Bug 103740 - Adjust our instance of the OpenSymbol font to use existing lighter weight glyphs, plus sign and arrows
Summary: Adjust our instance of the OpenSymbol font to use existing lighter weight gly...
Status: NEW
Alias: None
Product: LibreOffice
Classification: Unclassified
Component: graphics stack (show other bugs)
Version:
(earliest affected)
Inherited From OOo
Hardware: All All
: medium enhancement
Assignee: Not Assigned
URL:
Whiteboard:
Keywords:
: 103584 103898 104959 (view as bug list)
Depends on:
Blocks: Formula-Editor Font-Rendering
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Reported: 2016-11-06 20:09 UTC by V Stuart Foote
Modified: 2020-06-02 19:13 UTC (History)
7 users (show)

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Description V Stuart Foote 2016-11-06 20:09:54 UTC
Description:
Mike, Khaled, *

Would it be possible to adjust OpenSymbol font to swap mappings of a few of the oddly heavy "weight" glyphs present in the font?

Most annoying is the glyph currently assigned to the "plus" (U+002b), but also the set assigned to the arrow glyphs.

These alternate glyphs are already in OpenSymbol assigned PUA codepoints, so can we just swap the assignment?

U+002B PLUS SIGN <--> U+E083 <private-use-E083>
U+2190 LEFTWARDS ARROW  <--> U+E0DB <private-use-E0DB>
U+2191 UPWARDS ARROW  <--> U+E0DC <private-use-E0DC>
U+2192 RIGHTWARDS ARROW  <--> U+E08C <private-use-E08C>
U+2193 DOWNWARDS ARROW  <--> U+E0DD <private-use-E0DD>

With this minor change, the glyph used for Plus sign will match the weight of the other binary operators the "minus" (U+2212), "multiplication" (U+00D7), "division" (U+00F7), and "equal" (U+003d).  Also the weights/lengths of all the arrows would be consistent. 

At that point, there are three glyphs that probably need replacement glyphs:

U+003C LESS-THAN SIGN and
U+003E GREATER-THAN SIGN both too heavy, and

U+00F7 DIVISION SIGN--which for some reason uses square dots in the obelus, has always looked weird in that all other glyphs in the font use round points.

But these are not presently in the font. 

Steps to Reproduce:
1. Open the Math module formula editor and from the Element pane select the Unary/Binary category.
2. select the Plus, and the Minus unary objects into a formula
3. select the Binary - addition, subtraction, multiplication objects
4. from the Relations category, select the toward object into a formula

Actual Results:  
The "plus" sign, and the "rightwards" arrow are of a notably heavier weight than all other glyphs.

Expected Results:
All glyphs in the Formula editor and as rendered as an OLE to document canvas would have consistent weight.  The font is assigning glyphs that are too heavy.


Reproducible: Always

User Profile Reset: No

Additional Info:
=-ref-=
http://opengrok.libreoffice.org/xref/core/starmath/inc/types.hxx
http://opengrok.libreoffice.org/xref/core/extras/source/truetype/symbol/OpenSymbol.sfd



User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:49.0) Gecko/20100101 Firefox/49.0
Comment 1 Mike Kaganski 2016-11-06 22:52:14 UTC
Agree :) I already thought about that. At least about +
Comment 2 V Stuart Foote 2016-11-13 06:26:28 UTC
*** Bug 103898 has been marked as a duplicate of this bug. ***
Comment 3 V Stuart Foote 2016-11-18 01:04:18 UTC
*** Bug 103584 has been marked as a duplicate of this bug. ***
Comment 4 Khaled Hosny 2016-11-18 21:45:05 UTC
Before making such a change, we need to make sure these symbols are only used in math and not for other dingbats that might require the current form.
Comment 5 V Stuart Foote 2016-11-18 21:50:39 UTC
Hmm, looking at OpenSymbol v 102.7  not sure how I missed them when last I looked, but we also have the other alternates:

U+003C LESS-THAN SIGN <--> U+E084  <PUA E084>
U+003E GREATER-THAN SIGN <--> U+E085 <PUA E085>

So just the square dots of the obelus for U+00F7 DIVISION SIGN glyph might benefit from a new glyph at some point.
Comment 6 Mike Kaganski 2016-11-18 22:36:57 UTC
(In reply to V Stuart Foote from comment #5)
> looking at OpenSymbol v 102.7

Current version is 102.8?
Comment 7 V Stuart Foote 2016-11-18 23:11:22 UTC
(In reply to Khaled Hosny from comment #4)
> 
> Current version is 102.8?

That was looking at _installed_ for 5.2.3.3,
102.7 with 1008 characters 1012 glyphs

But yes, current master shows:
102.8 with 1030 characters & 1034 glyphs
Comment 8 V Stuart Foote 2016-11-18 23:13:27 UTC
try that with the right reply
(In reply to Mike Kaganski from comment #6)
> > looking at OpenSymbol v 102.7
> 
> Current version is 102.8?
 
That was looking at _installed_ for 5.2.3.3,
102.7 with 1008 characters 1012 glyphs

But yes, current master shows:
102.8 with 1030 characters & 1034 glyphs
Comment 9 V Stuart Foote 2016-12-28 16:44:34 UTC
*** Bug 104959 has been marked as a duplicate of this bug. ***
Comment 10 Georg Müller 2020-06-02 19:13:24 UTC
If I may make a suggestion, I would recommend to drop the OpenSymbol font for Math. It supports almost no symbols and does not even provide a regular alphabet. I created an Writer document to compare the font with several alternative and for me it seams, that almost all other fonts which are either common in Linux or in Latex provide much more characters much much more persistence in design of the characters including symbols.

The Latex Font Computer Modern provides many different typefaces (I tested Roman Serif and Roman Sans Serif) and a lot of symbols. Even the standard font Liberation Serif supports more characters, but has lacks of special symbols like arrows with strokes like U+219A, U+219B and U+21AE.

I tested also Open Sans, MathJax_Math and Ubuntu. Regarding to regular letters Computer Modern seams unbeatable in formulas, but if one is just thinking of symbols, there are many free alternatives, that provide much more UTF-8 characters than OpenSymbol. Please consider to change the math symbol font for a more state of the art font with more characters and more persistence.

A few questions:

1) Can one remap the characters without compiling LibreOffice?
2) In the linked issue was an comment about changing the font in 
/usr/share/fonts/truetype/openoffice/opens___.ttf
For me this didn't work. I restarted LibreOffice, but the applied font was the same. I don't know, if this font in that location is just used as fallback, but would be nice if you have any idea, how I could change that font or as I asked to change even the mapping including the font.