Qt之图片

widget.h:

#ifndef WIDGET_H
#define WIDGET_H
#include<QPaintEvent>
#include <QWidget>
#include<QPixmap>
#include<QImage>
class Widget : public QWidget
{
    Q_OBJECT

public:
    Widget(QWidget *parent = 0);
    ~Widget();
    void paintEvent(QPaintEvent *e);
private:
    QPixmap *qp;
    QImage *ql;
};

#endif // WIDGET_H

widget.cpp:

#include "widget.h"
#include<QPainter>
Widget::Widget(QWidget *parent)
    : QWidget(parent)
{
    //qp=new QPixmap("C:/Users/admin/Desktop/QT_Project/untitled15/1.png");
    ql=new QImage("C:/Users/admin/Desktop/QT_Project/untitled15/1.png");
}
void  Widget::paintEvent(QPaintEvent *e)
{
    QPainter paint;
    paint.begin(this);
   // paint.drawPixmap(0,0,qp->scaled(this->width(),this->height()));
    paint.drawImage(0,0,ql->scaled(this->width(),this->height()));
    paint.end();

}
Widget::~Widget()
{
delete qp;
}

main.cpp:

#include "widget.h"
#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    Widget w;
    w.show();

    return a.exec();
}

效果：