wallpaper: add options to modify scoring

bin/wallpaper

@@ -20,6 +20,7 @@ import collections
 import itertools
 import logging
 import logging.handlers
+import inspect
 
 from Xlib import display
 from Xlib.ext import randr
@@ -136,7 +137,7 @@ def get_random_images(directory, number):
     return images
 
 
-def get_best_parts(groups, images):
+def get_best_parts(groups, images, ratio_score=100, scale_score=60, wallpaper_score=2):
     """Find optimal association for images for the groups of covering rectangles.
 
     >>> gbp = get_best_parts
@@ -201,15 +202,15 @@ def get_best_parts(groups, images):
                 r = iratio / oratio
                 if r > 1:
                     r = 1 / r
-                score += r * 100
+                score += r * ratio_score
                 # Similar scale (when cropped)
                 opixels = assoc.rectangle.width * assoc.rectangle.height
                 ipixels = assoc.image.width * assoc.image.height * r
                 r = ipixels / opixels
                 if r >= 1:
                     r = 1
-                score += r * 60
-            score /= len(group) * len(group)
+                score += r * scale_score
+            score /= pow(len(group), wallpaper_score)
             logger.debug("association: %s, score %.2f", association, score)
             if score > best_score or best_association is None:
                 best_association = association
@@ -259,25 +260,43 @@ if __name__ == "__main__":
         default=False,
         help="enable debugging",
     )
-    parser.add_argument(
+    group = parser.add_argument_group("image selection")
+    group.add_argument(
         "-d",
         "--directory",
         default=".",
         help="search for images in DIRECTORY",
     )
-    parser.add_argument(
-        "-t",
-        "--target",
-        default="background.png",
-        help="write background to FILE",
-    )
-    parser.add_argument(
+    group.add_argument(
         "--extra-images",
         default=3,
         metavar="N",
         help="consider N additional images to choose the best combination",
     )
-    parser.add_argument(
+    params = inspect.signature(get_best_parts).parameters
+    group.add_argument(
+        "--ratio-score",
+        default=params["ratio_score"].default,
+        help="multiplicative weight applied to ratio matching for score",
+    )
+    group.add_argument(
+        "--scale-score",
+        default=params["scale_score"].default,
+        help="multiplicative weight applied to pixel matching for score",
+    )
+    group.add_argument(
+        "--wallpaper-score",
+        default=params["wallpaper_score"].default,
+        help="invert power weight applied to the number of wallpapers used",
+    )
+    group = parser.add_argument_group("image output")
+    group.add_argument(
+        "-t",
+        "--target",
+        default="background.png",
+        help="write background to FILE",
+    )
+    group.add_argument(
         "--compression", default=0, type=int, help="compression level when saving"
     )
     options = parser.parse_args()
@@ -299,7 +318,13 @@ if __name__ == "__main__":
         images = get_random_images(
             options.directory, len(outputs) + options.extra_images
         )
-        wallpaper_parts = get_best_parts(candidates, images)
+        wallpaper_parts = get_best_parts(
+            candidates,
+            images,
+            ratio_score=options.ratio_score,
+            scale_score=options.scale_score,
+            wallpaper_score=options.wallpaper_score,
+        )
         for part in wallpaper_parts:
             logger.info(
                 "wallpaper: {} ({}×{})".format(