Merge pull request #1231 from radarhere/image_palette

Copy image when saving in GifImagePlugin

PIL/GifImagePlugin.py

@@ -290,7 +290,7 @@ def _save(im, fp, filename):
             pass  # write uncompressed file
 
     if im.mode in RAWMODE:
-        im_out = im
+        im_out = im.copy()
     else:
         # convert on the fly (EXPERIMENTAL -- I'm not sure PIL
         # should automatically convert images on save...)

PIL/Image.py

@@ -509,7 +509,8 @@ class Image(object):
         new.im = im
         new.mode = im.mode
         new.size = im.size
-        new.palette = self.palette
+        if self.palette:
+            new.palette = self.palette.copy()
         if im.mode == "P" and not new.palette:
             from PIL import ImagePalette
             new.palette = ImagePalette.ImagePalette()

PIL/ImagePalette.py

@@ -34,6 +34,18 @@ class ImagePalette(object):
                 (size != 0 and size != len(self.palette))):
             raise ValueError("wrong palette size")
 
+    def copy(self):
+        new = ImagePalette()
+
+        new.mode = self.mode
+        new.rawmode = self.rawmode
+        if self.palette is not None:
+            new.palette = self.palette[:]
+        new.colors = self.colors.copy()
+        new.dirty = self.dirty
+
+        return new
+
     def getdata(self):
         """
         Get palette contents in format suitable # for the low-level

Tests/test_file_gif.py

@@ -92,20 +92,20 @@ class TestFileGif(PillowTestCase):
 
         def roundtrip(im, *args, **kwargs):
             out = self.tempfile('temp.gif')
-            im.save(out, *args, **kwargs)
+            im.copy().save(out, *args, **kwargs)
             reloaded = Image.open(out)
 
-            return [im, reloaded]
+            return reloaded
 
         orig = "Tests/images/test.colors.gif"
         im = Image.open(orig)
 
-        self.assert_image_equal(*roundtrip(im))
-        self.assert_image_equal(*roundtrip(im, optimize=True))
+        self.assert_image_similar(im, roundtrip(im), 1)
+        self.assert_image_similar(im, roundtrip(im, optimize=True), 1)
 
         im = im.convert("RGB")
         # check automatic P conversion
-        reloaded = roundtrip(im)[1].convert('RGB')
+        reloaded = roundtrip(im).convert('RGB')
         self.assert_image_equal(im, reloaded)
 
     @unittest.skipUnless(netpbm_available(), "netpbm not available")

Tests/test_imagefile.py

@@ -26,7 +26,7 @@ class TestImageFile(PillowTestCase):
 
             test_file = BytesIO()
 
-            im.save(test_file, format)
+            im.copy().save(test_file, format)
 
             data = test_file.getvalue()
 
@@ -37,7 +37,8 @@ class TestImageFile(PillowTestCase):
             return im, imOut
 
         self.assert_image_equal(*roundtrip("BMP"))
-        self.assert_image_equal(*roundtrip("GIF"))
+        im1, im2 = roundtrip("GIF")
+        self.assert_image_similar(im1.convert('P'), im2, 1)
         self.assert_image_equal(*roundtrip("IM"))
         self.assert_image_equal(*roundtrip("MSP"))
         if "zip_encoder" in codecs: