From: Leonard Rosenthol (leonardr@lazerware.com)
Date: Tue May 28 2002 - 13:48:57 EDT
At 9:21 AM -0700 5/28/02, Joaquin Cuenca Abela wrote:
> > I am no expert on these things at all, but Leonard
>> is,
>
>neither me. I'm more than eager to ear Leonard
>advices here.
I sent a response - let me know if you didn't get it...
>The scaling from the "high-size" to the "low-size"
>(say 12 points) has nothing to do with the resolution
>that we'll use in the device. It's a non-linear
>scaling that typographers do to make the font more
>readable at tiny sizes (making the font relatively
>wider at low physical sizes). That way, for instance,
>the "m" get the steams clearly readable even at low
>sizes.
This isn't as true with outline fonts as it once was with
bitmapped fonts. With outlines, the same vector data (and glyph
metrics) is used regardless of size - it is simply transformed to a
new size. HOWEVER, the font author may have included "hinting" for
smaller sizes, so that things (such as the "m" stems look better).
>So the metrics for a font at 12points can be (will be)
>different from the metrics of the same font at
>240points.
Better not be! Metrics of an outline font are computed by
taking the base metric stored in the font format and multiplying by
size (and a few other little things).
>Now, once you have the font at 12points, you still
>have to render it to your device.
That's 12pts at 72dpi. If the dpi changes, then you need to
request the font to be re-rendered at a different
size/scale/transform. FreeType handles this for you by simply
specifying output resolution and/or transformation when you request
the glyph bitmap.
>In your screen, things are different. The font have
>to be grid-fitted to a low resolution device, and that
>creates artifacts, that good hinted fonts should
>remove.
Grid-fitting is a different problem and AFAIK, AbiWord
doesn't deal with it right now. And again, FT2 will address this
for us with the hinting and anti-alias algorithms.
LDR
-- --------------------------------------------------------------------------- Leonard Rosenthol <mailto:leonardr@lazerware.com> <http://www.lazerware.com>
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