I have windows that are fixed in size, under which I have textual labels. Although I use the same font, the fonts look different on windows, mac and linux, up to the point where I can’t rely on where a label will end, even though the string and the font size are a constant in my application.
Is there any solution to that? Someone mentioned embedding TTF fonts and using them, but is that really necessary?
There is no font you can rely on being available on all platforms, and height/width ratios for different strings will differ for different fonts (fixed-width being slightly better). Additionally, things like different DPI settings will cause you headaches even if using the same font. I would rather reconsider whether your widgets really should be fixed size and you need those assumptions about the font size at all. In almost all cases, your UI will be more usable, readable and consistent with the rest of the desktop if you use flexible layouts and stick to whatever font and font size the platform suggests.