Update binary_tree_generator.py

binary_tree_generator.py

@@ -83,13 +83,17 @@ def generate_binary_tree_diagram(json_input: str, output_format: str) -> str:
             # Calculate color opacity based on depth
             max_depth = 5  # Assume maximum depth for color calculation
             if current_depth >= max_depth:
-                opacity = '80'  # Minimum opacity
+                opacity_value = 128  # Minimum opacity (50%)
             else:
                 opacity_value = int(255 * (1.0 - (current_depth * 0.6 / max_depth)))
-                opacity = format(opacity_value, '02x')
             
+            opacity = format(opacity_value, '02x')
             node_color = f"{base_color}{opacity}"
-            font_color = 'white' if current_depth < 3 else 'black'
+            
+            # Determine font color based on background brightness
+            # If opacity_value is high (dark background), use white text
+            # If opacity_value is low (light background), use black text
+            font_color = 'white' if opacity_value > 180 else 'black'
             
             # Add the current node
             dot.node(