Posted by Alex Crossley on
URL: https://forum.jogamp.org/SWT-GLCanvas-renders-incorrectly-at-175-scaling-and-above-on-Windows-tp4043628p4043851.html

For GLCanvas, the only fix I found to fix the Windows Display Scale problem (when at 125%, 150%, 175% etc...) was to use Toolkit to get the scale and apply the factor to width & height like this:

        Toolkit toolkit = Toolkit.getDefaultToolkit();
        int screenDPI = toolkit.getScreenResolution();
        // Standard DPI for 100% scaling is 96 DPI
        double standardDPI = 96.0;
        // Calculate the scaling
        scale = screenDPI / standardDPI;

Then set the viewport like this:

        int fbWidth = (int)(scale * width);
        int fbHeight = (int)(scale * height);
        gl.glViewport(0,0,fbWidth,fbHeight);

Hope this helps somebody