Merge pull request #5891 from shamrin/stable-jupyter-text-output

Keep IPython/Jupyter text/plain output stable

Tests/test_image.py

@@ -89,6 +89,17 @@ class TestImage:
         # with pytest.raises(MemoryError):
         #   Image.new("L", (1000000, 1000000))
 
+    def test_repr_pretty(self):
+        class Pretty:
+            def text(self, text):
+                self.pretty_output = text
+
+        im = Image.new("L", (100, 100))
+
+        p = Pretty()
+        im._repr_pretty_(p, None)
+        assert p.pretty_output == "<PIL.Image.Image image mode=L size=100x100>"
+
     def test_open_formats(self):
         PNGFILE = "Tests/images/hopper.png"
         JPGFILE = "Tests/images/hopper.jpg"

src/PIL/Image.py

@@ -641,6 +641,22 @@ class Image:
             id(self),
         )
 
+    def _repr_pretty_(self, p, cycle):
+        """IPython plain text display support"""
+
+        # Same as __repr__ but without unpredicatable id(self),
+        # to keep Jupyter notebook `text/plain` output stable.
+        p.text(
+            "<%s.%s image mode=%s size=%dx%d>"
+            % (
+                self.__class__.__module__,
+                self.__class__.__name__,
+                self.mode,
+                self.size[0],
+                self.size[1],
+            )
+        )
+
     def _repr_png_(self):
         """iPython display hook support