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void Sample::paintEvent(QPaintEvent *)
{
QPixmap pixmap(size());
pixmap.fill(Qt::transparent);
QPainter painter(&pixmap);
painter.setPen(Qt::red);
painter.setBackgroundMode(Qt::TransparentMode);
//随机生成x,y坐标
qsrand(QTime(0,0,0).secsTo(QTime::currentTime()));
int test =qrand()%100;
//这里模仿人脸框
painter.drawRect(test, test, 50, 50);
painter.begin(this); //在Widget上开始绘制
painter.drawPixmap(0, 0, pixmap); //在控件上绘制pixmap图像
painter.end(); //画完了
//新加代码:paintEvent()结束后,使用update()更新界面
update();
} |
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