Bug 61886 - At certain scaling levels, the √ symbol and overbar show noticeable gap and/or vertical offset difference
Summary: At certain scaling levels, the √ symbol and overbar show noticeable gap and/o...
Status: RESOLVED WORKSFORME
Alias: None
Product: LibreOffice
Classification: Unclassified
Component: Formula Editor (show other bugs)
Version:
(earliest affected)
4.0.0.3 release
Hardware: Other All
: medium normal
Assignee: Not Assigned
URL:
Whiteboard:
Keywords:
Depends on:
Blocks:
 
Reported: 2013-03-06 05:07 UTC by Robinson Tryon (qubit)
Modified: 2017-03-06 16:20 UTC (History)
2 users (show)

See Also:
Crash report or crash signature:

Attachments
Example of rendering issue (42.53 KB, image/png)
2013-03-06 05:16 UTC, Robinson Tryon (qubit) 		Details
Another example of rendering issue (62.23 KB, image/png)
2013-03-06 05:17 UTC, Robinson Tryon (qubit) 		Details
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Description Robinson Tryon (qubit) 2013-03-06 05:07:36 UTC 
As first noted on bug 61622, there are some rendering issues with certain functions in Math.

Here are my repro steps on Ubuntu 12.04.2 + LO 4.0.0.3:

- Use original function "y=sqrt{ x} < x <= x^2"
- Fonts set as follows:
(TNR = Times New Roman)
 Variables: TNR, Italic
 Functions: TNR
 Numbers: TNR
 Text: TNR

- Zoom at the following levels shows issues (gap between the root symbol and overbar, or the top of the root sign poking above the overbar):

  - 100%
  - 150%
  - 200%
  - 225% - gap
  - 275%
  - 300% - very close
  - 425% - close
  - 475%
  - 500%
  - 675% - small gap
  - 700% - noticeable gap
  - 800% - close

Same type of problem noticed with the 2nd function from bug 61622 ("y =  sqrt {{x}over {sqrt {{x} over sqrt {x}}}}"), but different roots experiencing the issue at different zoom levels.
Comment 1 Robinson Tryon (qubit) 2013-03-06 05:16:46 UTC 
Created attachment 75997 [details]
Example of rendering issue
Comment 2 Robinson Tryon (qubit) 2013-03-06 05:17:43 UTC 
Created attachment 75998 [details]
Another example of rendering issue
Comment 3 Jacques Guilleron 2013-03-06 07:58:50 UTC 
Confirmed with Windows 7 and LO 4.0.1.1. No gap for me.

Jacques Guilleron
Comment 4 QA Administrators 2015-02-19 15:40:43 UTC Comment hidden (obsolete)
Comment 5 Robinson Tryon (qubit) 2015-02-19 16:06:21 UTC 
TESTING again with 4.4.0.3 + Ubuntu 14.04

(In reply to Robinson Tryon (qubit) from comment #0)
> - Use original function "y=sqrt{ x} < x <= x^2"
> - Fonts set as follows:
> (TNR = Times New Roman)
>  Variables: TNR, Italic
>  Functions: TNR
>  Numbers: TNR
>  Text: TNR
> 
> - Zoom at the following levels shows issues (gap between the root symbol and
> overbar, or the top of the root sign poking above the overbar):
> 
>   - 100%
>   - 150%
>   - 200%
>   - 225% - gap
>   - 275%
>   - 300% - very close
>   - 425% - close
>   - 475%
>   - 500%
>   - 675% - small gap
>   - 700% - noticeable gap
>   - 800% - close

Tested at 700%: Some gap noticed, so bug is still present.
Comment 6 QA Administrators 2016-02-21 08:37:17 UTC Comment hidden (obsolete)
Comment 7 QA Administrators 2017-03-06 15:46:18 UTC Comment hidden (obsolete)
Comment 8 V Stuart Foote 2017-03-06 16:20:51 UTC 
This has been corrected with the HarfBuzz implementation using the Default rendering. Radix for the root are well formed and meet their overbars cleanly.

But rendering with OpenGL remains issue of bug 99351 in calculating scale and position of nodes.

Test scaling of these formulas with default rendering, and then with OpenGL rendering to reveal issue of bug 99351:

y=sqrt{ x} < x <= x^2 newline

y =  sqrt {{x}over {sqrt {{x} over sqrt {x}}}} newline

nroot{3}{27 over 2} cdot sqrt{9}