OASIS Open Document Format for Office Applications (OpenDocument) TC

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  • 1.  Defining Alternative Glyphs

    Posted 07-07-2008 20:51
    Greetings!
    
    I think there may be two separate cases that are being covered by the 
    term "alternative" glyphs.
    
    Properly speaking, Unicode points represent characters and not glyphs, 
    so any glyph associated with a character is a matter of the font you 
    choose and not an "alternative glyph." To say "alternative" glyph 
    implies there is some default glyph, which is not true. The glyphs shown 
    in the Unicode standard are illustrative only.
    
    The first case for "alternative" glyphs is where I wish to specify a 
    particular glyph for a character but other that perhaps being 
    unattractive display, the information content of the text is the same. 
    Choosing any of the Latin fonts would be a good example.
    
    The second case and I am not sure how often it would come up, would be 
    where I use a particular code point, say for Middle Egyptian, but I want 
    a particular glyph, which was used for that character in a particular 
    historic period or type of text, and not some other glyph for that 
    character. While it is true that it is the "same" character, the meaning 
    on of the text would be changed if another glyph were substituted for 
    the one I specify. Typically that sort of additional information is left 
    by Unicode to the markup layer.
    
    Rather than saying "alternative" glyphs I think it would be more 
    accurate to speak of specifying a particular glyph or set of glyphs for 
    some portion of text.
    
    Considered that way, how it that different from specifying a specific 
    font be used with some particular span of text?
    
    Hope everyone is having a great day!
    
    Patrick
    
    -- 
    Patrick Durusau
    patrick@durusau.net
    Chair, V1 - US TAG to JTC 1/SC 34
    Convener, JTC 1/SC 34/WG 3 (Topic Maps)
    Editor, OpenDocument Format TC (OASIS), Project Editor ISO/IEC 26300
    Co-Editor, ISO/IEC 13250-1, 13250-5 (Topic Maps)
    
    


  • 2.  Re: [office] Defining Alternative Glyphs

    Posted 07-07-2008 21:30

    This is a specific feature in OpenType called "Alternative Glyphs" where a single font can contain alternative glyphs for the same unicode character.

    See, for example:  http://allthingsdesigned.com/alternativeglyphs

    -Rob

    Patrick Durusau <patrick@durusau.net> wrote on 07/07/2008 04:50:40 PM:

    > Greetings!
    >
    > I think there may be two separate cases that are being covered by the
    > term "alternative" glyphs.
    >
    > Properly speaking, Unicode points represent characters and not glyphs,
    > so any glyph associated with a character is a matter of the font you
    > choose and not an "alternative glyph." To say "alternative" glyph
    > implies there is some default glyph, which is not true. The glyphs shown
    > in the Unicode standard are illustrative only.
    >
    > The first case for "alternative" glyphs is where I wish to specify a
    > particular glyph for a character but other that perhaps being
    > unattractive display, the information content of the text is the same.
    > Choosing any of the Latin fonts would be a good example.
    >
    > The second case and I am not sure how often it would come up, would be
    > where I use a particular code point, say for Middle Egyptian, but I want
    > a particular glyph, which was used for that character in a particular
    > historic period or type of text, and not some other glyph for that
    > character. While it is true that it is the "same" character, the meaning
    > on of the text would be changed if another glyph were substituted for
    > the one I specify. Typically that sort of additional information is left
    > by Unicode to the markup layer.
    >
    > Rather than saying "alternative" glyphs I think it would be more
    > accurate to speak of specifying a particular glyph or set of glyphs for
    > some portion of text.
    >
    > Considered that way, how it that different from specifying a specific
    > font be used with some particular span of text?
    >
    > Hope everyone is having a great day!
    >
    > Patrick
    >
    > --
    > Patrick Durusau
    > patrick@durusau.net
    > Chair, V1 - US TAG to JTC 1/SC 34
    > Convener, JTC 1/SC 34/WG 3 (Topic Maps)
    > Editor, OpenDocument Format TC (OASIS), Project Editor ISO/IEC 26300
    > Co-Editor, ISO/IEC 13250-1, 13250-5 (Topic Maps)
    >
    >
    > ---------------------------------------------------------------------
    > To unsubscribe from this mail list, you must leave the OASIS TC that
    > generates this mail.  Follow this link to all your TCs in OASIS at:
    >
    https://www.oasis-open.org/apps/org/workgroup/portal/my_workgroups.php
    >


  • 3.  Re: [office] Defining Alternative Glyphs

    Posted 07-07-2008 21:57
    Rob,
    
    robert_weir@us.ibm.com wrote:
    >
    > This is a specific feature in OpenType called "Alternative Glyphs" 
    > where a single font can contain alternative glyphs for the same 
    > unicode character.
    >
    Yes, but that is the same point that I made from a different perspective.
    
    With OpenType you have a font and hence a "default" glyph, so specifying 
    an "alternative" glyph makes sense. But that presumes the use of an 
    OpenType font which has that capability.
    
    My point was that in the abstract there is no default glyph, only the 
    Unicode character point. For more you either have to rely on font 
    technology (thanks for the OpenType reminder) or the markup layer. The 
    point being that the support does not reside in the Unicode encoding.
    
    Hope you are having a great day!
    
    Patrick
    
    
    > See, for example:  http://allthingsdesigned.com/alternativeglyphs
    >
    > -Rob
    >
    > Patrick Durusau 


  • 4.  Re: [office] Defining Alternative Glyphs

    Posted 07-07-2008 22:02

    Patrick Durusau <patrick@durusau.net> wrote on 07/07/2008 05:56:35 PM:

    > Rob,
    >
    > robert_weir@us.ibm.com wrote:
    > >
    > > This is a specific feature in OpenType called "Alternative Glyphs"
    > > where a single font can contain alternative glyphs for the same
    > > unicode character.
    > >
    > Yes, but that is the same point that I made from a different perspective.
    >


    Then I think we are in agreement.

    > With OpenType you have a font and hence a "default" glyph, so specifying
    > an "alternative" glyph makes sense. But that presumes the use of an
    > OpenType font which has that capability.
    >
    > My point was that in the abstract there is no default glyph, only the
    > Unicode character point. For more you either have to rely on font
    > technology (thanks for the OpenType reminder) or the markup layer. The
    > point being that the support does not reside in the Unicode encoding.
    >
    > Hope you are having a great day!
    >
    > Patrick


    Right.  This is purely an OpenType font feature.

    -Rob


  • 5.  Re: [office] Defining Alternative Glyphs

    Posted 07-07-2008 22:17
    Rob,
    
    Ah, so the question is one of how a format indicates some OpenType 
    feature that should be invoked, assuming the application supports 
    OpenType? In other words, how the application interacts with OpenType 
    isn't our concern but simply indicating that it should and what 
    information it should convey are.
    
    Hope you are having a great day!
    
    Patrick
    
    robert_weir@us.ibm.com wrote:
    >
    > Patrick Durusau 


  • 6.  Re: [office] Defining Alternative Glyphs

    Posted 07-07-2008 22:44
    
    
    
    
    I’d like to suggest if this is done, some form of anti-phishing operation is established to prevent people from spoofing URL’s using glyphs.  IRI’s can be used to trick people.

    Duane


    On 07/07/08 2:56 PM, "Patrick Durusau" <patrick@durusau.net> wrote:

    Rob,

    robert_weir@us.ibm.com wrote:
    >
    > This is a specific feature in OpenType called "Alternative Glyphs"
    > where a single font can contain alternative glyphs for the same
    > unicode character.
    >
    Yes, but that is the same point that I made from a different perspective.

    With OpenType you have a font and hence a "default" glyph, so specifying
    an "alternative" glyph makes sense. But that presumes the use of an
    OpenType font which has that capability.

    My point was that in the abstract there is no default glyph, only the
    Unicode character point. For more you either have to rely on font
    technology (thanks for the OpenType reminder) or the markup layer. The
    point being that the support does not reside in the Unicode encoding.

    Hope you are having a great day!

    Patrick


    > See, for example:  http://allthingsdesigned.com/alternativeglyphs
    >
    > -Rob
    >
    > Patrick Durusau <patrick@durusau.net> wrote on 07/07/2008 04:50:40 PM:
    >
    > > Greetings!
    > >
    > > I think there may be two separate cases that are being covered by the
    > > term "alternative" glyphs.
    > >
    > > Properly speaking, Unicode points represent characters and not glyphs,
    > > so any glyph associated with a character is a matter of the font you
    > > choose and not an "alternative glyph." To say "alternative" glyph
    > > implies there is some default glyph, which is not true. The glyphs
    > shown
    > > in the Unicode standard are illustrative only.
    > >
    > > The first case for "alternative" glyphs is where I wish to specify a
    > > particular glyph for a character but other that perhaps being
    > > unattractive display, the information content of the text is the same.
    > > Choosing any of the Latin fonts would be a good example.
    > >
    > > The second case and I am not sure how often it would come up, would be
    > > where I use a particular code point, say for Middle Egyptian, but I
    > want
    > > a particular glyph, which was used for that character in a particular
    > > historic period or type of text, and not some other glyph for that
    > > character. While it is true that it is the "same" character, the
    > meaning
    > > on of the text would be changed if another glyph were substituted for
    > > the one I specify. Typically that sort of additional information is
    > left
    > > by Unicode to the markup layer.
    > >
    > > Rather than saying "alternative" glyphs I think it would be more
    > > accurate to speak of specifying a particular glyph or set of glyphs for
    > > some portion of text.
    > >
    > > Considered that way, how it that different from specifying a specific
    > > font be used with some particular span of text?
    > >
    > > Hope everyone is having a great day!
    > >
    > > Patrick
    > >
    > > --
    > > Patrick Durusau
    > > patrick@durusau.net
    > > Chair, V1 - US TAG to JTC 1/SC 34
    > > Convener, JTC 1/SC 34/WG 3 (Topic Maps)
    > > Editor, OpenDocument Format TC (OASIS), Project Editor ISO/IEC 26300
    > > Co-Editor, ISO/IEC 13250-1, 13250-5 (Topic Maps)
    > >
    > >
    > > ---------------------------------------------------------------------
    > > To unsubscribe from this mail list, you must leave the OASIS TC that
    > > generates this mail.  Follow this link to all your TCs in OASIS at:
    > > https://www.oasis-open.org/apps/org/workgroup/portal/my_workgroups.php
    > >

    --
    Patrick Durusau
    patrick@durusau.net
    Chair, V1 - US TAG to JTC 1/SC 34
    Convener, JTC 1/SC 34/WG 3 (Topic Maps)
    Editor, OpenDocument Format TC (OASIS), Project Editor ISO/IEC 26300
    Co-Editor, ISO/IEC 13250-1, 13250-5 (Topic Maps)


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  • 7.  Re: [office] Defining Alternative Glyphs

    Posted 07-08-2008 06:49
    I think I have got a rough understanding what alternative glyphs are, 
    but I still have a couple of questions whose answers would help to get 
    an understanding what supporting alternative glyphs would mean for ODF?
    
    How are the alternative glyphs used from user perspective? Do I enter a 
    Unicode character, let's say a "g". The rendering engine then detects 
    that there are multiple glyphs available for the Unicode character, and 
    asks me which to show? Or does it select one for me that I can 
    overwrite, similar to how I can make a character bold? Or does it select 
      one based on some algorithms, and this is used?
    
    In the first two cases we would probably need a new formatting property. 
    In the last case alternative glyphs could be supported by application 
    without any change to ODF itself.
    
    How many alternative glyphs may exist for a Unicode character? Could 
    there be more than two glyphs for a character, and is one of these the 
    default?
    
    How are the alternative glyphs identified? Do they have names? If there 
    is only a default glyph and an alternative glyph a boolean attribute may 
    be sufficient. Otherwise there must be a way to identify the alternative 
    glyphs.
    
    Best regards
    
    Michael
    
    
    
    Duane Nickull wrote:
    > I’d like to suggest if this is done, some form of anti-phishing 
    > operation is established to prevent people from spoofing URL’s using 
    > glyphs.  IRI’s can be used to trick people.
    > 
    > Duane
    > 
    > 
    > On 07/07/08 2:56 PM, "Patrick Durusau" 


  • 8.  Re: [office] Defining Alternative Glyphs

    Posted 07-07-2008 21:44

    I'm reminded of an related set of proposals I heard back in 2006 at a KDE conference.

    Tim Eves, at SIL International, gave a presentation on the need to add "font feature" and "alternative glyph" support to ODF, in order to better support minority languages.

    You can see his presentation here:  http://conference2006.kde.org/codingmarathon/opendocumentday.php

    I hesitate to go too far down the "desktop publishing" route, but if there is a good case for supporting these OpenType features, then I think we should consider it.

    -Rob


  • 9.  Re: [office] Defining Alternative Glyphs

    Posted 07-08-2008 07:47
      |   view attached



  • 10.  Re: [office] Defining Alternative Glyphs

    Posted 07-08-2008 08:47
    2008/7/8 Thomas Zander 


  • 11.  Re: [office] Defining Alternative Glyphs

    Posted 07-08-2008 09:36
    Dave,
    
    Le 8 juil. 08 à 10:46, Dave Pawson a écrit :
    
    > 2008/7/8 Thomas Zander 


  • 12.  Re: [office] Defining Alternative Glyphs

    Posted 07-08-2008 12:45
    Hi Thomas,
    
    thank you very much for your explanations. What is still not clear to me 
      is how the selection of a particular glyph is controlled. See my 
    questions below.
    
    Thomas Zander wrote:
    > On Monday 7. July 2008 23:45:05 robert_weir@us.ibm.com wrote:
    >> I'm reminded of an related set of proposals I heard back in 2006 at a KDE
    >> conference.
    >>
    >> Tim Eves, at SIL International, gave a presentation on the need to add
    >> "font feature" and "alternative glyph" support to ODF, in order to better
    >> support minority languages.
    > 
    > The initial proposal for Alternate glyps on this list came from me, so I think 
    > I should tell you why I suggested it :)
    > 
    > I like explaining things in a usecase, which would help here already.
    > 
    > If I have some text in small-caps (see attached image, second row) you will 
    > notice that the glyphs used for the digits look different from the full caps 
    > ones.  The 3 is below the baseline, for example.
    > Using these old style figures in ODF is currently problematic. They don't have 
    > unique unicode code points and since the advent of openType and fonts with 
    > thousands of glyphs, its no longer feasible to use font name.
    > In the days that a postscript font could hold just 256 glyphs the solution was 
    > simple; use a different font for the alternate glyphs, but using opentype we 
    > have to use the same font but specify that we want a specific font-feature 
    > for this character.
    
    My understanding is that an opentype fonts may provide glyphs to be used 
    for small caps in addition to the regular glyphs, and that both kind of 
    glyphs actually share a Unicode character. That is, given a certain 
    Unicode character, an opentype fonts provides (at least) two glyphs that 
    may be displayed. The regular glyph, and one for small caps. But how is 
    it controlled which glyph is used? ODF does already have a formatting 
    property for small caps. So, my assumption would be that an application 
    that does support opentype would simply take the small-caps glyphs if 
    the formatting property for small caps is present. But this would not 
    require any change to ODF but would be just application logic. So it may 
    be the case that I am missing something, or that this is example is too 
    simple.
    
    > 
    > This is all for latin fonts, things get much more complex for minority fonts, 
    > so I won't explain that here. The simplest is to choose a slashed-zero in 
    > some cases, which is a user choice for the glyph, but manually forcing the 
    > usage of a ligature is another good example.
    
    How would one manually force the use of a particular glyph? That is, 
    what information must be present in an ODF document so that the an ODF 
    rendering engine can choose a particular glyph?
    
    Best regards
    
    Michael
    
    > 
    > In my opinion this feature is needed for making that last step from nice 
    > looking text to professional looking text.
    > 
    > 
    > 
    > ------------------------------------------------------------------------
    > 
    
    
    -- 
    Michael Brauer, Technical Architect Software Engineering
    StarOffice/OpenOffice.org
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