fix: 修复H5端onReady内往画布添加的内容会一闪消失的Bug

同时对齐微信小程序画布大小改变内容不消失

src/core/view/components/canvas/index.vue

@@ -121,8 +121,12 @@ export default {
         method(data)
       }
     },
-    _resize () {
-      wrapper(this.$refs.canvas)
+    _resize () {
+      var canvas = this.$refs.canvas
+      var context = canvas.getContext('2d')
+      var imageData = context.getImageData(0, 0, canvas.width, canvas.height)
+      wrapper(this.$refs.canvas)
+      context.putImageData(imageData, 0, 0)
     },
     _touchmove (event) {
       event.preventDefault()