[AGG] Filling rasterizer instead of rendering

[Stephan A. <sup...@gm...>]

Hi guys,

it's been a while that I worked with AGG code, and I feel a bit rusty. I 
want to change some code that renders cached glyph bitmaps one by one 
using agg::render_scanlines() to transfer the bitmap contents instead to 
the rasterizer cells, and then agg::render_scanlines() the complete 
string in just one call.

Perhaps some background: The text rendering code I have here uses 
different code-paths for when the glyphs are cached bitmaps (originating 
from FreeType), or when they are vector paths. In case of bitmaps, each 
glyph is rendered by itself, in case of vector paths, each glyph is 
rasterized into the same rasterizer, and then after processing the last 
glyph, there is a final render pass. I need to make it so the processing 
is the same for the bitmap path as it is for the vector path. The reason 
being that there is a difference in output when a glyph touches the same 
pixels as the previous glyph (overlap). That's due to some strange way 
in which some drawing modes render the glyphs. It would not matter if it 
were normal alpha blending the foreground color with the existing 
background, but that's not always the case.

So is there an easy way to do something equivalent to 
rasterizer.add_path() with the glyph bitmap that's already rasterized, 
to have it end up as the rasterizer contents? Basically, I need to copy 
it into the rasterizer cells at the correct location.

Thanks a lot & best regards,
-Stephan