[ft] sub pixel positioning when Auto hinter and cache are used
From:
Maggy Anastasia
Subject:
[ft] sub pixel positioning when Auto hinter and cache are used
Date:
Wed, 3 Jun 2009 14:16:52 +0800
Hi all
I have a question on whether it is possible to perform sub pixel positioning when my system is using Auto Hinting and FreeType's cache subsystem. If yes, I would be really keen to know how. I need to perform text rendering that is fast (thus it requires cache to be activated), support sub pixel positioning and all glyphs are hinted.
From my understanding, when cache subsystem is used, we can obtain glyph's buffer and metrics using FTC_SBitCache_Lookup(). Text rendering will be much faster if the glyph cache hit is high. There is one problem with this which I know not yet how to solve, which is that FTC_SBit only return the metric values in pixels instead of in 1/64th points. In addition to that, when we perform Auto hinting, we can't get the lsb_delta and rsb_delta of a glyph when FTC_SBitCache_Lookup() is used. I hope I am wrong.