adding image extraction scripts

.image-extraction/extract_spell.py

@@ -0,0 +1,76 @@
+import glob
+
+import numpy
+from PIL import Image, ImageDraw
+
+
+def extract_image(filename: str, output_path: str) -> None:
+    """
+    Extract a spell card from a screenshot from a device. Mask is valid for 1304x603
+    screenshot from an iPhone 12 Pro.
+
+    Args:
+        filename (str): Full path to the input image.
+        output_path (str): Full path where the image should be saved.
+    """
+    # Open the image, add alpha channel for transparency
+    initial_image = Image.open(filename).convert("RGBA")
+
+    # Check for size
+    if initial_image.size[0] != 1304:
+        basewidth = 1304
+        wpercent = basewidth / float(initial_image.size[0])
+        hsize = int((float(initial_image.size[1]) * float(wpercent)))
+        initial_image = initial_image.resize((basewidth, hsize), Image.ANTIALIAS)
+
+    # Convert to numpy array
+    initial_image_array = numpy.asarray(initial_image)
+
+    # Create mask polygon using points of the card border (iPhone 12 Pro screenshot)
+    mask_polygon = [
+        (535, 60),
+        (768, 60),
+        (788, 85),
+        (788, 567),
+        (515, 567),
+        (515, 130),
+        (496, 110),
+        (496, 89),
+        (513, 7),
+        (523, 7),
+    ]
+
+    # Create the mask
+    mask_image = Image.new(
+        "L", (initial_image_array.shape[1], initial_image_array.shape[0]), 0
+    )
+    ImageDraw.Draw(mask_image).polygon(mask_polygon, outline=1, fill=1)
+    mask = numpy.array(mask_image)
+
+    # create a new empty image
+    extracted_image_array = numpy.empty(initial_image_array.shape, dtype="uint8")
+
+    # copy the colours from the first 3 columns
+    extracted_image_array[:, :, :3] = initial_image_array[:, :, :3]
+
+    # apply transparency to the alpha channel (4th column)
+    extracted_image_array[:, :, 3] = mask * 255
+
+    # convert back to an image
+    extracted_image = Image.fromarray(extracted_image_array, "RGBA")
+
+    # save the image
+    extracted_image.save(f"{output_path}/{filename.split('/')[-1].split('.')[-2]}.png")
+
+
+if __name__ == "__main__":
+    for image in glob.glob(
+        "/Users/dtomlinson/git-repos/web-dev/onmyoji-deck-builder/."
+        "image-extraction/images/spells/in/*.jpeg"
+    ):
+        print(image)
+        extract_image(
+            image,
+            "/Users/dtomlinson/git-repos/web-dev/onmyoji-deck-builder/."
+            "image-extraction/images/spells/out",
+        )