add depth conversion and usage

utils/imgtobitmap.py

-#!/usr/local/bin/python3.6
+#!python3
 '''
     Convert image file to python module for use with blit_bitmap.
 
-    Usage imgtobitmap image_file bits-per-pixel >image.py
+    Usage imgtobitmap image_file bits_per_pixel >image.py
 '''
 
 import sys
 from PIL import Image
 from itertools import groupby
+import argparse
 
-bits = int(sys.argv[2])                         # output bits per pixel (1-8)
-img = Image.open(sys.argv[1])
-img = img.convert("P", palette=Image.ADAPTIVE)  # Make sure we are in 8-bit RGB
-palette = img.getpalette()                      # Make copy of palette colors
+def main():
 
-# For all the colors in the palette
-colors = []
-for color in range(1<<bits):
+    parser = argparse.ArgumentParser(
+        prog='imgtobitmap',
+        description='Convert image file to python module for use with bitmap method.')
+
+    parser.add_argument('image_file',
+         help='Name of file containing image to convert')
+
+    parser.add_argument('bits_per_pixel',
+        type=int,
+        choices=range(1,9),
+        default=1,
+        metavar='bits_per_pixel',
+        help='The number of bits to use per pixel (1..8)')
+
+    args = parser.parse_args()
+
+    bits = args.bits_per_pixel
+    img = Image.open(args.image_file)
+    img = img.convert("P", palette=Image.ADAPTIVE, colors=2**bits)
+    palette = img.getpalette()                      # Make copy of palette colors
+
+    # For all the colors in the palette
+    colors = []
+    for color in range(1<<bits):
 
         # get rgb values and convert to 565
         color565 = (
@@ -31,13 +50,13 @@ for color in range(1<<bits):
         colors.append(f'{color:04x}')
 
 
-image_bitstring = ''
-bit_index = 0
-max_colors = 1<<bits
+    image_bitstring = ''
+    bit_index = 0
+    max_colors = 1<<bits
 
-# Run through the image and create a string with the ascii binary representation
-# of the color of each pixel.
-for y in range(img.height):
+    # Run through the image and create a string with the ascii binary representation
+    # of the color of each pixel.
+    for y in range(img.height):
         for x in range(img.width):
             pixel =  img.getpixel((x, y))
             color =  pixel
@@ -46,29 +65,29 @@ for y in range(img.height):
                 bstring += '1' if (color & (1 << bit-1)) else '0'
             image_bitstring += bstring
 
-bitmap_bits = len(image_bitstring)
+    bitmap_bits = len(image_bitstring)
 
-# Create python source with image parameters
-print(f'HEIGHT = {img.height}')
-print(f'WIDTH = {img.width}')
-print(f'COLORS = {max_colors}')
-print(f'BITS = {bitmap_bits}')
-print(f'BPP = {bits}')
-print('PALETTE = [', sep='', end='')
+    # Create python source with image parameters
+    print(f'HEIGHT = {img.height}')
+    print(f'WIDTH = {img.width}')
+    print(f'COLORS = {max_colors}')
+    print(f'BITS = {bitmap_bits}')
+    print(f'BPP = {bits}')
+    print('PALETTE = [', sep='', end='')
 
-for color,rgb in enumerate(colors):
+    for color,rgb in enumerate(colors):
         if color:
             print(',', sep='', end='')
         print(f'0x{rgb}', sep='', end='')
-print("]")
+    print("]")
 
-# Run though image bit string 8 bits at a time
-# and create python array source for memoryview
+    # Run though image bit string 8 bits at a time
+    # and create python array source for memoryview
 
-print("_bitmap =\\", sep='')
-print("b'", sep='', end='')
+    print("_bitmap =\\", sep='')
+    print("b'", sep='', end='')
 
-for i in range(0, bitmap_bits, 8):
+    for i in range(0, bitmap_bits, 8):
 
         if i and i % (16*8) ==0:
             print("'\\\nb'", end='', sep='')
@@ -77,4 +96,7 @@ for i in range(0, bitmap_bits, 8):
         color = int(value,2)
         print(f'\\x{color:02x}', sep='', end='')
 
-print("'\nBITMAP = memoryview(_bitmap)")
+    print("'\nBITMAP = memoryview(_bitmap)")
+
+
+main()