Why does rxvt-unicode sometimes leave pixel droppings?
Most fonts were not designed for terminal use, which means that character size varies a lot. A font that is otherwise fine for terminal use might contain some characters that are simply too wide. Rxvt-unicode will avoid these characters. For characters that are just “a bit” too wide a special “careful” rendering mode is used that redraws adjacent characters. All of this requires that fonts do not lie about character sizes, however: Xft fonts often draw glyphs larger than their acclaimed bounding box, and rxvt-unicode has no way of detecting this (the correct way is to ask for the character bounding box, which unfortunately is wrong in these cases). It’s not clear (to me at least), whether this is a bug in Xft, freetype, or the respective font. If you encounter this problem you might try using the “-lsp” option to give the font more height. If that doesn’t work, you might be forced to use a different font. All of this is not a problem when using X11 core fonts, as their bounding box dat
