Re: [ft-devel] color framework

[Werner LEMBERG]

>> FT_LOAD_COLOR should trigger a standard case with some default
>> blending; for finer color and blending control separate functions
>> should be provided to allow direct layer access.
> 
> Which [of] is these flags is spurious?
> FT_LOAD_COLOR | FT_LOAD_RENDER | FT_LOAD_TARGET_BGRA
> 
> I am ok with assuming FT_LOAD_TARGET_BGRA if FT_LOAD_COLOR is set.
> FT_LOAD_RENDER should be explicit!  It is absolutely crazy to
> enforce slow rendering unless explicitly asked for.  FT_LOAD_COLOR
> should just merge all outlines/layers/contours and tag them with
> COLOR, of course.  I am just warning. FT_LOAD_COLOR does not imply
> FT_LOAD_RENDER yet.  Keep it this way.

Alexei, I think we miscommunicate.  FT_LOAD_COLOR will *never* set
FT_LOAD_RENDER.  How do you come to this impression?  We are only
talking about the effect of FT_LOAD_COLOR on the rendering of
color-layered glyphs.

Actually, the current FreeType code *does* separate loading and
rendering.  If you say

  FT_Load_Glyph(... | FT_LOAD_COLOR);
  FT_Render_Glyph(... FT_RENDER_MODE_NORMAL);

you get grayscale rendering of the normal outline.  You must rather
say

  FT_Load_Glyph(... | FT_LOAD_COLOR);
  FT_Render_Glyph(..., FT_RENDER_MODE_NORMAL | FT_LOAD_COLOR);

to get a default blending of the color layers.

I consider this hacky.  The main reason is that currently
FT_LOAD_COLOR makes FT_Load_Glyph load *both* the normal outline and
the colored-layered data.  It would be better if this flag makes the
function load only a contours array with glyph color information so
that

  FT_Render_Glyph(..., FT_RENDER_MODE_NORMAL)

automatically produces a BGRA bitmap.  The definition of
FT_RENDER_MODE_NORMAL should be then changed to

  Default render mode; it corresponds to 8-bit anti-aliased bitmaps
  for normal outlines (FT_PIXEL_MODE_GRAY) and color bitmaps for
  color-layered glyphs (FT_PIXEL_MODE_BGRA).

I think this is more user-friendly than introducing
FT_RENDER_MODE_BGRA.  In other words, the presence of a `color' array
in the glyph slot makes the renderer select colour output.


    Werner