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#!/usr/bin/env python3
# SPDX-License-Identifier: LGPL-3.0-or-later
# Copyright (C) 2020 Daniel Thompson
import argparse
import sys
import os.path
from PIL import Image
def varname(p):
return os.path.basename(os.path.splitext(p)[0])
def encode(im):
pixels = im.load()
rle = []
rl = 0
px = pixels[0, 0]
def encode_pixel(px, rl):
while rl > 255:
rle.append(255)
rle.append(0)
rl -= 255
rle.append(rl)
for y in range(im.height):
for x in range(im.width):
newpx = pixels[x, y]
if newpx == px:
rl += 1
assert(rl < (1 << 21))
continue
# Code the previous run
encode_pixel(px, rl)
# Start a new run
rl = 1
px = newpx
# Handle the final run
encode_pixel(px, rl)
return (im.width, im.height, bytes(rle))
def encode_8bit(im):
pixels = im.load()
rle = []
rl = 0
px = pixels[0, 0]
def encode_pixel(px, rl):
print(rl)
px = (px[0] & 0xe0) | ((px[1] & 0xe0) >> 3) | ((px[2] & 0xc0) >> 6)
rle.append(px)
if rl > 0:
rle.append(px)
rl -= 2
if rl > (1 << 14):
rle.append(0x80 | ((rl >> 14) & 0x7f))
if rl > (1 << 7):
rle.append(0x80 | ((rl >> 7) & 0x7f))
if rl >= 0:
rle.append( rl & 0x7f )
for y in range(im.height):
for x in range(im.width):
newpx = pixels[x, y]
if newpx == px:
rl += 1
assert(rl < (1 << 21))
continue
# Code the previous run
encode_pixel(px, rl)
# Start a new run
rl = 1
px = newpx
# Handle the final run
encode_pixel(px, rl)
return (im.width, im.height, bytes(rle))
def render_c(image, fname):
print(f'// 1-bit RLE, generated from {fname}, {len(image[2])} bytes')
print(f'static const uint8_t {varname(fname)}[] = {{')
print(' ', end='')
i = 0
for rl in image[2]:
print(f' {hex(rl)},', end='')
i += 1
if i == 12:
print('\n ', end='')
i = 0
print('\n};')
def decode_to_ascii(image):
(sx, sy, rle) = image
data = bytearray(2*sx)
dp = 0
black = ord('#')
white = ord(' ')
color = black
for rl in rle:
while rl:
data[dp] = color
data[dp+1] = color
dp += 2
rl -= 1
if dp >= (2*sx):
print(data.decode('utf-8'))
dp = 0
if color == black:
color = white
else:
color = black
# Check the image is the correct length
assert(dp == 0)
parser = argparse.ArgumentParser(description='RLE encoder tool.')
parser.add_argument('files', nargs='+',
help='files to be encoded')
parser.add_argument('--ascii', action='store_true',
help='Run the resulting image(s) through an ascii art decoder')
parser.add_argument('--c', action='store_true',
help='Render the output as C instead of python')
args = parser.parse_args()
for fname in args.files:
image = encode(Image.open(fname))
if args.c:
render_c(image, fname)
else:
print(f'# 1-bit RLE, generated from {fname}, {len(image[2])} bytes')
print(f'{varname(fname)} = {image}')
print()
if args.ascii:
print()
decode_to_ascii(image)
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