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NiLuJe · 08-07-2014, 07:50 PM

I think Hitch is aware of that, since I dimly remember bringing it up here once before, but one reason KDP might be so finicky with custom fonts is the (heavily? weirdly? patched) font rendering engine used on the eInk Kindles. Since the K3, we (when playing with custom font hacks) have demonstrated that it sometimes horribly mangles some fonts, or just plain crashes when rendering some fonts. And it's specifically an issue with Amazon's patches, since replacing the library responsible for font rendering with a recent vanilla copy miraculously solves everything (well, except truetype fonts with broken bytecode, of course, but those are relatively few and far between, and easy to check for, since they're broken on anything using FreeType's BCI).

Don't ask me why they haven't bothered fixing it since the K3, though ;D. Although they did close a somewhat easily accessible undocumented entry point for system-wide user-configurable custom fonts at one point of FW 5.x's life, probably for that reason.

08-07-2014, 07:50 PM	#33
NiLuJe BLAM! Posts: 13,506 Karma: 26047202 Join Date: Jun 2010 Location: Paris, France Device: Kindle 2i, 3g, 4, 5w, PW, PW2, PW5; Kobo H2O, Forma, Elipsa, Sage, C2E	I think Hitch is aware of that, since I dimly remember bringing it up here once before, but one reason KDP might be so finicky with custom fonts is the (heavily? weirdly? patched) font rendering engine used on the eInk Kindles. Since the K3, we (when playing with custom font hacks) have demonstrated that it sometimes horribly mangles some fonts, or just plain crashes when rendering some fonts. And it's specifically an issue with Amazon's patches, since replacing the library responsible for font rendering with a recent vanilla copy miraculously solves everything (well, except truetype fonts with broken bytecode, of course, but those are relatively few and far between, and easy to check for, since they're broken on anything using FreeType's BCI). Don't ask me why they haven't bothered fixing it since the K3, though ;D. Although they did close a somewhat easily accessible undocumented entry point for system-wide user-configurable custom fonts at one point of FW 5.x's life, probably for that reason. Last edited by NiLuJe; 08-07-2014 at 08:03 PM.