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)
Version:
(earliest affected)
Inherited From OOo
Hardware: All All
: low minor
Assignee: Not Assigned
URL:
Whiteboard:
Keywords: haveBacktrace, perf
Depends on:
Blocks: Smooth-Scroll Scrolling-Performance
  Show dependency tree / graph
 
Reported: 2019-02-05 12:11 UTC by Buovjaga
Modified: 2021-12-05 15:43 UTC (History)
8 users (show)

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

Attachments
Callgrind output from master (1.29 MB, application/x-xz)
2019-02-05 12:11 UTC, Buovjaga 		Details
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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
Version: 6.3.0.0.alpha0+
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: 6.3.0.0.alpha0+ (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

3.3.0
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.