Background: running gvum 7.1.135 on OS X version 10.4.10
Using font DejaVuAgainSansMono.jjt, which is DejaVuSansMono.jjt expanded with Deseret Alphabet (supplementary area) glyphs.
In .gvimrc, if I specify
set nomacatsui anti guifont=DejaVuAgain\ Sans\ Mono:h14
then gvim renders Roman glyphs, from the Basic Multilingual Plane, well, but the Deseret glyphs (from the supplementary area) are rendered as sequences of Roman glyphs and spaces. Completely garbled
If I change .gvimrc to
set macatsui anti guifont=DejaVuAgain\ Sans\ Mono:h14
(i.e. if I specify macatsui rather than nomacatsui, and this is the only change) then I see Roman and Deseret glyphs rendered as expected, but all the glyphs look scraggly on the screen.
Can anyone explain to me what is happening here and how I might get sharp renderings of both BMP and supplementary glyphs?
> Background: running gvum 7.1.135 on OS X version 10.4.10
> Using font DejaVuAgainSansMono.jjt, which is DejaVuSansMono.jjt > expanded with Deseret Alphabet (supplementary area) glyphs.
> In .gvimrc, if I specify
> set nomacatsui anti guifont=DejaVuAgain\ Sans\ Mono:h14
> then gvim renders Roman glyphs, from the Basic Multilingual Plane, > well, > but the Deseret glyphs (from the supplementary area) are rendered as > sequences of Roman glyphs and spaces. Completely garbled
> If I change .gvimrc to
> set macatsui anti guifont=DejaVuAgain\ Sans\ Mono:h14
> (i.e. if I specify macatsui rather than nomacatsui, and this is the > only change) > then I see Roman and Deseret glyphs rendered as expected, but all the > glyphs > look scraggly on the screen.
> Can anyone explain to me what is happening here and how I might get > sharp renderings of both BMP and supplementary glyphs?
I don't expect this to work at all without 'macatsui'. My experience is that vim assigns not enough horizontal space to supparea glyphs (is that what "scraggly" means). This is because vim needs a monospaced font for correct display, and the supparea glyphs are too wide for the monospaced width of the current font (this can happen because the font is not monospaced for all glyphs or because some glyphs are subsitituted from other fonts, because they are missing in the current font). This also does happen for some BMP glyphs (U+0E5B ๛ for example, and many others).
One way that _might_ work is to get MacVim ( http://code.google.com/p/ macvim/ ), set its MMCellWidthMultiplier user default to something a bit larger than 1 (do `defaults write org.vim.MacVim MMCellWidthMultiplier 1.3`, see http://code.google.com/p/macvim/wiki/ UserDefaults for more information) and use that. This widens up all glyphs, but perhaps it's good enough.
I don't know if it's possible at all to have a monospaced font that works for all writing systems. The Right Thing is probably to make vim work with variable width fonts, but I guess that's very very complicated and won't happen :-\
> One way that _might_ work is to get MacVim ( http://code.google.com/ > p/macvim/ ), set its MMCellWidthMultiplier user default to > something a bit larger than 1 (do `defaults write org.vim.MacVim > MMCellWidthMultiplier 1.3`, see http://code.google.com/p/macvim/ > wiki/UserDefaults for more information) and use that. This widens > up all glyphs, but perhaps it's good enough.
The MacVim looks great but as a newbie I'm not sure how to get it to work from the command window. I have the mvim.htm file but not sure where to save it or what to name it to etc. Any advice would be much appreciated. Thanks, Joe
Nico Weber <nicolaswe...@gmx.de> wrote: > One way that _might_ work is to get MacVim ( http://code.google.com/ > p/macvim/ ), set its MMCellWidthMultiplier user default to > something a bit larger than 1 (do `defaults write org.vim.MacVim > MMCellWidthMultiplier 1.3`, see http://code.google.com/p/macvim/ > wiki/UserDefaults for more information) and use that. This widens > up all glyphs, but perhaps it's good enough.
>> set nomacatsui anti guifont=DejaVuAgain\ Sans\ Mono:h14
>> then gvim renders Roman glyphs, from the Basic Multilingual Plane, >> well, >> but the Deseret glyphs (from the supplementary area) are rendered as >> sequences of Roman glyphs and spaces. Completely garbled
>> If I change .gvimrc to
>> set macatsui anti guifont=DejaVuAgain\ Sans\ Mono:h14
>> (i.e. if I specify macatsui rather than nomacatsui, and this is the >> only change) >> then I see Roman and Deseret glyphs rendered as expected, but all the >> glyphs >> look scraggly on the screen.
>> Can anyone explain to me what is happening here and how I might get >> sharp renderings of both BMP and supplementary glyphs?
> I don't expect this to work at all without 'macatsui'. My experience > is that vim assigns not enough horizontal space to supparea glyphs > (is that what "scraggly" means).
Hello Nico,
Thanks for the message. With 'nomacatsui' I see sharp, legible glyphs. By "scraggly" I mean thin glyphs, with thin, shaky lines. These "scraggly" glyphs are legible, but they look bad.
> This is because vim needs a > monospaced font for correct display, and the supparea glyphs are too > wide for the monospaced width of the current font (this can happen > because the font is not monospaced for all glyphs or because some > glyphs are subsitituted from other fonts, because they are missing in > the current font). This also does happen for some BMP glyphs (U+0E5B > ๛ for example, and many others).
The Deseret glyphs (Unicode block starting U+10400) are alphabetic and fit into the same width as the other glyphs. As far as I can tell, the font I'm using is monowidth. When merging the Deseret glyphs, I first reset their width to the width of the characters in the existing font (DejaVu Sans Mono). So whatever my problem is, it is not that the new glyphs I've added are too wide, or wider than the original glyphs.
> One way that _might_ work is to get MacVim ( http://code.google.com/p/ > macvim/ ), set its MMCellWidthMultiplier user default to something a > bit larger than 1 (do `defaults write org.vim.MacVim > MMCellWidthMultiplier 1.3`, see http://code.google.com/p/macvim/wiki/ > UserDefaults for more information) and use that. This widens up all > glyphs, but perhaps it's good enough.
As just explained, too-wide glyphs are not the problem, as far as I can tell.
> I don't know if it's possible at all to have a monospaced font that > works for all writing systems. The Right Thing is probably to make > vim work with variable width fonts, but I guess that's very very > complicated and won't happen :-\
For my current work, I just need a few alphabets (Roman, Shavian, Deseret) that can all fit in a reasonable width. I don't need "all writing systems". I am (as far as I can tell) using a monowidth font. The complication is that Shavian and Deseret are in the supplementary area, and Vim 7.1 just recently added patch 116 that is supposed to allow glyphs from the supplementary area to be rendered, for the first time. Previous to 116, you could edit supplementary characters, but even with a proper font, vim couldn't display the glyphs from the supplementary area.
> The MacVim looks great but as a newbie I'm not sure how to get it > to work from the command window. I have the mvim.htm file but not > sure where to save it or what to name it to etc. Any advice would > be much appreciated. > Thanks, > Joe
> Nico Weber <nicolaswe...@gmx.de> wrote: > > One way that _might_ work is to get MacVim ( http://code.google.com/ > > p/macvim/ ), set its MMCellWidthMultiplier user default to > > something a bit larger than 1 (do `defaults write org.vim.MacVim > > MMCellWidthMultiplier 1.3`, see http://code.google.com/p/macvim/ > > wiki/UserDefaults for more information) and use that. This widens > > up all glyphs, but perhaps it's good enough.
> Doing `:set ambiwidth=double` might help as well.
> The MacVim looks great but as a newbie I'm not sure how to get it > to work from the command window. I have the mvim.htm file but not > sure where to save it or what to name it to etc. Any advice would > be much appreciated. > Thanks, > Joe
> Nico Weber wrote: > > One way that _might_ work is to get MacVim ( http://code.google.com/ > > p/macvim/ ), set its MMCellWidthMultiplier user default to > > something a bit larger than 1 (do `defaults write org.vim.MacVim > > MMCellWidthMultiplier 1.3`, see http://code.google.com/p/macvim/ > > wiki/UserDefaults for more information) and use that. This widens > > up all glyphs, but perhaps it's good enough.
> Doing `:set ambiwidth=double` might help as well.
Forwarding this to vim_mac as Bjorn is not subscribed to vim_multibyte as far as i know. Kenneth, I guess it would help if you could post links to screenshots of the text as it's supposed to look and of the garbled look, as well as the font you're using so we can reproduce this.
> From: Kenneth Beesley <krbees...@gmail.com> > Date: October 5, 2007 6:35:27 PM GMT+02:00 > To: vim_multibyte@googlegroups.com > Subject: Re: Vim on OS X, (no)macatsui problem > Reply-To: vim_multibyte@googlegroups.com
> On 5 Oct 2007, at 03:59, Nico Weber wrote:
>> Hi Ken,
>>> In .gvimrc, if I specify
>>> set nomacatsui anti guifont=DejaVuAgain\ Sans\ Mono:h14
>>> then gvim renders Roman glyphs, from the Basic Multilingual Plane, >>> well, >>> but the Deseret glyphs (from the supplementary area) are rendered as >>> sequences of Roman glyphs and spaces. Completely garbled
>>> If I change .gvimrc to
>>> set macatsui anti guifont=DejaVuAgain\ Sans\ Mono:h14
>>> (i.e. if I specify macatsui rather than nomacatsui, and this is the >>> only change) >>> then I see Roman and Deseret glyphs rendered as expected, but all >>> the >>> glyphs >>> look scraggly on the screen.
>>> Can anyone explain to me what is happening here and how I might get >>> sharp renderings of both BMP and supplementary glyphs?
>> I don't expect this to work at all without 'macatsui'. My experience >> is that vim assigns not enough horizontal space to supparea glyphs >> (is that what "scraggly" means).
> Hello Nico,
> Thanks for the message. With 'nomacatsui' I see sharp, legible > glyphs. > By "scraggly" I mean thin glyphs, with thin, shaky lines. These > "scraggly" > glyphs are legible, but they look bad.
>> This is because vim needs a >> monospaced font for correct display, and the supparea glyphs are too >> wide for the monospaced width of the current font (this can happen >> because the font is not monospaced for all glyphs or because some >> glyphs are subsitituted from other fonts, because they are missing in >> the current font). This also does happen for some BMP glyphs (U+0E5B >> ๛ for example, and many others).
> The Deseret glyphs (Unicode block starting U+10400) are alphabetic and > fit into the same width as the other glyphs. As far as I can tell, > the font I'm > using is monowidth. When merging the Deseret glyphs, I first reset > their > width to the width of the characters in the existing font (DejaVu > Sans Mono). > So whatever my problem is, it is not that the new glyphs I've added > are too > wide, or wider than the original glyphs.
>> One way that _might_ work is to get MacVim ( http:// >> code.google.com/p/ >> macvim/ ), set its MMCellWidthMultiplier user default to something a >> bit larger than 1 (do `defaults write org.vim.MacVim >> MMCellWidthMultiplier 1.3`, see http://code.google.com/p/macvim/wiki/ >> UserDefaults for more information) and use that. This widens up all >> glyphs, but perhaps it's good enough.
> As just explained, too-wide glyphs are not the problem, as far as I > can tell.
>> I don't know if it's possible at all to have a monospaced font that >> works for all writing systems. The Right Thing is probably to make >> vim work with variable width fonts, but I guess that's very very >> complicated and won't happen :-\
> For my current work, I just need a few alphabets (Roman, Shavian, > Deseret) that can all fit in a reasonable width. I don't need "all > writing > systems". I am (as far as I can tell) using a monowidth font. The > complication is that Shavian and Deseret are in the supplementary > area, and Vim 7.1 just recently added patch 116 that is supposed to > allow > glyphs from the supplementary area to be rendered, for the first time. > Previous to 116, you could edit supplementary characters, but even > with a proper font, vim couldn't display the glyphs from the > supplementary > area.
> Ugh. I tried sifting through the forwarded posts, but it was kind of > hard to understand them. I will try to read the posts on google > groups instead, unless somebody can summarize the problem(s) for me?
Would have been easier if you'd "Reply all"d. Here's what I think Kenneth problems are:
> I just installed the latest MacVim and tried it with a version of > DejaVuSansMono.ttf, augmented > with (monowidth) glyphs, the same width as the original > DejaVuSansMono.ttf glyphs, > for the Deseret Alphabet block (U+10400). It doesn't seem to work > for me. When I select my > Deseret Alphabet keymap and try to type Deseret Alphabet, I see > pseudo glyphs in boxes > rendered on the screen.
You can enter desert characters by opening the Character Palette, putting "deseret" in the search box at the bottom and ... well, you know the rest. MacVim displays a "character not found" sign which is probably the Right Thing as the default DejaVu font seems not to include these characters, but Kenneth uses a font that _does_ have them. Having access to Kenneth's font would help...
He also reports that mapping numbers `:map 3 ...` doesn't work. I can't reproduce this.
> > He also reports that mapping numbers `:map 3 ...` doesn't work. I > > can't reproduce this.
> I got this one wrong. See the other thread for Kenneth's > clarification. Sorry.
Hi Ken,
I have looked into why MacVim fails to render the deseret glyphs and I now have an answer, but unfortunately no solution.
The problem is that one deseret character for some reason takes up _two_ characters when put in the text storage (I guess this have something to do with Unicode?). Specifically, calling "length" on an NSString containing one deseret character returns 2 instead of 1, as I would expect.
Now, I do know how to fix this problem, but since Jiang is working on moving his drawing code to MacVim I don't really want to spend any time doing this, since the problem will disappear as soon as he is finished. I'm sorry about that.
björn wrote: >>> He also reports that mapping numbers `:map 3 ...` doesn't work. I >>> can't reproduce this. >> I got this one wrong. See the other thread for Kenneth's >> clarification. Sorry.
> Hi Ken,
> I have looked into why MacVim fails to render the deseret glyphs and I > now have an answer, but unfortunately no solution.
> The problem is that one deseret character for some reason takes up > _two_ characters when put in the text storage (I guess this have > something to do with Unicode?). Specifically, calling "length" on an > NSString containing one deseret character returns 2 instead of 1, as I > would expect.
> Now, I do know how to fix this problem, but since Jiang is working on > moving his drawing code to MacVim I don't really want to spend any > time doing this, since the problem will disappear as soon as he is > finished. I'm sorry about that.
> /Björn
UTF-8 uses: 1 byte for each codepoint in the range U+0000 - U+007F 2 bytes for each codepoint in the range U+0080 - U+07FF 3 bytes for each codepoint in the range U+0800 - U+FFFF 4 bytes for each codepoint in the range U+10000 - U+1FFFFF Actually, current standards mandate that no codepoints higher than U+10FFFD will "ever" be used. (Vim supports up to U+3FFFFFFF, with up to 6 bytes per codepoint, following an earlier draft of the standard.)
Unicode also has the notion of "composing characters", which are characters which are "superimposed" on the preceding character, possibly changing its shape. These are usually diacritics: most of the accents of Latin can be either precomposed or spacing-non-accented + composing-accent, but the optional vowel marks of Hebrew and Arabic exist only as composing characters.
Since your Deseret characters are outside the BMP, each of them requires 4 bytes in UTF-8 (also two 16-bit words in UTF-16 and one 32-bit doubleword in UTF-32); but maybe that's not what your measured "length" means? Does your NSString include a final null (as C strings do) or an initial bytecount (as Pascal strings do)? Or do your Deseret characters include "composing" elements?
Best regards, Tony. -- hundred-and-one symptoms of being an internet addict: 55. You ask your doctor to implant a gig in your brain.
> > The problem is that one deseret character for some reason takes up > > _two_ characters when put in the text storage (I guess this have > > something to do with Unicode?). Specifically, calling "length" on an > > NSString containing one deseret character returns 2 instead of 1, as I > > would expect.
> UTF-8 uses: > 1 byte for each codepoint in the range U+0000 - U+007F > 2 bytes for each codepoint in the range U+0080 - U+07FF > 3 bytes for each codepoint in the range U+0800 - U+FFFF > 4 bytes for each codepoint in the range U+10000 - U+1FFFFF > Actually, current standards mandate that no codepoints higher than U+10FFFD > will "ever" be used. (Vim supports up to U+3FFFFFFF, with up to 6 bytes per > codepoint, following an earlier draft of the standard.)
> Unicode also has the notion of "composing characters", which are characters > which are "superimposed" on the preceding character, possibly changing its > shape. These are usually diacritics: most of the accents of Latin can be > either precomposed or spacing-non-accented + composing-accent, but the > optional vowel marks of Hebrew and Arabic exist only as composing characters.
> Since your Deseret characters are outside the BMP, each of them requires 4 > bytes in UTF-8 (also two 16-bit words in UTF-16 and one 32-bit doubleword in > UTF-32); but maybe that's not what your measured "length" means? Does your > NSString include a final null (as C strings do) or an initial bytecount (as > Pascal strings do)? Or do your Deseret characters include "composing" elements?
I'm sorry about the confusion with posting this thread separately on vim_multibyte and vim_mac...I'll try to bring the diverging threads together by posting this reply to both groups.
Tim Allen replied to the vim_mac thread saying that NSString uses utf-16 internally and this is indeed why it says one deseret char has length 2 (since it needs two 16 bit chars to store one deseret char, as has been pointed out already).
I was under the mistaken impression that NSString always returned length 1 for one character (not counting composing characters), which is why I thought MacVim would work in all situations except when composing characters were used. Again, this can be fixed by getting rid of the assumption that each line in the text storage has the same length (as returned by NSString), but this is a rather big code change.
Thanks to Tony and Tim for educating me on the finer points of Unicode... :-)
> I'm sorry about the confusion with posting this thread separately on > vim_multibyte and vim_mac...I'll try to bring the diverging threads > together by posting this reply to both groups.
> Tim Allen replied to the vim_mac thread saying that NSString uses > utf-16 internally and this is indeed why it says one deseret char has > length 2 (since it needs two 16 bit chars to store one deseret char, > as has been pointed out already).
Yes, obviously (if one thinks about it) one UTF-16 16-bit word cannot represent anything above U+FFFF. For codepoints U+10000 to U+10FFFF (including Deseret, among others), two "surrogate characters" are used -- two 16-bit words, one in the range 0xD800-0xDBFF and the other in the range 0xDC00-0xDFFF : see http://en.wikipedia.org/wiki/UTF-16#Encoding_of_characters_outside_th... for details. Unlike UTF-8 and UTF-32, UTF-16 inherently cannot, even with surrogates, represent anything above U+10FFFF, and (I suppose) that's (one of the reasons) why it was decided to bring the "upper range" of Unicode down from U+7FFFFFFF to U+10FFFF (and even U+10FFFD since for other reasons, the last two codepoints of every plane -- U+xxFFFE and U+xxFFFF -- are "invalid").
> I was under the mistaken impression that NSString always returned > length 1 for one character (not counting composing characters), which > is why I thought MacVim would work in all situations except when > composing characters were used. Again, this can be fixed by getting > rid of the assumption that each line in the text storage has the same > length (as returned by NSString), but this is a rather big code > change.
> Thanks to Tony and Tim for educating me on the finer points of Unicode... :-)
My pleasure. :-)
> /Björn
Best regards, Tony. -- Court, n.: A place where they dispense with justice. -- Arthur Train
Yeah, the term Character is a technical term in Unicode, and each Unicode character has a code point value that ranges from 0x0 to 0x10FFFF.
In the original vision of Unicode, code point values ranged from 0x0 to 0xFFFF, allowing just 64k distinct characters. This old limited range is now known as the Basic Multilingual Plane (BMP). The current vision of Unicode, now 10 years old, allows about a million characters, and the characters with code point values beyond 0xFFFF are known as supplementary characters.
Many software applications still haven't caught up with supplementary characters. They're still stuck in the BMP.
In Java, there is a type called "char" that has 16 bits and so can represent any code point value in the BMP, 0x0 to 0xFFFF. It is important not to confuse "char" with the Unicode notion of Character. In Java, to store a supplementary Unicode character, two "chars" are used, in a coding system known as UTF-16. It sounds like MacVim has a similar storage system, and that the length-in-chars is being confused with the length-in-Unicode-characters.
>>> He also reports that mapping numbers `:map 3 ...` doesn't work. I >>> can't reproduce this.
>> I got this one wrong. See the other thread for Kenneth's >> clarification. Sorry.
> Hi Ken,
> I have looked into why MacVim fails to render the deseret glyphs and I > now have an answer, but unfortunately no solution.
> The problem is that one deseret character for some reason takes up > _two_ characters when put in the text storage (I guess this have > something to do with Unicode?). Specifically, calling "length" on an > NSString containing one deseret character returns 2 instead of 1, as I > would expect.
> Now, I do know how to fix this problem, but since Jiang is working on > moving his drawing code to MacVim I don't really want to spend any > time doing this, since the problem will disappear as soon as he is > finished. I'm sorry about that.
> björn wrote: >>>> He also reports that mapping numbers `:map 3 ...` doesn't work. I >>>> can't reproduce this. >>> I got this one wrong. See the other thread for Kenneth's >>> clarification. Sorry.
>> Hi Ken,
>> I have looked into why MacVim fails to render the deseret glyphs >> and I >> now have an answer, but unfortunately no solution.
>> The problem is that one deseret character for some reason takes up >> _two_ characters when put in the text storage (I guess this have >> something to do with Unicode?). Specifically, calling "length" on an >> NSString containing one deseret character returns 2 instead of 1, >> as I >> would expect.
>> Now, I do know how to fix this problem, but since Jiang is working on >> moving his drawing code to MacVim I don't really want to spend any >> time doing this, since the problem will disappear as soon as he is >> finished. I'm sorry about that.
>> /Björn
Tony responds:
> UTF-8 uses: > 1 byte for each codepoint in the range U+0000 - U+007F > 2 bytes for each codepoint in the range U+0080 - U+07FF > 3 bytes for each codepoint in the range U+0800 - U+FFFF > 4 bytes for each codepoint in the range U+10000 - U+1FFFFF
KRB: The current modern Unicode character set has code point values ranging from U+0 to U+10FFFF, allowing about a million distinct "characters". These Unicode Characters are slightly abstract and need to be distinguished carefully from how they are "encoded" in a file or in a programming language. In UTF-8 encoding, the "code unit" is one byte, and each Unicode character (each code point value) is stored in one to four bytes as you describe above. The conversion between code point values (integers) and the bit/byte representations requires some trivlal bit extraction and shifting.
What Bjôrn describes sounds more like UTF-16, where each Unicode character (code point value) is stored in either one 16-bit "code unit" or in two 16-bit code units. Characters from the Basic Multilingual Plane, U+0 to U+FFFF, are stored in a single 16-bit code unit. Supplementary characters, those beyond the Basic Multilingual Plane, are stored in two 16-bit code units. (Again there is some trivial bit manipulation involved in conversion between code point values and the bit representations in the 16-bit code units.)
Perl stores Unicode strings internally as UTF-8, but you should hardly ever have to know that. If you ask for the length of a Perl Unicode string, Perl gives you the length in Unicode Characters. If you loop through the characters in a Perl Unicode string, it loops through Unicode Characters, taking care of the underlying UTF-8 encoding in the background. The underlying encoding in UTF-8 is effectively hidden from the programmer. At the programming level, you can always think of a Perl Unicode string as a sequence of Unicode Characters (including supplementary characters).
Java from the very beginning took Unicode very seriously. But Java emerged in the olden days of Unicode, when code point values ranged only from U+0 to U+FFFF, so every original Unicode character could be stored in a single 16-bit "char". The length of a Unicode string was simply the number of chars. Easy and clean. The introduction of supplementary Unicode characters 10 years ago created quite a challenge for Java and other programming languages that wanted to take Unicode seriously. Instead of accommodating the New Unicode by making char 32 bits (which would allow each New Unicode character to be stored straightforwardly in a single 32-bit char) the Java gurus opted to keep "char" at 16-bits and use UTF-16 to store Unicode strings. If you ask for the "length" of a Unicode string in Java, it still returns the length in chars rather than the length in Unicode Characters. This is (arguably) quite a mess, and you have to be very aware of it as a programmer if you want to handle Supplementary Unicode Characters.
The way that Python handles Unicode strings internally depends on how it is configured/built. If configured for "ucs2", Python stores Unicode strings as UTF-16, returns the "length" of strings as the number of 16-bit code units, and if you try to loop through the elements of a string, it loops through 16-bit values, which creates a mess if your string contains supplementary characters. This is comparable to the situation in Java.
If you configure Python for "ucs4", then each Unicode string is stored internally as a string of 32-bit code units, "length" is returned as the number of Unicode characters, and if you loop through the characters in a string, you get one Unicode character (code point value) at a time, even for supplementary characters. This "ucs4" option is now formally termed UTF-32 in Unicode circles.
> Actually, current standards mandate that no codepoints higher than U > +10FFFD > will "ever" be used. (Vim supports up to U+3FFFFFFF, with up to 6 > bytes per > codepoint, following an earlier draft of the standard.)
> Unicode also has the notion of "composing characters", which are > characters > which are "superimposed" on the preceding character, possibly > changing its > shape. These are usually diacritics: most of the accents of Latin > can be > either precomposed or spacing-non-accented + composing-accent, but the > optional vowel marks of Hebrew and Arabic exist only as composing > characters.
Quite right. "Character" is a technical term in Unicode, and includes spaces, punctuation and these Composing Diacritical Marks (block starting U +0300) that might not fall under the everyday notion of character. An acute-accented é, for example, can be represented in Unicode either as a single character,
U+00E9
which has the name LATIN SMALL LETTER E WITH ACUTE
You can alternatively represent é as a sequence of two Unicode characters
U+0065 LATIN SMALL LETTER E U+0301 COMBINING ACUTE ACCENT
The Unicode gods have explicitly decreed that these two representations are equivalent, which means that any proper Unicode-capable editor should handle and display them equivalently.
In Hopi (spoken in Arizona) orthography (as defined at the University of Arizona), you have some double-accented graphemes like o with both diaeresis and an acute, grave or circumflex accent. In Unicode you can represent o with diaeresis and acute (the acute accent is rendered above the diaeresis) as either the three-character sequence
U+006F UNICODE SMALL LETTER O U+0308 COMBINING DIAERESIS U+0301 COMBINING ACUTE ACCENT
or as the two-character sequence
U+00F6 LATIN SMALL LETTER O WITH DIAERESIS U+0301 COMBINING ACUTE ACCENT
But there is no single "pre-composed" Unicode character for this purpose.
This whole issue of Combining Diacritical Marks is separate from the issue of encoding (UTF-8, UTF-16 or UTF-32). Some conversion between "pre- composed" and "decomposed" representations can be done using "Normalization" routines available in Perl, Python, Java, ICU, etc.
These Combining Diacritical Marks need to be rendered above or below, or attached in particular places, as appropriate, to any letter character. For that to work properly, you need a font (e.g. Doulos SIL or Charis SIL) that contains the diacritic-positioning information, and you need a sophisticated rendering engine (as in XeTeX) that reads and uses that diacritic-positioning information.
Most software, including text editors, still do a poor job of handling Combining Diacritical Marks and supplementary characters in general.
> Since your Deseret characters are outside the BMP, each of them > requires 4 > bytes in UTF-8 (also two 16-bit words in UTF-16 and one 32-bit > doubleword in > UTF-32); but maybe that's not what your measured "length" means? > Does your > NSString include a final null (as C strings do) or an initial > bytecount (as > Pascal strings do)? Or do your Deseret characters include > "composing" elements?
Because the "length" of each Deseret Character is being returned as 2 rather than 1, it sounds like the MacVim code is using a Java-like UTF-16 internal representation for storing Unicode characters (including supplementary characters).
There are no Combining Diacritical Marks required in the traditional Deseret Alphabet, per se, although proper rendering software _should_ allow you to associate one or more Combining Diacritics Marks with any letter character and have it rendered acceptably. (Handling combining diacritical marks with Deseret Alphabet is very low priority.)
Each Deseret Alphabet letter is a single Unicode character, with a single code point value in the supplementary area (block starting U+10400). The Shavian alphabet is much the same (in the block starting U+10450). The glyphs are straightforward, rendered left-to-right, requiring no ligatures, and could be forced into a fixed-pitch (mono) font about as easily as Roman glyphs.
> Yeah, the term Character is a technical term in Unicode, and each > Unicode character has a code point value that ranges from 0x0 to > 0x10FFFF.
> In the original vision of Unicode, code point values ranged from 0x0 > to 0xFFFF, allowing just 64k distinct characters. This old limited > range > is now known as the Basic Multilingual Plane (BMP). The current > vision of Unicode, now 10 years old, allows about a million characters, > and the characters with code point values beyond 0xFFFF are known > as supplementary characters.
> Many software applications still haven't caught up with supplementary > characters. They're still stuck in the BMP.
> In Java, there is a type called "char" that has 16 bits and so can > represent any code point value in the BMP, 0x0 to 0xFFFF. It is > important > not to confuse "char" with the Unicode notion of Character. In Java, > to store a supplementary Unicode character, two "chars" are used, in a > coding system known as UTF-16. It sounds like MacVim has a similar > storage system, and that the length-in-chars is being confused with > the length-in-Unicode-characters.
> Best wishes,
> Ken
Vim doesn't use UTF-16 internally, because the many intervening nulls would wreak havoc with the C requirement of null-terminated strings. If you set 'encoding' to UCS-4, UTF-16 or UTF-32 (of any endianness), Vim will actually use UTF-8 internally, because 0x00 in UTF-8 is the NULL character (codepoint U+0000), nothing else, and Vim already knows how to handle that.
When you set 'fileencoding' to UTF-16, the internal UTF-8 representation of the text will be converted to and from UTF-16 when writing or reading (respectively), using surrogate pairs for any codepoint above U+FFFF, so that, _on disk_, they take two UTF-16 words rather than one.
I don't know what function you used to count characters, but the Vim string-length function, strlen(), gives a string's length in _bytes_ in the current internal representation: for Unicode, "a" (U+0061) is one, "é" (e-acute, U+00E9) is two, "†" (dagger, U+2020) is three and any Deseret character is four. (Under ":help strlen()" you can see how to count "characters" in a string, as opposed to "bytes".)
>>>> He also reports that mapping numbers `:map 3 ...` doesn't work. I >>>> can't reproduce this. >>> I got this one wrong. See the other thread for Kenneth's >>> clarification. Sorry. >> Hi Ken,
>> I have looked into why MacVim fails to render the deseret glyphs and I >> now have an answer, but unfortunately no solution.
>> The problem is that one deseret character for some reason takes up >> _two_ characters when put in the text storage (I guess this have >> something to do with Unicode?). Specifically, calling "length" on an >> NSString containing one deseret character returns 2 instead of 1, as I >> would expect.
>> Now, I do know how to fix this problem, but since Jiang is working on >> moving his drawing code to MacVim I don't really want to spend any >> time doing this, since the problem will disappear as soon as he is >> finished. I'm sorry about that.
>> /Björn
Best regards, Tony. -- During a grouse hunt in North Carolina two intrepid sportsmen were blasting away at a clump of trees near a stone wall. Suddenly a red-faced country squire popped his head over the wall and shouted, "Hey, you almost hit my wife." "Did I?" cried the hunter, aghast. "Terribly sorry. Have a shot at mine, over there."
> Great message, as usual. > I insert some friendly comments below.
> On 13 Oct 2007, at 18:30, Tony Mechelynck wrote:
>> björn wrote: >>>>> He also reports that mapping numbers `:map 3 ...` doesn't work. I >>>>> can't reproduce this. >>>> I got this one wrong. See the other thread for Kenneth's >>>> clarification. Sorry. >>> Hi Ken,
>>> I have looked into why MacVim fails to render the deseret glyphs >>> and I >>> now have an answer, but unfortunately no solution.
>>> The problem is that one deseret character for some reason takes up >>> _two_ characters when put in the text storage (I guess this have >>> something to do with Unicode?). Specifically, calling "length" on an >>> NSString containing one deseret character returns 2 instead of 1, >>> as I >>> would expect.
>>> Now, I do know how to fix this problem, but since Jiang is working on >>> moving his drawing code to MacVim I don't really want to spend any >>> time doing this, since the problem will disappear as soon as he is >>> finished. I'm sorry about that.
>>> /Björn
> Tony responds: >> UTF-8 uses: >> 1 byte for each codepoint in the range U+0000 - U+007F >> 2 bytes for each codepoint in the range U+0080 - U+07FF >> 3 bytes for each codepoint in the range U+0800 - U+FFFF >> 4 bytes for each codepoint in the range U+10000 - U+1FFFFF
> KRB: The current modern Unicode character set has code point > values ranging from U+0 to U+10FFFF, allowing about a million > distinct "characters". These Unicode Characters are slightly abstract > and need to be distinguished carefully from how they are "encoded" > in a file or in a programming language. In UTF-8 encoding, the "code > unit" > is one byte, and each Unicode character (each code point value) is > stored in one > to four bytes as you describe above. The conversion between code point > values (integers) and the bit/byte representations requires some trivlal > bit extraction and shifting.
> What Bjôrn describes sounds more like UTF-16, where each Unicode > character (code point value) is stored in either one 16-bit "code unit" > or in two 16-bit code units. Characters from the Basic Multilingual > Plane, > U+0 to U+FFFF, are stored in a single 16-bit code unit. Supplementary > characters, those beyond the Basic Multilingual Plane, are stored in two > 16-bit code units. (Again there is some trivial bit manipulation > involved > in conversion between code point values and the bit representations > in the 16-bit code units.)
> Perl stores Unicode strings internally as UTF-8, but you should > hardly ever > have to know that. If you ask for the length of a Perl Unicode > string, Perl gives > you the length in Unicode Characters. If you loop through the > characters in > a Perl Unicode string, it loops through Unicode Characters, taking > care of > the underlying UTF-8 encoding in the background. The underlying > encoding > in UTF-8 is effectively hidden from the programmer. At the > programming level, > you can always think of a Perl Unicode string as a sequence of Unicode > Characters (including supplementary characters).
> Java from the very beginning took Unicode very seriously. But Java > emerged > in the olden days of Unicode, when code point values ranged only from > U+0 to > U+FFFF, so every original Unicode character could be stored in a single > 16-bit "char". The length of a Unicode string was simply the number > of chars. > Easy and clean. > The introduction of supplementary Unicode characters 10 years ago > created > quite a challenge for Java and other programming languages that wanted > to take Unicode seriously. Instead of accommodating the New Unicode by > making char 32 bits (which would allow each New Unicode character to be > stored straightforwardly in a single 32-bit char) the Java gurus > opted to keep "char" at 16-bits > and use UTF-16 to store Unicode strings. If you ask for the "length" > of a Unicode > string in Java, it still returns the length in chars rather than the > length in Unicode > Characters. This is (arguably) quite a mess, and you have to be very > aware of it > as a programmer if you want to handle Supplementary Unicode Characters.
Hm. I guess I'll stay with Vim and vim-script, where I know what to expect.
> The way that Python handles Unicode strings internally depends on how > it is configured/built. If configured for "ucs2", Python stores > Unicode strings as > UTF-16, returns the "length" of strings as the number of 16-bit code > units, and > if you try to loop through the elements of a string, it loops through > 16-bit > values, which creates a mess if your string contains supplementary > characters. > This is comparable to the situation in Java.
> If you configure Python for "ucs4", then each Unicode string is > stored internally as > a string of 32-bit code units, "length" is returned as the number of > Unicode characters, and if you loop through the characters in a > string, you > get one Unicode character (code point value) at a time, even for > supplementary > characters. This "ucs4" option is now formally termed UTF-32 in Unicode > circles.
>> Actually, current standards mandate that no codepoints higher than U >> +10FFFD >> will "ever" be used. (Vim supports up to U+3FFFFFFF, with up to 6 >> bytes per >> codepoint, following an earlier draft of the standard.)
>> Unicode also has the notion of "composing characters", which are >> characters >> which are "superimposed" on the preceding character, possibly >> changing its >> shape. These are usually diacritics: most of the accents of Latin >> can be >> either precomposed or spacing-non-accented + composing-accent, but the >> optional vowel marks of Hebrew and Arabic exist only as composing >> characters.
> Quite right. "Character" is a technical term in Unicode, and > includes spaces, > punctuation and these Composing Diacritical Marks (block starting U > +0300) > that might not fall under the everyday notion of character. An
also control characters (carriage return, line feed, form feed, horizontal tab, soft hyphen, byte-order mark, zero-width joiner, etc.), which also might not all fall under the everyday notion of "character".
> acute-accented é, > for example, can be represented in Unicode either as a single character,
> U+00E9
> which has the name LATIN SMALL LETTER E WITH ACUTE
> You can alternatively represent é as a sequence of two Unicode > characters
> U+0065 LATIN SMALL LETTER E > U+0301 COMBINING ACUTE ACCENT
> The Unicode gods have explicitly decreed that these two > representations are > equivalent, which means that any proper Unicode-capable editor should > handle and display them equivalently.
> In Hopi (spoken in Arizona) orthography (as defined at the University of > Arizona), you have some double-accented graphemes like o with both > diaeresis and an acute, grave or circumflex accent. In Unicode you > can represent o with diaeresis and acute (the acute accent is rendered > above the diaeresis) as either the three-character sequence
> U+006F UNICODE SMALL LETTER O > U+0308 COMBINING DIAERESIS > U+0301 COMBINING ACUTE ACCENT
> or as the two-character sequence
> U+00F6 LATIN SMALL LETTER O WITH DIAERESIS > U+0301 COMBINING ACUTE ACCENT
> But there is no single "pre-composed" Unicode character for this > purpose.
> This whole issue of Combining Diacritical Marks is separate from the > issue > of encoding (UTF-8, UTF-16 or UTF-32). Some conversion between "pre- > composed" > and "decomposed" representations can be done using "Normalization" > routines > available in Perl, Python, Java, ICU, etc.
but not in Vim. AFAIK, the only "normalization" routines afforded by Vim (other than not using a separate screen cell for composing character) are: (a) the 'delcombine' option, which, if set, allows <BS> to erase one combining character at a time, while when clear (default) it will erase one spacing character together with any number of combining characters in the same screen cell; and (b) the \Z pattern atom, which will ignore combining characters anywhere in the text while matching. But AFAIK Vim will always treat "é" (U+00E9 LATIN SMALL LETTER E WITH ACUTE) and "é" (U+0065 LATIN SMALL LETTER E + U+0301 COMBINING ACUTE ACCENT) as different even if it displays them the same.
> These Combining Diacritical Marks need to be rendered above or below, > or attached in particular places, as appropriate, to any letter > character. For > that to work properly, you need a font (e.g. Doulos SIL or Charis > SIL) that > contains the diacritic-positioning information, and you need a > sophisticated rendering > engine (as in XeTeX) that reads and uses that diacritic-positioning > information.
> Most software, including text editors, still do a poor job of handling > Combining Diacritical Marks and supplementary characters in general.
In Arabic, Vim handles combining vowels etc. ("harakaat" as Arabic grammarians call them) quite well, including several per character as e.g. in (spacing) seen (Arabic S) + combining shadda (geminated-consonant sign) + combining fatha (Arabic short vowel a), a combination which appears in the fully vocalized form of "as-salaam" (Peace). Starting recently (7.1.116), Vim can now display (not only edit) any codepoint in the current 'guifont', not only those in the BMP. From what you say above, it looks like Vim is ahead of "most software including text editors", but I don't doubt that the situation will get better as time goes on.
>> Since your Deseret characters are outside the BMP, each of them >> requires 4 >> bytes in UTF-8 (also two 16-bit words in UTF-16 and one 32-bit >> doubleword in >> UTF-32); but maybe that's not what your measured "length" means? >> Does your >> NSString
