Re: [Freetype] FT 2.0.9 rendering for some glyphs

[David Turner]

Hi Vadim,

Vadim Plessky a écrit :
> 
> 1) testcases (using HTML) for Arial and TNR attached (5k all together)
> 2) screenshots uploaded to this location:
> 
> http://htmltests.newmail.ru/test/ft209-arial.png
> http://htmltests.newmail.ru/test/ft209-TNR.png
> 
> So, as you can see, TNR (as was expected) has much worse rendering, and text
> at 10px-12px sizes is almost unreadbale.
> Plus, number of artefacts increased (comparing to Arial)
> 
> BTW: I also noticied that (in Arial) "Ð" and "Ç" are more narrow than "Î" - to
> my best knoledge, they should have equal widths (according to native Cyrillic
> reader, and general font definitions for those glyphs)
>
Thanks for the images. They demonstrate two kinds of weaknesses in the 
auto-hinter:

  - apparently, some stems are not properly recognized and hinted,
    which creates strange artefacts like un-aligned or disappearing
    bars. I'll need to investigate this in more details

  - generally speaking, serifed fonts like TNR are not processed too well.
    the problem being that the auto-hinter detects too many potential
    "hint" zones (due to the serifs), and try to align them all, which
    isn't easy (especially when many of the stems overlap).

there are several ways to fix all of these, but they require quite a
bit of experimentation. I'd like to note that I won't start working on
this before 2.2 is out (which should be pretty soon I hope).


> Testing environment:
> * Konqueror 3.0/KDE 3.0
> * QT 3.0.1
> * XFree86 4.2, anti-aliasing for 8pt-12pt font sizes in Turned On (using
> XftConfig)
> * FreeType 2.0.9 from Mandrake Cooker (I guess Bytecode Interpreter is Turned
> Off - at least that was the case with FT 2.0.6)
>
Yes, it seems so !
 
Thanks

- David Turner
- The FreeType Project