Opal: update TODO and README

git-svn-id: svn+ssh://svn.gna.org/svn/gnustep/libs/opal/trunk@31143 72102866-910b-0410-8b05-ffd578937521

README

@@ -16,8 +16,8 @@ in the quartz group of minerals.
 There is a homepage (which may not be updated too frequently) at
 <http://goliat.eik.bme.hu/~balaton/gnustep/opal>
 
-The sources are available from the Étoile project repository at
-<http://gna.org/projects/etoile/>
+The sources are available from the GNUstep repository at
+<svn://svn.gna.org/svn/gnustep/libs/opal/trunk>
 
 *** Warning! *** This version is not yet suitable for general use.
 It may be interesting for developers only, contributions are much welcome!

TODO

@@ -1,18 +1,63 @@
-There's a lot to do, really.
+TODO:
+=====
 
-- Add proper build system
-- Port to other platforms (Windows anyone?)
-- Try different Cairo surfaces (ps, pdf, png, OpenGL, etc.)
+CGContext:
+ - Have a CGColorSpaceRef attached to the context (currently assumed to be
+   sRGB). This will enable things like:
+   - Creating a CGBitmapContext in a given color space, then drawing in it
+     to convert colors to that color space
+   - For people with wide-gamut monitors, we would want to set the appropriate
+     color space on the window CGContext.
+ - Shadow support is not finished.
+ - Image masks are not supported.
+ - Need to write a OPGState class that encapsulates the graphics state,
+   like CairoGState in -back.
+ - Could follow the example of GNUstep back, and factor 
+   out Cairo specific code in CGContext to a OPCairoContext subclass.
 
-- Implement TextMatrix in CGContext (may need to use internal Cairo APIs)
-- Implement missing glyph drawing functions and finish ShowText
-- Implement Image drawing
-- Implement Patterns and Shading
-- Implement Path handling functions
-- Implement color management (could use lcms?)
+PostScript/PDF parsing classes are unimplemented.
 
-- Fix device transform in Cairo and get rid of CTM patching hacks
+CGPattern and CGShading unimplemented
 
+Image framework:
+ - Need to add TIFF writing
+ - The decoders/encoders could be polished:
+   - They should read colorspace info, now that Opal can take advantage of it
+   - They use the decoding libs to convert to RGBA32, but should pass though
+     higher bit-depth images in to Opal and let Opal convert.
+ - Could add a plugin which uses ImageMagick for more format support
+
+Build system:
+ - Set up so that image plugins, and LCMS classes are only compiled if the 
+   libraries are available.
+
+CGFont:
+ - Need to refactor to share implementation with OpalText
+
+CGGradient:
+ - Should clip the gradient to match Quartz output
+
+Color space and image conversion:
+ - Add a placeholder color space conversion class which does non-color managed
+   conversions so that LCMS isn't a necessary dependency
+
+OpalText:
+ - Still in very early stages. Here is a sketch of what needs to be done:
+   - Finish CTFont/CTFontDescriptor/CTFontCollection/CTFontManager with 
+     both Fontconfig/Freetype and Windows GDI backends.
+     (The basics of CTFontDescriptor currently with Fontconfig)
+   - Implement CTTypesetter, the core part, which requies:
+     - Identifying permissible places to break a string with the Unicode
+       linebreaking algorithm
+     - Run GNU fribidi on the string if needed
+     - Deciding what font to use for each range in the string, doing fallback
+       where necessary
+     - Itemizing the attributed string using 
+       -attributesAtIndex:longestEffectiveRange:inRange
+       to get the character runs
+     - Calling harfbuzz to do OpenType layout, yielding glyph runs and advances
+       (+ other simpler layout routines for non-OpenType fonts?)
+   - Finish CTFramesetter
 
 Design principles to follow:
 ============================