Rendering in geode

[Jonathan Morton]

On Wed, 2010-06-23 at 15:54 +0800, Huang, FrankR wrote:
> ...the side effect is that firefox has some characters missing.

I would suspect a bug in your "coordinate range" handling code.  It may
be related to the dimensions of individual glyphs.

Text rendering goes through the following stages:

- A fresh temporary pixmap, A8 format, is allocated and cleared.

- Individual glyphs are placed in this pixmap using ADD operation,
sourced from a large (1024x320) pixmap serving as a glyph cache.

- The complete pixmap is used as a mask for an OVER operation onto the
original target.  The source is normally a solid colour.

- The temporary pixmap is thrown away.

If you accelerate the ADD operation, it should have the same coordinate
handling as the OVER operation; areas outside images are no-ops when
Repeat is disabled.

-- 
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From: Jonathan Morton
      jonathan.morton at movial.com