ID

39c4c42

date

2024-04-10 23:04:09+00:00

author

Alex Chan <alex@alexwlchan.net>

parent

f53b4c2

message

Add a test for srgbify'ing images with a CMYK profile

changed files

3 files, 23 additions, 5 deletions

• images/examples/the-design-of-everyday-things.jpg
• images/srgbify.py
• images/test_srgbify.py

Changed files

images/examples/the-design-of-everyday-things.jpg (0) → images/examples/the-design-of-everyday-things.jpg (954637)

diff --git a/images/examples/the-design-of-everyday-things.jpg b/images/examples/the-design-of-everyday-things.jpg
new file mode 100644
index 0000000..f9527ee
Binary files /dev/null and b/images/examples/the-design-of-everyday-things.jpg differ

images/srgbify.py (2475) → images/srgbify.py (2777)

diff --git a/images/srgbify.py b/images/srgbify.py
index 08f164c..2396485 100755
--- a/images/srgbify.py
+++ b/images/srgbify.py
@@ -27,6 +27,12 @@ from pillow_heif import register_heif_opener
 register_heif_opener()
 
 
+def get_profile_description(icc_profile):
+    f = io.BytesIO(icc_profile)
+    prf = ImageCms.ImageCmsProfile(f)
+    return prf.profile.profile_description
+
+
 def convert_image_to_srgb(im: Image) -> typing.Union[Image, None]:
     """
     Convert an image to sRGB and return a new Image instance.
@@ -55,11 +61,12 @@ def convert_image_to_srgb(im: Image) -> typing.Union[Image, None]:
             outputProfile=ImageCms.createProfile("sRGB"),
         )
     except PyCMSError as err:
-        if (
-            im.mode == "L"
-            and b"GRAYXYZ" in icc_profile
-            and err.args[0].args == ("cannot build transform",)
-        ):
+        profile_name = get_profile_description(icc_profile)
+
+        is_gray_xyz = im.mode == "L" and b"GRAYXYZ" in icc_profile
+        is_cmyk = im.mode == "CMYK" and profile_name == "U.S. Web Coated (SWOP) v2"
+
+        if err.args[0].args == ("cannot build transform",) and (is_gray_xyz or is_cmyk):
             return ImageCms.profileToProfile(
                 im,
                 inputProfile=io.BytesIO(icc_profile),

images/test_srgbify.py (2378) → images/test_srgbify.py (2665)

diff --git a/images/test_srgbify.py b/images/test_srgbify.py
index a4172d2..790ec75 100644
--- a/images/test_srgbify.py
+++ b/images/test_srgbify.py
@@ -82,3 +82,14 @@ def test_it_preserves_rotation_from_exif_orientation(tmp_path: pathlib.Path):
     new_im = convert_image_to_srgb(im)
 
     assert new_im.size == (3024, 4032)
+
+
+def test_it_converts_images_with_a_cmyk_profile():
+    """
+    If an image has a CMYK colour profile, that gets converted to sRGB.
+    """
+    im = Image.open("images/examples/the-design-of-everyday-things.jpg")
+
+    new_im = convert_image_to_srgb(im)
+
+    assert new_im.mode == "RGB"