[cairo] GTKCairo development

[Turner David]

Hello,

> Will Pango layout text on a curve? If so that will solve an 
> SVG problem.
> 

> Also, does freetype2 know how to rasterize SVG font files? 
> 
There is no official "SVG font file" format. The Adobe SVG viewer
does read files ending with the ".cef" extension that are supported
by FreeType 2, but these are a vendor-specific extensions.

Fonts can be specified in a SVG file as a set of XML elements.
There is no plan to support this within FreeType for the moment,
and frankly, I don't see any use for this in the font engine.

> Should the Cairo text API only consist of two entries:
> 1) Cache this set of glyphs for me
> 2) Draw this list of glyphs at these x/y locations
> 
> It's better for the low level drawing engine if the glyphs 
> are collected into larger bitmaps than 1000's of individual ones. 
> That way one  bitmap can be bound into a texture unit and all 
> of the glyphs accessed without setting the unit up again. It
> also makes it easier to track the cache at the server.
> 
That's only if you assume a GL-based backend. If you use the Render
backend, you'd better send individual glyph images since these are
stored as singletons on the server (through hashing/refcounting),
saving _tons_ of memory when multiple applications use the same
glyphs.

> To build the cache with OpenGL first make the composite 
> bitmap using Freetype. Then call the Cairo cache function with 
> the bitmap and an array of x,y,w,h for each glyph. Cairo would 
> then make a display list for the bitmap (causing it to
> be cached in the server) and a little display list for each 
> glyph that embeds the x,y,w,h and bitmap id. These display list
> ids need to be added to the input x,y,w,h array. 
> 
> To draw glyphs pass in an array of x,y,display list id. Cairo 
> would then make a
> chain of calls to the display lists passing in the 
> destination x,y coordinates.
> 
Wouldn't be better if the backend was capable of performing the
"compositing" itself, according to its needs and best uses ?
Otherwise, you're passing a serious complexity burden to
application and toolkit writers, and I can't imagine that none
of these is going to make truly horrible things with such an
API, or simply ignore it and pass individual glyph images
anyway.

Just my 0.02 EUR :-)

- David Turner
- The FreeType Project  (www.freetype.org)

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