Make algorithm recursive

When a new color is required, repeat the color assignment process. This is the fastest part of the algorithm, so there's no noticable speed drop. Repeating the whole coloring ensures that newly added colors are properly balanced with respect to other colors, and avoids the situation where one of the last features to be colored requires a whole new class to be created, which will only have a few possible members. Overall this results in more balanced color assignment.
qgis · Feb 22, 2017 · 2fd78b8 · 2fd78b8
1 parent ff10cf4
commit 2fd78b8
Showing 1 changed file with 3 additions and 3 deletions.
diff --git a/python/plugins/processing/algs/qgis/TopoColors.py b/python/plugins/processing/algs/qgis/TopoColors.py
@@ -203,9 +203,9 @@ def balanced(features, graph, feedback, balance=BalanceMethod.BY_COUNT, min_colo
 
             feature_color=-1
             if len(available_colors) == 0:
-                # no existing colors available for this feature, so add new color to pool
-                feature_color = len(color_pool) + 1
-                color_pool.add(feature_color)
+                # no existing colors available for this feature, so add new color to pool and repeat
+                min_colors += 1
+                return ColoringAlgorithm.balanced(features,graph,feedback,balance,min_colors)
             else:
                 if balance==BalanceMethod.BY_COUNT:
                     # choose least used available color