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Re: [ft] Emboldening and then hinting a glyph with FreeType
From: |
Werner LEMBERG |
Subject: |
Re: [ft] Emboldening and then hinting a glyph with FreeType |
Date: |
Fri, 20 Jan 2017 08:57:35 +0100 (CET) |
> Is there any other possibility to "hint" transformed glyphs? For
> example, by calling hinting function directly or something like
> that?
Well, the TrueType hinting mechanism is tightly bound to the outline
and its rasterization to the grid depending on the selected PPEM.
Basically, it is *not* possible to apply TrueType hints after a
transformation while yielding sensible results. Nikolaus tries to
replace the horizontal hinting with horizontal emboldening (note the
word `replace'), but even this is quite a complicated issue; right
now, he is stuck.
> Also I have noticed that proper scaling could help to improve font
> displaying dramatically. If x-height is aligned to pixel grid, the
> result looks much like "light hinting" even without hinting at all.
Indeed, this is what the light hinter mainly does: it scales the
glyphs vertically so that the x height gets aligned to the grid, then
it shifts the outlines so that horizontal tangents lie on the grid
also (if possible and sensible).
> I appreciate any thoughts and advice on this.
I fear that I can't give much advice here.[*]
Werner
[*] I assume that you know that FreeType produces *coverage* bitmaps,
this is, you have apply proper alpha blending and gamma
correction.
https://www.freetype.org/freetype2/docs/reference/ft2-base_interface.html#FT_Render_Glyph