Qt☞之QPainterPath

QPainterPath

QPainterPath类为绘画操作提供了一个容器，允许构造和重用图形形状。

代码一加运算：

void MainWindow::painterPathDemo(QPainter *painter)
{
    painter->save();
    QPainterPath path;
    path.moveTo(200,200);
    path.lineTo(220,240);
    path.cubicTo(200,0,50,90,100,120);
    QPainterPath pathE;
    pathE.addEllipse(-100,-100,200,200);
    QPainterPath pathR;
    pathR.addRect(0,0,100,100);

    painter->drawPath(/*path+*/pathR+pathE);
    painter->restore();
}

演示图片：

代码二加运算： 

void MainWindow::painterPathDemo(QPainter *painter)
{
    painter->save();
    QPainterPath path;
    path.moveTo(200,200);
    path.lineTo(220,240);
    path.cubicTo(200,0,50,90,100,120);
    QPainterPath pathE;
    pathE.addEllipse(-100,-100,200,200);
    QPainterPath pathR;
    pathR.addRect(0,0,100,100);

    painter->drawPath(path+pathR+pathE);
    painter->restore();
}

演示图片：

代码三减运算Ⅰ：

void MainWindow::painterPathDemo(QPainter *painter)
{
    painter->save();
    QPainterPath path;
    path.moveTo(200,200);
    path.lineTo(220,240);
    path.cubicTo(200,0,50,90,100,120);
    QPainterPath pathE;
    pathE.addEllipse(-100,-100,200,200);
    QPainterPath pathR;
    pathR.addRect(0,0,100,100);

    painter->drawPath(/*path+*/pathR-pathE);
    painter->restore();
}

 

 代码三减运算Ⅱ：

void MainWindow::painterPathDemo(QPainter *painter)
{
    painter->save();
    QPainterPath path;
    path.moveTo(200,200);
    path.lineTo(220,240);
    path.cubicTo(200,0,50,90,100,120);
    QPainterPath pathE;
    pathE.addEllipse(-100,-100,200,200);
    QPainterPath pathR;
    pathR.addRect(0,0,100,100);

    painter->drawPath(/*path+*/pathE-pathR);
    painter->restore();
}

 

代码四或运算：

void MainWindow::painterPathDemo(QPainter *painter)
{
    painter->save();
    QPainterPath path;
    path.moveTo(200,200);
    path.lineTo(220,240);
    path.cubicTo(200,0,50,90,100,120);
    QPainterPath pathE;
    pathE.addEllipse(-100,-100,200,200);
    QPainterPath pathR;
    pathR.addRect(0,0,100,100);

    painter->drawPath(/*path+*/pathR|pathE);
    painter->restore();
}

 

代码五与运算：

void MainWindow::painterPathDemo(QPainter *painter)
{
    painter->save();
    QPainterPath path;
    path.moveTo(200,200);
    path.lineTo(220,240);
    path.cubicTo(200,0,50,90,100,120);
    QPainterPath pathE;
    pathE.addEllipse(-100,-100,200,200);
    QPainterPath pathR;
    pathR.addRect(0,0,100,100);

    painter->drawPath(/*path+*/pathR&pathE);
    painter->restore();
}

总结：

1.QPainterPath可以进行加减与或等运算。

QPainterPath path1,path2;
path1+path2  ==  void addPath(const QPainterPath &path);

path1-path2 == QPainterPath subtracted(const QPainterPath &p) const;

2.QPainterPath进行相减，如path1-path2,将path1与path2重合的部分去掉后，只保留path1剩余的部分。

3.或运算等同于加运算，可以理解为将重合的部分去掉，不重合的部分保留。

4.与运算保留重合部分，可以理解为将路径上共有的容器保留下来。

上述是部分源代码，整个代码连接如下：

https://download.csdn.net/download/weixin_41882459/12040558

该代码包含了线性渐变、圆锥渐变、半径渐变、填充图，擦除图，绘制饼图，绘制三角形，圆，qpainterpath的例子等代码。