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Re: [ft] Bytecode hinter producing bad results, seems to be a regression
From: |
Vinnie |
Subject: |
Re: [ft] Bytecode hinter producing bad results, seems to be a regression |
Date: |
Sat, 1 Jan 2011 12:20:06 -0800 (PST) |
> The function FT_Get_Gasp tells you,
> for a given ppem, whether you should
> render a glyph as monochrome
> (i.e., black-white) or with anti-aliasing.
ppem? is that what I understand to be the "font height"? Pixels per EM unit? By
monochrome I assume you mean, two intensity levels (on or off). As in, an old
school bitmap font (like Apple II+).
All of my font-drawing is anti-aliased, I'm the middle man passing the
grid-fitted control points over to another third party library that I'm using.
Why would I ever want to render a glyph as monochrome (two-color) only?
> TrueType hinting doesn't work like this. For
> monochrome rendering, the hinting engine also
> specifies how to rasterize the glyphs
> (selecting a drop-out mode, for example).
From how I interpret those words, I think monochrome rendering is not a
use-case for me.
> > I'm not using FreeType to render...just to extract
> outlines.
>
> This is tricky...
Can you elaborate? Or tell me anything I should know about that is non-obvious
or non-intuitive?
I'm actually getting really good results with the auto hinter. I can see very
clearly that it is working, and I painstakingly analyzed the output of each
glyph to make sure that things are right. Here's a screenshot:
This is using the auto-hinter, with FreeType providing the outlines and my 3rd
party library (Juce) rasterizing the vector data:
http://rawmaterialsoftware.com/download/file.php?id=186
Here is the same output, only with the autohinter turned off.
http://rawmaterialsoftware.com/download/file.php?id=185
Here's an animation for comparison
http://rawmaterialsoftware.com/download/file.php?id=184
> > And by the way, the autohinting module works pretty
> damn good!
>
> Then use it!
Okay well just to make sure I did things right, I loaded up Adobe Kaiti Std
Regular (a thin serif font) and performed the comparisons. First thing I
noticed, is the Adobe font is a hefty 16.5 megabytes, while my Neue Helvetica
is a wimpy 127 kilobytes.
I tried bytecode hinting with the Adobe font and WHOA! amazing outlines! So I
guess that my problem is not that FreeType wasn't using my bytecodes, its just
that my Helvetica didn't have them.
My intuition and eyesight tells me that a font with hints is going to look
better with the bytecode hinting than with the auto-hinter. This is definitely
the case with this beefy Adobe font.
I wish there was a flag to FT_Open_Face that says "hey use the bytecode hinter
if the font has those hints, or else use the auto-hinter."
So now I am going to trying grasping for the Gasp / Grasp whateveritis table
and see if I can get some mileage. My goal is to use bytecodes if they are
there, else use the autohinter.
Thanks
- Re: [ft] Bytecode hinter producing bad results, seems to be a regression, Werner LEMBERG, 2011/01/01
- Re: [ft] Bytecode hinter producing bad results, seems to be a regression, Vinnie, 2011/01/01
- Re: [ft] Bytecode hinter producing bad results, seems to be a regression, Werner LEMBERG, 2011/01/01
- Re: [ft] Bytecode hinter producing bad results, seems to be a regression,
Vinnie <=
- Re: [ft] Bytecode hinter producing bad results, seems to be a regression, Werner LEMBERG, 2011/01/01
- Re: [ft] Bytecode hinter producing bad results, seems to be a regression, Vinnie, 2011/01/01
- Re: [ft] Bytecode hinter producing bad results, seems to be a regression, Werner LEMBERG, 2011/01/02
- Re: [ft] Bytecode hinter producing bad results, seems to be a regression, Stuart Longland, 2011/01/02
- Re: [ft] Bytecode hinter producing bad results, seems to be a regression, Werner LEMBERG, 2011/01/03