I have a button on my ribbon that uses a 40x40 PNG image. On a non-scaled desktop the control draws fine. When I go to a 4k monitor scaled at 200%, we supply a 80x80 image. The result is that the image draws such that it overlaps the text under the image.

Debugging led me to GetStretchIconSizeDPIAwareness. DPI icon scaling is not enabled so the code goes to the "else" statement.

        //save original size of icon
        szIcon.cx = pImage->GetWidth();
        szIcon.cy = pImage->GetHeight();

        //reduce icon size if it is bigger than control
        if (szIcon.cx > szAvailable.cx || szIcon.cy > szAvailable.cy)
        {
            szAvailable.cx -= nDpiScallingButtonMarginX * 2;
            szAvailable.cy -= nDpiScallingButtonMarginY * 2;

            szIcon = GetStretchIconSize(pImage, szAvailable);
        }

Examining the if statement note sizIcon.cx is 80 and szAvailable is (84,123). So the available size is not reduced by the margins (4 and 4) * 2 and the call to GetStretchIconSize is not made. It appears that this leads to the image displaying over the text that is under the icon (style is icon with caption below).

My quick fix is to avoid allowing images to exceed 64x64. But that isn't really correct. The 80x80 image should display correctly even if it gets slightly reduced.

Note: in Ribbon Image Resources specification states the following

"At 96 dpi, large images are 32x32 pixels in size and small images are 16x16 pixels in size." And at 192 dpi, large images are 64x64 pixels in size and small images are 32x32 pixels in size.

(https://docs.microsoft.com/en-us/windows/win32/windowsribbon/windowsribbon-imageformats)

Thus for you can use icon sizes specified in the specification to fix this problem.

Since version 19.0 you can use xaml icons for ribbon it fixed many problems with DPIs.

Regards,

Artem Gontarenko

I've fixed button size and function GetStretchIconSizeDPIAwareness.

Thus icons 40*40 (100 DPI) and 80*80 (200 DPI) are scaled and not go out of the button edge in below.

Artem Gontarenko

Great! What version will the fix be in?

Even if I can't move to that version, I can see what code change is actually needed and apply the fix locally.

Hello,

Fix will be available in the next beta or final release.

Artem Gontarenko