Re: Glyph Outlines in Trace Driver
Allen Blaylock <AllenB <at> epiloglaser.com>
2015-07-09 19:25:10 GMT
Where is the decision made for determining if a glyph is large enough to be rendered as a path as opposed to
rendered by freetype? Looking at FreeType (it looks like gs uses the original FreeType?) there are a good
deal of tools for extracting just the font outline from a given glyph but the text processing in GS is still
fairly opaque to me. For instance I cannot work out how FreeType is called from GS, I cannot find any calls to
TT_* functions that are defined in ttobjs.h. Is there documentation of this or some comments that discuss
how the glyph processing is done?
From: Ken Sharp [mailto:ken.sharp <at> artifex.com]
Sent: Tuesday, June 16, 2015 1:21 AM
To: Allen Blaylock
Subject: RE: [gs-devel] Glyph Outlines in Trace Driver
At 23:47 15/06/2015 +0000, Allen Blaylock wrote:
>I remember coming across GS producing large glyphs as outlines the
>first time I went through making a GS driver. At some point GS must
>know of the outlines to render the font correctly? This is purely an academic question.
In general no, it doesn't. FreeType is used to render the glyph description to a bitmap.
For large glyphs, as stated, we do retrieve the path from FreeType instead and render it as a path rather than
a cached bitmap.
>Maybe it would be worthwhile for me to revisit the SVG driver (I think it
>has been removed from the source the last time I looked) and think about
>how to best revive it.
The SVG output device was never completed, and didn't work well. In
particular text didn't work well (though this is more to do with the
limitations of SVG in this area), so the device was dropped.