QImage to Numpy Array using PySide

Question

I am currently switching from PyQt to PySide.

With PyQt I converted QImage to a Numpy.Array using this code that I found on SO :

def convertQImageToMat(incomingImage):
    '''  Converts a QImage into an opencv MAT format  '''

    incomingImage = incomingImage.convertToFormat(4)

    width = incomingImage.width()
    height = incomingImage.height()

    ptr = incomingImage.bits()
    ptr.setsize(incomingImage.byteCount())
    arr = np.array(ptr).reshape(height, width, 4)  #  Copies the data
    return arr

However ptr.setsize(incomingImage.byteCount()) does not work with PySide as this is part of the void* support of PyQt.

My Question is: How can I convert a QImage to a Numpy.Array using PySide.

EDIT:

Version Info
> Windows 7 (64Bit)
> Python 2.7
> PySide Version 1.2.1
> Qt Version 4.8.5

Answer 1

The trick is to use QImage.constBits() as suggested by @Henry Gomersall. The code I use now is:

def QImageToCvMat(self,incomingImage):
    '''  Converts a QImage into an opencv MAT format  '''

    incomingImage = incomingImage.convertToFormat(QtGui.QImage.Format.Format_RGB32)

    width = incomingImage.width()
    height = incomingImage.height()

    ptr = incomingImage.constBits()
    arr = np.array(ptr).reshape(height, width, 4)  #  Copies the data
    return arr

Answer 2

PySide doesn't seem to offer a bits method. How about using constBits to get the pointer to the array?

Answer 3

For me the solution with constBits() did not work, but the following worked:

def QImageToCvMat(incomingImage):
    '''  Converts a QImage into an opencv MAT format  '''

    incomingImage = incomingImage.convertToFormat(QtGui.QImage.Format.Format_RGBA8888)

    width = incomingImage.width()
    height = incomingImage.height()

    ptr = incomingImage.bits()
    ptr.setsize(height * width * 4)
    arr = np.frombuffer(ptr, np.uint8).reshape((height, width, 4))
    return arr