="InkCanvas">
198.     </Canvas>
199. </Window>    }<Window x:
200.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
201.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
202.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
203.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
204.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
205.         mc:Ignorable="d"
206.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
207.     <Canvas x:Name="InkCanvas">
209.     </Canvas>
210. </Window>    // 笔迹粗细的一半，一边用一半，合起来就是笔迹粗细了<Window x:
211.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
212.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
213.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
214.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
215.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
216.         mc:Ignorable="d"
217.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
218.     <Canvas x:Name="InkCanvas">
220.     </Canvas>
221. </Window>    var halfThickness = inkSize / 2d;<Window x:
222.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
223.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
224.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
225.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
226.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
227.         mc:Ignorable="d"
228.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
229.     <Canvas x:Name="InkCanvas">
231.     </Canvas>
232. </Window>    // 压感这里是直接乘法而已<Window x:
233.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
234.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
235.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
236.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
237.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
238.         mc:Ignorable="d"
239.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
240.     <Canvas x:Name="InkCanvas">
242.     </Canvas>
243. </Window>    halfThickness *= currentPoint.Pressure;<Window x:
244.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
245.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
246.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
247.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
248.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
249.         mc:Ignorable="d"
250.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
251.     <Canvas x:Name="InkCanvas">
253.     </Canvas>
254. </Window>    // 不能让笔迹粗细太小<Window x:
255.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
256.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
257.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
258.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
259.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
260.         mc:Ignorable="d"
261.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
262.     <Canvas x:Name="InkCanvas">
264.     </Canvas>
265. </Window>    halfThickness = Math.Max(0.01, halfThickness);<Window x:
266.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
267.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
268.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
269.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
270.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
271.         mc:Ignorable="d"
272.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
273.     <Canvas x:Name="InkCanvas">
275.     </Canvas>
276. </Window>    var leftX = currentPoint.Point.X + (Math.Cos(angle) * halfThickness);<Window x:
277.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
278.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
279.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
280.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
281.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
282.         mc:Ignorable="d"
283.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
284.     <Canvas x:Name="InkCanvas">
286.     </Canvas>
287. </Window>    var leftY = currentPoint.Point.Y + (Math.Sin(angle) * halfThickness);<Window x:
288.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
289.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
290.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
291.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
292.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
293.         mc:Ignorable="d"
294.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
295.     <Canvas x:Name="InkCanvas">
297.     </Canvas>
298. </Window>    var rightX = currentPoint.Point.X - (Math.Cos(angle) * halfThickness);<Window x:
299.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
300.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
301.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
302.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
303.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
304.         mc:Ignorable="d"
305.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
306.     <Canvas x:Name="InkCanvas">
308.     </Canvas>
309. </Window>    var rightY = currentPoint.Point.Y - (Math.Sin(angle) * halfThickness);<Window x:
310.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
311.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
312.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
313.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
314.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
315.         mc:Ignorable="d"
316.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
317.     <Canvas x:Name="InkCanvas">
319.     </Canvas>
320. </Window>    outlinePointList[i + 1] = new Point(leftX, leftY);<Window x:
321.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
322.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
323.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
324.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
325.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
326.         mc:Ignorable="d"
327.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
328.     <Canvas x:Name="InkCanvas">
330.     </Canvas>
331. </Window>    outlinePointList[pointCount - i - 1] = new Point(rightX, rightY);<Window x:
332.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
333.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
334.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
335.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
336.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
337.         mc:Ignorable="d"
338.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
339.     <Canvas x:Name="InkCanvas">
341.     </Canvas>
342. </Window>}

复制代码

接着再加上首末两个点就完成了方法

1.     public static Point[] GetOutlinePointList(List pointList, int inkSize)    {<Window x:
2.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
3.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
4.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
5.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
6.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
7.         mc:Ignorable="d"
8.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
9.     <Canvas x:Name="InkCanvas">
11.     </Canvas>
12. </Window>if (pointList.Count < 2)<Window x:
13.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
14.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
15.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
16.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
17.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
18.         mc:Ignorable="d"
19.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
20.     <Canvas x:Name="InkCanvas">
22.     </Canvas>
23. </Window>{<Window x:
24.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
25.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
26.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
27.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
28.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
29.         mc:Ignorable="d"
30.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
31.     <Canvas x:Name="InkCanvas">
33.     </Canvas>
34. </Window>    throw new ArgumentException("小于两个点的无法应用算法");<Window x:
35.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
36.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
37.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
38.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
39.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
40.         mc:Ignorable="d"
41.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
42.     <Canvas x:Name="InkCanvas">
44.     </Canvas>
45. </Window>}<Window x:
46.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
47.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
48.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
49.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
50.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
51.         mc:Ignorable="d"
52.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
53.     <Canvas x:Name="InkCanvas">
55.     </Canvas>
56. </Window>var pointCount = pointList.Count * 2 /*两边的笔迹轨迹*/ + 1 /*首点重复*/ + 1 /*末重复*/;<Window x:
57.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
58.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
59.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
60.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
61.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
62.         mc:Ignorable="d"
63.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
64.     <Canvas x:Name="InkCanvas">
66.     </Canvas>
67. </Window>var outlinePointList = new Point[pointCount];<Window x:
68.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
69.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
70.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
71.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
72.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
73.         mc:Ignorable="d"
74.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
75.     <Canvas x:Name="InkCanvas">
77.     </Canvas>
78. </Window>// 用来计算笔迹点的两点之间的向量角度<Window x:
79.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
80.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
81.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
82.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
83.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
84.         mc:Ignorable="d"
85.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
86.     <Canvas x:Name="InkCanvas">
88.     </Canvas>
89. </Window>double angle = 0.0;<Window x:
90.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
91.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
92.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
93.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
94.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
95.         mc:Ignorable="d"
96.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
97.     <Canvas x:Name="InkCanvas">
99.     </Canvas>
100. </Window>for (var i = 0; i < pointList.Count; i++)<Window x:
101.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
102.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
103.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
104.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
105.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
106.         mc:Ignorable="d"
107.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
108.     <Canvas x:Name="InkCanvas">
110.     </Canvas>
111. </Window>{<Window x:
112.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
113.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
114.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
115.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
116.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
117.         mc:Ignorable="d"
118.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
119.     <Canvas x:Name="InkCanvas">
121.     </Canvas>
122. </Window>    var currentPoint = pointList[i];<Window x:
123.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
124.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
125.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
126.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
127.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
128.         mc:Ignorable="d"
129.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
130.     <Canvas x:Name="InkCanvas">
132.     </Canvas>
133. </Window>    // 如果不是最后一点，那就可以和笔迹当前轨迹点的下一点进行计算向量角度<Window x:
134.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
135.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
136.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
137.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
138.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
139.         mc:Ignorable="d"
140.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
141.     <Canvas x:Name="InkCanvas">
143.     </Canvas>
144. </Window>    if (i < pointList.Count - 1)<Window x:
145.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
146.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
147.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
148.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
149.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
150.         mc:Ignorable="d"
151.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
152.     <Canvas x:Name="InkCanvas">
154.     </Canvas>
155. </Window>    {<Window x:
156.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
157.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
158.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
159.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
160.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
161.         mc:Ignorable="d"
162.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
163.     <Canvas x:Name="InkCanvas">
165.     </Canvas>
166. </Window><Window x:
167.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
168.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
169.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
170.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
171.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
172.         mc:Ignorable="d"
173.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
174.     <Canvas x:Name="InkCanvas">
176.     </Canvas>
177. </Window>var nextPoint = pointList[i + 1];<Window x:
178.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
179.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
180.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
181.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
182.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
183.         mc:Ignorable="d"
184.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
185.     <Canvas x:Name="InkCanvas">
187.     </Canvas>
188. </Window><Window x:
189.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
190.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
191.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
192.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
193.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
194.         mc:Ignorable="d"
195.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
196.     <Canvas x:Name="InkCanvas">
198.     </Canvas>
199. </Window>var x = nextPoint.Point.X - currentPoint.Point.X;<Window x:
200.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
201.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
202.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
203.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
204.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
205.         mc:Ignorable="d"
206.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
207.     <Canvas x:Name="InkCanvas">
209.     </Canvas>
210. </Window><Window x:
211.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
212.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
213.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
214.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
215.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
216.         mc:Ignorable="d"
217.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
218.     <Canvas x:Name="InkCanvas">
220.     </Canvas>
221. </Window>var y = nextPoint.Point.Y - currentPoint.Point.Y;<Window x:
222.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
223.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
224.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
225.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
226.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
227.         mc:Ignorable="d"
228.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
229.     <Canvas x:Name="InkCanvas">
231.     </Canvas>
232. </Window><Window x:
233.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
234.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
235.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
236.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
237.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
238.         mc:Ignorable="d"
239.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
240.     <Canvas x:Name="InkCanvas">
242.     </Canvas>
243. </Window>// 拿着纸笔自己画一下吧，这个是简单的数学计算<Window x:
244.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
245.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
246.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
247.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
248.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
249.         mc:Ignorable="d"
250.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
251.     <Canvas x:Name="InkCanvas">
253.     </Canvas>
254. </Window><Window x:
255.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
256.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
257.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
258.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
259.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
260.         mc:Ignorable="d"
261.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
262.     <Canvas x:Name="InkCanvas">
264.     </Canvas>
265. </Window>angle = Math.Atan2(y, x) - Math.PI / 2;<Window x:
266.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
267.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
268.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
269.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
270.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
271.         mc:Ignorable="d"
272.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
273.     <Canvas x:Name="InkCanvas">
275.     </Canvas>
276. </Window>    }<Window x:
277.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
278.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
279.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
280.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
281.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
282.         mc:Ignorable="d"
283.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
284.     <Canvas x:Name="InkCanvas">
286.     </Canvas>
287. </Window>    // 笔迹粗细的一半，一边用一半，合起来就是笔迹粗细了<Window x:
288.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
289.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
290.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
291.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
292.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
293.         mc:Ignorable="d"
294.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
295.     <Canvas x:Name="InkCanvas">
297.     </Canvas>
298. </Window>    var halfThickness = inkSize / 2d;<Window x:
299.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
300.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
301.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
302.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
303.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
304.         mc:Ignorable="d"
305.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
306.     <Canvas x:Name="InkCanvas">
308.     </Canvas>
309. </Window>    // 压感这里是直接乘法而已<Window x:
310.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
311.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
312.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
313.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
314.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
315.         mc:Ignorable="d"
316.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
317.     <Canvas x:Name="InkCanvas">
319.     </Canvas>
320. </Window>    halfThickness *= currentPoint.Pressure;<Window x:
321.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
322.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
323.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
324.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
325.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
326.         mc:Ignorable="d"
327.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
328.     <Canvas x:Name="InkCanvas">
330.     </Canvas>
331. </Window>    // 不能让笔迹粗细太小<Window x:
332.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
333.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
334.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
335.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
336.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
337.         mc:Ignorable="d"
338.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
339.     <Canvas x:Name="InkCanvas">
341.     </Canvas>
342. </Window>    halfThickness = Math.Max(0.01, halfThickness);<Window x:
343.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
344.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
345.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
346.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
347.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
348.         mc:Ignorable="d"
349.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
350.     <Canvas x:Name="InkCanvas">
352.     </Canvas>
353. </Window>    var leftX = currentPoint.Point.X + (Math.Cos(angle) * halfThickness);<Window x:
354.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
355.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
356.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
357.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
358.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
359.         mc:Ignorable="d"
360.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
361.     <Canvas x:Name="InkCanvas">
363.     </Canvas>
364. </Window>    var leftY = currentPoint.Point.Y + (Math.Sin(angle) * halfThickness);<Window x:
365.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
366.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
367.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
368.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
369.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
370.         mc:Ignorable="d"
371.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
372.     <Canvas x:Name="InkCanvas">
374.     </Canvas>
375. </Window>    var rightX = currentPoint.Point.X - (Math.Cos(angle) * halfThickness);<Window x:
376.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
377.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
378.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
379.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
380.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
381.         mc:Ignorable="d"
382.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
383.     <Canvas x:Name="InkCanvas">
385.     </Canvas>
386. </Window>    var rightY = currentPoint.Point.Y - (Math.Sin(angle) * halfThickness);<Window x:
387.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
388.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
389.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
390.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
391.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
392.         mc:Ignorable="d"
393.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
394.     <Canvas x:Name="InkCanvas">
396.     </Canvas>
397. </Window>    outlinePointList[i + 1] = new Point(leftX, leftY);<Window x:
398.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
399.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
400.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
401.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
402.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
403.         mc:Ignorable="d"
404.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
405.     <Canvas x:Name="InkCanvas">
407.     </Canvas>
408. </Window>    outlinePointList[pointCount - i - 1] = new Point(rightX, rightY);<Window x:
409.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
410.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
411.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
412.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
413.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
414.         mc:Ignorable="d"
415.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
416.     <Canvas x:Name="InkCanvas">
418.     </Canvas>
419. </Window>}<Window x:
420.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
421.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
422.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
423.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
424.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
425.         mc:Ignorable="d"
426.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
427.     <Canvas x:Name="InkCanvas">
429.     </Canvas>
430. </Window>outlinePointList[0] = pointList[0].Point;<Window x:
431.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
432.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
433.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
434.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
435.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
436.         mc:Ignorable="d"
437.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
438.     <Canvas x:Name="InkCanvas">
440.     </Canvas>
441. </Window>outlinePointList[pointList.Count + 1] = pointList[^1].Point;<Window x:
442.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
443.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
444.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
445.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
446.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
447.         mc:Ignorable="d"
448.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
449.     <Canvas x:Name="InkCanvas">
451.     </Canvas>
452. </Window>return outlinePointList;    }

复制代码

在通过 GetOutlinePointList 拿到笔迹轮廓点之后，即可构建出 Polygon 对象，如以下代码

1.     public static Polygon CreatePath(InkInfo inkInfo, int inkSize)    {<Window x:
2.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
3.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
4.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
5.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
6.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
7.         mc:Ignorable="d"
8.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
9.     <Canvas x:Name="InkCanvas">
11.     </Canvas>
12. </Window>List pointList = inkInfo.PointList;<Window x:
13.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
14.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
15.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
16.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
17.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
18.         mc:Ignorable="d"
19.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
20.     <Canvas x:Name="InkCanvas">
22.     </Canvas>
23. </Window>var outlinePointList = GetOutlinePointList(pointList, inkSize);<Window x:
24.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
25.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
26.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
27.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
28.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
29.         mc:Ignorable="d"
30.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
31.     <Canvas x:Name="InkCanvas">
33.     </Canvas>
34. </Window>var polygon = new Polygon();<Window x:
35.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
36.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
37.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
38.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
39.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
40.         mc:Ignorable="d"
41.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
42.     <Canvas x:Name="InkCanvas">
44.     </Canvas>
45. </Window>foreach (var point in outlinePointList)<Window x:
46.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
47.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
48.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
49.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
50.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
51.         mc:Ignorable="d"
52.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
53.     <Canvas x:Name="InkCanvas">
55.     </Canvas>
56. </Window>{<Window x:
57.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
58.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
59.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
60.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
61.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
62.         mc:Ignorable="d"
63.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
64.     <Canvas x:Name="InkCanvas">
66.     </Canvas>
67. </Window>    polygon.Points.Add(point);<Window x:
68.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
69.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
70.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
71.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
72.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
73.         mc:Ignorable="d"
74.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
75.     <Canvas x:Name="InkCanvas">
77.     </Canvas>
78. </Window>}<Window x:
79.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
80.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
81.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
82.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
83.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
84.         mc:Ignorable="d"
85.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
86.     <Canvas x:Name="InkCanvas">
88.     </Canvas>
89. </Window>polygon.Fill = new SolidColorBrush(Colors.Red);<Window x:
90.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
91.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
92.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
93.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
94.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
95.         mc:Ignorable="d"
96.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
97.     <Canvas x:Name="InkCanvas">
99.     </Canvas>
100. </Window>return polygon;    }

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尽管以上代码是在 UNO 框架下编写的，但可以直接拷贝代码在 UWP 应用上直接运行
拿到 Polygon 对象之后，将此对象加入到界面里面，如以下代码，即可完成笔迹的绘制。在不断落点输入点数据过程中，将不断执行 Polygon 的 Points 的清理和重新添加，于是就可以不断跟随落点更新笔迹内容，完成笔迹书写的功能

1.     private void DrawStroke(InkInfo inkInfo)    {<Window x:
2.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
3.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
4.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
5.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
6.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
7.         mc:Ignorable="d"
8.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
9.     <Canvas x:Name="InkCanvas">
11.     </Canvas>
12. </Window>var pointList = inkInfo.PointList;<Window x:
13.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
14.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
15.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
16.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
17.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
18.         mc:Ignorable="d"
19.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
20.     <Canvas x:Name="InkCanvas">
22.     </Canvas>
23. </Window>if (pointList.Count < 2)<Window x:
24.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
25.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
26.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
27.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
28.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
29.         mc:Ignorable="d"
30.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
31.     <Canvas x:Name="InkCanvas">
33.     </Canvas>
34. </Window>{<Window x:
35.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
36.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
37.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
38.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
39.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
40.         mc:Ignorable="d"
41.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
42.     <Canvas x:Name="InkCanvas">
44.     </Canvas>
45. </Window>    // 小于两个点的无法应用算法<Window x:
46.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
47.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
48.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
49.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
50.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
51.         mc:Ignorable="d"
52.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
53.     <Canvas x:Name="InkCanvas">
55.     </Canvas>
56. </Window>    return;<Window x:
57.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
58.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
59.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
60.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
61.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
62.         mc:Ignorable="d"
63.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
64.     <Canvas x:Name="InkCanvas">
66.     </Canvas>
67. </Window>}<Window x:
68.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
69.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
70.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
71.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
72.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
73.         mc:Ignorable="d"
74.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
75.     <Canvas x:Name="InkCanvas">
77.     </Canvas>
78. </Window>var inkElement = MyInkRender.CreatePath(inkInfo, inkSize);<Window x:
79.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
80.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
81.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
82.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
83.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
84.         mc:Ignorable="d"
85.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
86.     <Canvas x:Name="InkCanvas">
88.     </Canvas>
89. </Window>if (inkInfo.InkElement is null)<Window x:
90.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
91.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
92.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
93.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
94.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
95.         mc:Ignorable="d"
96.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
97.     <Canvas x:Name="InkCanvas">
99.     </Canvas>
100. </Window>{<Window x:
101.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
102.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
103.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
104.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
105.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
106.         mc:Ignorable="d"
107.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
108.     <Canvas x:Name="InkCanvas">
110.     </Canvas>
111. </Window>    InkCanvas.Children.Add(inkElement);<Window x:
112.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
113.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
114.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
115.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
116.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
117.         mc:Ignorable="d"
118.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
119.     <Canvas x:Name="InkCanvas">
121.     </Canvas>
122. </Window>}<Window x:
123.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
124.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
125.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
126.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
127.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
128.         mc:Ignorable="d"
129.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
130.     <Canvas x:Name="InkCanvas">
132.     </Canvas>
133. </Window>inkInfo.InkElement = inkElement;    }

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完成到这里，其实就算完成了一个简单的在绘制的过程，可根据压感参数变更笔迹粗细的算法了
但是一般的输入设备，比如鼠标或者渣触摸屏都是没有压感的，或者是没有正确的压感的，那这个时候似乎体现不出以上算法的优势。这时候可以继续和大家介绍另一个有趣的功能实现，模拟笔锋
很多人都喜欢写字的时候带笔锋，无论是写中文还是写英文的时候。模拟笔锋也许可以让用户感谢写出来的字更好看，通过压感模拟笔锋是一个非常简单的实现。实现思路就是从笔尖到笔身的顺序，让输入的点集的压感从小到大，大概如下图所示，如此即可做出类似笔锋的效果

大概的实现代码如下

1. <Window x:
2.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
3.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
4.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
5.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
6.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
7.         mc:Ignorable="d"
8.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
9.     <Canvas x:Name="InkCanvas">
11.     </Canvas>
12. </Window>// 模拟笔锋<Window x:
13.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
14.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
15.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
16.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
17.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
18.         mc:Ignorable="d"
19.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
20.     <Canvas x:Name="InkCanvas">
22.     </Canvas>
23. </Window>// 用于当成笔锋的点的数量<Window x:
24.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
25.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
26.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
27.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
28.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
29.         mc:Ignorable="d"
30.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
31.     <Canvas x:Name="InkCanvas">
33.     </Canvas>
34. </Window>var tipCount = 20;<Window x:
35.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
36.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
37.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
38.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
39.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
40.         mc:Ignorable="d"
41.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
42.     <Canvas x:Name="InkCanvas">
44.     </Canvas>
45. </Window>for (int i = 0; i < pointList.Count; i++)<Window x:
46.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
47.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
48.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
49.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
50.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
51.         mc:Ignorable="d"
52.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
53.     <Canvas x:Name="InkCanvas">
55.     </Canvas>
56. </Window>{<Window x:
57.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
58.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
59.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
60.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
61.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
62.         mc:Ignorable="d"
63.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
64.     <Canvas x:Name="InkCanvas">
66.     </Canvas>
67. </Window>    if ((pointList.Count - i) < tipCount)<Window x:
68.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
69.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
70.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
71.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
72.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
73.         mc:Ignorable="d"
74.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
75.     <Canvas x:Name="InkCanvas">
77.     </Canvas>
78. </Window>    {<Window x:
79.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
80.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
81.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
82.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
83.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
84.         mc:Ignorable="d"
85.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
86.     <Canvas x:Name="InkCanvas">
88.     </Canvas>
89. </Window><Window x:
90.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
91.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
92.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
93.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
94.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
95.         mc:Ignorable="d"
96.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
97.     <Canvas x:Name="InkCanvas">
99.     </Canvas>
100. </Window>pointList[i] = pointList[i] with<Window x:
101.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
102.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
103.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
104.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
105.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
106.         mc:Ignorable="d"
107.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
108.     <Canvas x:Name="InkCanvas">
110.     </Canvas>
111. </Window><Window x:
112.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
113.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
114.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
115.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
116.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
117.         mc:Ignorable="d"
118.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
119.     <Canvas x:Name="InkCanvas">
121.     </Canvas>
122. </Window>{<Window x:
123.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
124.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
125.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
126.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
127.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
128.         mc:Ignorable="d"
129.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
130.     <Canvas x:Name="InkCanvas">
132.     </Canvas>
133. </Window><Window x:
134.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
135.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
136.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
137.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
138.         xmlns:local="clr-namespace:YegeenurcairwheBeahealelbewe"
139.         mc:Ignorable="d"
140.         Title="MainWindow" Height="450" Width="800" StylusDown="MainWindow_OnStylusDown" StylusMove="MainWindow_OnStylusMove" StylusUp="MainWindow_OnStylusUp">
141.     <Canvas x:Name="InkCanvas">
143.     </Canvas>
144. </Window>    Pressure = (pointList.Count - i) * 1f / tipCount<Window x:
145.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
146.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
147.         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
148.         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
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加上模拟笔锋之后，即可使用以上的算法画出如下图的笔迹效果

上图是我开了调试模式的效果，调试模式就是在原笔迹元素的基础上，绘制出蓝色的原始输入的点集，以及黄色的端点
以上的代码放在github 和 gitee 欢迎访问
可以通过如下方式获取本文的源代码，先创建一个空文件夹，接着使用命令行 cd 命令进入此空文件夹，在命令行里面输入以下代码，即可获取到本文的代码

1. git init
2. git remote add origin https://gitee.com/lindexi/lindexi_gd.git
3. git pull origin 8d59a96e0d4e390ae78946ff556a759901961856

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以上使用的是 gitee 的源，如果 gitee 不能访问，请替换为 github 的源。请在命令行继续输入以下代码

1. git remote remove origin
2. git remote add origin https://github.com/lindexi/lindexi_gd.git
3. git pull origin 8d59a96e0d4e390ae78946ff556a759901961856

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获取代码之后，进入 HallgaiwhiyiwaLejucona 文件夹
欢迎大家将代码拉下来，运行看试试效果。以上代码是写在 UNO 框架里的，可以在 Windows 平台上使用 WinUI 或 WPF 运行，也可以在 Linux 系统使用 GTK 运行
但大家也可以很轻松就看出来以上算法存在的不足还是有很多的，比如是采用折线连接笔迹轮廓的点集，这就导致了在触摸采样不够密或鼠标精度很低的情况下，画出来的笔迹存在很明显的折线效果，不够顺滑。另外，从以上的简单数学计算上，也存在着输入轨迹大角度的折弯时存在计算错误
接下来我将和大家介绍更加进阶的算法，解决以上简单算法所遇到的问题
顺滑的笔迹算法

以上的用两条折线绘制笔迹的算法被我称为十字法笔迹算法，这是一个简单的算法，无法作出顺滑的笔迹效果。接下来将和大家介绍被我命名为米字法笔迹算法的算法
接下来介绍的米字法笔迹算法是为触摸设计的笔迹书写轨迹算法，可以实现比较顺滑的笔迹绘制效果，同时可以有多组参数可配置，配合高阶拟合函数可以写出特别多不同的笔迹效果，比如毛笔字、钢笔字等
以下介绍的算法被我申请了专利保护，现在专利已经公开授权，我就不放出来具体的代码了。原本专利里面是有详细公开信息的，但是专利本身写得难以阅读，为了让大家能够更清晰知道具体的笔迹实现算法，我就准备使用更白话的方式向大家介绍算法内容
必须提醒大家的是，如果在商业软件上使用，必须绕过本文接下来介绍的方法，本文接下来介绍的方法只能借鉴不能抄哦。不然等你大赚时，法务小姐姐会去找你麻烦的
当然，非商业用途等不怕专利的情况，那就随意咯
接下来介绍的方法按照顺序分别是 CN109284059A 和 CN115373534A 两篇专利里面包含的内容，你可以认为本文只是记录读了以上两篇专利之后的自己所学到的内容。我自己发布博客在我自己的非盈利非商业的博客上是可以的，属于非营利实施，但是如果有伙伴想要在商业用途上转载本文，那就是侵犯专利的权利，违法的哦
本文以下介绍的算法部分只介绍大概思路，不会包含具体实现细节以及代码，更详细的实施方法还请自行参阅专利的内容
本文以下的算法将默认是为触摸设计的笔迹书写轨迹算法，输入的原始点被称为原始触摸点。触摸点数据将包含 X Y 信息，以及可选的压感和宽度高度信息，还有一个隐含的速度信息。如下图，蓝色的点就是触摸过来的触摸点信息，触摸点是一些离散的点。我这里产品里主打的触摸框都是红外触摸框，红外触摸框从原理上也只能获取到离散的触摸点，但如果点足够密，那将离散的点视为连续的线段也是没有问题的

在进入实际算法之前，还需要进行一步点的过滤。也就是将一些奇怪的点给过滤掉，比如在一些渣触摸框上，可能存在报点存在离群点的情况，或者是出现在 0 0 点的情况，需要自己根据具体的硬件设备进行丢点处理。这一步不是必须的，基本只有在大屏幕触摸框下才需要进行
骨架计算

完成点集的处理之后，即可开始计算笔迹的骨架。可以将笔迹骨架认为是一个最简单展示一段顺滑笔迹的轨迹，也就是当笔迹各处的粗细都一致时，即没有棱角和笔锋时的一段几何轨迹。实际上的算法后续的棱角和笔锋、跟随压感变更等等都是在笔迹的骨架的基础上，修改笔迹某一段的粗细变化。骨架的计算十分简单，可以采用贝塞尔等算法将收到的触摸点进行平滑计算，此过程如果需要补点，即在触摸点不够密集时进行补点，则可以自己再叠加一些魔改的贝塞尔算法，比如 一种简单的贝塞尔拟合算法_贝塞尔曲线拟合-CSDN博客 介绍的方法
一般是将收集到的触摸点每两个点的中心做定点，使用收集到的触摸点做控制点，如下图

对于许多业务情况来说，只需要到这一步就可以算画出一段平滑的笔迹了
接下来的步骤将和大家介绍如何画出更好看的笔迹效果
棱角优化

棱角优化步骤是一个专门为中文书写笔迹轨迹优化的方法。用途是让写出来的汉字比较有棱角，适合用户手写类似黑体或楷体，不适合用在草书的情况。大概的算法思路如下，假定有类似如下的输入触摸点

这时需要把这些点分为两个线段，分为两个线段的大概效果如下图

对于汉字而言，我认为如果以上两个线段构成的内角在 90 度以下时，有棱的好看，超过 90 度时，使用圆角的好看

通过输入可以拿到触摸点，按照两个触摸点连接为线，求相邻线段的夹角，判断角度可以知道用户是否希望画出棱还是画出圆。加上这个优化之后就可以在写汉字时，比微软默认的 WPF 或 UWP 的笔迹算法在棱角方面处理更好

如图的 α 就是两个线段的角度，判卷角度如果大于 90° 就是用户希望画圆的角，使用贝塞尔算法。如果小于 90° 那就可以判断用户希望画有棱的，直接把点分开为两个线段
当然了，上文提到的 90° 是我自己测试发现的数值，大家可以根据自己的实际需要修改参数。在不需要让笔迹有笔锋以及跟随压感时，以上的棱角优化步骤可以用在骨架计算的步骤上，直接作用到使用骨架绘制出的笔迹上。也可以在带压感时的在下文继续介绍的更复杂的米字法笔迹算法的最后呈现时使用
笔迹轨迹宽度优化

无论是否有压感，都可以应用上笔迹轨迹宽度的优化，笔迹轨迹的宽度可以认为是在骨架的基础上，进行填充，让原本只有骨架的很细的笔迹变粗。可以认为在骨架计算步骤拿到的是一条没有宽度的线条，进行笔迹轨迹宽度优化计算就可以画出更好看的笔迹效果。比如说写一个汉字的“一”字，就可以写出两端宽度比较大，中间宽度比较小的笔效果

简单的笔迹轨迹宽度优化算法大概如下，下面将会用到一点点公式，相信大家一看就明白，以下使用到的公式

用户可以设置笔迹轨迹线条的宽度，这个设置的宽度为初始宽度，将用户设置的笔迹粗细宽度记为 T 参数。速度参数 v 的计算有些取巧，因为收集到的点的时间间隔是只有很小的误差，为了优化计算，就把两个点直接的距离作为用户的画线速度
上图公式里面的 u(v) 函数计算方法就是取用户正常最慢速度，记为 w 值，这里的 w 为常量 1 的值。为了防止在静止距离获得最小的点为负数，这里使用 u(v)=Max(v-w,x) 限制最小值为 x 的值，按照经验，这里取 x 为常量 2 的值。为了防止用户的画线速度太快，所以按照经验取最高的速度只能是 5 的值。以上的效果就是在用户书写速度超过最高速度 5 单位长度 1 毫秒的时候取 80% 的用户设置粗细。在用户使用很慢速度画线的时候采用120%的用户设置粗细
最后的常量 a 我按照经验取的是 T/0.12 的值
以上的常量部分指的不是 C# 里面的常量，而是参与数学计算公式里面的常量，即和自变量对应的常量。这些常量大家都可以根据自己的经验进行修改，或者写一个修改参数的工具让美工或设计师去优化
经过这一个步骤之后，就可以实现在用户使用快速画线，画出来的线就会变细，在用户画线的速度变慢，就会画出宽度比较大的线
米字法

这部分属于写出顺滑的笔迹的核心算法。在经过了笔迹轨迹宽度优化之后，尽管看起来已经有些顺滑了，其实依然无法写出毛笔字效果，比如刀锋等效果，最多只能写出有粗细变更的笔迹。接下来的算法部分将使用到棱角优化步骤处理的骨架轨迹算出的骨架点，以及笔迹轨迹宽度优化步骤输出的每个点的笔迹粗细大小信息，进行更高级的优化
通过上文的描述，大家也知道笔迹元素可以由笔迹轮廓两边的曲线组合而成，因此求笔迹的几何图形本质就是求笔迹的轮廓线，由笔迹的轮廓线填充即可获取笔迹。如下图，只需要将如下两条曲线相连接，那么将获得一条笔迹的几何图形

在经过骨架计算步骤之后，即可拿到骨架轨迹，通过骨架轨迹即可拿到相应的骨架点。拿到相应的骨架点的算法不固定，可以是求均匀的距离下的骨架轨迹上的点，也可以求对原始触摸点的骨架校正点。如果难以理解如何通过骨架轨迹拿到相应的骨架点，那可以将骨架点当成原始的触摸点来看，因为缺少骨架点这一步不用影响对接下来的算法的理解
如下图，假定以下拿到的蓝色的点就是骨架点

根据触摸点的每个点的状态可以决定骨架点的每个点的状态，对应的就是每个点的上下左右边距，如下图。决定每个点的上下左右边距算法叫做惯性边距算法，这个惯性边距算法将放在下文再描述

经过了惯性边距算法，可以获取骨架点的上下左右边距，取边距的端点，作为笔廓点。如下图，笔廓点就是蓝色的圆圈

如下图，连接笔迹的笔廓点就可以获得笔迹的轮廓线，也就是获得笔迹的几何图形。但仅仅采用如上述算法，可以看到笔迹的轮廓相对粗糙，虽然比上文给的算法好了一点，但也没好多少。想要实现更好的效果，还需要继续添加更多逻辑

在开始介绍算法之前，需要引入不对称椭圆的概念，默认的椭圆都是对称的，如上下对称或左右对称。而不对称椭圆是上下左右都不对称的椭圆。如下图，从不对称椭圆的圆心的上下左右四个方向有着不同的长度

不对称椭圆的算法相当于绘制出四个对称的椭圆，分别取其中的四分之一拼接起来的椭圆

如下图，是将绘制出来的四个对称的椭圆各取四分之一部分拼接起来，其中填充部分就是非对称椭圆

这里的非对称椭圆是用在将笔迹的骨架点按照惯性边距算法上下左右分别采用不同的长度，创建出来的椭圆

沿着椭圆的切线方向连接的线段就可以作出平滑的笔迹轮廓线，如下图。下图绘制仅仅只是参考，部分线段连接不是采用椭圆的切线

特别的，为了性能优化部分，因为笔迹的粗细一般都很小，在笔迹粗细很小的时候，可以使用多边形近似代替椭圆。因为对多边形的求值计算的性能要远远高于椭圆，同时求椭圆切线的代码也不好写。如下图，采用如 米 字的方式代替椭圆

只需要连接椭圆的外接轮廓点即可作出笔迹效果，如下图

当骨架点足够密集的时候，这时候连接椭圆的外接轮廓点使用线段连接，再将这个线段组成闭合的折线即可写出十分顺滑的笔迹效果了。经过我的实际测试，通过骨架轨迹算出比较密集的骨架点，从而让外接轮廓点连接画出的笔迹效果，既顺滑且渲染性能高。在骨架点不够密集时，如直接将触摸点当骨架点时，可以使用贝赛尔曲线形式连接外接轮廓点，从而画出顺滑的笔迹效果，但经过实际测试我发现此方法无论是笔迹的顺滑还是渲染性能都不如让骨架点足够密集的方法
此算法除了能够让笔迹效果十分顺滑之外，还能实现笔迹刀锋效果。核心实现是根据惯性边距算法可以决定边距，通过边距的不同，可以实现出如毛笔的刀锋效果，如下图所示。在运笔绘制刀锋效果时，如图情况将会更改左边距距离，让笔迹的一边贴近直线而另一边是曲线的效果。采用此算法可以做到更好的写出毛笔字效果

惯性边距算法就是通过一系列的代码处理，决定每个骨架点的上下左右边距的值，比如运动轨迹方向，比如运动速度，比如预测字形等等。这部分更多的是靠设计师或美工进行优化
以下是我给出的一个认为简单的算法例子，大家也可以自行发挥
在笔迹轨迹宽度优化的基础上，将笔迹轨迹宽度优化的输出结果作为笔迹粗细参考值。将每个骨架点的上下左右边距先采用笔迹粗细的一半作为基准值，然后分别附加各自的缩放系数。根据笔迹的运动轨迹方向，可以将方向分为上下左右四个方向，再按照运动的速度以及多个笔迹点的偏移累计值决定缩放系数的值。如上图，按照笔迹轨迹是向左下方向，将会取笔迹的多个触摸点，计算累计的偏移值，如取笔迹的距离当前的前n个触摸点，如上图是取5个触摸点的坐标，求出距离当前坐标的偏移值也就是相当于求当前点和前第5个点的距离。如果在这前5个触摸点中，有方向不一致的触摸点存在，如第三个触摸点的方向和其他点的触摸方向不同，那么将偏移值减去方向不一致的触摸点的相对于其下一个触摸点的距离。再根据触摸偏移值决定对应方向的缩放系数，决定缩放系数的方法就是取n个触摸点的对应方向的最大距离数，如发现是存在左右方向的偏移那么取水平方向距离值，将距离值减去偏移值除的值处以距离值乘以给特定触摸框优化的常数，即可获取方向上的触摸偏移缩放系数。根据不同的上下左右边距的不同缩放系数就可以实现如上图的效果。同样的，采用此方法进行不同缩放系数最终还是需要乘以笔迹触摸点压感变化的缩放系数，才是最终的各个方向的缩放系数
通过以上的算法即可实现比较好看的笔迹效果
本文只讨论了笔迹的算法，而不包含如何优化笔迹绘制的性能以及更多的触摸相关内容。如果大家对这部分感兴趣，请参阅 WPF 触摸相关

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