QT 不规则窗体

• QPixmap pix; pix.load(“16.png”, nullptr, Qt::AvoidDither | Qt::ThresholdDither | Qt::ThresholdAlphaDither); 为QPixmap对象填入图像值；
• resize(piz.size()):重设主窗体的尺寸为所读取的图像大小；
• setMask(QBitmap(pix.mask())):为调用它的控件增加一个遮罩，遮住所选区域以外的部分使之看起来是透明的，它的参数可以为一个QBitmap对象或一个QRegion对象。

shapewidget.h

#ifndef SHAPEWIDGET_H
#define SHAPEWIDGET_H

#include <QWidget>

class ShapeWidget : public QWidget
{
    
    
    Q_OBJECT

public:
    ShapeWidget(QWidget *parent = nullptr);
    ~ShapeWidget();
protected:
    void mousePressEvent(QMouseEvent *);
    void mouseMoveEvent(QMouseEvent *);
    void paintEvent(QPaintEvent *event);
private:
    QPoint dragPosition;
};
#endif // SHAPEWIDGET_H

shapewidget.cpp

#include "shapewidget.h"

#include <QMouseEvent>
#include <QPainter>
#include <QPixmap>
#include <QBitmap>

ShapeWidget::ShapeWidget(QWidget *parent)
    : QWidget(parent)
{
    
    
    QPixmap pix;
    pix.load("16.png", nullptr, Qt::AvoidDither | Qt::ThresholdDither | Qt::ThresholdAlphaDither);
    resize(pix.size());
    setMask(QBitmap(pix.mask()));
}

ShapeWidget::~ShapeWidget()
{
    
    

}

void ShapeWidget::mousePressEvent(QMouseEvent *event)
{
    
    
    if (event->button() == Qt::LeftButton) {
    
    
        dragPosition = event->globalPos() - frameGeometry().topLeft();
        event->accept();
    }
    if (event->button() == Qt::RightButton) {
    
    
        close();
    }
}

void ShapeWidget::mouseMoveEvent(QMouseEvent *event)
{
    
    
    if (event->buttons() & Qt::LeftButton) {
    
    
        move(event->globalPos() - dragPosition);
        event->accept();
    }
}

void ShapeWidget::paintEvent(QPaintEvent *event)
{
    
    
    QPainter painter(this);
    painter.drawPixmap(0, 0, QPixmap("16.png"));
}

main.cpp

#include "shapewidget.h"

#include <QApplication>

int main(int argc, char *argv[])
{
    
    
    QApplication a(argc, argv);
    ShapeWidget w;
    w.show();
    return a.exec();
}