Re: [ft-devel] glyph metrics don't match bitmap size (2.8.1)

[Alexei Podtelezhnikov]

On Wed, Sep 20, 2017 at 4:08 PM, Alexei Podtelezhnikov
<address@hidden> wrote:
>> https://www.freetype.org/freetype2/docs/reference/ft2-base_interface.html#FT_LOAD_BITMAP_METRICS_ONLY
>> I proposed expanding FT_LOAD_BITMAP_METRICS_ONLY flag to work for
>> outline glyphs as well. If I understand correctly this should help
>> with GPU font atlases, rectangle packing, whatever is the Skia
>> issue... The stars aligned for the recipients list.
>
> Its easier said than done. The renderers do not see all load_flags but
> only the 4-bit (0-5 actually) render_mode enum. I can pass the
> FT_LOAD_BITMAP_METRICS_ONLY flag to FT_Render_Glyph at bit 5 or above
> to force the renderers to bail once the bitmap metrics are set. Can I
> set a bits in enum? This technically changes the type from
> FT_Render_Mode to int. Unfortunately, the enum persists deep inside.
> Any other ideas?

Another idea is to pretend that the bitmap dimensions is a special
kind of metrics and calculate them in FT_Load_Gyph in most cases
except FT_LOAD_NO_SCALE maybe. Then FT_Render_Glyph would just take
the measurements as is if render mode matches the pixel mode, or
recalculate them accordingly otherwise.