Re: [ft] parallel glyph rendering

[Werner LEMBERG]

> 1. I want to create a bunch of glyph bitmaps quickly (so the
> sequence FT_Get_Char_Index, FT_Load_Glyph, FT_Render_Glyph,
> FT_Get_Glyph for a bunch of font/size/character combinations).  Can
> I do anything lighter weight than multiple library objects?

AFAIK, no.

> Some reason I thought that the finest granularity is an FT_Face
> object, but I'm getting seg faults when I assign one Face per
> thread.

Hmm.  In the documentation of FT_Library you can find this:

  For multi-threading applications each thread should have its own
  FT_Library object.

How comes that you got a different impression?

> If it is indeed still possible, the documentation mentioned changing
> a macro in <arch>/.../ftbuild.h to make a Library obj reentrant, but
> I didn't see anything in there -- any hints on what to change?

Where did you find this?  I can't find this in the FreeType 2
documentation.

> 2. If there is no finer granularity (as suggested by a message
> earlier this week) and I need to use multiple Library objects, are
> there any special flags / edits for supporting multiple libraries?
> [Perhaps the ftbuild.h note was for this?]

ftbuild.h?  This file has been replaced with ft2build.h about 9 years
ago, I think.  And no, there are no special flags needed to support
multiple libraries.

> 3. Finally, perhaps I'm going about this wrong.  Any suggested path
> for basic rendering of a bunch of glyphs of a few fonts (each at
> various sizes)?  My approach was to use the call sequence mentioned
> above en masse, iterating by: font, size, glyph.  E.g., for better,
> cache behavior, it might be better to iterate font/glyph/size.

font/size/glyph should be better at rendering time, at least for
TrueType fonts.  Reason: Selecting a different size makes the TrueType
interpreter run the font's `prep' table again.

> I'll post whatever I get working because this is sort of basic
> functionality :)

Thanks.


    Werner