Qt5开发及实例学习之不规则窗体：没看懂

一、新建QT GUI工程，项目名称“ShapeWidget”, 基类QWidget， 类名ShapeWidget，取消“建立界面”

二、ShapeWidget.h

#ifndef SHAPEWIDGET_H
#define SHAPEWIDGET_H

#include <QWidget>

class ShapeWidget : public QWidget
{
    Q_OBJECT

public:
    ShapeWidget(QWidget *parent = 0);
    ~ShapeWidget();

protected:
    void mousePressEvent(QMouseEvent *);
    void mouseMoveEvent(QMouseEvent *);
    void paintEvent(QPaintEvent *);

private:
    QPoint dragPosition;
};

#endif // SHAPEWIDGET_H

三、

#include "shapewidget.h"
#include <QMouseEvent>
#include <QPainter>
#include <QPixmap>
#include <QBitmap>


ShapeWidget::ShapeWidget(QWidget *parent)
    : QWidget(parent)
{
    QPixmap pix;
    pix.load("F:\\MyCode\\test1.bmp", 0, 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("F:\\MyCode\\test1.bmp"));
}