Redesign invalid node indicator (#358)

* nit

* Remove unused code

Gradient can (and should) be impl. directly by caching a CanvasGradient.

* nit

* nit - Refactor

* Remove redundant code

* Add line width & colour options to shape stroke

* Rename drawSelectionBounding to strokeShape

* nit - Doc

* Fix rounded corners not scaling with padding

* Optimise node badge draw

* Redesign invalid node visual indication

Customisable boundary indicator now used, replacing red background.

* Update snapshot

---------

Co-authored-by: huchenlei <huchenlei@proton.me>

src/LiteGraphGlobal.ts

@@ -52,6 +52,7 @@ export class LiteGraphGlobal {
   NODE_DEFAULT_BOXCOLOR = "#666"
   NODE_DEFAULT_SHAPE = "box"
   NODE_BOX_OUTLINE_COLOR = "#FFF"
+  NODE_ERROR_COLOUR = "#E00"
   DEFAULT_SHADOW_COLOR = "rgba(0,0,0,0.5)"
   DEFAULT_GROUP_FONT = 24
   DEFAULT_GROUP_FONT_SIZE?: any
@@ -252,6 +253,9 @@ export class LiteGraphGlobal {
   // Whether to highlight the bounding box of selected groups
   highlight_selected_group = true
 
+  /** If `true`, the old "eye-melting-red" error indicator will be used for nodes */
+  use_legacy_node_error_indicator = false
+
   // TODO: Remove legacy accessors
   LGraph = LGraph
   LLink = LLink