How to make progressive JPEG on QWidget as it loads?

Question

With Qt, rendering a fully loaded image in QWidget is pretty simple. However, I want to display the partially loaded progressive jpg (or png) as it is received.

Answer 1

As I recall, only the GIF format is suitable for these purposes. And I see no way to do this with the QT tools and libraries. Think that you need to find the hidden partially loaded (gif) image in QPixmap or QImage and show it.

Answer 2

You can display the image in QGraphicsView. To this end, you can write a QGraphicsItem that has two QImage pointers as member variables. One of them can be used as a buffer, so new bytes can be written to the buffer. Another image can be used for rendering. Paint () function should be lower

painter->drawImage(0,0,*mRenderImage);