Bug 88302 - Embedding graphics slows down scrolling massively
Summary: Embedding graphics slows down scrolling massively
Status: RESOLVED DUPLICATE of bug 80659
Alias: None
Product: LibreOffice
Classification: Unclassified
Component: Writer (show other bugs)
Version:
(earliest affected)
4.2.6.3 release
Hardware: Other All
: medium normal
Assignee: Not Assigned
URL:
Whiteboard:
Keywords: perf
Depends on:
Blocks:
 
Reported: 2015-01-11 22:05 UTC by barade.barade
Modified: 2016-09-30 07:53 UTC (History)
3 users (show)

See Also:
Crash report or crash signature:

Attachments
Test document with bg image that slows down scrolling (38.31 KB, application/vnd.oasis.opendocument.text)
2015-03-24 00:32 UTC, Hannes 		Details
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Description barade.barade 2015-01-11 22:05:36 UTC 
The embedded graphic is a JPEG file with a resolution of 2480x3507 but scaled down to a DINA page. scrolling through the document is slow as hell.
Comment 1 barade.barade 2015-01-11 23:07:46 UTC 
Scrolling is only that slow when a part of the image is visible. Scrolling through other pages works fine.
Comment 2 Robinson Tryon (qubit) 2015-01-14 20:11:49 UTC 
(In reply to barade.barade from comment #0)
> The embedded graphic is a JPEG file with a resolution of 2480x3507 but
> scaled down to a DINA page. scrolling through the document is slow as hell.

Hi barade,
Please attach a test document that demonstrates the slow-down problem, then change Status back to 'UNCONFIRMED'. Thanks!

Status -> NEEDINFO
Comment 3 Hannes 2015-03-24 00:32:57 UTC 
Created attachment 114286 [details]
Test document with bg image that slows down scrolling
Comment 4 Hannes 2015-03-24 00:34:17 UTC 
Attached a test document.
Comment 5 Buovjaga 2015-03-25 20:01:20 UTC 
(In reply to Hannes from comment #3)
> Created attachment 114286 [details]
> Test document with bg image that slows down scrolling

Yep, this is slow.

Win 7 Pro 64-bit, LibO Version: 4.4.1.2
Build ID: 45e2de17089c24a1fa810c8f975a7171ba4cd432
Locale: fi_FI
Comment 6 Robinson Tryon (qubit) 2015-12-09 18:08:12 UTC Comment hidden (obsolete)
Comment 7 Aron Budea 2016-05-03 15:00:29 UTC 
Profiling points to function scalePallete8bit2(ScaleContext &rCtx, long nStartY, long nEndY):
http://opengrok.libreoffice.org/xref/core/vcl/source/bitmap/bitmapscalesuper.cxx#285

4 levels of nested loops... yummy.
Comment 8 Aron Budea 2016-05-03 15:49:52 UTC 
However, since different image types, where this function is not involved also show similar behavior during scrolling (eg. bug 96880), the real issue could be in how repainting is done.
Comment 9 Michael Meeks 2016-09-30 07:53:10 UTC 
Aaron is basically right - we should be caching interpolated-down images - even if we have H/W acceleration enabled - on Windows you can enable OpenGL and get fast rendering and interpolation of that if your GL driver is supported but ... ;-)

Looks like a dup; thanks for the report !

*** This bug has been marked as a duplicate of bug 80659 ***