feat: added invert_colors method (#367)

Closes #[282].

### Summary of Changes

added `invert_colors` method to `Image`
added tests


Co-authored-by: PhilipGutberlet
<92990487+PhilipGutberlet@users.noreply.github.com>

---------

Co-authored-by: PhilipGutberlet <92990487+PhilipGutberlet@users.noreply.github.com>
Co-authored-by: megalinter-bot <129584137+megalinter-bot@users.noreply.github.com>

src/safeds/data/image/containers/_image.py

@@ -6,7 +6,7 @@
 from typing import Any, BinaryIO
 
 import PIL
-from PIL import ImageFilter
+from PIL import ImageFilter, ImageOps
 from PIL.Image import Image as PillowImage
 from PIL.Image import open as open_image
 
@@ -316,3 +316,24 @@ def blur(self, radius: int = 1) -> Image:
         new_image = Image(data, self._format)
         new_image._image = new_image._image.filter(ImageFilter.BoxBlur(radius))
         return new_image
+
+    def invert_colors(self) -> Image:
+        """
+        Return the image with inverted colors.
+
+        Returns
+        -------
+        result : Image
+            The image with inverted colors.
+        """
+        data = io.BytesIO()
+        repr_png = self._repr_png_()
+        repr_jpeg = self._repr_jpeg_()
+        if repr_png is not None:
+            data = io.BytesIO(repr_png)
+        elif repr_jpeg is not None:
+            data = io.BytesIO(repr_jpeg)
+
+        new_image = Image(data, self._format)
+        new_image._image = ImageOps.invert(new_image._image)
+        return new_image

tests/safeds/data/image/containers/test_image.py

@@ -265,6 +265,23 @@ def test_should_be_original(self) -> None:
         assert image == image2
 
 
+class TestInvertColors:
+    def test_should_invert_colors_png(self) -> None:
+        image = Image.from_png_file(resolve_resource_path("image/original.png"))
+        image = image.invert_colors()
+        image2 = Image.from_png_file(resolve_resource_path("image/inverted_colors_original.png"))
+        assert image == image2
+
+    def test_should_invert_colors_jpeg(self) -> None:
+        image = Image.from_jpeg_file(resolve_resource_path("image/original.jpg"))
+        image = image.invert_colors()
+        image.to_jpeg_file(resolve_resource_path("image/inverted_colors_original1.jpg"))
+        image = Image.from_jpeg_file(resolve_resource_path("image/inverted_colors_original1.jpg"))
+        image2 = Image.from_jpeg_file(resolve_resource_path("image/inverted_colors_original.jpg"))
+        assert image == image2
+        Path.unlink(Path(resolve_resource_path("image/inverted_colors_original1.jpg")))
+
+
 class TestBlur:
     def test_should_return_blurred_png_image(self) -> None:
         image = Image.from_png_file(resolve_resource_path("image/boy.png"))