Hi Yoshiki,

Unfortunately, I haven't yet looked at the code, but here's something that
might be of help. For >= 8 bpp you can use rule 34 (this is what Balloon
uses). There is one gotcha though since rule 34 expects *prescaled* rgb in the
source. Meaning that the encoding for rule 34 needs to be like what you see in
#scaledPixelValue32 (that's what this method is for). This will perform alpha
blending regardless of destination depth but it's pretty clear that the
results will be less than optimal for 8bpp. However, for 16bpp (which is the most
likely use) you even get a very reasonable ordered dither for free.

Cheers,
  - Andreas

>   Craig,
> 
> > 	Thanks!
> > 
> > 	After trying it, I'm wondering if you have any particular optimizations
> > planned. On my machine (550 MHz), typing speed and menu performance are
> > noticeably decreased (using 13-point Verdana). Are there still some
> > relatively easy speedups possible?
> 
>   You're using it for code pane(s) with some hundreds of characters in
> it?  Yes, it can be slow.  The purpose of mine was pretty much for the
> Presentation slides where typical slide only has dozens of characters.
> 
>   Regarding the optimization, I can suggest a few things:
> 
>   * First of all, if you don't use any fancy background colors,
> 
>        TTFontReader>>installTTF:asTextStyle:sizes:
> 
>     should be good enough.  For a single colored background, you don't
>     have to worry about the anti-alias fringe of pre-rendered bitmaps
>     with alpha channel.
> 
>   * I was thinking to render the glyphs on 32 bit form and draw them
>     onto the destForm with combination rule=24.  But this only works
>     when the destForm is 32 bit depth as well.  I was trying this
>     approach, but didn't get to a point where I'm happy with the
>     result for some reason...  If I remember correctly, it was related
>     to the black/transparent pixels (Balloon engine renders black as
>     16rFF000000, instead of 16rFF000001 and because it is 32 bit form,
>     I can't map colors easily) or something like that.  It is worth to
>     investigate again.  Anyway, I even wrote the simple LRU bitmap
>     font cache handling mechanism for the multi-octet character set.
> 
>   * It may be possible to store the "cached" bitmaps as 8-bit
>     grayscale, map the grays to the alpha value and render them.  But
>     still the restriction for the destForm applys.
> 
>   * The minor point is that the glyphs are stored upside down and it
>     is flipped every time.  It wouldn't save too much, but you can
>     flip the all glyphs by calling #flipAroundY beforehand.
> 
>   As you know, it is mostly about Andreas' code, so let's wait for his
> opinion:-)
> 
> -- Yoshiki
> 

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