Progress

scripts/remove_bg.py

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+"""Remove white background from an image by flood-filling from edges only."""
+
+import sys
+from collections import deque
+from PIL import Image
+
+def remove_white_bg(path: str, tolerance: int = 20, out: str | None = None):
+    img = Image.open(path).convert("RGBA")
+    pixels = img.load()
+    w, h = img.size
+    threshold = 255 - tolerance
+
+    visited = set()
+    queue = deque()
+
+    # Seed from all edge pixels
+    for x in range(w):
+        queue.append((x, 0))
+        queue.append((x, h - 1))
+    for y in range(h):
+        queue.append((0, y))
+        queue.append((w - 1, y))
+
+    while queue:
+        x, y = queue.popleft()
+        if (x, y) in visited or x < 0 or y < 0 or x >= w or y >= h:
+            continue
+        visited.add((x, y))
+        r, g, b, a = pixels[x, y]
+        if r >= threshold and g >= threshold and b >= threshold:
+            pixels[x, y] = (r, g, b, 0)
+            queue.append((x + 1, y))
+            queue.append((x - 1, y))
+            queue.append((x, y + 1))
+            queue.append((x, y - 1))
+
+    # Crop to bounding box of non-transparent pixels
+    bbox = img.getbbox()
+    if bbox:
+        img = img.crop(bbox)
+
+    dest = out or path
+    img.save(dest)
+    print(f"Saved to {dest} ({img.size[0]}x{img.size[1]})")
+
+if __name__ == "__main__":
+    if len(sys.argv) < 2:
+        print("Usage: python remove_bg.py <image> [tolerance] [output]")
+        sys.exit(1)
+    path = sys.argv[1]
+    tol = int(sys.argv[2]) if len(sys.argv) > 2 else 20
+    out = sys.argv[3] if len(sys.argv) > 3 else None
+    remove_white_bg(path, tol, out)