bugGNU Octave - Bugs: bug #56146, Qt graphics toolkit reports...


bug #56146: Qt graphics toolkit reports "text_renderer: skipping missing glyph" when creating button, but result is correct

Submitted by:  Valdas <zmogas>
Submitted on:  Wed 17 Apr 2019 02:21:57 PM UTC  
Category:  Plotting with OpenGL Severity:  2 - Minor
Priority:  5 - Normal Item Group:  None
Status:  Fixed Assigned to:  None
Originator Name:  Open/Closed:  Closed
Release:  dev Operating System:  GNU/Linux

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Mon 15 Jul 2019 09:56:09 PM UTC, comment #7: 

Thanks, I pushed the patch. Closing this report since you confirmed it was also fixed.

Pantxo Diribarne <pantxo>
Project Member
Mon 15 Jul 2019 09:51:11 PM UTC, comment #6: 

@Pantxo: Right, when using uicontrol() the warning message is no longer printed.

Rik <rik5>
Project Administrator
Mon 15 Jul 2019 09:44:01 PM UTC, comment #5: 

@Rik: You get this warning because the "⏮" character is actually missing from FreeSans font, and the text renderer can't draw it (note it is also missing on-screen): so in your example the warning is expected. The bug at hand is that you currently also get a warning about missing glyphs in uicontrol objects although Qt is able to draw them using its default font. The test case is:

uicontrol ("style", "pushbutton", "string", "⏮")

Pantxo Diribarne <pantxo>
Project Member
Mon 15 Jul 2019 09:34:35 PM UTC, comment #4: 

I tried the patch over on bug #48446, but it doesn't seem to resolve this report.  I still get

>>  clf;
>> ht = text (0.5, 0.5, '⏮')
warning: text_renderer: skipping missing glyph for character '23ee'
warning: called from
    text at line 173 column 10

Rik <rik5>
Project Administrator
Sun 14 Jul 2019 10:02:34 AM UTC, comment #3: 

The patch attached to bug #48446 fixes this bug as well.

Pantxo Diribarne <pantxo>
Project Member
Wed 17 Apr 2019 07:36:29 PM UTC, comment #2: 

This is partly related to bug #48446: in order to get an idea of the text extent, we currently use our internal text rendering engine, with the default font (FreeSans). Looks like our copy of FreeSans features '◂' but not '⏮'.
As Rik said, Qt must be using a font that has both characters. So either we wait for bug #48446 to be solved, or we change the default font for uicontrol objects to match Qt's. The former may take a while, the latter may be difficult since Qt's font is probably OS/theme dependent.

Pantxo Diribarne <pantxo>
Project Member
Wed 17 Apr 2019 03:25:47 PM UTC, comment #1: 

Confirmed.  Although the text engine warning does seem to be accurate.  The following does not show the requested glyph.

ht = text (0.5, 0.5, '⏮')

It seems that uicontrol must be finding a font where the character is known.

Rik <rik5>
Project Administrator
Wed 17 Apr 2019 02:21:57 PM UTC, original submission:  

If I execute this code:

figure; uicontrol('style', 'pushbutton', 'string', '⏮')

in console I get:
warning: text_renderer: skipping missing glyph for character '23ee'
warning: called from
    uicontrol at line 117 column 8

But Octave creates button with correct char anyways (see screenshot).

I get no warnings when execute: figure; uicontrol('style', 'pushbutton', 'string', '◂')

Valdas <zmogas>


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    Follow 8 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2019-07-15 pantxo StatusPatch Reviewed => Fixed
        Open/ClosedOpen => Closed
    2019-07-15 rik5 StatusConfirmed => Patch Reviewed
    2019-07-14 pantxo Dependencies- => Depends on bugs #48446
    2019-04-17 rik5 CategoryPlotting => Plotting with OpenGL
        Severity3 - Normal => 2 - Minor
        StatusNone => Confirmed
    2019-04-17 zmogas Attached File- => Added Screenshot_20190417_171844.png, #46782

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