Bug 140753

Summary: Image tearing while scrolling GDI/SKIA raster with high zoom level
Product: LibreOffice Reporter: Telesto <telesto>
Component: WriterAssignee: Not Assigned <libreoffice-bugs>
Status: RESOLVED WORKSFORME    
Severity: normal CC: vsfoote
Priority: medium    
Version: 7.0.0.0.alpha1+   
Hardware: All   
OS: All   
Whiteboard:
Crash report or crash signature: Regression By:
Bug Depends on:    
Bug Blocks: 129062    
Attachments: Example file
Example file which does show it
Example file (to check after commit pushed)

Description Telesto 2021-03-02 08:31:33 UTC
Description:
Image tearing while scrolling GDI/SKIA with high zoom level

Steps to Reproduce:
1. Open attached file
2. Zoom in to 200/300% so only 1/4 or less is visible
3. Scroll down with the scrollwheel

Actual Results:
Notice tearing

Expected Results:
Not so:


Reproducible: Always


User Profile Reset: No



Additional Info:
Found in
7.2

not in
Version: 6.4.0.0.beta1+ (x64)
Build ID: 20be5cd0bdc57d812bf34a2debfe48caa51de881
CPU threads: 4; OS: Windows 6.3 Build 9600; UI render: default; VCL: win; 
Locale: nl-NL (nl_NL); UI-Language: en-US
Calc: CL
Comment 1 Telesto 2021-03-02 08:31:49 UTC
Created attachment 170169 [details]
Example file
Comment 2 Telesto 2021-03-02 08:38:55 UTC
Still OK with
Version: 7.2.0.0.alpha0+ (x64) / LibreOffice Community
Build ID: 380ab85b6594a013f34f5e6ec69fb569336bbb48
CPU threads: 4; OS: Windows 6.3 Build 9600; UI render: Skia/Raster; VCL: win
Locale: nl-NL (nl_NL); UI: en-US
Calc: CL
Comment 3 Telesto 2021-03-02 18:26:01 UTC
Profile corruption somehow
Comment 4 Telesto 2021-03-02 19:36:17 UTC
Created attachment 170186 [details]
Example file which does show it
Comment 5 Telesto 2021-03-02 19:37:33 UTC
Also in
Version: 7.0.0.0.alpha1+ (x64)
Build ID: 574c57090642347980d2395e1e183cc7b5c171ad
CPU threads: 4; OS: Windows 6.3 Build 9600; UI render: default; VCL: win
Locale: nl-NL (nl_NL); UI: nl-NL
Calc: CL

not in
6.4
Comment 6 V Stuart Foote 2021-03-02 20:20:10 UTC
Can not reproduce no tearing of the image frames nor of the text (what little there was) nor of the page background image.

Version: 7.2.0.0.alpha0+ (x64) / LibreOffice Community
Build ID: af64bc49d872d8a040d66387303def98eae5cd51
CPU threads: 8; OS: Windows 10.0 Build 18363; UI render: Skia/Raster; VCL: win
Locale: en-US (en_US); UI: en-US
Calc: CL

Windows 10 Ent, nVidia Quadro K2000

with skia.log with Vulkan rendering enabled
RenderMethod: vulkan
Vendor: 0x10de
Device: 0xffe
API: 1.2.142
Driver: 457.36.0
DeviceType: discrete
DeviceName: Quadro K2000
Denylisted: no
Comment 7 V Stuart Foote 2021-03-02 20:21:17 UTC
By zoom you mean the LibreOffice canvas zoom--and not the os/DE GUI scaling, correct?
Comment 8 Telesto 2021-03-03 16:18:00 UTC
(In reply to V Stuart Foote from comment #7)
> By zoom you mean the LibreOffice canvas zoom--and not the os/DE GUI scaling,
> correct?

Canvas zoom.. I assume Vulkan to be to powerful to notice the lag. Tearing is happening at GDI. Skia raster simply slows down (not smooth scroll, but with certain lag)

I assume other backends being affected too. But have to check that
Comment 9 Roman Kuznetsov 2021-03-03 18:58:35 UTC
https://gerrit.libreoffice.org/c/core/+/111893
Comment 10 Telesto 2021-03-03 19:43:34 UTC
(In reply to Roman Kuznetsov from comment #9)
> https://gerrit.libreoffice.org/c/core/+/111893

Related to this: the document in tdf#140753 has a PNG which technically has
an alpha channel, but it's actually completely opaque

-> the image is created by LibreOffice, I inserted a PDF and saved it as DOCX. I'm  asking myself is it actually desired to export alpha channel in cases where the image is completely opaque?
Comment 11 Telesto 2021-03-04 15:44:22 UTC
Created attachment 170214 [details]
Example file (to check after commit pushed)

Another file showing slowness scrolling left/right top/down with some zoom-level set. I hope it's dealt with already... but well you never know.
Comment 12 Luboš Luňák 2021-03-05 10:41:41 UTC
I do not see any redraw problems with any of the documents. Please provide more info (such as a screenshot).
Comment 13 Telesto 2021-03-05 10:53:01 UTC
(In reply to Luboš Luňák from comment #12)
> I do not see any redraw problems with any of the documents. Please provide
> more info (such as a screenshot).

Have to look again.. You're recent commit https://gerrit.libreoffice.org/c/core/+/111893 improved things a lot already.

I'm waiting for: https://gerrit.libreoffice.org/c/core/+/111966 and will re-test everything with different backends..

It's fine with Skia Raster with 
Version: 7.2.0.0.alpha0+ (x64) / LibreOffice Community
Build ID: 722ec600e85cca2e94e82e69f8d13773061172b9
CPU threads: 4; OS: Windows 6.3 Build 9600; UI render: Skia/Raster; VCL: win
Locale: nl-NL (nl_NL); UI: nl-NL
Calc: CL
Comment 14 QA Administrators 2021-03-06 03:47:00 UTC Comment hidden (obsolete)
Comment 15 Telesto 2021-03-09 18:34:50 UTC
Version: 7.2.0.0.alpha0+ (x64) / LibreOffice Community
Build ID: dc3b64dcbfb0a49c0be65bd8d73ed4e6d3828a21
CPU threads: 4; OS: Windows 6.3 Build 9600; UI render: Skia/Raster; VCL: win
Locale: nl-NL (nl_NL); UI: nl-NL
Calc: CL