Slow jpeg rendering

[matysek]

There is an issue in openlp with slow rendering of jpeg images.

When png images are used as background then the rendering is almost instantaneous in contrast to jpeg.

[Andreas Preikschat (googol-deactivatedaccount)]

I don't think we can do anything about this (apart from improving image processing in general), because we don't support any format; Qt/PyQt does. To say it in other words, we don't have any impact on the speed/quality a particularly format is rendered.

Thus I'll set it to incomplete (if you find something we can improve then you may change the status).

[matysek (mzibricky)]

It seems to me like webkit has to do the rendering twice: once for 2nd monitor and once for the preview in live.

We could get some performance if the implementation would be to really create screenshot of the 2nd monitor and then scale this screenshot for use for the preview in live.

The following Qt4 classes allow direct manipulation with 2D scene:

QGraphicsScene, QGraphicsView or use directly QGraphicsWebView instead QWebView.

Then for direct access to web page as a screenshot we could use method

QGraphicsWebView.scene().render(QPainter)

This is not jpeg specific.

[Tim Bentley (trb143)]

We already do this using QWebView there have been problems in the past using Graphics views but these may have been over come.

[Tim Bentley (trb143)]

http://www.websiteoptimization.com/speed/tweak/inline-images/

[Andreas Preikschat (googol-deactivatedaccount)]

http://manual.openlp.org/songs.html#song-importer
The following screenshot has to be updated: http://manual.openlp.org/_images/songimporterchoices.png

[Andreas Preikschat (googol-deactivatedaccount)]

Sorry, wrong bug report.

[Andreas Preikschat (googol-deactivatedaccount)]

Set to "Won't fix" as we cannot do anything about it.