PyQt TGA QImage

import sys
from PyQt4 import QtGui

def main(*args, **kwargs):
    return readTga(*args, **kwargs)

def readTga(file, asPixmap=True):
    'Given the path to a TGA file, return either a QImage or QPixmap if asPixmap is True'
    with open(file, 'rb') as f:
        header = f.read(12)
        imageSpec = f.read(6)

        header = [ord(c) for c in header]
        imageSpec = [ord(c) for c in imageSpec]

        width = imageSpec[1]*256+imageSpec[0]
        height = imageSpec[3]*256+imageSpec[2]
        bitDepth = imageSpec[4]
        bytesPerPixel = bitDepth/8
        descriptor =imageSpec[5]

        bits = []
        for i in xrange(8):
            bits.append((descriptor >> i) & 1)

        bottomUp = bool(not bits[5])
        rightToLeft = bool(bits[4])

        #print 'Read tga - Image info:'
        #print '- (width, height, bitDepth, bytesPerPixel)', width, height, bitDepth, bytesPerPixel
        image = QtGui.QImage(width, height, QtGui.QImage.Format_ARGB32)

        if header[2] == 2:
            #print '- True color, uncompressed'
            for y in range(height):
                for x in range(width):
                    color = getPixel(f, bytesPerPixel)

                    pX = x
                    pY = y
                    if rightToLeft:
                        pX = (width-1)-x

                    if bottomUp:
                        pY = (height-1)-y
                    image.setPixel(pX, pY, color)

        if header[2] == 10:
            #print '- True color, rle compressed'
            y=0
            x=0
            while y<height:
                while x<width:
                    #rle chunk
                    pack = ord(f.read(1))
                    #if pack is less than 127, indicates how many normal pixels until the next rle pack value
                    #if pack is more than 127, the distance from 127 is how many times to repeat the same pixel
                    if pack>127:
                        length = pack-127
                        color = getPixel(f, bytesPerPixel)
                    else:
                        length = pack + 1

                    for i in range(length): #set the chunk pixels
                        if pack<=127:
                            color = getPixel(f, bytesPerPixel)
                        pX = x
                        pY = y
                        if rightToLeft:
                            pX = (width-1)-x

                        if bottomUp:
                            pY = (height-1)-y

                        image.setPixel(pX, pY, color)
                        x+=1
                x=0
                y+=1
        else:
            raise Exception, 'Header value %s is not supported by loadTga.'%header[2]

        if asPixmap:
            image = QtGui.QPixmap().fromImage(image)
        return image

def getPixel(f, bytesPerPixel):
    'Given the file object f, and number of bytes per pixel, read in the next pixel and return a qRgba uint'
    pixel = []
    for i in range(bytesPerPixel):
        pixel.append(ord(f.read(1)))

    if bytesPerPixel==4:
        pixel = [pixel[2], pixel[1], pixel[0], pixel[3]]
        color = QtGui.qRgba(*pixel)
    else:
        pixel = [pixel[2], pixel[1], pixel[0]]
        color = QtGui.qRgb(*pixel)
    return color