Class around PixMap objects that allows more python-like access. By Joe Strout.

Mac/Lib/PixMapWrapper.py

+"""PixMapWrapper - defines the PixMapWrapper class, which wraps an opaque
+QuickDraw PixMap data structure in a handy Python class.  Also provides 
+methods to convert to/from pixel data (from, e.g., the img module) or a
+Python Imaging Library Image object.
+
+J. Strout <joe@strout.net>  February 1999"""
+
+import Qd
+import QuickDraw
+import struct
+import MacOS
+import img
+import imgformat
+
+# PixMap data structure element format (as used with struct)
+_pmElemFormat = {
+	'baseAddr':'l',		# address of pixel data
+	'rowBytes':'h',		# bytes per row, plus 0x8000
+	'bounds':'hhhh',	# coordinates imposed over pixel data
+		'top':'h',
+		'left':'h',
+		'bottom':'h',
+		'right':'h',
+	'pmVersion':'h',	# flags for Color QuickDraw
+	'packType':'h',		# format of compression algorithm
+	'packSize':'l',		# size after compression
+	'hRes':'l',			# horizontal pixels per inch
+	'vRes':'l',			# vertical pixels per inch
+	'pixelType':'h',	# pixel format
+	'pixelSize':'h',	# bits per pixel
+	'cmpCount':'h',		# color components per pixel
+	'cmpSize':'h',		# bits per component
+	'planeBytes':'l',	# offset in bytes to next plane
+	'pmTable':'l',		# handle to color table
+	'pmReserved':'l'	# reserved for future use
+}
+
+# PixMap data structure element offset
+_pmElemOffset = {
+	'baseAddr':0,
+	'rowBytes':4,
+	'bounds':6,
+		'top':6,
+		'left':8,
+		'bottom':10,
+		'right':12,
+	'pmVersion':14,
+	'packType':16,
+	'packSize':18,
+	'hRes':22,
+	'vRes':26,
+	'pixelType':30,
+	'pixelSize':32,
+	'cmpCount':34,
+	'cmpSize':36,
+	'planeBytes':38,
+	'pmTable':42,
+	'pmReserved':46
+}
+
+class PixMapWrapper:
+	"""PixMapWrapper -- wraps the QD PixMap object in a Python class,
+	with methods to easily get/set various pixmap fields.  Note: Use the
+	PixMap() method when passing to QD calls."""
+
+	def __init__(self):
+		self.__dict__['data'] = ''
+		self._header = struct.pack("lhhhhhhhlllhhhhlll",
+			id(self.data)+MacOS.string_id_to_buffer,
+			0,						# rowBytes
+			0, 0, 0, 0,				# bounds
+			0,						# pmVersion
+			0, 0,					# packType, packSize
+			72<<16, 72<<16,			# hRes, vRes
+			QuickDraw.RGBDirect,	# pixelType
+			16,						# pixelSize
+			2, 5,					# cmpCount, cmpSize,
+			0, 0, 0)				# planeBytes, pmTable, pmReserved
+		self.__dict__['_pm'] = Qd.RawBitMap(self._header)
+	
+	def _stuff(self, element, bytes):
+		offset = _pmElemOffset[element]
+		fmt = _pmElemFormat[element]
+		self._header = self._header[:offset] \
+			+ struct.pack(fmt, bytes) \
+			+ self._header[offset + struct.calcsize(fmt):]
+		self.__dict__['_pm'] = None
+	
+	def _unstuff(self, element):
+		offset = _pmElemOffset[element]
+		fmt = _pmElemFormat[element]
+		return struct.unpack(fmt, self._header[offset:offset+struct.calcsize(fmt)])[0]
+
+	def __setattr__(self, attr, val):
+		if attr == 'baseAddr':
+			raise 'UseErr', "don't assign to .baseAddr -- assign to .data instead"
+		elif attr == 'data':
+			self.__dict__['data'] = val
+			self._stuff('baseAddr', id(self.data) + MacOS.string_id_to_buffer)
+		elif attr == 'rowBytes':
+			# high bit is always set for some odd reason
+			self._stuff('rowBytes', val | 0x8000)
+		elif attr == 'bounds':
+			# assume val is in official Left, Top, Right, Bottom order!
+			self._stuff('left',val[0])
+			self._stuff('top',val[1])
+			self._stuff('right',val[2])
+			self._stuff('bottom',val[3])
+		elif attr == 'hRes' or attr == 'vRes':
+			# 16.16 fixed format, so just shift 16 bits
+			self._stuff(attr, int(val) << 16)
+		elif attr in _pmElemFormat.keys():
+			# any other pm attribute -- just stuff
+			self._stuff(attr, val)
+		else:
+			self.__dict__[attr] = val	
+
+	def __getattr__(self, attr):
+		if attr == 'rowBytes':
+			# high bit is always set for some odd reason
+			return self._unstuff('rowBytes') & 0x7FFF
+		elif attr == 'bounds':
+			# return bounds in official Left, Top, Right, Bottom order!
+			return ( \
+				self._unstuff('left'),
+				self._unstuff('top'),
+				self._unstuff('right'),
+				self._unstuff('bottom') )
+		elif attr == 'hRes' or attr == 'vRes':
+			# 16.16 fixed format, so just shift 16 bits
+			return self._unstuff(attr) >> 16
+		elif attr in _pmElemFormat.keys():
+			# any other pm attribute -- just unstuff
+			return self._unstuff(attr)
+		else:
+			return self.__dict__[attr]	
+
+		
+	def PixMap(self):
+		"Return a QuickDraw PixMap corresponding to this data."
+		if not self.__dict__['_pm']:
+			self.__dict__['_pm'] = Qd.RawBitMap(self._header)
+		return self.__dict__['_pm']
+
+	def blit(self, x1=0,y1=0,x2=None,y2=None, port=None):
+		"""Draw this pixmap into the given (default current) grafport.""" 
+		src = self.bounds
+		dest = [x1,y1,x2,y2]
+		if x2 == None:
+			dest[2] = x1 + src[2]-src[0]
+		if y2 == None:
+			dest[3] = y1 + src[3]-src[1]
+		if not port: port = Qd.GetPort()
+		Qd.CopyBits(self.PixMap(), port.portBits, src, tuple(dest),
+				QuickDraw.srcCopy, None)
+	
+	def fromstring(self,s,width,height,format=imgformat.macrgb):
+		"""Stuff this pixmap with raw pixel data from a string.
+		Supply width, height, and one of the imgformat specifiers."""
+		# we only support 16- and 32-bit mac rgb...
+		# so convert if necessary
+		if format != imgformat.macrgb and format != imgformat.macrgb16:
+			# (LATER!)
+			raise "NotImplementedError", "conversion to macrgb or macrgb16"
+		self.data = s
+		self.bounds = (0,0,width,height)
+		self.cmpCount = 3
+		self.pixelType = QuickDraw.RGBDirect
+		if format == imgformat.macrgb:
+			self.pixelSize = 32
+			self.cmpSize = 8
+		else:
+			self.pixelSize = 16
+			self.cmpSize = 5
+		self.rowBytes = width*self.pixelSize/8
+
+	def tostring(self, format=imgformat.macrgb):
+		"""Return raw data as a string in the specified format."""
+		# is the native format requested?  if so, just return data
+		if (format == imgformat.macrgb and self.pixelSize == 32) or \
+		   (format == imgformat.macrgb16 and self.pixelsize == 16):
+			return self.data
+		# otherwise, convert to the requested format
+		# (LATER!)
+			raise "NotImplementedError", "data format conversion"
+
+	def fromImage(self,im):
+		"""Initialize this PixMap from a PIL Image object."""
+		# We need data in ARGB format; PIL can't currently do that,
+		# but it can do RGBA, which we can use by inserting one null
+		# up frontpm = 
+		if im.mode != 'RGBA': im = im.convert('RGBA')
+		data = chr(0) + im.tostring()
+		self.fromstring(data, im.size[0], im.size[1])
+
+	def toImage(self):
+		"""Return the contents of this PixMap as a PIL Image object."""
+		import Image
+		# our tostring() method returns data in ARGB format,
+		# whereas Image uses RGBA; a bit of slicing fixes this...
+		data = self.tostring()[1:] + chr(0)
+		bounds = self.bounds
+		return Image.fromstring('RGBA',(bounds[2]-bounds[0],bounds[3]-bounds[1]),data)
+
+def test():
+	import MacOS
+	import macfs
+	import Image
+	fsspec, ok = macfs.PromptGetFile("Image File:")
+	if not ok: return
+	path = fsspec.as_pathname()
+	pm = PixMapWrapper()
+	pm.fromImage( Image.open(path) )
+	pm.blit(20,20)
+	return pm
+