<![CDATA[I have a problem with GraphicsView]]>7a752758-697d-451a-ab5a-8287a192e6de-image.png
When I drag the vertical line in A with the mouse, the movement of the vertical line in B is always delayed;

After I did this, the delay disappeared:

A.onMouseMove: 
{
     ... cur_scene_rect ...

     scene->setSceneRect(cur_scene_rect.left - 1,  ....);
     scene->setSceneRect(cur_scene_rect.left + 1,  ....);
     
     vline->setLine(....)
}

B.onMouseMoveFromA: 
{
     ... cur_scene_rect ...

     scene->setSceneRect(cur_scene_rect.left - 1,  ....);
     scene->setSceneRect(cur_scene_rect.left + 1,  ....);
     
     vline->setLine(....)
}

Why is this? Why does calling setSceneRect to change scene_rect make the delay disappear, but if we don't call setSceneRect twice and keep scene_rect unchanged, there will be a delay?

]]>https://forum.qt.io/topic/164397/i-have-a-problem-with-graphicsviewRSS for NodeWed, 22 Apr 2026 07:27:41 GMTSun, 08 Mar 2026 03:48:40 GMT60<![CDATA[Reply to I have a problem with GraphicsView on Sun, 08 Mar 2026 04:09:44 GMT]]>I asked Gemini and they removed the method of calling setSceneRect twice and replaced it with the method of graphicsview->viewport()->update(), which has the same effect.

]]>https://forum.qt.io/post/836943https://forum.qt.io/post/836943Sun, 08 Mar 2026 04:09:44 GMT