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Bug 1217

Summary:	kpdf: Slow to render certain documents
Product:	TDE	Reporter:	Darrell <darrella>
Component:	tdegraphics	Assignee:	Timothy Pearson <kb9vqf>
Status:	NEW ---
Severity:	normal	CC:	bugwatch, darrella
Priority:	P1
Version:	R14.0.x [Trinity]
Hardware:	Other
OS:	Other
Compiler Version:		TDE Version String:
Application Version:		Application Name:

Description Darrell 2012-09-17 14:40:36 CDT

kpdf is slow and cpu intensive when displaying certain documents. Those documents seem to include documents with graphics, and scanned documents --- which basically are rasterized images.

Part of the problem can be alleviated by enabling two options that are not intuitive:

Settings->Performance->CPU Usage->Enable transparency effects
Settings->Performance->CPU Usage->Enable background generation

Those two Settings descriptions imply additional rendering overhead rather than helping improve with rendering speed, and many users likely leave these options disabled. Regardless, even when enabled kpdf is slow with certain documents.

A comment in the developer's mail list implied that kpdf tries to re-render pages while scrolling.

Comment 1 Darrell 2012-09-17 15:06:51 CDT

Some online bug reports that might be related or help:

https://bugs.kde.org/show_bug.cgi?id=99486 (the attached document does not render at all in kpdf R14)

https://bugs.launchpad.net/ubuntu/+source/kdegraphics/+bug/178771

https://bugs.kde.org/show_bug.cgi?id=113949

Comment 2 Darrell 2012-09-17 19:45:19 CDT

Although the underlying xpdf sources have been patched with the latest 3.02 security updates, the xpdf base has not been updated with the latest 3.03 version. Thus, bug report 1175 might be related to this bug report.