Move icon code into module

This, combined with lazy loading, has the advantage of using icons in property definitions before the actual registration code runs

blender/arm/nodes_logic.py

@@ -8,6 +8,7 @@ import arm.logicnode.arm_nodes as arm_nodes
 import arm.logicnode.replacement
 import arm.logicnode
 import arm.props_traits
+import arm.ui_icons as ui_icons
 import arm.utils
 
 registered_nodes = []
@@ -174,7 +175,7 @@ class ARM_PT_LogicNodePanel(bpy.types.Panel):
             layout.operator('arm.open_node_documentation', icon='HELP')
             column = layout.column(align=True)
             column.operator('arm.open_node_python_source', icon='FILE_SCRIPT')
-            column.operator('arm.open_node_haxe_source', icon_value=arm.props_traits.icons_dict['haxe'].icon_id)
+            column.operator('arm.open_node_haxe_source', icon_value=ui_icons.get_id("haxe"))
 
 
 class ArmOpenNodeHaxeSource(bpy.types.Operator):

blender/arm/props_traits.py

@@ -11,6 +11,7 @@ import bpy.utils.previews
 import arm.make as make
 from arm.props_traits_props import *
 import arm.proxy as proxy
+import arm.ui_icons as ui_icons
 import arm.utils
 import arm.write_data as write_data
 
@@ -94,13 +95,13 @@ class ARM_UL_TraitList(bpy.types.UIList):
         custom_icon = "NONE"
         custom_icon_value = 0
         if item.type_prop == "Haxe Script":
-            custom_icon_value = icons_dict["haxe"].icon_id
+            custom_icon_value = ui_icons.get_id("haxe")
         elif item.type_prop == "WebAssembly":
-            custom_icon_value = icons_dict["wasm"].icon_id
+            custom_icon_value = ui_icons.get_id("wasm")
         elif item.type_prop == "UI Canvas":
             custom_icon = "NODE_COMPOSITING"
         elif item.type_prop == "Bundled Script":
-            custom_icon_value = icons_dict["bundle"].icon_id
+            custom_icon_value = ui_icons.get_id("bundle")
         elif item.type_prop == "Logic Nodes":
             custom_icon = 'NODETREE'
 
@@ -862,8 +863,8 @@ def draw_traits_panel(layout: bpy.types.UILayout, obj: Union[bpy.types.Object, b
                 row = layout.row()
                 row.template_list("ARM_UL_PropList", "The_List", item, "arm_traitpropslist", item, "arm_traitpropslist_index", rows=propsrows)
 
+
 def register():
-    global icons_dict
     bpy.utils.register_class(ArmTraitListItem)
     bpy.utils.register_class(ARM_UL_TraitList)
     bpy.utils.register_class(ArmTraitListNewItem)
@@ -891,14 +892,8 @@ def register():
     bpy.types.Scene.arm_traitlist = CollectionProperty(type=ArmTraitListItem)
     bpy.types.Scene.arm_traitlist_index = IntProperty(name="Index for arm_traitlist", default=0)
 
-    icons_dict = bpy.utils.previews.new()
-    icons_dir = os.path.join(os.path.dirname(__file__), "custom_icons")
-    icons_dict.load("haxe", os.path.join(icons_dir, "haxe.png"), 'IMAGE')
-    icons_dict.load("wasm", os.path.join(icons_dir, "wasm.png"), 'IMAGE')
-    icons_dict.load("bundle", os.path.join(icons_dir, "bundle.png"), 'IMAGE')
 
 def unregister():
-    global icons_dict
     bpy.utils.unregister_class(ARM_OT_CopyTraitsFromActive)
     bpy.utils.unregister_class(ArmTraitListItem)
     bpy.utils.unregister_class(ARM_UL_TraitList)
@@ -920,4 +915,3 @@ def unregister():
     bpy.utils.unregister_class(ArmRefreshCanvasListButton)
     bpy.utils.unregister_class(ARM_PT_TraitPanel)
     bpy.utils.unregister_class(ARM_PT_SceneTraitPanel)
-    bpy.utils.previews.remove(icons_dict)

blender/arm/props_ui.py

@@ -15,6 +15,7 @@ import arm.props_properties
 import arm.props_traits
 import arm.nodes_logic
 import arm.proxy
+import arm.ui_icons as ui_icons
 import arm.utils
 
 from arm.lightmapper.utility import icon
@@ -2574,7 +2575,7 @@ def draw_custom_node_menu(self, context):
             layout = self.layout
             layout.separator()
             layout.operator("arm.open_node_documentation", text="Show documentation for this node", icon='HELP')
-            layout.operator("arm.open_node_haxe_source", text="Open .hx source in the browser", icon_value=arm.props_traits.icons_dict['haxe'].icon_id)
+            layout.operator("arm.open_node_haxe_source", text="Open .hx source in the browser", icon_value=ui_icons.get_id("haxe"))
             layout.operator("arm.open_node_python_source", text="Open .py source in the browser", icon='FILE_SCRIPT')
 
     elif context.space_data.tree_type == 'ShaderNodeTree':

blender/arm/ui_icons.py

@@ -0,0 +1,34 @@
+"""
+Blender user interface icon handling.
+"""
+import os.path
+from typing import Optional
+
+import bpy.utils.previews
+
+_icons_dict: Optional[bpy.utils.previews.ImagePreviewCollection] = None
+"""Dictionary of all loaded icons, or `None` if not loaded"""
+
+_icons_dir = os.path.join(os.path.dirname(__file__), "custom_icons")
+"""Directory of the icon files"""
+
+
+def _load_icons() -> None:
+    """(Re)loads all icons"""
+    global _icons_dict
+
+    if _icons_dict is not None:
+        bpy.utils.previews.remove(_icons_dict)
+
+    _icons_dict = bpy.utils.previews.new()
+    _icons_dict.load("armory", os.path.join(_icons_dir, "armory.png"), 'IMAGE')
+    _icons_dict.load("bundle", os.path.join(_icons_dir, "bundle.png"), 'IMAGE')
+    _icons_dict.load("haxe", os.path.join(_icons_dir, "haxe.png"), 'IMAGE')
+    _icons_dict.load("wasm", os.path.join(_icons_dir, "wasm.png"), 'IMAGE')
+
+
+def get_id(identifier: str) -> int:
+    """Returns the icon ID from the given identifier"""
+    if _icons_dict is None:
+        _load_icons()
+    return _icons_dict[identifier].icon_id