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Qt-interest Archive, March 2007
QGraphicsScene performance issues in Qt 4.3 beta.

• Subject: QGraphicsScene performance issues in Qt 4.3 beta.
• From: "Daniel Hedberg" <daniel.hedberg@xxxxxxxxxxxx>
• Date: Fri, 30 Mar 2007 14:53:02 +0200
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• Thread-topic: QGraphicsScene performance issues in Qt 4.3 beta.
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Hi,

 

I downloaded and installed Qt 4.3 beta a few days ago and started playing around with the new functionality introduced in QGraphicsScene. However, when trying to make use of the QGraphicsItem:: ItemIgnoresTransformations flag I noticed an extreme decrease in performance of the QGraphicsScene/QGraphicsView. Has anyone else noticed this?

 

We use the ItemIgnoresTransformations flag on the QGraphicsItem objects that in our application represents "transformation handles", i.e. the small little squares that let your resize and rotate items in an application such as Microsoft Visio or Adobe Photoshop, etc. This new feature is convenient as we do not want the handles to the transformations applied to the QCanvasView, but as it is now it is way too slow to be of any use.

 

Best Regards,

Daniel Hedberg

 

-----

Daniel Hedberg, M.Sc., Software Engineer

MathCore Engineering AB

Teknikringen 1B, SE-583 30 Linköping, Sweden

Phone: +46 13 32 85 05, Fax: +46 13 21 27 01

http://www.mathcore.com <http://www.mathcore.com/>