bugFree UCS Outline Fonts - Bugs: bug #52566, Misplaced tremolos without stems


bug #52566: Misplaced tremolos without stems

Submitted by:  David Corbett <dscorbett>
Submitted on:  Fri 01 Dec 2017 12:25:47 AM UTC  
Category:  individual character(s) Severity:  3 - Normal
Item Group:  letter positioning poor Status:  Proceeding
Privacy:  Public Assigned to:  Steve White <Stevan_White>
Open/Closed:  Open Release:  development

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Fri 15 Dec 2017 09:14:31 PM UTC, comment #5: 

Many valid Unicode strings are nonsense and there is no reason for a font to support them. For example, if you put a flag before a stem, it looks bad in FreeSerif; but that is a problem with the string, not the font.

I agree that a tremolo on a sixty-fourth note is probably too impractical for anyone to use it, so it is not worth spending much effort on that combination. If you did want to support something like that, I suppose you’d have to find an attestation, or do something reasonable-looking if it is unattested.

For combinations which are valid and attested, but which Unicode does not explain in enough detail, there are a few possible solutions. You could deduce what the standard should say, based on similar characters in other blocks and based on the relevant proposal. Often the proposal goes into great detail which the standard summarizes in one page.

Alternatively, you could report the omission to Unicode and hope they clarify things in the next version.

The particular case of tremolos on stemless notes, though, I don’t think is a matter of personal feelings. It is clear what the Unicode encoding is (because nothing else would make sense and because one of the proposals explicitly calls this case out) and what it should look like (because it is attested in sheet music).

David Corbett <dscorbett>
Fri 15 Dec 2017 06:45:53 PM UTC, comment #4: 


What is the "right place" for "combining tremolo 3" followed by "combining flag 4"?  Well, I think the fancy tremolo on such a short note probebly makes no sense musically, but Unicode-wise it's a combination.  The question is, to what extent do we pursue our feelings of how things ought to work, in the absence of standard direction?

Steve White <Stevan_White>
Project AdministratorIn charge of this item.
Fri 15 Dec 2017 06:38:23 PM UTC, comment #3: 

The goal is to put tremolos in the right place. You may consider it crude, but I’d say your commit fixed this. Uniscribe is a lost cause for music so I am only testing with HarfBuzz.

David Corbett <dscorbett>
Fri 15 Dec 2017 03:42:10 PM UTC, comment #2: 

OK, this commit puts the tremolo in different places depending on whether it is followed by a flag or not.  It's pretty crude.  But again, I'm not sure what the goal is.

Steve White <Stevan_White>
Project AdministratorIn charge of this item.
Fri 01 Dec 2017 01:34:51 PM UTC, comment #1: 

And as I understand it, you have told me that uniscribe has deactivated most of the usual lookups for this range.  Peachy.

Since harfbuzz applies the normalization forms to these characters, putting the tremolo marks before stems, and harfbuzz turns some lookups on for the range, and as you have said, uniscribe does not, we're in a bit of a bind here.  It might be best to just go for harfbuzz -- our primary target is Linux, even if many of our users are on other systems, and to turn common features off for this range is -- just wrong.

With a full complement of lookups, I could implement a conditional chain with a lookahead to see if a stem is following.  What a mess.

Steve White <Stevan_White>
Project AdministratorIn charge of this item.
Fri 01 Dec 2017 12:25:47 AM UTC, original submission:  

In FreeSerif, the combining tremolos U+1D167 through U+1D169 are positioned above and to the right of noteheads to overlap stems. However, not all notes have stems. Stemless notes’ tremolos should be placed directly above.


data:text/html;charset=utf-8,<div style="font: 300px FreeSerif">%F0%9D%85%9D%F0%9D%85%A9

David Corbett <dscorbett>


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    Date Changed by Updated Field Previous Value => Replaced by
    2017-12-01 Stevan_White StatusNone => Proceeding
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