Passing pixel pointer from a Maya MImage to Qt's QImage

MImage_to_QImage.py

"""
Simplified version of original forum post:
http://tech-artists.org/forum/showthread.php?4547-Passing-uchar-pointer-with-PySide-in-Maya
"""

import ctypes
import maya.OpenMaya as om
from PySide import QtCore, QtGui

# Build a test MImage
p = "/path/to/test/image.png"
mIm = om.MImage()
mIm.readFromFile(p)

# Prep MImage
mIm.verticalFlip()

# Get the width and height
wUtil = om.MScriptUtil()
wUtil.createFromInt(0)
wPtr = wUtil.asUintPtr()

hUtil = om.MScriptUtil()
hUtil.createFromInt(0)
hPtr = hUtil.asUintPtr()

mIm.getSize(wPtr, hPtr)

width = wUtil.getUint(wPtr)
height = hUtil.getUint(hPtr)

# byte size
imSize = width * height * 4

# pass pointer to QImage
buf = ctypes.c_ubyte * imSize
buf = buf.from_address(long(mIm.pixels()))
qIm = QtGui.QImage(buf, width, height, QtGui.QImage.Format_RGB32).rgbSwapped()
    
# Test
pix = QtGui.QPixmap.fromImage(qIm)
l = QtGui.QLabel()
l.setPixmap(pix)
l.setScaledContents(True)
l.resize(640,480)
l.show()

@mottosso I don't even remember saving this! Guess it pays to just document everything incase someone can find it in a search result later.