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Added conversion between RGB/RGBA/RGBX and LAB #6647

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Merged
hugovk merged 1 commit into from
Oct 19, 2022
+24 −0
Merged

Added conversion between RGB/RGBA/RGBX and LAB #6647

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11 changes: 11 additions & 0 deletions Tests/test_image_convert.py
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Original file line number Diff line number Diff line change
Expand Up @@ -242,6 +242,17 @@ def test_p2pa_palette():
assert im_pa.getpalette() == im.getpalette()


@pytest.mark.parametrize("mode", ("RGB", "RGBA", "RGBX"))
def test_rgb_lab(mode):
im = Image.new(mode, (1, 1))
converted_im = im.convert("LAB")
assert converted_im.getpixel((0, 0)) == (0, 128, 128)

im = Image.new("LAB", (1, 1), (255, 0, 0))
converted_im = im.convert(mode)
assert converted_im.getpixel((0, 0))[:3] == (0, 255, 255)


def test_matrix_illegal_conversion():
# Arrange
im = hopper("CMYK")
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13 changes: 13 additions & 0 deletions src/PIL/Image.py
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Original file line number Diff line number Diff line change
Expand Up @@ -1027,6 +1027,19 @@ def convert_transparency(m, v):
warnings.warn("Couldn't allocate palette entry for transparency")
return new

if "LAB" in (self.mode, mode):
other_mode = mode if self.mode == "LAB" else self.mode
if other_mode in ("RGB", "RGBA", "RGBX"):
from . import ImageCms

srgb = ImageCms.createProfile("sRGB")
lab = ImageCms.createProfile("LAB")
profiles = [lab, srgb] if self.mode == "LAB" else [srgb, lab]
transform = ImageCms.buildTransform(
profiles[0], profiles[1], self.mode, mode
)
return transform.apply(self)

# colorspace conversion
if dither is None:
dither = Dither.FLOYDSTEINBERG
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