Code to change contrast (#1060)

* Add files via upload

* Update requirements.txt

* Add files via upload

* Add files via upload

* Add files via upload

* Add files via upload

digital_image_processing/change_contrast.py

@@ -0,0 +1,35 @@
+"""
+Changing contrast with PIL
+
+This algorithm is used in
+https://noivce.pythonanywhere.com/ python web app.
+
+python/black: True
+flake8 : True
+"""
+
+from PIL import Image
+
+
+def change_contrast(img: Image, level: float) -> Image:
+    """
+    Function to change contrast
+    """
+    factor = (259 * (level + 255)) / (255 * (259 - level))
+
+    def contrast(c: int) -> float:
+        """
+        Fundamental Transformation/Operation that'll be performed on
+        every bit.
+        """
+        return 128 + factor * (c - 128)
+
+    return img.point(contrast)
+
+
+if __name__ == "__main__":
+    # Load image
+    with Image.open("image_data/lena.jpg") as img:
+        # Change contrast to 170
+        cont_img = change_contrast(img, 170)
+        cont_img.save("image_data/lena_high_contrast.png", format="png")

requirements.txt

@@ -5,6 +5,7 @@ mypy
 numpy
 opencv-python
 pandas
+pillow
 pytest
 sklearn
 sympy