Merge pull request #5594 from radarhere/convert

If default conversion from P is RGB with transparency, convert to RGBA
python-pillow · Aug 6, 2021 · 3307bf6 · 3307bf6
2 parents b8b4bf4 + fdfa9e8
commit 3307bf6
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Showing 2 changed files with 11 additions and 5 deletions.
diff --git a/Tests/test_image_convert.py b/Tests/test_image_convert.py
@@ -42,10 +42,14 @@ def test_default():
 
     im = hopper("P")
     assert_image(im, "P", im.size)
-    im = im.convert()
-    assert_image(im, "RGB", im.size)
-    im = im.convert()
-    assert_image(im, "RGB", im.size)
+    converted_im = im.convert()
+    assert_image(converted_im, "RGB", im.size)
+    converted_im = im.convert()
+    assert_image(converted_im, "RGB", im.size)
+
+    im.info["transparency"] = 0
+    converted_im = im.convert()
+    assert_image(converted_im, "RGBA", im.size)
 
 
 # ref https://github.com/python-pillow/Pillow/issues/274

diff --git a/src/PIL/Image.py b/src/PIL/Image.py
@@ -914,16 +914,18 @@ def convert(self, mode=None, matrix=None, dither=None, palette=WEB, colors=256):
 
         self.load()
 
+        has_transparency = self.info.get("transparency") is not None
         if not mode and self.mode == "P":
             # determine default mode
             if self.palette:
                 mode = self.palette.mode
             else:
                 mode = "RGB"
+            if mode == "RGB" and has_transparency:
+                mode = "RGBA"
         if not mode or (mode == self.mode and not matrix):
             return self.copy()
 
-        has_transparency = self.info.get("transparency") is not None
         if matrix:
             # matrix conversion
             if mode not in ("L", "RGB"):