I am trying to understand how GLFW window sizes works in conjunction with system scaling.. I am using Ubuntu 24.04 with X11. When I request a window using GFLW of size, for example 1600x1200, I get a window with identical frame buffer size and window size.
However, the size of the window on screen gets smaller as I increase the system scaling. At 100%, the size seems correct on my 2560x1600 pixel display. But it keeps shrinking as I increase the system scaling, even though the window/frame buffer sizes are held constant. Why is this happening? Shouldn’’t the frame buffer size reflect the actual number of pixels on screen?
This sounds like Display - wrong behaviour of scale (#259) · Issues · Xfce / xfce4-settings · GitLab i.e. display resolution scaling, which would make windows smaller when you increase the scale because you have increased the effective resolution of the display.
Also read: GLFW: Window guide