#include <QMouseEvent>
#include <QPainter>
#include <QPixmap>
#include <QBitmap>
Dialog::Dialog(QWidget *parent) :
    QDialog(parent),
    ui(new Ui::Dialog)
{
    ui->setupUi(this);

    QPixmap pix;
    /*
        以下四行代码，任意一行都是有效的
    */
    pix.load("D:\\VS\\qtCreator\\ShapeWidget\\puppy.png", 0, Qt::AvoidDither);
    //pix.load("D:\\VS\\qtCreator\\ShapeWidget\\puppy.png",0, Qt::ThresholdAlphaDither);
    //pix.load("D:\\VS\\qtCreator\\ShapeWidget\\puppy.png", 0,  Qt::ThresholdDither );
    //pix.load("D:\\VS\\qtCreator\\ShapeWidget\\puppy.png", 0, Qt::AvoidDither | Qt::ThresholdAlphaDither | Qt::ThresholdDither );
    resize(pix.size());
    setMask(QBitmap(pix.mask()));
}

Dialog::~Dialog()
{
    delete ui;
}

void Dialog::paintEvent(QPaintEvent* event) {
    QPainter painter(this);
    painter.drawPixmap(rect(),QPixmap("D:\\VS\\qtCreator\\ShapeWidget\\puppy.png"),QRect());
}