feat: add scale event

Author: SSShooter

package.json

@@ -1,6 +1,6 @@
 {
   "name": "mind-elixir",
-  "version": "4.2.1",
+  "version": "4.2.2",
   "type": "module",
   "description": "Mind elixir is a free open source mind map core.",
   "keywords": [

src/interact.ts

@@ -160,10 +160,12 @@ export const disableEdit = function (this: MindElixirInstance) {
 export const scale = function (this: MindElixirInstance, scaleVal: number) {
   // TODO: recalculate the position of the map
   // plan A: use transform-origin
+  // deprecated, center will be changed even if the scale function is doing well, which is very difficult to solve
   // plan B: use transform: translate
   // https://github.com/markmap/markmap/blob/e3071bc34da850ed7283b7d5b1a79b6c9b631a0e/packages/markmap-view/src/view.tsx#L640
   this.scaleVal = scaleVal
   this.map.style.transform = 'scale(' + scaleVal + ')'
+  this.bus.fire('scale', scaleVal)
 }
 /**
  * @function

src/plugin/toolBar.ts

@@ -32,11 +32,11 @@ function createToolBarRBContainer(mind: MindElixirInstance) {
   }
   zo.onclick = () => {
     if (mind.scaleVal < 0.6) return
-    mind.scale((mind.scaleVal -= 0.2))
+    mind.scale(mind.scaleVal - 0.2)
   }
   zi.onclick = () => {
     if (mind.scaleVal > 1.6) return
-    mind.scale((mind.scaleVal += 0.2))
+    mind.scale(mind.scaleVal + 0.2)
   }
   return toolBarRBContainer
 }

src/utils/pubsub.ts

@@ -84,6 +84,7 @@ export type EventMap = {
   unselectNodes: () => void
   expandNode: (nodeObj: NodeObj) => void
   linkDiv: () => void
+  scale: (scale: number) => void
 }
 
 const Bus = {