Generate color based on strings, cryptomatte style

Author: cesioarg

example_auto_nodes/node_base/auto_node.py

@@ -2,19 +2,27 @@
 from NodeGraphQt.base.port import Port
 from NodeGraphQt.constants import NODE_PROP
 from NodeGraphQt import QtCore
-import random
+import hashlib
 import copy
 import time
 
-def rand_color(seed_type):
-    seed = id(seed_type)
-    random.seed(seed + 10)
-    r = random.randint(50, 200)
-    random.seed(seed + 5)
-    g = random.randint(50, 200)
-    random.seed(seed + 3421)
-    b = random.randint(50, 200)
-    return (r, g, b, 255)
+
+# Generate random color based on strings
+class CryptoColors(object):
+    def __init__(self):
+        self.colors = {}
+
+    def get(self, text, Min=50, Max=200):
+        if text in self.colors:
+            return self.colors[text]
+        h = hashlib.sha256(text.encode('utf-8')).hexdigest()
+        d = int('0xFFFFFFFFFFFFFFFF', 0)
+        r = int(Min + (int("0x" + h[:16], 0) / d) * (Max - Min))
+        g = int(Min + (int("0x" + h[16:32], 0) / d) * (Max - Min))
+        b = int(Min + (int("0x" + h[32:48], 0) / d) * (Max - Min))
+        a = int(Min + (int("0x" + h[48:], 0) / d) * (Max - Min))
+        self.colors[text] = (r, g, b, 255)
+        return self.colors[text]
 
 
 class AutoNode(BaseNode,QtCore.QObject):
@@ -29,6 +37,7 @@ def __init__(self, defaultInputType=None, defaultOutputType=None):
         self.matchTypes = [[float, int]]
         self.errorColor = (200, 50, 50)
         self.stopCookColor = (200, 200, 200)
+        self._cryptoColors = CryptoColors()
 
         self.defaultColor = self.get_property("color")
         self.defaultValue = None
@@ -186,8 +195,8 @@ def set_port_type(self, port, value_type):
             else:
                 current_port.DataType = value_type
 
-            current_port.border_color = rand_color(value_type)
-            current_port.color = rand_color(value_type)
+            current_port.border_color = self._cryptoColors.get(str(value_type))
+            current_port.color = self._cryptoColors.get(str(value_type))
             conn_type = 'multi' if current_port.multi_connection() else 'single'
             data_type_name = value_type.__name__ if value_type else "all"
             current_port.view.setToolTip('{}: {} ({}) '.format(current_port.name(), data_type_name, conn_type))