RE: [Freetype] Arial.ttf with no anti-aliasing problem...

[Michael Jansson]

Yes, I would recommend that you always use the 'gasp' table.

Even without the patented byte code interpreter, FreeType does a fair job at
(auto-)hinting characters. There are no legal constraints in hinting
character with FT as long as FreeType is compiled without the byte code
interpreter, as far as I can tell.

On a related topic - You should also make sure that you use the embedded
bitmap tables (bloc/bdat and EBDT/EBLC) correctly. This is absolutely
essential for CJK fonts (CJK = Chinese+Japanese+Korean). Note that the gasp
table may tell you to use gray scales at a size when the bloc/bdat tables
tells you to use b/w bitmaps. For CJK fonts, you should go with the b/w
bitmaps because they were created manually and may not be based on the
outlines at all (i.e. because of "stroke reduction"). For latin fonts, you
should go with the 'gasp' data, so that you don't mix b/w and gray text of
the same point size.

Regards,
- Michael

> -----Original Message-----
> From: Brian Stell [mailto:address@hidden
> Sent: Thursday, December 13, 2001 6:14 PM
> Cc: address@hidden
> Subject: Re: [Freetype] Arial.ttf with no anti-aliasing problem...
> 
> 
> thanks for the tip!
> 
> If FreeType2 is compiled with TrueType hinting off because
> of patent issues are the values in the GASP table still
> useful?
> 
> Michael Jansson wrote:
> > 
> > We are using Freetype 2.0.5 as well, without the problem 
> you are seeing so
> > it looks like you have a few bugs to track down!?
> > 
> > btw - Are you aware of the use of the GASP table in 
> OpenType? It contains
> > information about at what sizes Mozilla is supposed to use 
> b/w, grayscale
> > and hints. Turning on hints at all sizes, or grayscale at 
> all sizes is not a
> > good idea. I do not believe that Freetype uses this table 
> for you (and it
> > should not), so you need to read this table yourself and use it
> > appropriately.
> > 
> > Some fonts, e.g. hollow/outlined, very light fonts and 
> script fonts are way
> > to light to be gray scaled at smaller sizes. You end up 
> with light gray
> > pixels that are not legible at all (e.g. the strokes of the 
> characters are
> > less than 1/8 of a pixel, making them almost white). Also, 
> hinting at _very_
> > small sizes (e.g. below 7px) usually produce bad results, 
> so a GASP table
> > would typically tell you to do grayscales but no hints 
> below a certain size.
> > In the mid range (e.g. 8-15px), you usually don't want to 
> do grayscales as
> > it produces too many gray pixels it relation to black 
> pixels, which makes
> > the glyph look fuzzy (there are some debates on this). At 
> larger size you
> > typically want both hinting and gray scaling.
> > 
> > Don't use global thresholds for all fonts. It's doesn't 
> work. Just look at
> > what Apple did with OS9 (yikes!). These thresholds are set 
> on a per font
> > basis for a reason.
> > 
> > Anyway, use the 'gasp' table if you are not already using 
> it. More info at:
> > http://www.microsoft.com/typography/otspec/gasp.htm
> > 
> > Regards,
> > em2 Solutions
> > Michael Jansson
> > 
> > > -----Original Message-----
> > > From: Brian Stell [mailto:address@hidden
> > > Sent: Thursday, December 13, 2001 12:41 AM
> > > To: address@hidden
> > > Subject: Re: [Freetype] Arial.ttf with no anti-aliasing problem...
> > >
> > >
> > > oops, I reveresed the image and bug:
> > >
> > > I posted the image here:
> > > http://bugzilla.mozilla.org/attachment.cgi?id=61480&action=view
> > >
> > > as part of this bug:
> > > http://bugzilla.mozilla.org/show_bug.cgi?id=114885
> > > >
> > > > Antoine Leca wrote:
> > > > >
> > > > > HI Niels,
> > > > >
> > > > > Niels Moseley wrote:
> > > > > >
> > > > > > I'm having problems with the Arial.ttf font at small
> > > sizes.. I am
> > > > > > currently using Freetype 2.0.5 with the bytecode
> > > interpreter enabled
> > > > > > (compiled using the Borland CBuilder 5.0 compiler).
> > > > > >
> > > > > > Even the supplied example programs ftstring and ftview
> > > display the font
> > > > > > rather badly.
> > > > >
> > > > > What is the command line you use (or in other words, what
> > > is the point
> > > > > size you ask for)?
> > > > >
> > > > > > I've tried a host of things like enabling and disabling
> > > hinting [...]
> > > > >
> > > > > Does it works? (i.e., does the drawing change?)
> > > > >
> > > > > Antoine
> > > > >
> > > --
> > > Brian Stell
> > >
> > > _______________________________________________
> > > Freetype mailing list
> > > address@hidden
> > > http://www.freetype.org/mailman/listinfo/freetype
> > >
> 
> -- 
> Brian Stell
> mailto:address@hidden
> 
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