Re: Why people still want to encode precomposed letters

From: Hans Aberg (
Date: Sun Nov 23 2008 - 06:37:35 CST

  • Next message: Don Osborn: "RE: Why people still want to encode precomposed letters"

    On 23 Nov 2008, at 13:08, philip chastney wrote:

    >> I experimented a bit, one and a half decade ago, with creating the
    >> Swedish letter (U00C5) in TeX, which then was necessary to do by
    >> combining an A writing a small circle above it. It turns out to be
    >> quite complicated, because characters may have a slant, to center
    >> the circle on. So one needs to have a more advanced font model,
    >> which for each character contains information where to position
    >> combining characters. I am not sure about the state of this matter
    >> - one can have Chinese fonts that combine the radicals - so it
    >> ought to be possible to do for the combining characters as well.
    >> as you say, combining marks are not always "centred"
    > how about changing the terminology, and saying combining marks are
    > placed on the "main vertical axis"?
    > with roman-style letters, the main axis would normally be truly
    > vertical, with italic-style letters the main axis might be anything
    > from 12 to 18 off the vertical
    > note that, with italic-style letters, unless it's a perfect circle
    > showing no contrast, the circle itself may also need to be slanted

    It is in fact even more complicated, because even it is called
    one can have, as a matter of rendering style, the ring dipping into
    the main character, even being partly obscured. So one may not get
    around recognizing certain combination and provide special designs
    for those.


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