RE: [ft] Differences between FT 2.3.9 & 2.4.4 that may cause poor rendering quality

[John C. Turnbull]

Actually, I have rebuilt FreeType and VL after un-defining
TT_CONFIG_OPTION_BYTECODE_INTERPRETER and things have improved.  However, we
are still not quite back to the FT 2.3.9 rendering quality so perhaps
something more is in play here.  Any idea what that may be?

Another updated screenshot is attached.

-JCT

-----Original Message-----
From: Werner LEMBERG [mailto:address@hidden 
Sent: Sunday, 6 March 2011 17:57
To: address@hidden
Cc: address@hidden
Subject: Re: [ft] Differences between FT 2.3.9 & 2.4.4 that may cause poor
rendering quality


> I use an OpenGL library called Visualization Library which utilises
> FreeType in providing the font rendering information in its text
> renderer.  In upgrading to their latest version I noticed a
> significant degradation in the quality of the rendered text and the
> only difference in this area with respect to VL was that they
> started using FreeType 2.4.4 instead of 2.3.9 that they had used
> previously.

In version 2.4.0 the bytecode interpreter (for TTFs) has been
activated as the default.  Looking at the large rendering differences
of your images, I suppose this is what you experience.

> Does anyone know if any special compiler flags or options need to be
> set when compiling FT 2.4.4 or some other reason why text rendering
> quality would be worse under the latest version?  It looks as though
> some degree of antialiasing has been lost perhaps.

The right way IMHO is to call FT_Load_Glyph with
FT_LOAD_FORCE_AUTOHINT.  If that is not possible for you, undefine
TT_CONFIG_OPTION_BYTECODE_INTERPRETER while compiling FreeType.


    Werner

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