Re: Font, layout units et al.

From: Leonard Rosenthol (
Date: Tue May 28 2002 - 13:48:57 EDT

  • Next message: Patrick Lam: "Re: ispell and aspell"

    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

            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

            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

            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.


    Leonard Rosenthol                            <>

    This archive was generated by hypermail 2.1.4 : Tue May 28 2002 - 13:53:25 EDT