bugThe FreeType Project - Bugs: bug #47064, FT_Get_Advance() should respect...

 
 

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bug #47064: FT_Get_Advance() should respect variations

Submitter:  None
Submitted:  Fri 05 Feb 2016 08:09:12 AM UTC
   
 
Severity:  3 - Normal Item Group:  Incorrect behaviour
Status:  Fixed Privacy:  Public
Assigned to:  wl Open/Closed:  Closed
Planned Release:  2.6.3

Fri 05 Feb 2016 11:52:41 AM UTC, comment #1: 

Fixed in git, thanks.

Werner LEMBERG <wl>
Group administrator
Fri 05 Feb 2016 08:09:12 AM UTC, original submission:  

Currently, FT_Get_Advance() does not respect variations. For example, with Apple's Skia.ttf font, FreeType correctly interpolates the glyph shapes including phantom points. However, FT_Get_Advance() always returns metrocs for the base font, without taking variations into account.

Here's a (pretty ugly, sorry) ad-hoc program to visualize the effect. If you click the shaping checkbox, it will call HarfBuzz for shaping, which in turn invokes FT_Get_Advance(). With the checkbox clicked, the glyphs are positioned as if all design axes were set to 1.0.
https://github.com/brawer/playground/tree/master/fonts/atm

For faster speed, it might be possible to implement a special 'gvar' decoder in FreeType that only decodes the phantom points without loading the entire glyph.

-- Sascha

Sascha Brawer, -email is unavailable-

Anonymous

 

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    Follow 4 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2016-02-05 wl StatusNone Fixed
        Assigned toNone wl
        Open/ClosedOpen Closed
        Planned ReleaseNone 2.6.3

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