Bug 113810 - LibreOffice does not display/print some Unicode line drawing characters properly
Summary: LibreOffice does not display/print some Unicode line drawing characters properly
Status: RESOLVED NOTABUG
Alias: None
Product: LibreOffice
Classification: Unclassified
Component: Writer (show other bugs)
Version:
(earliest affected)
5.4.3.2 release
Hardware: x86-64 (AMD64) Linux (All)
: low minor
Assignee: Not Assigned
URL:
Whiteboard:
Keywords:
Depends on:
Blocks: Font-Rendering
  Show dependency treegraph
 
Reported: 2017-11-13 20:14 UTC by Roger House
Modified: 2022-12-28 18:55 UTC (History)
3 users (show)

See Also:
Crash report or crash signature:


Attachments
PDF showing expected display and actual display by LibreOffice (13.07 KB, application/pdf)
2017-11-13 20:18 UTC, Roger House
Details
Correct display of line drawing Unicode characters by cat (5.18 KB, image/png)
2017-11-13 20:21 UTC, Roger House
Details
Incorrect display of line drawing Unicode characters by LibreOffice (6.42 KB, image/png)
2017-11-13 20:23 UTC, Roger House
Details

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Description Roger House 2017-11-13 20:14:55 UTC
Description:
LibreOffice seems to render certain Unicode line drawing characters
improperly.  This text:

│  │  │        │        │     │        │     │     │     │        │     │
┝━━┿━━┷━━━━━━━━┷━━━━━┯━━┷━━━━━┷━━━━━━━━┷┯━━━━┷━━━━━┷━━━━━┷━┯━━━━━━┷━━━━━┥
│  │                 │                  │                  │            │

uses these characters to form the heavy horizontal line:
    
    U+2501 horizontal heavy
    U+2525 vertical light left heavy
    U+251D vertical light right heavy
    U+2537 horizontal heavy up light
    U+252F horizontal heavy down light
    U+253F horizontal heavy vertical light

When the text is displayed by cat, vi, or the text editor joe, it is fine. 
When it is displayed or printed with LibreOffice, it is not fine.



Steps to Reproduce:
1.Select the line drawing text in the description box above
2.Insert it into a LibreOffice text document
3.Observe the skewed lines that don't match up properly

Actual Results:  
See attachment

Expected Results:
See attachment


Reproducible: Always


User Profile Reset: No



Additional Info:
Version: 5.4.3.2
Build ID: 1:5.4.3~rc2-0ubuntu0.16.04.1~lo1
CPU threads: 4; OS: Linux 4.4; UI render: default; VCL: gtk2; 
Locale: en-US (en_US.UTF-8); Calc: group


User-Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:56.0) Gecko/20100101 Firefox/56.0
Comment 1 Roger House 2017-11-13 20:18:49 UTC
Created attachment 137724 [details]
PDF showing expected display and actual display by LibreOffice
Comment 2 Roger House 2017-11-13 20:21:56 UTC
Created attachment 137725 [details]
Correct display of line drawing Unicode characters by cat
Comment 3 Roger House 2017-11-13 20:23:36 UTC
Created attachment 137726 [details]
Incorrect display of line drawing Unicode characters by LibreOffice
Comment 4 Buovjaga 2017-11-15 15:02:00 UTC
Yeah. It kind of depends on the zoom level. With an old version like 3.3, at some zoom level it appears correct.

Arch Linux 64-bit
Version: 6.0.0.0.alpha1+
Build ID: 17cfe6e25d479428de308c22fcd218dcf8827840
CPU threads: 8; OS: Linux 4.13; UI render: default; VCL: kde4; 
Locale: fi-FI (fi_FI.UTF-8); Calc: group
Built on November 15th 2017
Comment 5 QA Administrators 2018-11-16 03:42:45 UTC Comment hidden (obsolete)
Comment 6 mattia.b89 2019-01-27 10:55:07 UTC
I confirm the bug!
I confirm that a) different zoom-level and b) different fonts, lead to different results but each wrong.

my system,
Version: 6.1.4.2
Build ID: 6.1.4-4
CPU threads: 4; OS: Linux 4.20; UI render: default; VCL: gtk3; 
Locale: it-IT (en_GB.UTF-8); Calc: group threaded
Comment 7 QA Administrators 2021-01-27 04:28:07 UTC Comment hidden (obsolete)
Comment 8 BogdanB 2022-12-27 17:38:46 UTC
Also in
Version: 7.5.0.0.alpha0+ / LibreOffice Community
Build ID: a09c5c69e3b5fbf448cae1d6c476f39067e40023
CPU threads: 4; OS: Linux 5.19; UI render: default; VCL: gtk3
Locale: ro-RO (ro_RO.UTF-8); UI: en-US
Calc: threaded
Comment 9 V Stuart Foote 2022-12-28 18:55:57 UTC
Hold on!

By definition the line-drawing art require use of a fixed-width non-proportional font.

Also, the font must have pretty much complete coverage of the Unicode 2500-257F  "Box Drawing" chart [1] or unexpected font fall back will occur and where the layout is certain to be disrupted.

Using MS Consolas, or DejaVu Sans Mono, both of which are complete for the Box Drawing Unicode block will render the box drawing correctly at any font size. 

Liberation Mono is incomplete, and fall back distorts the line work. Likewise Courier Mono, or Noto Mono.

Verify coverage of the Unicode 2500-257F Box Drawing block and select appropriate font. LibreOffice renders correctly to canvas. Nothing to do with Zoom level when the font has the codepoints covered.  And only the fallback font is affected by zoom of canvas.

=-ref-=


[1] https://www.unicode.org/charts/PDF/U2500.pdf