papermario/tools/convert_image.py
2020-11-02 16:39:29 +00:00

194 lines
6.9 KiB
Python
Executable File

#! /usr/bin/python3
from sys import argv, stderr
from math import floor, ceil
from itertools import zip_longest
import png
def unpack_color(s):
r = (s >> 11) & 0x1F
g = (s >> 6) & 0x1F
b = (s >> 1) & 0x1F
a = (s & 1) * 0xFF
r = ceil(0xFF * (r / 31))
g = ceil(0xFF * (g / 31))
b = ceil(0xFF * (b / 31))
return r, g, b, a
def pack_color(r, g, b, a):
r = floor(31 * (r / 255))
g = floor(31 * (g / 255))
b = floor(31 * (b / 255))
s = round(a / 0xFF)
s |= (r & 0x1F) << 11
s |= (g & 0x1F) << 6
s |= (b & 0x1F) << 1
return s
def rgb_to_intensity(r, g, b):
return round(r * 0.2126 + g * 0.7152 + 0.0722 * b)
def iter_in_groups(iterable, n, fillvalue=None):
args = [iter(iterable)] * n
return zip_longest(*args, fillvalue=fillvalue)
def reversed_if(iterator, cond):
if cond:
return reversed(list(iterator))
else:
return iterator
class Converter():
def __init__(self, mode, infile, outfile, *argv):
self.mode = mode
self.infile = infile
self.outfile = outfile
self.flip_y = "--flip-y" in argv
self.warned = False
def warn(self, msg):
if not self.warned:
self.warned = True
print(self.infile + ": warning: " + msg, file=stderr)
def convert(self):
img = png.Reader(self.infile)
if self.mode == "rgba32":
with open(self.outfile, "wb") as f:
for row in reversed_if(img.asRGBA()[2], self.flip_y):
f.write(row)
elif self.mode == "rgba16":
with open(self.outfile, "wb") as f:
for row in reversed_if(img.asRGBA()[2], self.flip_y):
for rgba in iter_in_groups(row, 4):
if rgba[3] not in (0, 0xFF):
self.warn("alpha mask mode but translucent pixels used")
color = pack_color(*rgba)
f.write(color.to_bytes(2, byteorder="big"))
elif self.mode == "ci8":
with open(self.outfile, "wb") as f:
for row in reversed_if(img.read()[2], self.flip_y):
f.write(row)
elif self.mode == "ci4":
with open(self.outfile, "wb") as f:
for row in reversed_if(img.read()[2], self.flip_y):
for a, b in iter_in_groups(row, 2):
byte = (a << 4) | b
f.write(byte.to_bytes(1, byteorder="big"))
elif self.mode == "palette":
img.preamble(True)
palette = img.palette(alpha="force")
with open(self.outfile, "wb") as f:
for rgba in palette:
if rgba[3] not in (0, 0xFF):
self.warn("alpha mask mode but translucent pixels used")
color = pack_color(*rgba)
f.write(color.to_bytes(2, byteorder="big"))
elif self.mode == "ia4":
with open(self.outfile, "wb") as f:
for row in reversed_if(img.asRGBA()[2], self.flip_y):
for c1, c2 in iter_in_groups(iter_in_groups(row, 4), 2):
i1 = rgb_to_intensity(*c1[:3])
a1 = c1[3]
i2 = rgb_to_intensity(*c2[:3])
a2 = c2[3]
i1 = floor(7 * (i1 / 0xFF))
i2 = floor(7 * (i2 / 0xFF))
if a1 not in (0, 0xFF) or a2 not in (0, 0xFF):
self.warn("alpha mask mode but translucent pixels used")
if c1[0] != c1[1] != c1[2]:
self.warn("grayscale mode but image is not")
if c2[0] != c2[1] != c2[2]:
self.warn("grayscale mode but image is not")
a1 = 1 if a1 > 128 else 0
a2 = 1 if a2 > 128 else 0
h = (i1 << 1) | a1
l = (i2 << 1) | a2
byte = (h << 4) | l
f.write(byte.to_bytes(1, byteorder="big"))
elif self.mode == "ia8":
with open(self.outfile, "wb") as f:
for row in reversed_if(img.asRGBA()[2], self.flip_y):
for rgba in iter_in_groups(row, 4):
i = rgb_to_intensity(*rgba[:3])
a = rgba[3]
i = floor(15 * (i / 0xFF))
a = floor(15 * (a / 0xFF))
if rgba[0] != rgba[1] != rgba[2]:
self.warn("grayscale mode but image is not")
byte = (i << 4) | a
f.write(byte.to_bytes(1, byteorder="big"))
elif self.mode == "ia16":
with open(self.outfile, "wb") as f:
for row in reversed_if(img.asRGBA()[2], self.flip_y):
for rgba in iter_in_groups(row, 4):
i = rgb_to_intensity(*rgba[:3])
a = rgba[3]
if rgba[0] != rgba[1] != rgba[2]:
self.warn("grayscale mode but image is not")
f.write(bytes((i, a)))
elif self.mode == "i4":
with open(self.outfile, "wb") as f:
for row in reversed_if(img.asRGBA()[2], self.flip_y):
for c1, c2 in iter_in_groups(iter_in_groups(row, 4), 2):
if c1[3] != 0xFF or c2[3] != 0xFF:
self.warn("discarding alpha channel")
i1 = rgb_to_intensity(*c1[:3])
i2 = rgb_to_intensity(*c2[:3])
i1 = floor(15 * (i1 / 0xFF))
i2 = floor(15 * (i2 / 0xFF))
if c1[0] != c1[1] != c1[2]:
self.warn("grayscale mode but image is not")
if c2[0] != c2[1] != c2[2]:
self.warn("grayscale mode but image is not")
byte = (i1 << 4) | i2
f.write(byte.to_bytes(1, byteorder="big"))
elif self.mode == "i8":
with open(self.outfile, "wb") as f:
for row in reversed_if(img.asRGBA()[2], self.flip_y):
for rgba in iter_in_groups(row, 4):
if rgba[3] != 0xFF or rgba[3] != 0xFF:
self.warn("discarding alpha channel")
if rgba[0] != rgba[1] != rgba[2]:
self.warn("grayscale mode but image is not")
i = rgb_to_intensity(*rgba[:3])
f.write(i.to_bytes(1, byteorder="big"))
else:
print("unsupported mode", file=stderr)
exit(1)
if __name__ == "__main__":
if len(argv) < 4:
print("usage: convert_image.py MODE INFILE OUTFILE [--flip-y]")
exit(1)
Converter(*argv[1:]).convert()