Initial commit

pixelfont.py

@@ -0,0 +1,109 @@
+#!/usr/bin/env python
+#
+# This file provides a small 4x5 (width and height) font primarily designed to
+# present the current date and time.
+#
+# The .data property provides the bits for each character available in .alphabet.
+# For each character, the consumer must extract the bits (4x5 == 20 bits) from
+# the offset given by the the character's position in .alphabet * 20.
+#
+# Example:
+#
+#   font = PixelFont()
+#   digit = '2'   # Extract and plot the digit '2'
+#
+#   start_bit = font.alphabet.find(digit) * font.width * font.height
+#   font_byte = start_bit // 8
+#   font_bit = start_bit % 8
+#   for y in range(font.height):
+#     for x in range(font.width):
+#       is_lit = font.data[font_byte] & (1<<font_bit)
+#       put_pixel(x, y, is_lit)
+#       font_bit +=1
+#       if font_bit == 8:
+#         font_byte += 1
+#         font_bit = 0
+#
+# To add new symbols to the font, edit the `font` variable in to_bytearray(),
+# add a new 4x5 block representing the symbol, update the .alphabet property
+# and then run this file to generate updated data for Python and C:
+#
+#   $ ./pixelfont.py
+#
+# Update the variables in the constructor with the new output.
+#
+class PixelFont:
+	def __init__(self):
+		self.width = 4
+		self.height = 5
+		self.alphabet = ' %\'-./0123456789:cms'
+		self.data = bytearray("\x00\x00\x50\x24\x51\x66\x00\x00\x60\x00\x00\x00\x42\x24\x11\x57\x55\x27\x23\x72\x47\x17\x77\x64\x74\x55\x47\x74\x71\x74\x17\x57\x77\x44\x44\x57\x57\x77\x75\x74\x20\x20\x20\x15\x25\x75\x57\x75\x71\x74")
+
+	def to_bytearray(self):
+###|123|123|123|123|123|123|123|123|123|123|123|123|123|123|123|123|123|123|123|
+		font = """
+    # #  ##           # ###  #  ### ### # # ### ### ### ### ###      #  # # ### 
+      #  ##           # # # ##    #   # # # #   #     # # # # #  #  # # ### #   
+     #       ##      #  # #  #  ###  ## ### ### ###   # ### ###     #   ### ### 
+    #               #   # #  #  #     #   #   # # #   # # #   #  #  # # # #   # 
+    # #          #  #   ### ### ### ###   # ### ###   # ### ###      #  # # ### 
+""".strip('\n').replace('\n', '')
+###|123|123|123|123|123|123|123|123|123|123|123|123|123|123|123|123|123|123|123|
+
+		data = bytearray()
+		byte = bits = 0
+		num_digits = len(self.alphabet)
+		for i in range(num_digits):
+			pixels = bytearray()
+			for row in range(self.height):
+				for col in range(self.width):
+					pos = row * num_digits * self.width
+					pos += i * self.width + col
+					is_lit = int(font[pos] != ' ')
+					byte |= is_lit << bits
+					bits += 1
+					if bits == 8:
+						data.append(byte)
+						bits = byte = 0
+		if bits:
+			data.append(byte)
+		return data
+
+if __name__ == '__main__':
+	import sys
+
+	f = PixelFont()
+
+	data = f.to_bytearray()
+	print('')
+	print('# Computed with pixelfont.py')
+	print('    self.width = {}'.format(f.width))
+	print('    self.height = {}'.format(f.height))
+	print('    self.alphabet = "{}"'.format(f.alphabet))
+	print('    self.data = bytearray("{}")'.format("".join("\\x{:02x}".format(x) for x in data)))
+	print('')
+	print('/* Computed with pixelfont.py */')
+	print('static int font_width = {};'.format(f.width))
+	print('static int font_height = {};'.format(f.height))
+	print('static char font_alphabet[] = "{}";'.format(f.alphabet))
+	print('static unsigned char font_data[] = "{}";'.format("".join("\\x{:02x}".format(x) for x in data)))
+
+	debugstr = '12:30 1.8\'c'
+	for j in range(len(debugstr)):
+		digit = debugstr[j]
+		i = f.alphabet.find(digit)
+		if i < 0:
+			print('WARN: digit {} not found in alphabet'.format(digit))
+		font_byte = (i * f.height * f.width) // 8
+		font_bit = (i * f.height * f.width) % 8
+		for row in range(f.height):
+			for col in range(f.width):
+				val = 0
+				if data[font_byte] & (1 << font_bit):
+					val = 255
+				sys.stdout.write('#' if val else ' ')
+				font_bit += 1
+				if font_bit == 8:
+					font_byte += 1
+					font_bit = 0
+			sys.stdout.write('\n')