Font height is based on scalex of font.

[gnysek]

I'm not sure if internal value of yyFont named scalex can be different than 1 - (as we don't have function to change font scalex - maybe it's for some future usage ?), but still, returning height based on xscale sounds like bug, and rather scaley should be used here:

GameMaker-HTML5/scripts/yyFont.js

Line 421 in 82718d0

return this.max_glyph_height * this.scalex;