hhea: Horizontal Header
The horizontal header table contains global horizontal writing metrics which apply to all glyphs in the font.
Requirements
- The advanceWidthMax, minLeftSideBearing, and minRightSideBearing fields must reflect the actual data in 'glyf' and 'hmtx'. Glyphs with no contours should be ignored for the purposes of these calculations.
- The values of caretSlopeRise and caretSlopeRun should agree with the italicAngle in the 'post' table.
Recommendations
- The Ascender, Descender, and LineGap fields are typographic values, not strict calculations. The TTF specification contains additional information on baseline-to-baseline distances in the chapter "Recommendations for Windows Fonts".