Font Shifter

IMAGE_W = 128
TILE_W = 8
TILE_H = 16

with open('sfontorig.bmp','rb') as f:

    header = f.read(0x436)
    filedata = bytearray(f.read())

def find_leftmost(ROW, COL):
    leftmost = 7
    for TILE_ROW in range(16):
        pos = IMAGE_W * 97 + ROW * IMAGE_W * TILE_H + TILE_ROW * IMAGE_W + \
              COL * TILE_W
        for col in range(leftmost+1):
            if filedata[pos+col] != 0:
                break
        if col < leftmost:
            leftmost = col
    return leftmost

def shift_left(left_shift, ROW, COL):
    global filedata
    for TILE_ROW in range(16):
        pos = IMAGE_W * 97 + ROW * IMAGE_W * TILE_H + TILE_ROW * IMAGE_W + \
              COL * TILE_W
        filedata[pos:pos+8] = filedata[pos + left_shift:pos + 8] + \
                              b'\x00' * left_shift


for y in range(6):
    for x in range(16):
        leftmost = find_leftmost(y, x)
        if leftmost != 0:
            shift_left(leftmost, y, x)

with open('sfont.bmp', 'wb') as f:
    f.write(header)
    f.write(filedata)