feat(engines/pil.read_multiple): Use Pillow to save multipage images …

…as GIF

The functionality provided by the images2gif module is part of Pillow
since 2015 [1]. It also renders `gifsicle` unnecessary in this context.

  1. https://pillow.readthedocs.io/en/stable/releasenotes/3.0.0.html

Makefile

@@ -116,6 +116,7 @@ sample_images:
 	convert tests/fixtures/images/10_years_of_Wikipedia_by_Guillaume_Paumier.jpg -orient LeftBottom tests/fixtures/images/10_years_of_Wikipedia_by_Guillaume_Paumier.jpg
 	curl -s https://upload.wikimedia.org/wikipedia/commons/6/6d/Christophe_Henner_-_June_2016.jpg -o tests/fixtures/images/Christophe_Henner_-_June_2016.jpg
 	curl -s https://upload.wikimedia.org/wikipedia/commons/3/31/Giunchedi%2C_Filippo_January_2015_01.jpg -o tests/fixtures/images/Giunchedi%2C_Filippo_January_2015_01.jpg
+	curl -s https://upload.wikimedia.org/wikipedia/commons/2/2c/Rotating_earth_%28large%29.gif -o tests/fixtures/images/Rotating_earth_\(large\).gif
 	convert tests/fixtures/images/Giunchedi%2C_Filippo_January_2015_01.jpg -colorspace CMYK tests/fixtures/images/Giunchedi%2C_Filippo_January_2015_01-cmyk.jpg
 	convert tests/fixtures/images/Giunchedi%2C_Filippo_January_2015_01.jpg tests/fixtures/images/Giunchedi%2C_Filippo_January_2015_01.png
 	convert tests/fixtures/images/Giunchedi%2C_Filippo_January_2015_01.jpg -colorspace gray tests/fixtures/images/Giunchedi%2C_Filippo_January_2015_01-grayscale.jpg

tests/engines/test_pil.py

@@ -91,6 +91,33 @@ def test_load_tif_16bit_per_channel_lsb(self):
         expect(image_file.format).to_equal("PNG")
         expect(image_file.size).to_equal((100, 100))
 
+    def test_load_animated_gif(self):
+        engine = Engine(self.context)
+        with open(join(STORAGE_PATH, "animated.gif"), "rb") as image_file:
+            buffer = image_file.read()
+        expect(buffer).not_to_equal(None)
+        engine.load(buffer, None)
+
+        final_bytes = BytesIO(engine.read())
+        image_file = Image.open(final_bytes)
+        expect(image_file.format).to_equal("GIF")
+        expect(image_file.size).to_equal((100, 100))
+        expect(image_file.is_animated).to_be_true()
+
+    def test_load_rotating_earth_gif(self):
+        engine = Engine(self.context)
+        with open(
+            join(STORAGE_PATH, "Rotating_earth_(large).gif"), "rb"
+        ) as image_file:
+            buffer = image_file.read()
+        expect(buffer).not_to_equal(None)
+        engine.load(buffer, None)
+
+        final_bytes = BytesIO(engine.read())
+        image_file = Image.open(final_bytes)
+        expect(image_file.format).to_equal("GIF")
+        expect(image_file.size).to_equal((400, 400))
+
     def test_load_tif_16bit_per_channel_msb(self):
         engine = Engine(self.context)
         with open(

tests/fixtures/images/README.mkd

@@ -12,4 +12,6 @@ They should ideally all be regenerated (or, should they not be possible to creat
 
 [Commons-logo.svg](https://en.wikipedia.org/wiki/File:Commons-logo.svg) - Wikimedia Foundation - [CC BY-SA 3.0](https://creativecommons.org/licenses/by-sa/3.0/deed.en)
 
-[10_years_of_Wikipedia_by_Guillaume_Paumier.jpg](https://commons.wikimedia.org/wiki/File:10_years_of_Wikipedia_by_Guillaume_Paumier.jpg) - Pierre-Selim Huard - [CC BY-SA 3.0](https://creativecommons.org/licenses/by-sa/3.0/deed.en)
+[10_years_of_Wikipedia_by_Guillaume_Paumier.jpg](https://commons.wikimedia.org/wiki/File:10_years_of_Wikipedia_by_Guillaume_Paumier.jpg) - Pierre-Selim Huard - [CC BY-SA 3.0](https://creativecommons.org/licenses/by-sa/3.0/deed.en)
+
+[Rotating_earth_(large).gif](https://commons.wikimedia.org/wiki/File:Rotating_earth_(large).gif) - Marvel - [CC BY-SA 3.0](https://creativecommons.org/licenses/by-sa/3.0/deed.en)