Qt学习（一）-------- 定时器、绘图
1.定时器 QTimer⭐ 创建定时器对象 QTimer *timer = new QTimer(this);
⭐ 启动定时器 timer->start(毫秒);
⭐ 监听信号 connect(timer,&QTimer::timeout,[=](){ });
-----------------------------------------------------------例子-----------------------------------------------------------
QTimer *timer = new QTimer(this);
timer->start(500);
connect(timer,&QTimer::timeout,[=](){
static int num = 1;
ui->label->setText(QString::number(num++));
}); ⭐ 点击暂停，实现停止，点击开始，继续计时
https://img2023.cnblogs.com/blog/3295610/202310/3295610-20231009101925969-438575482.gif
connect(ui->pushButton_stop,&QPushButton::clicked,[=](){
timer->stop();
});
connect(ui->pushButton_start,&QPushButton::clicked,[=](){
timer->start();
});
2.绘图 QPainter
⭐ 创建绘图事件 void paintEvent(QPaintEvent *);
⭐ 实例化画家对象QPainter painter(this);
⭐ 画线---drawLine，画圆---drawEllipse，画矩形---drawRect，画文字---drawText
⭐ 设置画笔---QPen pen， 设置画刷---QBrush brush，让画家使用画笔、画刷
-----------------------------------------------------------例子-----------------------------------------------------------
https://img2023.cnblogs.com/blog/3295610/202310/3295610-20231008172726623-850190820.png
void MainWindow::paintEvent(QPaintEvent *)
{
QPainter painter(this);
// 设置画笔
QPen pen(QColor(255,0,0));
pen.setWidth(3);
pen.setStyle(Qt::DotLine);
painter.setPen(pen);
// 设置画刷
QBrush brush(Qt::cyan);
brush.setStyle(Qt::Dense7Pattern);
painter.setBrush(brush);
// 画线
painter.drawLine(QPoint(0,0), QPoint(100,100));
// 画圆
painter.drawEllipse(QPoint(100,100), 50 ,50);
// 画矩形
painter.drawRect(QRect(20,20,50,50));
// 画文字
painter.drawText(QRect(20,200,120,50),"好好学习，天天向上");<br>} ⭐ 抗锯齿，效率低 painter.setRenderHint(QPainter::Antialiasing);
⭐ 对画家进行移动 painter.translate(100,0);
⭐ 保存状态---save，还原状态---restore
-----------------------------------------------------------例子-----------------------------------------------------------
https://img2023.cnblogs.com/blog/3295610/202310/3295610-20231008174313535-318585782.png
painter.drawRect(QRect(20,300,50,50));
painter.translate(100,0);
painter.save(); // 保存画家状态
painter.drawRect(QRect(20,300,50,50));
painter.restore(); // 还原画家保存状态
painter.drawRect(QRect(20,300,50,50)); ⭐ 手动调用绘图事件，点击按钮，进行图片移动
-----------------------------------------------------------例子-----------------------------------------------------------
https://img2023.cnblogs.com/blog/3295610/202310/3295610-20231009101252688-253436244.gif
connect(ui->pushButton_move,&QPushButton::clicked,[=](){
posX+=20;
update(); // 手动调用，用update更新
});
void MainWindow::paintEvent(QPaintEvent *)
{
QPainter painter(this);
// 如果超出屏幕，从0开始
if(posX > this->width())
{
posX = 0;
}
painter.drawPixmap(posX,200,QPixmap(":/img/lufei.jpg"));
}
免责声明：如果侵犯了您的权益，请联系站长，我们会及时删除侵权内容，谢谢合作！
页:
[1]