text: #
  # The Python Imaging Library.
  # $Id: ImageQt.py 2741 2006-06-18 16:17:20Z fredrik $
  #
  # a simple Qt image interface.
  #
  # history:
  # 2006-06-03 fl: created
  # 2006-06-04 fl: inherit from QImage instead of wrapping it
  # 2006-06-05 fl: removed toimage helper; move string support to ImageQt
  #
  # Copyright (c) 2006 by Secret Labs AB
  # Copyright (c) 2006 by Fredrik Lundh
  #
  # See the README file for information on usage and redistribution.
  #
  
  import Image
  
  from PyQt4.QtGui import QImage, qRgb
  
  ##
  # (Internal) Turns an RGB color into a Qt compatible color integer.
  
  def rgb(r, g, b):
      # use qRgb to pack the colors, and then turn the resulting long
      # into a negative integer with the same bitpattern.
      return (qRgb(r, g, b) & 0xffffff) - 0x1000000
  
  ##
  # An PIL image wrapper for Qt.  This is a subclass of PyQt4's QImage
  # class.
  #
  # @param im A PIL Image object, or a file name (given either as Python
  #     string or a PyQt string object).
  
  class ImageQt(QImage):
  
      def __init__(self, im):
  
          data = None
          colortable = None
  
          # handle filename, if given instead of image name
          if hasattr(im, "toUtf8"):
              # FIXME - is this really the best way to do this?
              im = unicode(im.toUtf8(), "utf-8")
          if Image.isStringType(im):
              im = Image.open(im)
  
          if im.mode == "1":
              format = QImage.Format_Mono
          elif im.mode == "L":
              format = QImage.Format_Indexed8
              colortable = []
              for i in range(256):
                  colortable.append(rgb(i, i, i))
          elif im.mode == "P":
              format = QImage.Format_Indexed8
              colortable = []
              palette = im.getpalette()
              for i in range(0, len(palette), 3):
                  colortable.append(rgb(*palette[i:i+3]))
          elif im.mode == "RGB":
              data = im.tostring("raw", "BGRX")
              format = QImage.Format_RGB32
          elif im.mode == "RGBA":
              try:
                  data = im.tostring("raw", "BGRA")
              except SystemError:
                  # workaround for earlier versions
                  r, g, b, a = im.split()
                  im = Image.merge("RGBA", (b, g, r, a))
              format = QImage.Format_ARGB32
          else:
              raise ValueError("unsupported image mode %r" % im.mode)
  
          # must keep a reference, or Qt will crash!
          self.__data = data or im.tostring()
  
          QImage.__init__(self, self.__data, im.size[0], im.size[1], format)
  
          if colortable:
              self.setColorTable(colortable)
  