Bug 152027

Summary:	Gap in field shading
Product:	LibreOffice	Reporter:	Eyal Rozenberg <eyalroz1>
Component:	Writer	Assignee:	Not Assigned <libreoffice-bugs>
Status:	NEW ---
Severity:	trivial	CC:	caolan.mcnamara, stephane.guillou
Priority:	medium
Version:	Inherited From OOo
Hardware:	All
OS:	All
See Also:	https://bugs.documentfoundation.org/show_bug.cgi?id=103643 https://bugs.documentfoundation.org/show_bug.cgi?id=35907 https://bugs.documentfoundation.org/show_bug.cgi?id=77279
Whiteboard:
Crash report or crash signature:		Regression By:
Bug Depends on:
Bug Blocks:	43808, 107739
Attachments:	Illustration of gap Document with field exhibiting the gap Font family used in the sample document

Description Eyal Rozenberg 2022-11-13 22:23:47 UTC

Created attachment 183568 [details]
Illustration of gap

Sometimes, with Hebrew text in some fonts, the shading of a field exhibits gaps. I also see weird shading shaping when the font size or family changes sometimes, but for the purposes of this bug: Exactly the same font.

Seen with:

Version: 7.5.0.0.alpha0+ (X86_64) / LibreOffice Community
Build ID: 2486d99c6053af1414117faac2c0db18c0d344c4
CPU threads: 4; OS: Linux 6.0; UI render: default; VCL: gtk3
Locale: en-IL (en_IL); UI: en-US

and with 7.4.1.2 release on same platform and same VCL.

Comment 1 Eyal Rozenberg 2022-11-13 22:24:35 UTC

Created attachment 183569 [details]
Document with field exhibiting the gap

Note this document uses an uncommon Hebrew font. I'll attach that as well.

Comment 2 Eyal Rozenberg 2022-11-13 22:31:25 UTC

Created attachment 183570 [details]
Font family used in the sample document

Comment 3 Stéphane Guillou (stragu) 2022-11-15 12:25:47 UTC

Reproduced in:

Version: 7.5.0.0.alpha0+ (X86_64) / LibreOffice Community
Build ID: 6e66b5d75b4cda0314b64f4d12ef9e4350751470
CPU threads: 8; OS: Linux 5.15; UI render: default; VCL: gtk3
Locale: en-AU (en_AU.UTF-8); UI: en-US
Calc: threaded

and

Version: 7.4.2.3 / LibreOffice Community
Build ID: 382eef1f22670f7f4118c8c2dd222ec7ad009daf
CPU threads: 8; OS: Linux 5.15; UI render: default; VCL: gtk3
Locale: en-AU (en_AU.UTF-8); UI: en-US
Calc: threaded

and

Version: 6.3.6.2
Build ID: 2196df99b074d8a661f4036fca8fa0cbfa33a497
CPU threads: 8; OS: Linux 5.15; UI render: default; VCL: gtk3; 
Locale: en-AU (en_AU.UTF-8); UI-Language: en-US
Calc: threaded

Looks like it happens at the junction between LTR and RTL. Doesn't happen with text highlighting.

Comment 4 ⁨خالد حسني⁩ 2022-12-08 15:56:00 UTC

I suspect this is similar to bug 35907 and bug 103643, and bug 77279. I suspect that calculating the text extents to draw the underline or background is using low resolution or has rounding issues, so when the text is more than one portion a gap is shown.

Perhaps Caolán McNamara has some idea.

Comment 5 Stéphane Guillou (stragu) 2024-02-01 10:56:56 UTC

Reproduced in OOo 3.3 as well (although it breaks even more in the number: 2|02|2| נובמבר)