[Devel] Curious regression in ftview on MacOS X

[Steve Hartwell]

I recently built ftview on MacOS X and have discovered that the 
antialiased view (the default) is showing bluish color tinges around 
the edges of the glyphs instead of grayscale antialiasing.

I saw this problem awhile back when I was adding rgb32 support to the 
mac version of the graphics surface, and found it to be due to the 
assumption in the existing mono- and gray-to-RGB32 code that RGB bytes 
are stored first, with the unused byte following (i.e. RGBx).  Since on 
MacOS X, the GDI requires that for RGB32, the unused byte must come 
first (i.e. xRGB), the easiest solution was to offset the MacOS X GDI 
base address by -1; it was a bit of a hack, but legal, and it worked 
without touching the rest of the ftview code.

Well, now 256-gray glyphs are rendered with the GBlender code, which is 
very nice, but its code stores RGB32 as xRGB already, so my GDI offset 
is wrong for that case.

However, the original mono-to-RGB32 conversion is still used when 
antialiasing is turned off, which still assumes an RGBx alignment.

So we probably ought to resolve this; suggestions?

Regards,

Steve Hartwell
http://stevehartwell.home.comcast.net/proj/fontinspector

PS.: There are two bugs in grblit.c:blit_mono_to_rgb32(), lines 453 and 
459, which should be "_read++", without which the non-antialiased glyph 
doesn't render properly anyway; my apologies for not having noticed 
this when submitting the original patch.