Re: [ft-devel] Make FT_GlyphSlot_Embolden standard API?

[Chia I Wu]

On Fri, May 13, 2005 at 05:33:54PM +0900, address@hidden wrote:
> >> * switch to enable/disable changing glyph metrics in embolding
> >> * switch to enable/disable embolding of bitmap font
> >I think glyph metrics should be changed automagically.
> 
> Umm, yes, so, when fixed-width font is embolded, the result can be
> proportional? I think there are many X applications (terminal emulators
> and curses applications may be typical examples) which assumes/expects
> the Hanzi glyphs are always fixed to full-width, regardless with
> bold/oblique style. Therefore (if i'm not misunderstanding) switch
> to enable/disable changing glyph metrics is required.
> 
If we don't change glyph metrics accordingly, won't the script be
rendered wrongly (e.g. two glyphs comes too close)?

I think we should always keep glyph metrics correct, i.e. since "width",
"height", "bearings" are changed, we should keep it up-to-date. Then
there leaves some flexibility in "advance".

I don't know how applications determine whether a font is monospace or
not. Fontconfig uses "advance" to do so and I think it's reasonable. So
maybe we can let user set whether they want fixed advance or not.

> >Bitmap glyph should be emboldened automatically too.
> >As we are synthesizing, you know you can't expect a high-quality result,
> >thus it makes no difference which format the glyph is in.
> 
> Yet I've not tested in detail, I have no strong objection at present.
> One of my anxiety is: in some UCS collective fonts, bitmap data is
> provided to partial glyphs. For example, TrueType font bundled in AIX
> has bitmap data for Hanzi, but no bitmap data for Bopomofo.
You are worrying about inconsistency? When one tries to embolden a mixed
sequence of both outline and bitmap glyphs, yes, he gets inconsistency
, since we use different algorithms for both kinds of glyphs. But if we
embolden only outline glyphs, he still gets inconsistency. Furthermore,
we are not forcing he to embolden every glyph. He can just skip bitmap
glyphs.
> 
> >> * choosing embolding algorithm
> >> 
> >BTW, I have done some experiment to embolden a bitmap glyph, by printing
> >the same glyph severial times (depending on strength), with starting
> >point shift to the right by 1 pixel each time. The result is ok.
> 
> How do you think of embolding procedure for high-resolution output
> (like printing device) and vector device?
Well, I don't know how that work. Does it make a big difference? (I am
really asking :P)
> 
> Regards,
> mpsuzuki