Improved wl-paste mimetype handling in ImageGrab

.ci/install.sh

@@ -22,7 +22,8 @@ set -e
 if [[ $(uname) != CYGWIN* ]]; then
     sudo apt-get -qq install libfreetype6-dev liblcms2-dev python3-tk\
                              ghostscript libffi-dev libjpeg-turbo-progs libopenjp2-7-dev\
-                             cmake meson imagemagick libharfbuzz-dev libfribidi-dev
+                             cmake meson imagemagick libharfbuzz-dev libfribidi-dev\
+                             sway wl-clipboard
 fi
 
 python3 -m pip install --upgrade pip

.github/workflows/test.yml

@@ -84,7 +84,9 @@ jobs:
           python3 -m pip install pytest-reverse
         fi
         if [ "${{ matrix.os }}" = "ubuntu-latest" ]; then
-          xvfb-run -s '-screen 0 1024x768x24' .ci/test.sh
+          xvfb-run -s '-screen 0 1024x768x24' sway&
+          export WAYLAND_DISPLAY=wayland-1
+          .ci/test.sh
         else
           .ci/test.sh
         fi

Tests/test_imagegrab.py

@@ -98,3 +98,18 @@ def test_grabclipboard_png(self):
 
         im = ImageGrab.grabclipboard()
         assert_image_equal_tofile(im, "Tests/images/hopper.png")
+
+    @pytest.mark.skipif(
+        (
+            sys.platform != "linux"
+            or not all(shutil.which(cmd) for cmd in ("wl-paste", "wl-copy"))
+        ),
+        reason="Linux with wl-clipboard only",
+    )
+    @pytest.mark.parametrize("ext", ("gif", "png", "ico"))
+    def test_grabclipboard_wl_clipboard(self, ext):
+        image_path = "Tests/images/hopper." + ext
+        with open(image_path, "rb") as fp:
+            subprocess.call(["wl-copy"], stdin=fp)
+        im = ImageGrab.grabclipboard()
+        assert_image_equal_tofile(im, image_path)

src/PIL/ImageGrab.py

@@ -142,7 +142,18 @@ def grabclipboard():
         return None
     else:
         if shutil.which("wl-paste"):
+            output = subprocess.check_output(["wl-paste", "-l"]).decode()
+            mimetypes = output.splitlines()
+            if "image/png" in mimetypes:
+                mimetype = "image/png"
+            elif mimetypes:
+                mimetype = mimetypes[0]
+            else:
+                mimetype = None
+
             args = ["wl-paste"]
+            if mimetype:
+                args.extend(["-t", mimetype])
         elif shutil.which("xclip"):
             args = ["xclip", "-selection", "clipboard", "-t", "image/png", "-o"]
         else: