Re: Panther PUA behavior

From: Dean Snyder (
Date: Tue Feb 03 2004 - 00:20:05 EST

  • Next message: D. Starner: "Re: Panther PUA behavior"

    Deborah Goldsmith wrote at 2:14 PM on Tuesday, January 13, 2004:

    >On Jan 13, 2004, at 1:23 PM, Dean Snyder wrote:
    >> For what it's worth, I have seen a difference between Jaguar
    >> and Panther in how Mac OS X treats characters
    >> in the PUA - in Panther they commonly show up with the indeterminate
    >> glyph symbol even when a suitable font, that worked in Jaguar, is
    >> installed.
    >FYI, Panther was changed to not do font substitution in the user part
    >of the PUA (it still does it in the corporate part). This was because
    >different fonts can use the same PUA code point for different things
    >(and do; this was not a hypothetical problem but one we have seen in
    >practice). The idea going forward is that use of PUA code points needs
    >to be accompanied by an explicit font specification. Picking the first
    >font you find for a PUA code point does not seem like the right
    >approach to us.
    >On Jan 13, 2004, at 5:47 PM, John Hudson wrote:
    >> If you have an existing document that already specifies a font, it
    >> should be fine. I believe Deborah's point is that Apple will no longer
    >> try to guess the best font to use when PUA codepoints are entered
    >> using another font or are found in a plain text document.
    >Yes, that's exactly right.

    I hope Apple re-thinks this, because it makes PUA useless in plain text.

    Apple may think that "picking the first font you find for a PUA code
    point does not seem like the right approach", but it is a whole lot
    better than displaying the indeterminate glyph symbol for everything in
    PUA plain text, primarily because, in the pick-the-first-font model, end
    users get to control display behavior by re-assigning PUA code points or
    de-installing fonts, whereas they have no control and no visual
    information if the OS just gives up.

    So, for example, in Jaguar I had been using a PUA-based cuneiform font
    for file and folder names, which I found to be very nice and very useful;
    but now in Panther there isn't quite the same level of visual information
    ;-) (See the attached image.)


    Dean A. Snyder

    Assistant Research Scholar
    Manager, Digital Hammurabi Project
    Computer Science Department
    Whiting School of Engineering
    218C New Engineering Building
    3400 North Charles Street
    Johns Hopkins University
    Baltimore, Maryland, USA 21218

    office: 410 516-6850


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