text: ##    pygame - Python Game Library
  ##    Copyright (C) 2007 Marcus von Appen
  ##
  ##    This library is free software; you can redistribute it and/or
  ##    modify it under the terms of the GNU Library General Public
  ##    License as published by the Free Software Foundation; either
  ##    version 2 of the License, or (at your option) any later version.
  ##
  ##    This library is distributed in the hope that it will be useful,
  ##    but WITHOUT ANY WARRANTY; without even the implied warranty of
  ##    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  ##    Library General Public License for more details.
  ##
  ##    You should have received a copy of the GNU Library General Public
  ##    License along with this library; if not, write to the Free
  ##    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  ##
  ##    Marcus von Appen
  ##    mva@sysfault.org
  
  """pygame module for accessing surface pixel data using numpy
  
  Functions to convert pixel data between pygame Surfaces and Numpy
  arrays. This module will only be available when pygame can use the
  external Numpy package.
  
  Note, that numpyarray is an optional module. It requires that Numpy is
  installed to be used. If not installed, an exception will be raised when
  it is used. eg. ImportError: no module named numpy
  
  Every pixel is stored as a single integer value to represent the red,
  green, and blue colors. The 8bit images use a value that looks into a
  colormap. Pixels with higher depth use a bit packing process to place
  three or four values into a single number.
  
  The Numpy arrays are indexed by the X axis first, followed by the Y
  axis. Arrays that treat the pixels as a single integer are referred to
  as 2D arrays. This module can also separate the red, green, and blue
  color values into separate indices. These types of arrays are referred
  to as 3D arrays, and the last index is 0 for red, 1 for green, and 2 for
  blue.
  
  In contrast to Numeric Numpy does use unsigned 16bit integers, images
  with 16bit data will be treated as unsigned integers.
  """
  
  import pygame
  from pygame.compat import bytes_
  from pygame.surfarray import blit_array
  import numpy
  
  
  def array2d (surface):
      """pygame.numpyarray.array2d (Surface): return array
  
      copy pixels into a 2d array
  
      Copy the pixels from a Surface into a 2D array. The bit depth of the
      surface will control the size of the integer values, and will work
      for any type of pixel format.
  
      This function will temporarily lock the Surface as pixels are copied
      (see the Surface.lock - lock the Surface memory for pixel access
      method).
      """
      bpp = surface.get_bytesize ()
      if bpp <= 0 or bpp > 4:
          raise ValueError("unsupported bit depth for 2D array")
  
      size = surface.get_size ()
      width, height = size
  
      # Taken from Alex Holkner's pygame-ctypes package. Thanks a lot.
      data = numpy.frombuffer (surface.get_buffer (), numpy.uint8)
      pitch = surface.get_pitch ()
      row_size = width * bpp
      if pitch != row_size:
          data.shape = (height, pitch)
          data = data[:, 0:row_size]
  
      dtype = (None, numpy.uint8, numpy.uint16, numpy.int32, numpy.int32)[bpp]
      array = numpy.zeros (size, dtype, 'F')
      array_data = numpy.frombuffer (array, numpy.uint8)
      if bpp == 3:
          data.shape = (height, width, 3)
          array_data.shape = (height, width, 4)
          array_data[:,:,:3] = data[...]
      else:
          data.shape = (height, row_size)
          array_data.shape = (height, row_size)
          array_data[...] =  data[...]
      return array
  
  def pixels2d (surface):
      """pygame.numpyarray.pixels2d (Surface): return array
  
      reference pixels into a 2d array
  
      Create a new 2D array that directly references the pixel values in a
      Surface. Any changes to the array will affect the pixels in the
      Surface. This is a fast operation since no data is copied.
  
      Pixels from a 24-bit Surface cannot be referenced, but all other
      Surface bit depths can.
  
      The Surface this references will remain locked for the lifetime of
      the array (see the Surface.lock - lock the Surface memory for pixel
      access method).
      """
      bpp = surface.get_bytesize ()
      if bpp == 3 or bpp < 1 or bpp > 4:
          raise ValueError("unsupported bit depth for 2D reference array")
  
      typecode = (numpy.uint8, numpy.uint16, None, numpy.int32)[bpp - 1]
      array = numpy.frombuffer (surface.get_buffer (), typecode)
      array.shape = surface.get_height (), surface.get_pitch () / bpp
  
      # Padding correction for certain depth due to padding bytes.
      array = array[:,:surface.get_width ()]
      array = numpy.transpose (array)
      return array
  
  def array3d (surface):
      """pygame.numpyarray.array3d (Surface): return array
  
      copy pixels into a 3d array
  
      Copy the pixels from a Surface into a 3D array. The bit depth of the
      surface will control the size of the integer values, and will work
      for any type of pixel format.
  
      This function will temporarily lock the Surface as pixels are copied
      (see the Surface.lock - lock the Surface memory for pixel access
      method).
      """
      bpp = surface.get_bytesize ()
      array = array2d (surface)
  
      # Taken from from Alex Holkner's pygame-ctypes package. Thanks a
      # lot.
      if bpp == 1:
          palette = surface.get_palette ()
          # Resolve the correct values using the color palette
          pal_r = numpy.array ([c[0] for c in palette])
          pal_g = numpy.array ([c[1] for c in palette])
          pal_b = numpy.array ([c[2] for c in palette])
          planes = [numpy.choose (array, pal_r),
                    numpy.choose (array, pal_g),
                    numpy.choose (array, pal_b)]
          array = numpy.array (planes, numpy.uint8)
          array = numpy.transpose (array, (1, 2, 0))
          return array
      elif bpp == 2:
          # Taken from SDL_GetRGBA.
          masks = surface.get_masks ()
          shifts = surface.get_shifts ()
          losses = surface.get_losses ()
          vr = (array & masks[0]) >> shifts[0]
          vg = (array & masks[1]) >> shifts[1]
          vb = (array & masks[2]) >> shifts[2]
          planes = [(vr << losses[0]) + (vr >> (8 - (losses[0] << 1))),
                    (vg << losses[1]) + (vg >> (8 - (losses[1] << 1))),
                    (vb << losses[2]) + (vb >> (8 - (losses[2] << 1)))]
          array = numpy.array (planes, numpy.uint8)
          return numpy.transpose (array, (1, 2, 0))
      else:
          masks = surface.get_masks ()
          shifts = surface.get_shifts ()
          losses = surface.get_losses ()
          planes = [((array & masks[0]) >> shifts[0]), # << losses[0], Assume 0
                    ((array & masks[1]) >> shifts[1]), # << losses[1],
                    ((array & masks[2]) >> shifts[2])] # << losses[2]]
          array = numpy.array (planes, numpy.uint8)
          return numpy.transpose (array, (1, 2, 0))
  
  def pixels3d (surface):
      """pygame.numpyarray.pixels3d (Surface): return array
  
      reference pixels into a 3d array
  
      Create a new 3D array that directly references the pixel values in a
      Surface. Any changes to the array will affect the pixels in the
      Surface. This is a fast operation since no data is copied.
  
      This will only work on Surfaces that have 24-bit or 32-bit
      formats. Lower pixel formats cannot be referenced.
  
      The Surface this references will remain locked for the lifetime of
      the array (see the Surface.lock - lock the Surface memory for pixel
      access method).
      """
      bpp = surface.get_bytesize ()
      if bpp < 3 or bpp > 4:
          raise ValueError("unsupported bit depth for 3D reference array")
      lilendian = pygame.get_sdl_byteorder () == pygame.LIL_ENDIAN
  
      start = 0
      step = 0
  
      # Check for RGB or BGR surface.
      shifts = surface.get_shifts ()
      if shifts[0] == 16 and shifts[1] == 8 and shifts[2] == 0:
          # RGB
          if lilendian:
              start = 2
              step = -1
          else:
              start = 0
              step = 1
      elif shifts[2] == 16 and shifts[1] == 8 and shifts[0] == 0:
          # BGR
          if lilendian:
              start = 0
              step = 1
          else:
              start = 2
              step = -1
      else:
          raise ValueError("unsupported colormasks for 3D reference array")
  
      if bpp == 4 and not lilendian:
          start += 1
  
      array = numpy.ndarray \
              (shape=(surface.get_width (), surface.get_height (), 3),
               dtype=numpy.uint8, buffer=surface.get_buffer (),
               offset=start, strides=(bpp, surface.get_pitch (),step))
      return array
  
  def array_alpha (surface):
      """pygame.numpyarray.array_alpha (Surface): return array
  
      copy pixel alphas into a 2d array
  
      Copy the pixel alpha values (degree of transparency) from a Surface
      into a 2D array. This will work for any type of Surface
      format. Surfaces without a pixel alpha will return an array with all
      opaque values.
  
      This function will temporarily lock the Surface as pixels are copied
      (see the Surface.lock - lock the Surface memory for pixel access
      method).
      """
      if (surface.get_bytesize () == 1 or
          surface.get_alpha () is None or
          surface.get_masks ()[3] == 0):
          # 1 bpp surfaces and surfaces without per-pixel alpha are always
          # fully opaque.
          array = numpy.empty (surface.get_width () * surface.get_height (),
                               numpy.uint8)
          array.fill (0xff)
          array.shape = surface.get_width (), surface.get_height ()
          return array
  
      array = array2d (surface)
      if surface.get_bytesize () == 2:
          # Taken from SDL_GetRGBA.
          va = (array & surface.get_masks ()[3]) >> surface.get_shifts ()[3]
          array = ((va << surface.get_losses ()[3]) +
                   (va >> (8 - (surface.get_losses ()[3] << 1))))
      else:
          # Taken from _numericsurfarray.c.
          array = array >> surface.get_shifts ()[3] << surface.get_losses ()[3]
      array = array.astype (numpy.uint8)
      return array
  
  def pixels_alpha (surface):
      """pygame.numpyarray.pixels_alpha (Surface): return array
  
      reference pixel alphas into a 2d array
  
      Create a new 2D array that directly references the alpha values
      (degree of transparency) in a Surface. Any changes to the array will
      affect the pixels in the Surface. This is a fast operation since no
      data is copied.
  
      This can only work on 32-bit Surfaces with a per-pixel alpha value.
  
      The Surface this array references will remain locked for the
      lifetime of the array.
      """
      if surface.get_bytesize () != 4:
          raise ValueError("unsupported bit depth for alpha reference array")
      lilendian = pygame.get_sdl_byteorder () == pygame.LIL_ENDIAN
  
      # ARGB surface.
      start = 0
  
      if surface.get_shifts ()[3] == 24 and lilendian:
          # RGBA surface.
          start = 3
      elif surface.get_shifts ()[3] == 0 and not lilendian:
          start = 3
      else:
          raise ValueError("unsupported colormasks for alpha reference array")
  
      array = numpy.ndarray \
              (shape=(surface.get_width (), surface.get_height ()),
               dtype=numpy.uint8, buffer=surface.get_buffer (),
               offset=start, strides=(4, surface.get_pitch ()))
      return array
  
  def array_colorkey (surface):
      """pygame.numpyarray.array_colorkey (Surface): return array
  
      copy the colorkey values into a 2d array
  
      Create a new array with the colorkey transparency value from each
      pixel. If the pixel matches the colorkey it will be fully
      tranparent; otherwise it will be fully opaque.
  
      This will work on any type of Surface format. If the image has no
      colorkey a solid opaque array will be returned.
  
      This function will temporarily lock the Surface as pixels are
      copied.
      """
      colorkey = surface.get_colorkey ()
      if colorkey == None:
          # No colorkey, return a solid opaque array.
          array = numpy.empty (surface.get_width () * surface.get_height (),
                               numpy.uint8)
          array.fill (0xff)
          array.shape = surface.get_width (), surface.get_height ()
          return array
  
      # Taken from from Alex Holkner's pygame-ctypes package. Thanks a
      # lot.
      array = array2d (surface)
      # Check each pixel value for the colorkey and mark it as opaque or
      # transparent as needed.
      val = surface.map_rgb (colorkey)
      array = numpy.choose (numpy.equal (array, val),
                            (numpy.uint8 (0xff), numpy.uint8 (0)))
      array.shape = surface.get_width (), surface.get_height ()
      return array
  
  def make_surface (array):
      """pygame.numpyarray.make_surface (array): return Surface
  
      copy an array to a new surface
  
      Create a new Surface that best resembles the data and format on the
      array. The array can be 2D or 3D with any sized integer values.
      """
      # Taken from from Alex Holkner's pygame-ctypes package. Thanks a
      # lot.
      bpp = 0
      r = g = b = 0
      shape = array.shape
      if len (shape) == 2:
          # 2D array
          bpp = 8
          r = 0xFF >> 6 << 5
          g = 0xFF >> 5 << 2
          b = 0xFF >> 6
      elif len (shape) == 3 and shape[2] == 3:
          bpp = 32
          r = 0xff << 16
          g = 0xff << 8
          b = 0xff
      else:
          raise ValueError("must be a valid 2d or 3d array")
  
      surface = pygame.Surface ((shape[0], shape[1]), 0, bpp, (r, g, b, 0))
      blit_array (surface, array)
      return surface
  
  def map_array (surface, array):
      """pygame.numpyarray.map_array (Surface, array3d): return array2d
  
      map a 3d array into a 2d array
  
      Convert a 3D array into a 2D array. This will use the given Surface
      format to control the conversion. Palette surface formats are not
      supported.
  
      Note: arrays do not need to be 3D, as long as the minor axis has
      three elements giving the component colours, any array shape can be
      used (for example, a single colour can be mapped, or an array of
      colours).
      """
      # Taken from from Alex Holkner's pygame-ctypes package. Thanks a
      # lot.
      bpp = surface.get_bytesize ()
      if bpp <= 1 or bpp > 4:
          raise ValueError("unsupported bit depth for surface array")
  
      shape = array.shape
      if shape[-1] != 3:
          raise ValueError("array must be a 3d array of 3-value color data")
  
      shifts = surface.get_shifts ()
      losses = surface.get_losses ()
      if array.dtype != numpy.int32:
          array = array.astype(numpy.int32)
      out       = array[...,0] >> losses[0] << shifts[0]
      out[...] |= array[...,1] >> losses[1] << shifts[1]
      out[...] |= array[...,2] >> losses[2] << shifts[2]
      if surface.get_flags() & pygame.SRCALPHA:
          out[...] |= numpy.int32(255) >> losses[3] << shifts[3]
      return out
  