WPF开发随笔收录-心电图曲线绘制 - ToB企服应用市场:ToB评测及商务社交产业平台

public class EcgDrawingVisual : FrameworkElement
{
private readonly List<Visual> visuals = new List<Visual>();
private DrawingVisual Layer;
private Pen ecg_pen = new Pen(Brushes.Orange, 1.5);
private int?[] ecg_points = new int?[2000];
private int currentStart = 0;
private double y_offset = 0;
private int ecg_max = 60;
private int ecg_min = -25;
public EcgDrawingVisual()
{
ecg_pen.Freeze();
Layer = new DrawingVisual();
visuals.Add(Layer);
}
public void SetupData(int ecg)
{
ecg_points[currentStart] = ecg;
for (int i = 1; i <= 20; i++)
{
ecg_points[currentStart + i] = null;
}
currentStart++;
if (currentStart >= RenderSize.Width / 2)
{
currentStart = 0;
}
DrawEcgLine();
InvalidateVisual();
}
private void DrawEcgLine()
{
var scale = RenderSize.Height / (ecg_max - ecg_min);
y_offset = ecg_min * -scale;
DrawingContext dc = Layer.RenderOpen();
Matrix mat = new Matrix();
mat.ScaleAt(1, -1, 0, RenderSize.Height / 2);
dc.PushTransform(new MatrixTransform(mat));
for (int i = 0, left = 0; left < RenderSize.Width; i++, left += 2)
{
if (ecg_points[i] == null || ecg_points[i + 1] == null) continue;
dc.DrawLine(ecg_pen, new Point(left, ecg_points[i].Value * scale + y_offset), new Point(left + 2, ecg_points[i + 1].Value * scale + y_offset));
}
dc.Pop();
dc.Close();
}
protected override int VisualChildrenCount => visuals.Count;
protected override Visual GetVisualChild(int index)
{
return visuals[index];
}
protected override void OnRenderSizeChanged(SizeChangedInfo sizeInfo)
{
base.OnRenderSizeChanged(sizeInfo);
}
protected override void OnRender(DrawingContext drawingContext)
{
drawingContext.DrawRectangle(Brushes.White, null, new Rect(0, 0, RenderSize.Width, RenderSize.Height));
base.OnRender(drawingContext);
}
}

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public partial class MainWindow : Window
{
private List<int> points = new List<int>() { 4, 4, 3, -1, -2, -2, -2, -2, -2, -2, -2, -2, -4, -3, 25, 37, 8, -7, -5, -3, -3, -3, -3, -3, -3, -3, -3, -2, -2, -2, -1, -1, 3, 5, 8, 9, 9, 10, 9, 7, 5, 1, -1, -4, -4, -4, -4, -4, -4, -4, -3, -3, -3, -3, -3, -3, -3, -3, -3, -2, -2, -2, -2, -2, -2, -1, 1, 3 };
private bool flag = true;
private int currentIndex = 0;
public MainWindow()
{
InitializeComponent();
new Thread(() =>
{
while (flag)
{
Thread.Sleep(10);
this.Dispatcher.BeginInvoke(new Action(() =>
{
if (currentIndex == points.Count) currentIndex = 0;
ecgDrawingVisual.SetupData(points[currentIndex]);
currentIndex++;
}));
}
}).Start();
}
protected override void OnClosed(EventArgs e)
{
base.OnClosed(e);
flag = false;
}
}

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