Create change_brightness.py (#2126)

* Create change_brightness.py

* Update change_brightness.py

* Update change_brightness.py

* Update change_brightness.py

* Update change_brightness.py

Co-authored-by: Christian Clauss <cclauss@me.com>

digital_image_processing/change_brightness.py

@@ -0,0 +1,26 @@
+from PIL import Image
+
+
+def change_brightness(img: Image, level: float) -> Image:
+    """
+    Change the brightness of a PIL Image to a given level.
+    """
+
+    def brightness(c: int) -> float:
+        """
+        Fundamental Transformation/Operation that'll be performed on
+        every bit.
+        """
+        return 128 + level + (c - 128)
+
+    if not -255.0 <= level <= 255.0:
+        raise ValueError("level must be between -255.0 (black) and 255.0 (white)")
+    return img.point(brightness)
+
+
+if __name__ == "__main__":
+    # Load image
+    with Image.open("image_data/lena.jpg") as img:
+        # Change brightness to 100
+        brigt_img = change_brightness(img, 100)
+        brigt_img.save("image_data/lena_brightness.png", format="png")