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test.sh: replace imagemagick with custom python script to produce bit-by-bit identical results on all architectures

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Johannes 'josch' Schauer 2019-03-12 03:07:43 +01:00
parent 8d7996709a
commit d1f101c36a
Signed by untrusted user: josch
GPG key ID: F2CBA5C78FBD83E1
2 changed files with 324 additions and 40 deletions
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306
magick.py Normal file
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@ -0,0 +1,306 @@
#!/usr/bin/env python3
import sys
import numpy
import scipy.signal
import zlib
import struct
def find_closest_palette_color(color, palette):
if color.ndim == 0:
idx = (numpy.abs(palette - color)).argmin()
else:
# naive distance function by computing the euclidean distance in RGB space
idx = ((palette - color) ** 2).sum(axis=-1).argmin()
return palette[idx]
def floyd_steinberg(img, palette):
for y in range(img.shape[0]):
for x in range(img.shape[1]):
oldpixel = img[y, x]
newpixel = find_closest_palette_color(oldpixel, palette)
quant_error = oldpixel - newpixel
img[y, x] = newpixel
if x + 1 < img.shape[1]:
img[y, x + 1] += quant_error * 7 / 16
if y + 1 < img.shape[0]:
img[y + 1, x - 1] += quant_error * 3 / 16
img[y + 1, x] += quant_error * 5 / 16
if x + 1 < img.shape[1] and y + 1 < img.shape[0]:
img[y + 1, x + 1] += quant_error * 1 / 16
return img
def convolve_rgba(img, kernel):
return numpy.stack(
(
scipy.signal.convolve2d(img[:, :, 0], kernel, "same"),
scipy.signal.convolve2d(img[:, :, 1], kernel, "same"),
scipy.signal.convolve2d(img[:, :, 2], kernel, "same"),
scipy.signal.convolve2d(img[:, :, 3], kernel, "same"),
),
axis=-1,
)
def rgb2gray(img):
result = numpy.zeros((60, 60), dtype=numpy.dtype("int64"))
for y in range(img.shape[0]):
for x in range(img.shape[1]):
clin = sum(img[y, x] * [0.2126, 0.7152, 0.0722]) / 0xFFFF
if clin <= 0.0031308:
csrgb = 12.92 * clin
else:
csrgb = 1.055 * clin ** (1 / 2.4) - 0.055
result[y, x] = csrgb * 0xFFFF
return result
def palettize(img, pal):
result = numpy.zeros((img.shape[0], img.shape[1]), dtype=numpy.dtype("int64"))
for y in range(img.shape[0]):
for x in range(img.shape[1]):
for i, col in enumerate(pal):
if numpy.array_equal(img[y, x], col):
result[y, x] = i
break
else:
raise Exception()
return result
def write_png(data, path, bitdepth, colortype, palette=None):
with open(path, "wb") as f:
f.write(b"\x89PNG\r\n\x1A\n")
# PNG image type Colour type Allowed bit depths
# Greyscale 0 1, 2, 4, 8, 16
# Truecolour 2 8, 16
# Indexed-colour 3 1, 2, 4, 8
# Greyscale with alpha 4 8, 16
# Truecolour with alpha 6 8, 16
block = b"IHDR" + struct.pack(
">IIBBBBB",
data.shape[1], # width
data.shape[0], # height
bitdepth, # bitdepth
colortype, # colortype
0, # compression
0, # filtertype
0, # interlaced
)
f.write(
struct.pack(">I", len(block) - 4)
+ block
+ struct.pack(">I", zlib.crc32(block))
)
if palette is not None:
block = b"PLTE"
for col in palette:
block += struct.pack(">BBB", col[0], col[1], col[2])
f.write(
struct.pack(">I", len(block) - 4)
+ block
+ struct.pack(">I", zlib.crc32(block))
)
raw = b""
for y in range(data.shape[0]):
raw += b"\0"
if bitdepth == 16:
raw += data[y].astype(">u2").tobytes()
elif bitdepth == 8:
raw += data[y].astype(">u1").tobytes()
elif bitdepth in [4, 2, 1]:
valsperbyte = 8 // bitdepth
for x in range(0, data.shape[1], valsperbyte):
val = 0
for j in range(valsperbyte):
if x + j >= data.shape[1]:
break
val |= (data[y, x + j].astype(">u2") & (2 ** bitdepth - 1)) << (
(valsperbyte - j - 1) * bitdepth
)
raw += struct.pack(">B", val)
else:
raise Exception()
compressed = zlib.compress(raw)
block = b"IDAT" + compressed
f.write(
struct.pack(">I", len(compressed))
+ block
+ struct.pack(">I", zlib.crc32(block))
)
block = b"IEND"
f.write(struct.pack(">I", 0) + block + struct.pack(">I", zlib.crc32(block)))
def main():
outdir = sys.argv[1]
# create a 256 color palette by first writing 16 shades of gray
# and then writing an array of RGB colors with 6, 8 and 5 levels
# for red, green and blue, respectively
pal8 = numpy.zeros((256, 3), dtype=numpy.dtype("int64"))
i = 0
for gray in range(15, 255, 15):
pal8[i] = [gray, gray, gray]
i += 1
for red in 0, 0x33, 0x66, 0x99, 0xCC, 0xFF:
for green in 0, 0x24, 0x49, 0x6D, 0x92, 0xB6, 0xDB, 0xFF:
for blue in 0, 0x40, 0x80, 0xBF, 0xFF:
pal8[i] = [red, green, blue]
i += 1
assert i == 256
# windows 16 color palette
pal4 = numpy.array(
[
[0x00, 0x00, 0x00],
[0x80, 0x00, 0x00],
[0x00, 0x80, 0x00],
[0x80, 0x80, 0x00],
[0x00, 0x00, 0x80],
[0x80, 0x00, 0x80],
[0x00, 0x80, 0x80],
[0xC0, 0xC0, 0xC0],
[0x80, 0x80, 0x80],
[0xFF, 0x00, 0x00],
[0x00, 0xFF, 0x00],
[0xFF, 0x00, 0x00],
[0x00, 0xFF, 0x00],
[0xFF, 0x00, 0xFF],
[0x00, 0xFF, 0x00],
[0xFF, 0xFF, 0xFF],
],
dtype=numpy.dtype("int64"),
)
# choose values slightly off red, lime and blue because otherwise
# imagemagick will classify the image as Depth: 8/1-bit
pal2 = numpy.array(
[[0, 0, 0], [0xFE, 0, 0], [0, 0xFE, 0], [0, 0, 0xFE]],
dtype=numpy.dtype("int64"),
)
# don't choose black and white or otherwise imagemagick will classify the
# image as bilevel with 8/1-bit depth instead of palette with 8-bit color
# don't choose gray colors or otherwise imagemagick will classify the
# image as grayscale
pal1 = numpy.array(
[[0x01, 0x02, 0x03], [0xFE, 0xFD, 0xFC]], dtype=numpy.dtype("int64")
)
# gaussian kernel with sigma=3
kernel = numpy.array(
[
[0.011362, 0.014962, 0.017649, 0.018648, 0.017649, 0.014962, 0.011362],
[0.014962, 0.019703, 0.02324, 0.024556, 0.02324, 0.019703, 0.014962],
[0.017649, 0.02324, 0.027413, 0.028964, 0.027413, 0.02324, 0.017649],
[0.018648, 0.024556, 0.028964, 0.030603, 0.028964, 0.024556, 0.018648],
[0.017649, 0.02324, 0.027413, 0.028964, 0.027413, 0.02324, 0.017649],
[0.014962, 0.019703, 0.02324, 0.024556, 0.02324, 0.019703, 0.014962],
[0.011362, 0.014962, 0.017649, 0.018648, 0.017649, 0.014962, 0.011362],
],
numpy.float,
)
# constructs a 2D array of a circle with a width of 36
circle = list()
offsets_36 = [14, 11, 9, 7, 6, 5, 4, 3, 3, 2, 2, 1, 1, 1, 0, 0, 0, 0]
for offs in offsets_36 + offsets_36[::-1]:
circle.append([0] * offs + [1] * (len(offsets_36) - offs) * 2 + [0] * offs)
alpha = numpy.zeros((60, 60, 4), dtype=numpy.dtype("int64"))
# draw three circles
for (xpos, ypos, color) in [
(12, 3, [0xFFFF, 0, 0, 0xFFFF]),
(21, 21, [0, 0xFFFF, 0, 0xFFFF]),
(3, 21, [0, 0, 0xFFFF, 0xFFFF]),
]:
for x, row in enumerate(circle):
for y, pos in enumerate(row):
if pos:
alpha[y + ypos, x + xpos] += color
alpha = numpy.clip(alpha, 0, 0xFFFF)
alpha = convolve_rgba(alpha, kernel)
write_png(alpha, outdir + "/alpha.png", 16, 6)
normal16 = alpha[:, :, 0:3]
write_png(normal16, outdir + "/normal16.png", 16, 2)
write_png(normal16 / 0xFFFF * 0xFF, outdir + "/normal.png", 8, 2)
write_png(0xFF - normal16 / 0xFFFF * 0xFF, outdir + "/inverse.png", 8, 2)
gray16 = rgb2gray(normal16)
write_png(gray16, outdir + "/gray16.png", 16, 0)
write_png(gray16 / 0xFFFF * 0xFF, outdir + "/gray8.png", 8, 0)
write_png(
floyd_steinberg(gray16, numpy.arange(16) / 0xF * 0xFFFF) / 0xFFFF * 0xF,
outdir + "/gray4.png",
4,
0,
)
write_png(
floyd_steinberg(gray16, numpy.arange(4) / 0x3 * 0xFFFF) / 0xFFFF * 0x3,
outdir + "/gray2.png",
2,
0,
)
write_png(
floyd_steinberg(gray16, numpy.arange(2) / 0x1 * 0xFFFF) / 0xFFFF * 0x1,
outdir + "/gray1.png",
1,
0,
)
write_png(
palettize(
floyd_steinberg(normal16, pal8 * 0xFFFF / 0xFF) / 0xFFFF * 0xFF, pal8
),
outdir + "/palette8.png",
8,
3,
pal8,
)
write_png(
palettize(
floyd_steinberg(normal16, pal4 * 0xFFFF / 0xFF) / 0xFFFF * 0xFF, pal4
),
outdir + "/palette4.png",
4,
3,
pal4,
)
write_png(
palettize(
floyd_steinberg(normal16, pal2 * 0xFFFF / 0xFF) / 0xFFFF * 0xFF, pal2
),
outdir + "/palette2.png",
2,
3,
pal2,
)
write_png(
palettize(
floyd_steinberg(normal16, pal1 * 0xFFFF / 0xFF) / 0xFFFF * 0xFF, pal1
),
outdir + "/palette1.png",
1,
3,
pal1,
)
main()

58
test.sh
View file

@ -90,48 +90,26 @@ tempdir=$(mktemp --directory --tmpdir img2pdf.XXXXXXXXXX)
trap error EXIT
# we use -strip to remove all timestamps (tIME chunk and exif data)
convert -size 60x60 \( xc:none -fill red -draw 'circle 30,21 30,3' -gaussian-blur 0x3 \) \
\( \( xc:none -fill lime -draw 'circle 39,39 36,57' -gaussian-blur 0x3 \) \
\( xc:none -fill blue -draw 'circle 21,39 24,57' -gaussian-blur 0x3 \) \
-compose plus -composite \
\) -compose plus -composite \
-strip \
"$tempdir/alpha.png"
convert "$tempdir/alpha.png" -background black -alpha remove -alpha off -strip "$tempdir/normal16.png"
convert "$tempdir/normal16.png" -depth 8 -strip "$tempdir/normal.png"
convert "$tempdir/normal.png" -negate -strip "$tempdir/inverse.png"
convert "$tempdir/normal16.png" -colorspace Gray -depth 16 -strip "$tempdir/gray16.png"
convert "$tempdir/normal16.png" -colorspace Gray -dither FloydSteinberg -colors 256 -depth 8 -strip "$tempdir/gray8.png"
convert "$tempdir/normal16.png" -colorspace Gray -dither FloydSteinberg -colors 16 -depth 4 -strip "$tempdir/gray4.png"
convert "$tempdir/normal16.png" -colorspace Gray -dither FloydSteinberg -colors 4 -depth 2 -strip "$tempdir/gray2.png"
convert "$tempdir/normal16.png" -colorspace Gray -dither FloydSteinberg -colors 2 -depth 1 -strip "$tempdir/gray1.png"
# use "-define png:exclude-chunk=bkgd" because otherwise, imagemagick will
# add the background color (white) as an additional entry to the palette
convert "$tempdir/normal.png" -dither FloydSteinberg -colors 2 -define png:exclude-chunk=bkgd -strip "$tempdir/palette1.png"
convert "$tempdir/normal.png" -dither FloydSteinberg -colors 4 -define png:exclude-chunk=bkgd -strip "$tempdir/palette2.png"
convert "$tempdir/normal.png" -dither FloydSteinberg -colors 16 -define png:exclude-chunk=bkgd -strip "$tempdir/palette4.png"
convert "$tempdir/normal.png" -dither FloydSteinberg -colors 256 -define png:exclude-chunk=bkgd -strip "$tempdir/palette8.png"
# instead of using imagemagick to craft the test input, we use a custom python
# script. This is because the output of imagemagick is not bit-by-bit identical
# across versions and architectures.
# See https://gitlab.mister-muffin.de/josch/img2pdf/issues/56
python3 magick.py "$tempdir"
cat << END | ( cd "$tempdir"; md5sum --check --status - )
a99ef2a356c315090b6939fa4ce70516 alpha.png
0df21ebbce5292654119b17f6e52bc81 gray16.png
6faee81b8db446caa5004ad71bddcb5b gray1.png
97e423da517ede069348484a1283aa6c gray2.png
cbed1b6da5183aec0b86909e82b77c41 gray4.png
c0df42fdd69ae2a16ad0c23adb39895e gray8.png
ac6bb850fb5aaee9fa7dcb67525cd0fc inverse.png
3f3f8579f5054270e79a39e7cc4e89e0 normal16.png
cbe63b21443af8321b213bde6666951f normal.png
2f00705cca05fd94406fc39ede4d7322 palette1.png
6cb250d1915c2af99c324c43ff8286eb palette2.png
ab7b3d3907a851692ee36f5349ed0b2c palette4.png
03829af4af8776adf56ba2e68f5b111e palette8.png
7ed200c092c726c68e889514fff0d8f1 alpha.png
bf56e00465b98fb738f6edd2c58dac3b gray16.png
f93c3e3c11dad3f8c11db4fd2d01c2cc gray1.png
d63167c66e8a65bd5c15f68c8d554c48 gray2.png
6bceb845d9c9946adad1526954973945 gray4.png
7ba8152b9146eb7d9d50529189baf7db gray8.png
75130ec7635919e40c7396d45899ddbe inverse.png
bd1a2c9f9dfc51a827eafa3877cf7f83 normal16.png
329eac79fec2e1bc30d7a50ba2e3f2a5 normal.png
9ffd3f592b399f9f9c23892db82369cd palette1.png
6d3a39fe5f2efea5975f048d11a5cb02 palette2.png
57add39e5c278249b64ab23314a41c39 palette4.png
192a3b298d812a156e6f248238d2bb52 palette8.png
END
# use img2pdfprog environment variable if it is set