304 lines
9.7 KiB
Python
Executable File
304 lines
9.7 KiB
Python
Executable File
#!/usr/bin/env python3
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# lid: lo-fi image dithering
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# written by sloum
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# licence: public domain - use it, improve it, share it!
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#########
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from PIL import Image
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import sys
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import os, os.path
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from random import randint
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class Dither:
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def __init__(self, data):
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self.source_image = Image.open(data["path"]).convert("L")
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self.width, self.height = self.source_image.size
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self.pixel_count = self.width * self.height
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self.new = self.create_image()
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self.new_pixels = self.new.load()
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self.output_format = data["-f"]
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self.output_name = data["out"]
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self.output_quality = data["-q"]
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self.threshold = data["-t"]
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#used for printing progress
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self.counter = 1
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self.percent_val = 0
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self.hash_val = 0
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def save_file(self):
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output_filename = "{}.{}".format(self.output_name, self.output_format.lower())
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self.new.save(output_filename, self.output_format.upper(), optimize=True, quality=self.output_quality)
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print("\033[20C\nFinished! ~ {}/{}\033[?25h".format(os.getcwd(), output_filename))
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# Default dithering
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def ordered_dither_4(self):
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dots = [[64, 128],[192, 0]]
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print("Dither method: ordered (4 levels)\033[?25l")
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for row in range(0, self.height):
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for col in range(0, self.width):
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dotrow = 1 if row % 2 else 0
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dotcol = 1 if col % 2 else 0
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px = self.get_pixel(col, row)
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self.new_pixels[col, row] = int(px > dots[dotrow][dotcol])
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self.update_progress()
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self.save_file()
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def ordered_dither_9(self):
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dots = [
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[0, 196, 84],
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[168, 140, 56],
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[112, 28, 224]
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]
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print("Dither method: ordered (9 levels)\033[?25l")
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for row in range(0, self.height):
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for col in range(0, self.width):
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if not row % 3:
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dotrow = 2
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elif not row % 2:
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dotrow = 1
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else:
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dotrow = 0
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if not col % 3:
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dotcol = 2
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elif not col % 2:
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dotcol = 1
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else:
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dotcol = 0
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px = self.get_pixel(col, row)
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self.new_pixels[col, row] = int(px > dots[dotrow][dotcol])
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self.update_progress()
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self.save_file()
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def threshold_dither(self):
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if not self.threshold:
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px_list = list(self.source_image.getdata())
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self.threshold = sum(px_list) // len(px_list)
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print("Dither method: threshold (set to: {})\033[?25l".format(self.threshold))
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for row in range(0, self.height):
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for col in range(0, self.width):
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px = self.get_pixel(col, row)
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self.new_pixels[col, row] = int(px > self.threshold)
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self.update_progress()
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self.save_file()
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def random_dither(self):
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print("Dither method: random\033[?25l".format(self.threshold))
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for row in range(0, self.height):
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for col in range(0, self.width):
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px = self.get_pixel(col, row)
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rand = randint(1,255)
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self.new_pixels[col, row] = int(px > rand)
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self.update_progress()
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self.save_file()
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def error_diffusion_dither(self):
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i = self.source_image.load()
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print("Dither method: error diffusion\033[?25l")
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for row in range(0, self.height):
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for col in range(0, self.width):
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self.new_pixels[col, row] = self.update_error(i, row, col)
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self.update_progress()
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self.save_file()
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# Helper for error_diffusion_dither
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def update_error(self, i, r, c):
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current = self.get_pixel(c, r)
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if current > 128:
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res = 1
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diff = -(255 - current)
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else:
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res = 0
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diff = abs(0 - current)
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mov = [[0, 1, 0.4375],[1, 1, 0.0625],[1, 0, 0.3125],[1, -1, 0.1875]]
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for x in mov:
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if r + x[0] >= self.height or c + x[1] >= self.width or c + x[1] <= 0:
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continue
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p = self.get_pixel(c + x[1], r + x[0])
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p = round(diff * x[2] + p)
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if p < 0:
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p = 0
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elif p > 255:
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p = 255
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i[c + x[1], r + x[0]] = p
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return res
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# Create a new image with the given size
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def create_image(self):
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image = Image.new("1", (self.width, self.height))
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return image
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# Get the pixel from the given image
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def get_pixel(self, col, row):
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if col > self.width or row > self.height:
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return None
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# Get Pixel
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pixel = self.source_image.getpixel((col, row))
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return pixel
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def update_progress(self):
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self.counter += 1
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new_percent_val = round(self.counter / self.pixel_count * 100)
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new_hash_val = round(self.counter / self.pixel_count * 10)
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if new_percent_val != self.percent_val or new_hash_val != self.hash_val:
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print("\r{:>3}% |{:<10}|".format(new_percent_val, "#" * new_hash_val), end="")
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self.percent_val = new_percent_val
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self.hash_val = new_hash_val
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#---- END Dither class ----#
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def display_help():
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helptext = """
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lid - lo-fi image dithering
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syntax:
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lid [option]... [infile] [outfile]
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options:
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-f output format. defaults to: png (recommended)
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-m dither mode. defaults to: o4. other options: e, o9, t, r, a
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-q image quality. defaults to: 90. only has effect on png/jpg
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-t threshold. default: image average tone. onls has effect in mode 't'
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arguments:
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infile path to a valid image file on your system
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outfile file name to output, do not include file extension
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example usage:
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lid -f jpeg -q 75 -m e ~/my_picture.png my_dithered_picture
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notes:
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it is highly recommended that users output their files as PNG. the file
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size will be significantly smaller than jpeg and the quality in most
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cases will be about the same.
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the quality flag mostly seems to effect jpegs and does not do a whole
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heap to PNG files, but play around with it as mileage may vary.
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to output an image with each type of dither, use mode a
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"""
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print(helptext)
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# Get and validate the arguments
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# returns dict or None
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def parse_input():
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args = sys.argv[1:]
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argmap = {
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"-f": "png", # output format
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"-q": 25, # optimization quality
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"-m": "o4", # mode, defaults to ordered
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"-t": None, # threshold
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"path": None, # path to file
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"out": "lid_file" # output filename
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}
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if len(args) < 1:
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print("lid error: expected image filepath, received None")
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return None
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if "help" in args or "-h" in args or "--help" in args:
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display_help()
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sys.exit(1)
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item = None
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for x in args:
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if x in argmap:
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item = x
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continue
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elif item:
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argmap[item] = x
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item = None
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elif len(x) > 0 and x[0] == "-":
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print("lid error: unknown flag {}".format(x))
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return None
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else:
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if argmap["path"]:
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argmap["out"] = x
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else:
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argmap["path"] = x
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if not argmap["-f"].lower() in ["jpeg", "jpg", "png", "gif"]:
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print("lid error: invalid format requested with -f flag. Options: jpeg, png, gif. Defaults to png")
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return None
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elif argmap["-f"] == "jpg":
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argmap["-f"] = "jpeg"
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if not argmap["-m"] in ["o4", "e", "o9", "t", "r", "a"]:
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print("lid error: invalid dither mode provided for -m. Options: o4, o9, e, t, r, a. Default: o4")
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return None
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try:
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if argmap["-t"]:
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argmap["-t"] = int(argmap["-t"])
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if argmap["-t"] < 0 or argmap["-t"] > 255:
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print("lid error: threshold value must be between 0 and 255")
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return None
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except ValueError:
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print("lid error: invalid threshold value provided for -m. Must be integer from 0 to 255")
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return None
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try:
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argmap["-q"] = int(argmap["-q"])
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if argmap["-q"] < 1 or argmap["-q"] > 100:
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print("lid error: -q value must be between 1 and 100")
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return None
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except ValueError:
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print("lid error: -q value must be an integer")
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return None
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if not argmap["path"] or not os.path.isfile(argmap["path"]):
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print("lid error: invalid filepath")
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return None
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return argmap
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if __name__ == "__main__":
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request = parse_input()
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if request:
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d = Dither(request)
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if request["-m"] == "o4":
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d.ordered_dither_4()
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elif request["-m"] == "o9":
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d.ordered_dither_9()
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elif request["-m"] == "e":
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d.error_diffusion_dither()
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elif request["-m"] == "t":
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d.threshold_dither()
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elif request["-m"] == "r":
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d.random_dither()
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elif request["-m"] == "a":
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name = request["out"]
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request["out"] = name + "_o4"
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d = Dither(request)
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d.ordered_dither_4()
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request["out"] = name + "_o9"
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d2 = Dither(request)
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d2.ordered_dither_9()
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request["out"] = name + "_t"
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d3 = Dither(request)
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d3.threshold_dither()
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request["out"] = name + "_e"
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d4 = Dither(request)
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d4.error_diffusion_dither()
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request["out"] = name + "_r"
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d4 = Dither(request)
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d4.random_dither()
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else:
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print("Unknown mode flag")
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sys.exit(2)
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sys.exit(0)
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sys.exit(1)
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