Re: [ft] Font Height Problem

[Alex]

On Sun, Jul 28, 2019 at 11:55:02AM +0200, Werner LEMBERG wrote:
> 
> > After upgrading from version 2.6.3 to 2.9.1, I noticed that the
> > DejaVu Sans font (and some others) now appear to be taller (for the
> > same font size) than before.  For example, with DejaVu Sans Mono
> > size 9.8 pt, the height increased by 2 pixels.
> >
> > I am absolutely sure that this is due to a change in FreeType,
> > because installing the old version (2.6.3) restores the old font
> > height.
> >
> > To correct the problem in the new version, I tried enabling autohint
> > in the font configuration, and enabling AF_CONFIG_TT_SIZE_METRICS at
> > compile-time, without success.
> >
> > Can someone explain what changed in FreeType, and how to get the old
> > font height back?
> 
> I think you are referring to the following change in version 2.8.
> 
>     - Global size  metrics values  in the  `FT_Size_Metrics' structure
>       can be  different for TrueType  fonts.  Reason is that  in older
>       FreeType  versions  the  metrics  were  rounded  differently  to
>       integer pixels compared  to all other font  formats, yielding an
>       inconsistent behaviour if you used non-native hinting.  Starting
>       with this  version, global size  metrics for TrueType  fonts are
>       handled the same as other  font formats: `ascender' gets rounded
>       up,  `descender'  gets  rounded  down,  `height'  gets  normally
>       rounded, and `max_advance' gets normally rounded, too.
> 
>       If you need more precise values of (global) ascender, descender,
>       height, or  `max_advance', please take the  corresponding values
>       from the `FT_Face' structure and scale them manually.
> 
> Please adjust your font size values.
> 
> 
>     Werner

I ended up reverting commit bcc74f4dafee25ea89f1d3144646cba7e30f9908 for my 
build.  It would be great if there was a compile-time option to use the old 
metrics, which, when enabled, makes sure that ascender - descender == height.
I realize that since this is a highly subjective thing, it most likely 
shouldn't be enabled by default.
The patch I applied to the latest git version is available here: 
http://paste.debian.net/1093378/

Regards,
Alex

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