Posted by gbburkhardt on Mar 05, 2023; 6:17pm
URL: https://forum.jogamp.org/DPI-scaling-not-working-tp4042206p4042289.html

Well, I've found the sweet spot, if nothing else.  Please see attached patch.scale.patch

I've made modest modifications to the test program that makes it easier to see the problem.  
OneTriangleSwingGLCanvas1.java

The picture using the patch now looks like


But, I wonder what else this will break.  It's not entirely clear to me how the variables 'hasPixelScale' and 'reqPixelScale' are supposed to be used in GLCanvas and JAWTWindow.

The debug output with -Dnativewindow.debug.JAWT is

JAWTUtil initialization (JAWT/JNI/...); SKIP_AWT_HIDPI false
JAWTUtil.getJAWT(tryOffscreenLayer false, tryOnscreen true)
JAWTUtil: Has sun.awt.SunToolkit: awtLock/awtUnlock true, disableBackgroundErase true
JAWTUtil: Has Java2D true
JAWTUtil: Is headless false
JAWTUtil: AWT Desktop hints 2
JAWTUtil: OffscreenLayer Supported: false - Required false
JAWTWindow[0x48aaecc3].invalidate @ Thread main - visible[isShowing false],
    ** THIS 0x1f3f4916: GLCanvas[visible true, showing false, valid false, displayable true, 0/0 640x480]
    ** THREAD main
JAWTWindow[0x48aaecc3].ctor @ Thread main
JAWTUtil.getJAWT(tryOffscreenLayer false, tryOnscreen true)
JAWTWindow.updateBounds: [ 0 / 0  0 x 0 ] -> [ 0 / 0  640 x 480 ]
JAWTWindow.updatePixelScale: updated req[0.0, 0.0], min[1.0, 1.0], max[1.25, 1.25], has[1.25, 1.25]
JAWTWindow[0x48aaecc3].attach @ Thread AWT-EventQueue-0: visible[isShowing true],
    ** THIS 0x1f3f4916: GLCanvas[visible true, showing true, valid true, displayable true, 5/5 640x480]
    ** THREAD AWT-EventQueue-0
JAWTWindow.updateBounds: [ 0 / 0  640 x 480 ] -> [ 5 / 5  640 x 480 ]
JAWTWindow: surface change 0x3b01187b -> 0xffffffffb7012b77
GLCanvas.setSurfaceScaleImpl reqPixelScale 0.00 0.00, hasPixelScale 1.25 1.25
reshape canvas 800 x 600
display drawable 800 x 600
display canvas bnds 640 x 480 at 5, 5
display panel 650 x 490
display frame 664 x 527

Without the patch, the only difference is

JAWTWindow.updatePixelScale: updated req[0.0, 0.0], min[1.0, 1.0], max[1.25, 1.25], has[1.0, 1.0]