* Improve status handling. Operations on surfaces with status other than
  "Success" should be ignored.

* Copy area operation.

* Text support. Glyph set management, glyph and string compositing
  operations. Some ideas: Multi-texturing for compositing multiple glyphs 
  per render pass, Sub-pixel rendering, vector text; glyphs loaded into 
  display lists.

* Projective transformations (Add filter type GLITZ_FILTER_ANISOTROPIC).

* A programmable surface type which can store a set of rendering operations
  in a display list.

* WGL (Windows GL) backend.
