Add note to PIL.Image.DecompressionBombError msgs

See #413

CHANGELOG.md

@@ -7,6 +7,7 @@ All notable changes to this project will be documented in this file. The format
 ### Added
 
 - Add `strict=True/False` parameter to `Page.crop(...)` and `Page.within_bbox(...)`; default is `True`, while `False` bypasses the `test_proposed_bbox(...)` check. ([#421](https://github.com/jsvine/pdfplumber/issues/421))
+- Add more guidance to exception when `.to_image(...)` raises `PIL.Image.DecompressionBombError`. ([#413](https://github.com/jsvine/pdfplumber/issues/413))
 
 ### Fixed
 

pdfplumber/display.py

@@ -62,7 +62,18 @@ def postprocess(img: WandImage) -> WandImage:
             colorspace="rgb",
         ) as bg:
             bg.composite(img, 0, 0)
-            im = PIL.Image.open(BytesIO(bg.make_blob("png")))
+            try:
+                im = PIL.Image.open(BytesIO(bg.make_blob("png")))
+            except PIL.Image.DecompressionBombError:
+                raise PIL.Image.DecompressionBombError(
+                    "Image conversion raised a DecompressionBombError. "
+                    "PIL.Image.MAX_IMAGE_PIXELS is currently set to "
+                    f"{PIL.Image.MAX_IMAGE_PIXELS}. "
+                    "If you trust this PDF, you can try setting "
+                    "PIL.Image.MAX_IMAGE_PIXELS to a higher value. "
+                    "See https://github.com/jsvine/pdfplumber/issues/413"
+                    "#issuecomment-1190650404 for more information."
+                )
         return im.convert("RGB")
 
 

tests/test_display.py

@@ -4,6 +4,7 @@
 import os
 import unittest
 
+import PIL.Image
 import pytest
 
 import pdfplumber
@@ -82,3 +83,10 @@ def test__repr_png_(self):
             71939,
             61247,
         )  # PNG encoder seems to work differently on different setups
+
+    def test_decompression_bomb(self):
+        original_max = PIL.Image.MAX_IMAGE_PIXELS
+        PIL.Image.MAX_IMAGE_PIXELS = 10
+        with pytest.raises(PIL.Image.DecompressionBombError):
+            self.pdf.pages[0].to_image()
+        PIL.Image.MAX_IMAGE_PIXELS = original_max