Add a --show-final-score to output the final image quality score.

This is useful when used as part of an image repository build
pipeline, to avoid replacing existing images if the new score is
higher.

Hide intermediate output behind --verbose

convert.py

@@ -73,7 +73,7 @@ class ClusterPalette:
                                          "CAM16UCS").astype(np.float32)
         return colours_cam
 
-    def _init_palette_lines(self, init_random = False):
+    def _init_palette_lines(self, init_random=False):
         palette_lines = defaultdict(list)
 
         if init_random:
@@ -143,7 +143,6 @@ class ClusterPalette:
 
         outer_iterations_since_improvement = 0
         while outer_iterations_since_improvement < max_outer_iterations:
-            print("New iteration")
             inner_iterations_since_improvement = 0
             self._palette_lines = self._init_palette_lines()
 
@@ -221,7 +220,7 @@ class ClusterPalette:
                 seen_colours.add(tuple(initial_centroids[i, :]))
             for i in range(self._fixed_colours, 16):
                 choice = np.random.randint(0, pixels_rgb_iigs.shape[
-                        0])
+                    0])
                 new_colour = pixels_rgb_iigs[choice, :]
                 if tuple(new_colour) in seen_colours:
                     continue
@@ -329,13 +328,17 @@ def main():
     parser.add_argument(
         '--fixed-colours', type=int, default=0,
         help='How many colours to fix as identical across all 16 SHR palettes '
-        '(default: 0)'
+             '(default: 0)'
     )
     parser.add_argument(
         '--save-preview', type=bool, default=True,
         help='Whether to save a .PNG rendering of the output image (default: '
              'True)'
     )
+    parser.add_argument(
+        '--show-final-score', type=bool, default=False,
+        help='Whether to output the final image quality score (default: False)'
+    )
     args = parser.parse_args()
     if args.lookahead < 1:
         parser.error('--lookahead must be at least 1')
@@ -382,7 +385,7 @@ def main():
          palettes_rgb12_iigs, palettes_linear_rgb) in cluster_palette.iterate(
         penalty, inner_iterations, outer_iterations):
 
-        if total_image_error is not None:
+        if args.verbose and total_image_error is not None:
             print("Improved quality +%f%% (%f)" % (
                 (1 - new_total_image_error / total_image_error) * 100,
                 new_total_image_error))
@@ -427,7 +430,8 @@ def main():
 
         unique_colours = np.unique(
             palettes_rgb12_iigs.reshape(-1, 3), axis=0).shape[0]
-        print("%d unique colours" % unique_colours)
+        if args.verbose:
+            print("%d unique colours" % unique_colours)
 
         seq += 1
 
@@ -443,6 +447,8 @@ def main():
         with open(args.output, "wb") as f:
             f.write(bytes(screen.memory))
 
+    if args.show_final_score:
+        print("FINAL_SCORE:", total_image_error)
 
 
 if __name__ == "__main__":