QT 任意区域截图

setWindowFlags(Qt::WindowStaysOnTopHint|Qt::ToolTip);

setWindowState(Qt::WindowActive|Qt::WindowFullScreen);//全屏无框架显示且处于激活状态

    resize(qApp->desktop()->rect().size());

    QPolygon vt_pos;   //定义多边形

    bgpixmap=QPixmap::grabWindow(QApplication::desktop()->winId());//抓取当前屏幕的图片

paintEvent(QPaintEvent *event)

{ 

    painter.begin(this);//进行重绘

painter.drawPixmap(0,0,loadpixmap);//将背景图片画到窗体上

    painter.setPen(QPen(Qt::blue,2,Qt::SolidLine,Qt::FlatCap));//设置画笔

painter.drawPolygon(vt_pos);

painter.end();

}

mouseMoveEvent(QMouseEvent *event)

{

vt_pos.push_back(event.pos);//将鼠标经过的点入栈

}

mouseReleaseEvent(QMouseEvent *event)

{

/*手动绘图*/

path.addPolygon(vt_pos);

path.setFillRule(Qt::WindingFill);//设置填充规则(和setClipPath()配合)

QRectFrf=path.controlPointRect();//获取路径所在矩形区域

QPixmapmap;

map=loadpixmap.copy(rf.topLeft().x(),rf.topLeft().y(),rf.width(),rf.height());

//坐标转换以（0-rf.topLeft().x(),0-rf.topLeft().y()为坐标原点）

QPainterPathpa=path.translated(0-rf.topLeft().x(),0-rf.topLeft().y());

//创建QPixmap设备，将需要的区域map绘到QPixmap上

temp_image=QPixmap(rf.width(),rf.height());

//temp_image.fill(Qt::transparent);

temp_image.fill(QColor(255,255,255));

temp_paint.begin(&temp_image);

temp_paint.setClipping(true);

temp_paint.setClipPath(pa);//设置裁剪路径

temp_paint.drawPixmap(0,0,map);

temp_paint.setClipping(false);

temp_paint.end();

shotPixmap=temp_image;//.copy(0,0,rf.width(),rf.height());//更新选区的Pixmap

}

转载于:https://www.cnblogs.com/jiushishuai/p/9452144.html