Bug 30740 - [Qt] QtWebKit should consider using QImageReader::setQuality(49)
Summary: [Qt] QtWebKit should consider using QImageReader::setQuality(49)
Status: RESOLVED FIXED
Alias: None
Product: WebKit
Classification: Unclassified
Component: Images (show other bugs)
Version: 528+ (Nightly build)
Hardware: PC OS X 10.5
: P2 Normal
Assignee: Nobody
URL:
Keywords: Qt
Depends on:
Blocks:
 
Reported: 2009-10-23 23:35 PDT by Holger Freyther
Modified: 2009-12-14 02:51 PST (History)
2 users (show)

See Also:

Attachments
Add an attachment (proposed patch, testcase, etc.)

Note You need to log in before you can comment on or make changes to this bug.
Description Holger Freyther 2009-10-23 23:35:07 PDT 
ImageDecoderQt.cpp should use QImageReader::setQuality(49) to use JDCT_IFAST in the Qt JPEG Image Decoder. This change can give a 5% speedup on the image_cycling reduction.

JDCT_IFAST is supposingly not generating as good results as the other integer based method but it is not certain how bad these are. The Palm developers have opted to use this for the WebOS.
Comment 1 Yael 2009-10-30 05:04:07 PDT 
(In reply to comment #0)
> ImageDecoderQt.cpp should use QImageReader::setQuality(49) to use JDCT_IFAST in
> the Qt JPEG Image Decoder. This change can give a 5% speedup on the
> image_cycling reduction.
> 
> JDCT_IFAST is supposingly not generating as good results as the other integer
> based method but it is not certain how bad these are. The Palm developers have
> opted to use this for the WebOS.

Sorry I did not get back to you in that. I was OOO until today. Will try to arrange testing during next week.
Comment 2 Yael 2009-10-30 14:22:23 PDT 
We collected a few JPG images and tested on N97. The colors of the images looked better after we applied this change.
Comment 3 Holger Freyther 2009-12-14 02:51:34 PST 
I landed a patch to do this in r52086. Let us see if someone is noticing the difference.