Bug 123181 - Scrolling document with Page Down is slow/choppy when Smooth scroll is turned on
Summary: Scrolling document with Page Down is slow/choppy when Smooth scroll is turned on
Status: NEW
Alias: None
Product: LibreOffice
Classification: Unclassified
Component: Writer (show other bugs)
(earliest affected)
Inherited From OOo
Hardware: All All
: low minor
Assignee: Not Assigned
Keywords: haveBacktrace, perf
Depends on:
Blocks: Smooth-Scroll Scrolling-Performance
  Show dependency treegraph
Reported: 2019-02-05 12:11 UTC by Buovjaga
Modified: 2023-12-06 03:17 UTC (History)
8 users (show)

See Also:
Crash report or crash signature:

Callgrind output from master (1.29 MB, application/x-xz)
2019-02-05 12:11 UTC, Buovjaga

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Description Buovjaga 2019-02-05 12:11:57 UTC
Created attachment 148903 [details]
Callgrind output from master

1. Open attachment 136239 [details]
2. Tools - Options - Writer - View: tick Smooth scroll
3. Scroll down the document by pressing Page Down on your keyboard

Only seen with gtk3, kde5 and win.

Arch Linux 64-bit
Build ID: 5408f0731b9cd8be0e1b7aa5145b825337baad84
CPU threads: 8; OS: Linux 4.20; UI render: default; VCL: gtk3; 
Locale: fi-FI (fi_FI.UTF-8); UI-Language: en-US
Calc: threaded
Built on 5 February 2019

Version: (x64)
Build ID: 573a473275ad7c76d0cada9b7e73d4923e7a79d5
CPU threads: 4; OS: Windows 10.0; UI render: default; VCL: win; 
TinderBox: Win-x86_64@42, Branch:master, Time: 2019-02-03_01:22:10
Locale: fi-FI (fi_FI); UI-Language: en-US
Calc: threaded

Comment 1 V Stuart Foote 2021-01-27 16:28:20 UTC
Wait, does smooth scroll even respond to PgDn/PgUp or CursorDn/CursorUp? All of which relocate the edit cursor.  Yes--but the edit cursor redraw seems to come after some amount of view scroll. That redraw/reposition seems to cause a pause in smooth scroll.

Conversely smooth scroll responds cleanly to the ScrollBar control which does not relocate the edit cursor, just the views of the canvas.
Comment 2 QA Administrators 2023-12-06 03:17:53 UTC
Dear Buovjaga,

To make sure we're focusing on the bugs that affect our users today, LibreOffice QA is asking bug reporters and confirmers to retest open, confirmed bugs which have not been touched for over a year.

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