Bug 133344 - Slow scrolling through preview pages with large complex file
Summary: Slow scrolling through preview pages with large complex file
Status: NEW
Alias: None
Product: LibreOffice
Classification: Unclassified
Component: Draw (show other bugs)
Version:
(earliest affected)
4.0.0.3 release
Hardware: All All
: medium normal
Assignee: Not Assigned
URL:
Whiteboard:
Keywords: perf
Depends on:
Blocks: Scrolling-PageUpDown
  Show dependency treegraph
 
Reported: 2020-05-24 11:01 UTC by Telesto
Modified: 2020-10-13 07:03 UTC (History)
1 user (show)

See Also:
Crash report or crash signature:
Regression By:


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Description Telesto 2020-05-24 11:01:58 UTC
Description:
Slow scrolling through preview pages with large complex file

Steps to Reproduce:
1. Open attachment 161226 [details]
2. Increase the preview size of the page
3. Scroll down in the preview panel

Actual Results:
Have to wait for every image being generated

Expected Results:
In LibreOffice 3.5.7.2 you can simply scroll. the preview is little high quality.. but speed is great


Reproducible: Always


User Profile Reset: No



Additional Info:
Found in
Version: 7.0.0.0.alpha1+ (x64)
Build ID: b587de60d4e6aa96238766272d94f1499b22f696
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

and in
4.0

but not in
LibreOffice 3.5.7.2 
Build ID: 3215f89-f603614-ab984f2-7348103-1225a5b
Comment 1 Buovjaga 2020-06-14 12:00:41 UTC
Scrolling is choppy with 3.5.0 for me as well. What is your proposal, make the previews shitty quality?
Comment 2 Telesto 2020-06-14 12:16:54 UTC
(In reply to Buovjaga from comment #1)
> Scrolling is choppy with 3.5.0 for me as well. What is your proposal, make
> the previews shitty quality?

Not rendering it in high quality does certainly help.. I prefer 'speed' above being awful accurate.

And caching the previews would certainly help.. resize the pages panel.. and the rendering starts over again.. 'low resolution' place holder is shown, until refresh occurs.. Render a preview larges panel size; buffer it, and shrink that one fitting the panel seems more effective... 

But only a 'random' thought
Comment 3 Telesto 2020-10-12 20:24:38 UTC
Is there some change that you're work on thumbnails (
https://gerrit.libreoffice.org/c/core/+/104156) will fix/improve things here.. or I'm I totally misinterpreting you're current work?
Comment 4 Buovjaga 2020-10-12 21:09:13 UTC
(In reply to Telesto from comment #3)
> Is there some change that you're work on thumbnails (
> https://gerrit.libreoffice.org/c/core/+/104156) will fix/improve things
> here.. or I'm I totally misinterpreting you're current work?

The patch was merged to master first https://gerrit.libreoffice.org/c/core/+/104114 so why not just wait for the next dailies?
Comment 5 Buovjaga 2020-10-13 07:03:25 UTC
Tested and there is no noticeable difference.

Arch Linux 64-bit
Version: 7.1.0.0.alpha0+
Build ID: 4f8b13267559e8e89a306a6c522f905322396bd0
CPU threads: 8; OS: Linux 5.8; UI render: default; VCL: kf5
Locale: fi-FI (fi_FI.UTF-8); UI: en-US
Calc: threaded
Built on 13 October 2020