QT painting event - set background picture

Preface

Set up widget Background image of , And put other pictures on the background picture

---

Go straight to the code ：

The header file

void paintEvent(QPaintEvent *);

cpp file ：

void MainWindow::paintEvent(QPaintEvent *)
{
    
        // Creating painters , Specify the drawing device 
        QPainter painter(this);
        // establish QPixmap object 
        QPixmap pix;
        // Loading pictures 
        pix.load(":/res/PlayLevelSceneBg.png");
        // Draw the background 
        painter.drawPixmap(0,0,this->width(),this->height(),pix);
        
        // Load title 
        pix.load(":/res/Title.png");
        // Zoom in and out 
        pix = pix.scaled(pix.width()*0.5,pix.height()*0.5);
        // Draw the title 
        painter.drawPixmap( 10,30,pix.width(),pix.height(),pix);
}

paintEvent The method is qt The original method , Call painting event , Just rewrite the method , stay cpp There is no need to actively call in the file

translate ：

Handle the drawing event passed in the event parameter .
The default implementation does nothing . Re implement this function to perform painting . If necessary, , Dirty areas can be retrieved from events .

design sketch ：

Be careful

The path of pictures is a problem we need to pay attention to , because qt Adopt the method of shadow construction , The location of the executable program is not in the same location as the source file . The relative path of the image depends on the executable ,…/ Is the current path of the executable

Right click on the picture , Can quickly copy the image path

Students who will not add resource files , Check out this article

link ：qt Add resource file

It's not easy to code words , If this blog is helpful to you , Please praise the collection , Thank you very much ！ There is something wrong , Can comment on the area of communication .