font_png_to_h.py

#!/usr/bin/python
# read an ascii ppm generated by gimp
#
import sys
import png

if len(sys.argv) < 2:
    print "usage: " + sys.argv[0] + " file.png\n\n"
    sys.exit(1)

fn = sys.argv[1]
fh = open(fn, "r")

pngr = png.Reader(fh)
(png_w, png_h, png_data, png_options) = pngr.read()

print png_options

raw_data = list(png_data)

font = [[], []]

for row in (raw_data):
    for x in range(0, len(row), 4):
        red = row[x]
        if (red == 0):
            # black
            font[1].append(1)
            font[0].append(0)
        elif (red == 255):
            # white
            font[1].append(0)
            font[0].append(1)
        else:
            # transparent
            font[1].append(0)
            font[0].append(0)

print ("got %d bytes of fotn data\n" % (len(font[0])))

#debug output image
max_char = 90
output_w = max_char * 16
output_h = png_h
pngh = open('font.png', 'wb')
pngw = png.Writer(output_w, output_h, greyscale=True)


# debug output png
# font data is one char after the other (12px x 18px)
pngdata = []
for y in range(output_h):
    row = []
    for x in range(max_char):
        for i in range(16):
            idx  = png_w * y + x * 16 + i
            if (font[1][idx] == 1):
                color = 0
            elif (font[0][idx] == 1):
                color = 255
            else:
                color = 128
            row.append(color)
    pngdata.append(row)

#print(pngdata)

pngw.write(pngh, pngdata)

pngh.close()


# dump to header
fheader =  open('src/font.h', 'w')

fheader.write("#ifndef __FONT_H__\n")
fheader.write("#define __FONT_H__\n")
fheader.write("\n")

fheader.write("// font data\n")
fheader.write("static const uint8_t font_data[2][18][256*2] =  {\n")

# blow up font to 16 bits per pixel, add 2 px in front and back
count = 0
for col in range(2):
    fheader.write("\n    {  // color %d" % (col))
    for row in range(18):
        fheader.write("\n        {  //row %d\n            " % (row))
        for char in range(256):
            for b in range(2):
                byte = 0
                for i in range(8):
                    index  = 256*8*2 * row + char * 2 * 8 + b*8 + i
                    bit = font[col][index]
                    byte = (byte << 1) | bit
                fheader.write(hex(byte) + ", ")
            fheader.write("\n            ")
            count = count + 1
        fheader.write("        },")
    fheader.write("    },")
fheader.write("};\n")

fheader.write("#endif  // __FONT_H__\n")

print ("wrote %d bytes font data" % ( count))