Use loader ?

http://www.slideshare.net/rajeshlal/qml-performance-tips-meego-conference-san-francisco-hyatt-regency-may-23252011

From: [email protected] 
[mailto:[email protected]] On Behalf Of ext 
Artem Marchenko
Sent: Thursday, September 29, 2011 12:46 PM
To: Pelle Johnsen
Cc: [email protected]
Subject: Re: [Qt-qml] Any tips or tricks to help with long app startup times?

Hello guys

In my old mobile gaming programming times I was solving similar issues by 
loading single very big image and making small images to just refer to 
different parts of that big image. That's quite standard technique for 2D 
gaming - loading many sprites takes time on all systems.

That is probably impossible if you go for pure QML, but if you are ready to 
experiment with QmlCanvas and/or with trying to implement your own image 
providers that would provide sprites from the single huge image, that could 
help. Guarantees quite some headache though.

BR,
Artem.

On Sep 29, 2011, at 10:39 PM, Pelle Johnsen wrote:


Hi again,

You are right in that you don't need to specify async for network images (sorry 
for not realizing that). In our tests we however found that it was not loading 
the image data itself that was taking time, but creating the QPixmaps, and 
because of QPixmap's limitation that can only be done in the main ui thread - 
which then blocks the whole ui :( I don't know if there has been improvements 
to this in 4.8, but it is a fundamental issue that QML Image items use QPixmap, 
and these can ONLY be created in the main ui thread.

I would guess QtQuick 2.0 would remedy this by not using QPixmaps, but OpenGL 
textures instead for QML Image.

 -Pelle
On Thu, Sep 29, 2011 at 9:09 PM, Artem Marchenko 
<[email protected]<mailto:[email protected]>> wrote:
Hmm, Pelle

Documentation tells that asynchronous works only with local filesystem, I am 
not sure if resource file counts as local filesystem - 
http://doc.qt.nokia.com/4.7-snapshot/qml-image.html#asynchronous-prop

It probably won't help, but if I was desperate I would have tried deploying 
images to file system and not to resource file and then tried asynchronous 
property.

Best regards,
Artem.



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