1  # The MIT License (MIT)
 2  #
 3  # Copyright (c) 2018 Scott Shawcroft for Adafruit Industries LLC
 4  #
 5  # Permission is hereby granted, free of charge, to any person obtaining a copy
 6  # of this software and associated documentation files (the "Software"), to deal
 7  # in the Software without restriction, including without limitation the rights
 8  # to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 9  # copies of the Software, and to permit persons to whom the Software is
10  # furnished to do so, subject to the following conditions:
11  #
12  # The above copyright notice and this permission notice shall be included in
13  # all copies or substantial portions of the Software.
14  #
15  # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16  # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17  # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
18  # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19  # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
20  # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
21  # THE SOFTWARE.
22  """
23  `adafruit_imageload.pnm.pgm.binary`
24  ====================================================
25  
26  Load pixel values (indices or colors) into a bitmap and colors into a palette.
27  
28  * Author(s): Matt Land, Brooke Storm, Sam McGahan
29  
30  """
31  
32  
33  def load(file, width, height, bitmap=None, palette=None):
34      """
35      Load a P5 format file (binary), handle PGM (greyscale)
36      """
37      palette_colors = set()
38      data_start = file.tell()
39      for y in range(height):
40          data_line = iter(bytes(file.read(width)))
41          for pixel in data_line:
42              palette_colors.add(pixel)
43  
44      if palette:
45          palette = build_palette(palette, palette_colors)
46      if bitmap:
47          bitmap = bitmap(width, height, len(palette_colors))
48          palette_colors = list(palette_colors)
49          file.seek(data_start)
50          for y in range(height):
51              data_line = iter(bytes(file.read(width)))
52              for x, pixel in enumerate(data_line):
53                  bitmap[x, y] = palette_colors.index(pixel)
54      return bitmap, palette
55  
56  
57  def build_palette(palette_class, palette_colors):
58      """
59      construct the Palette, and populate it with the set of palette_colors
60      """
61      palette = palette_class(len(palette_colors))
62      for counter, color in enumerate(palette_colors):
63          palette[counter] = bytes([color, color, color])
64      return palette