Qt-interest Archive, April 2008
Performance issues with QGraphicsView when using scaled pixmaps on X11
Message 1 in thread
Hello,
I think there is a problem with scaled pixmaps in qgraphicsview on X11.
Consider this simple program using PyQt (I have the same problem when using
pure C++) :*
import sys
from PyQt4 import QtCore, QtGui
some_file = "image.png"
a = 5
app = QtGui.QApplication(sys.argv)
scene = QtGui.QGraphicsScene()
scene.addPixmap(QtGui.QPixmap(some_file))
view = QtGui.QGraphicsView(scene)
view.scale(a, a)
view.show()
sys.exit(app.exec_())*
On X11, when a != 1, scrolling the image becomes very slow. This is even
more dramatic with larger images. If a == 1, scrolling is smooth.
On windows, scrolling is always smooth.
On linux, I used PyQt version 4.3.3 / Qt 4.3.4, and on windows, PyQt version
4.3.3 / Qt 4.3.3.
In the task tracker, I have found bug
136592<http://trolltech.com/developer/task-tracker/index_html?method=entry&id=136592>,
which should have been solved on 4.3.0.
So what do you think about this ?
Thanks,
FranÃois
