Window painting in QT-image painting

In QT, qpixmap is used to represent an image. It supports loading in PNG and jpg formats.

Qpixmap PM ("C:/test.png"); or qpixmap PM; PM. Load ("C:/test/PNG ");

In QT, there are two image paths:

(1) images in the file system: use absolute or relative paths.

(2) files in the resource: Start with a colon, for example,/test/source/logo.jpg

Drawn parameters:

(1) source rectangle

You can draw all or part of a graph.

QRect source(0,0,ima_width,img_height);

(2) Target rectangle

It can be filled in all windows, or only part of the window can be filled.

QRect target(0,0,width/2,height/2);

Called functions:

painter.drawPixmap(target,m_picture,source)

Circlewidget. h

#ifndef CIRCLAWIDGET_H#define CIRCLAWIDGET_H#include <QFrame>#include<QTimer>#include<QPixmap>class CircleWidget:public QFrame{    Q_OBJECTpublic:    CircleWidget(QWidget *parent);    ~CircleWidget();private:    void paintEvent(QPaintEvent *event);private:    QPixmap m_picture;};#endif // CIRCLAWIDGET_H

Circlewidget. cpp

# include"circlewidget.h"#include<QPainter>CircleWidget::CircleWidget(QWidget *parent):QFrame(parent){   m_picture.load("/home/jun/untitled1/backimage.PNG");}CircleWidget::~CircleWidget(){}void CircleWidget::paintEvent(QPaintEvent *event){        QPainter painter(this);       int width=this->width();       int height=this->height();       QRect target(0,0,width,height);       int img_width=m_picture.width();       int img_height=m_picture.height();       QRect source (0,0,img_width,img_height);       painter.drawPixmap(target,m_picture,source);}

Result:

Window painting in QT-image painting