PySide compared to PyQt4 : problem with QImage __init__()

lbordier

Hello,

I'm trying to create a pyside backend for matplotlib by modifying the qt4agg backend.
Now i'm stuck with a QImage problem :

In PyQt4 the syntax is :

img = QtGui.QImage(stringBuffer, 640,480,QtGui.QImage.Format_ARGB32)

But converting to PySide raise an error because no init method accept these inputs (because of stringBuffer data).
I tried with the staticmethod QImage.fromData(stringBuffer) but it does not work.

I don't understand why pyside does not have the QImage ( uchar * data, int width, int height, Format format ) constructor ??

Could someone help me on this topic ?
How can i have the same result with a pyside syntax ?

Thanks.

mairas

Hi,

This is a bug in PySide - see:

http://bugs.openbossa.org/show_bug.cgi?id=489

Add yourself as a CC to the bug to get automatic updates about its progress.

Due to the bug backlog we have, it might take a month or so before we have time to fix that, though. :-(

Anyway, it's utterly cool that you're working on a matplotlib backend! I've really used matplotlib a lot for different kinds of projects of my own, and have always found the visual quality quite unmatched!

ma.

lbordier

OK, thanks for the reply.
Is there any way to get it working with methods like fromData or loadFromData ?

mairas

I haven't tested it myself, but according to the documentation, loadFromData should do exactly what you want. If it doesn't, it's a bug that should really be reported.

lbordier

I think i don't use it properly because with PyQt and the following code :

from PyQt4 import QtGui

fid = open('/tmp/buffer.out','r')
stringBuffer = fid.read()
fid.close()

img1 = QtGui.QImage(640,440, QtGui.QImage.Format_ARGB32)
img1.loadFromData(stringBuffer)

img1.save('test_pyqt4_1.png',format='png')

--> this make an empty png file*

img2 = QtGui.QImage(stringBuffer,640,440, QtGui.QImage.Format_ARGB32)

img2.save('test_pyqt4_2.png',format='png')

--> this make a good png file with my figure

Any idea how to use loadFromData in the good way so that i can reproduce with pyside??