Posted by gbburkhardt on Apr 15, 2023; 4:35pm
URL: https://forum.jogamp.org/intent-of-reqPixelScale-in-GLCanvas-tp4042430p4042461.html

Is it the case that the use of 'reqPixelScale' is still a work in progress?  Using "-pixelScale 1.0" for the demo TestGearsES2NEWT doesn't affect the surface width/height.  I notice it printing this line:

HiDPI PixelScale: 1.0x1.0 (req) -> 1.0x1.0 (val) -> 1.25x1.25 (has)

Is there some demo that shows the expected use of 'setSurfaceScale()'?  I haven't been able to find one.

I suspect that it's intended to change the size of the drawable, but haven't found any code that changes the scaling for drawing.

My guess was that if the use changes the pixel scale with 'setSurfaceScale', drawing commands would give coordinates in scaled pixels.  For example, if DPI scaling is set to 125%, and the logical frame size is 640 x 480, the size of the region in device pixels will be 800x600.  Normally, 'hasPixelScale' would be 1.25.  If the user calls 'setSurfaceScale(1.0, 1.0)', my guess is that the intent was that drawing would be done in a region or 640x480, and that GL drawing calls would scale the commands to device area of 800x600.

I'm still puzzled by what 'setSurfaceScale()' is supposed to do.  Thanks.