screenshot

[NanLi]

When I use the screen>grabWindow function to obtain screen pixel data, the program runs normally on Windows and Ubuntu desktop systems, but on embedded Linux systems, the function returns NULL. My code is as follows:

QScreen * screen=QGuiApplication:: primaryScreen();

QPixmap pixmap=screen ->grabWindow (0)// Return null value

Pixmap. save ("screenshot. png");

[ChrisW67]

@NanLi Do you mean that pixmap.isNull() == true, screen == nullptr, or that the PNG file is the correct size but blank?

[NanLi]

@ChrisW67
Thank you for your reply！
After detailed debugging, it was found that it was due to
Screen==nullptr, so why does QGuiApplication:: primaryScreen() return null

[jeremy_k]

This is a duplicate of https://forum.qt.io/topic/151920/screenshot/2?_=1699508498491

Please stick to a single thread.