Expand PIL image support. (google-gemini#523)

* fixes#511

Change-Id: I7303becbbd6a9441c406a28e84ecc86d2fdd35bd

* add gif support

Change-Id: Ibc8e091c63d30626f78510156e8c024014dddcca

* link to references

Change-Id: I49b9ab206ade37a8a5535b21fa7fdf62a0c569d2

* describe logic

Change-Id: I813e8569b91e01a0884b1c2ff75dfa84fcf4a609

* add test gif

Change-Id: I1e4a62bb1e1fade244771027380b8a13f444885d

* format

Change-Id: Ifb93c70f8ad48dce0fd0921de0e9e117819dc55c

Author: MarkDaoust

google/generativeai/types/content_types.py

@@ -73,11 +73,34 @@
 
 
 def pil_to_blob(img):
+    # When you load an image with PIL you get a subclass of PIL.Image
+    # The subclass knows what file type it was loaded from it has a `.format` class attribute
+    # and the `get_format_mimetype` method. Convert these back to the same file type.
+    #
+    # The base image class doesn't know its file type, it just knows its mode.
+    # RGBA converts to PNG easily, P[allet] converts to GIF, RGB to GIF.
+    # But for anything else I'm not going to bother mapping it out (for now) let's just convert to RGB and send it.
+    #
+    # References:
+    #   - file formats: https://pillow.readthedocs.io/en/stable/handbook/image-file-formats.html
+    #   - image modes: https://pillow.readthedocs.io/en/stable/handbook/concepts.html#modes
+
     bytesio = io.BytesIO()
-    if isinstance(img, PIL.PngImagePlugin.PngImageFile) or img.mode == "RGBA":
+
+    get_mime = getattr(img, "get_format_mimetype", None)
+    if get_mime is not None:
+        # If the image is created from a file, convert back to the same file type.
+        img.save(bytesio, format=img.format)
+        mime_type = img.get_format_mimetype()
+    elif img.mode == "RGBA":
         img.save(bytesio, format="PNG")
         mime_type = "image/png"
+    elif img.mode == "P":
+        img.save(bytesio, format="GIF")
+        mime_type = "image/gif"
     else:
+        if img.mode != "RGB":
+            img = img.convert("RGB")
         img.save(bytesio, format="JPEG")
         mime_type = "image/jpeg"
     bytesio.seek(0)

tests/test_content.py

@@ -35,6 +35,10 @@
 TEST_JPG_URL = "https://storage.googleapis.com/generativeai-downloads/data/test_img.jpg"
 TEST_JPG_DATA = TEST_JPG_PATH.read_bytes()
 
+TEST_GIF_PATH = HERE / "test_img.gif"
+TEST_GIF_URL = "https://storage.googleapis.com/generativeai-downloads/data/test_img.gif"
+TEST_GIF_DATA = TEST_GIF_PATH.read_bytes()
+
 
 # simple test function
 def datetime():
@@ -88,6 +92,17 @@ def test_jpg_to_blob(self, image):
         self.assertEqual(blob.mime_type, "image/jpeg")
         self.assertStartsWith(blob.data, b"\xff\xd8\xff\xe0\x00\x10JFIF")
 
+    @parameterized.named_parameters(
+        ["PIL", PIL.Image.open(TEST_GIF_PATH)],
+        ["P", PIL.Image.fromarray(np.zeros([6, 6, 3], dtype=np.uint8)).convert("P")],
+        ["IPython", IPython.display.Image(filename=TEST_GIF_PATH)],
+    )
+    def test_gif_to_blob(self, image):
+        blob = content_types.image_to_blob(image)
+        self.assertIsInstance(blob, protos.Blob)
+        self.assertEqual(blob.mime_type, "image/gif")
+        self.assertStartsWith(blob.data, b"GIF87a")
+
     @parameterized.named_parameters(
         ["BlobDict", {"mime_type": "image/png", "data": TEST_PNG_DATA}],
         ["protos.Blob", protos.Blob(mime_type="image/png", data=TEST_PNG_DATA)],