Bug 94855 - Slow slideshow with SVG images
Summary: Slow slideshow with SVG images
Status: RESOLVED DUPLICATE of bug 83426
Alias: None
Product: LibreOffice
Classification: Unclassified
Component: Impress (show other bugs)
(earliest affected) release
Hardware: x86-64 (AMD64) All
: medium minor
Assignee: Not Assigned
Keywords: perf
Depends on:
Reported: 2015-10-07 11:15 UTC by Frederic Parrenin
Modified: 2015-12-15 11:05 UTC (History)
2 users (show)

See Also:
Crash report or crash signature:

.odp file to reproduce the problem (9.28 MB, application/vnd.oasis.opendocument.presentation)
2015-10-07 11:15 UTC, Frederic Parrenin

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Description Frederic Parrenin 2015-10-07 11:15:38 UTC
Created attachment 119385 [details]
.odp file to reproduce the problem

Steps to reproduce:
- open the attached .odp file in Impress
- go to "Slide Show"
- move from one slide to the next
=> it can be slow to go from one slide to the next. Sometimes it takes ~1s, and the situation is even worst (~5s) if I unplug the power cable of my laptop (which is a often encountered situation when one makes a presentation).
By comparison, if I export the presentation to pdf and make the slideshow in evince, the transitions always take <0.2s. So it seems some optimizations might be possible here.
Comment 1 Buovjaga 2015-10-08 17:37:47 UTC
It is a tad laggy at times.

Win 7 Pro 64-bit, Version: (x64)
Build ID: 37b43f919e4de5eeaca9b9755ed688758a8251fe
Locale: fi-FI (fi_FI)
Comment 2 V Stuart Foote 2015-10-09 03:28:57 UTC
On Windows 10 Pro 64-bit with i7-920 w/12GB RAM and nVidia GTX260
Version: (x64)
Build ID: fd8cfc22f7f58033351fcb8a83b92acbadb0749e
Locale: en-US (en_US)

Actually that is a very "intense" presentation. There are 95 high resolution images (PNG and SVG), with some obscenely large SVGs--they frankly have no place in a Impress presentation--and should be resampled to raster images. Despite its size it renders reasonably well except for a couple of the 2MB + SVGs.

When those Vector data are resampled (as with export to PDF, or if done externaly) to the ODP performance is quite zippy--with or without OpenGL support.
Comment 3 Frederic Parrenin 2015-10-09 09:18:27 UTC
I am actually surprised that the export to pdf resamples the elements of the figure. I thought it was keeping the vector information.

Of course it is possible to transform the figures in high-res png images, but it is convenient to use the svg format since you are sure you don't loose any information. I often extract svg images from scientific articles and reports using inkscape.
Comment 4 Frederic Parrenin 2015-10-15 17:05:39 UTC
Regarding this issue, I was wondering if it would be possible to cache a bitmap version of each svg image for a quick display of the slide, and then to re-process the svg in the background for a later, more refined display.
Comment 5 V Stuart Foote 2015-10-19 14:18:50 UTC
@Frederic, going to dupe this over to bug 83426

Still some of your more complex SVGs should be resampled to bitmaps for use in Impress. Left as SVGs they have to be composed into bitmaps for display during the slideshow.


*** This bug has been marked as a duplicate of bug 83426 ***
Comment 6 Robinson Tryon (qubit) 2015-12-15 11:05:09 UTC
Migrating Whiteboard tags to Keywords: (perf)