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[Devel] Re: [Freetype] Can FreeType rasterize the glyph bitmap in severa
From: |
David Turner |
Subject: |
[Devel] Re: [Freetype] Can FreeType rasterize the glyph bitmap in several bands? |
Date: |
Wed, 12 Jun 2002 00:25:16 +0200 |
Hello net pl,
net pl a écrit :
>
> Hi,
>
> I'd like to use the FT library to rasterize the fonts for our application.
> In our own memory allocation, the maximum memory allocated for a block is
> 35K. In this case, we will have a problem if the glyph bitmap is bigger than
> 35K.
> I saw in a document (old changes 14/apr/2000)that FT supports sub-banding to
> render large glyphs. Is it possible now to render the glyph by sub-banding?
>
sub-banding is an internal feature of the rasterizers that allow any outline
to be rendered into any bitmap with a fixed amount of memory during the
rasterization process.
if your bitmap sizes are limited, you can simply do something like:
- load the glyph outlines without rendering them
- compute their bounding boxes in pixels to compute
the corresponding bitmap buffer size
- create as many "bitmap buffer bands" that you need
- and render the outline into them with FT_Outline_Get_Bitmap
(this function accepts a pre-allocated bitmap as argument),
one call per "band", provided that you correctly shift
the outline before each rendering.
you won't be able to use the FT_Glyph facility of the cache
sub-system, but that's still better than nothing..
Hope this helps,
- David Turner
- The FreeType Project (www.freetype.org)