This is a quick-and-dirty utility for checking if a TrueType font exhibits kerning offsets when used in LÖVE 11.4. It loads TTF fonts in LÖVE, and checks Font:getKerning() against a list of common kerning pairs which are taken from The Ultimate List of Kerning Pairs.
Inspector Kern defaults to an interactive mode: drag-and-drop TTF files onto the application window to get a report on the number of non-zero kerning offsets detected. It starts with the default LÖVE font (Vera Sans in 11.x).
A bulk test mode is also available, accessible from the command line. It will recursively scan a directory for TrueType fonts (identified by having a .ttf extension) and list those fonts which exhibit any non-zero kerning pair offsets.
Additionally, for each font loaded, Inspector Kern can run a sequence of strings against Font:hasGlyphs() and print the results.
The following assumes you are in the same directory as main.lua.
love .
- Interactive mode. Drag-and-drop a TTF file onto the window to check the number of non-zero kerning offsets.
love . --bulk path/to/fonts
- Uses love.filesystem to recursively test all fonts in a given path. The testing loop is time-limited to prevent the application from becoming unresponsive.
love . --bulk-nfs path/to/fonts
- Like above, but uses the nativefs i/o library instead of love.filesystem, which may be able to reach more paths (but may not work the same on all platforms.)
- Escape: Quit the application.
- Up/Down: Scroll the list of fonts.
- PageUp/PageDown: Scroll the list 10 at a time.
- Home/End: Jump to the top or bottom of the list.
- Escape: Quit the application.
"hasGlyphs" mode can be enabled by passing the command line argument --has-glyphs. When this mode is active, each loaded font is tested against a series of strings with the Font:hasGlyphs() method. In interactive mode, the results are printed below the kerning pair examples. In bulk mode, the results are printed to the console/terminal only. (It's a horrible mess. Sorry. You may need to paste the results into a spreadsheet, or run them through a text processor to make it readable.)
The glyphs_t table contains the strings that are tested. Each entry is a sub-table: the first index is an identifier, and the second index is the actual string to test. The glyph_t defaults are all common ASCII whitespace chars, because those were the glyphs that I originally wanted to check when I added this option.
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Inspector Kern doesn't know anything about the TrueType format, including whether a given font actually has kerning information. It only reports if
Font:getKerning()detects any non-zero kerning offsets, among a predefined set of glyph pairs, at size 72. -
Some fonts don't have kerning information by design. Check the font in a known-good application to be sure. A common kerning pair which is easy to identify at a glance is upper-case "LT" at a large font size.