[PATCH] gdi32: Antialias fake bold or italic fonts regardless of GASP table.

[Nikolay Sivov]

On 29.09.2015 10:27, Ken Thomases wrote:
> If the client requests a bold typeface of a font which doesn't actually provide
> a bold typeface, Wine fakes it using FT_Outline_Embolden().  Likewise, it fakes
> italic by apply a shear transform.
>
> These techniques work passably when antialiasing is in effect.  However, when
> antialiasing is disabled at small sizes by the font's GASP table, the results
> are horrible.  The glyphs have many spurs or appear furry.
>
> On the theory that fonts disable antialiasing via the GASP table at small sizes
> because hinting should produce pixel-perfect results and that that rationale is
> voided by the application of procedural bolding or italicizing, we ignore the
> GASP table and always antialias for fake bold or italic fonts.

Hi.

I think in some cases it makes sense to disable emboldening entirely, 
because as you said rendered images are ruined, but not only by moving 
outline points around. Some fonts, I think it applies to CJK fonts more 
than others, have prerendered embedded bitmaps to improve legibility in 
small sizes, but when we fake bold or oblique styles we disable bitmaps 
explicitly, and this goes against the idea font designer had in mind. 
Enabling AA could probably help, but not necessary as well as using 
bitmaps. Of course this has to be tested on windows using fonts that 
provide bitmaps, to see if they respond to bold simulation at all at 
sizes that are supposed to use bitmaps.

P.S. unrelated but still, since faked styles effectively invalidate the 
job hinting does, maybe it makes sense to try to load with 
FT_LOAD_NO_HINTING in such cases as it's supposed to be faster, and I 
think we disable outline caching for simulated fonts. Just a thought, I 
haven't tried it myself.

>
> There is a new registry setting to disable this and revert to the previous
> behavior:
>
> [HKEY_CURRENT_USER\Software\Wine\Fonts]
> "AntialiasFakeBoldOrItalic"="n"

What's a problem of ignoring GASP and following global AA settings in 
such cases? I mean are you aware of any problems that could potentially 
need such switch?

>
> Signed-off-by: Ken Thomases <ken at codeweavers.com>