One Dog v. the Windows 3.1 Graphics Stack

January 4, 2025 · Ninji

URL: https://wuffs.org/blog/windows-3x-graphics

“Entering full-screen mode and then returning to the Windows GUI will leave you with a corrupted screen.”

SVGAPatch adds VESA support to Windows 3.11 but leaves the screen-switching routine alone. That routine sets an invalid video mode, so a trip to full-screen DOS corrupts the display. Ninji traced it and patched the driver to call the right function.