Fix:修复当思维导图全部移除可视区域后小地图中的指示器也会移除小地图区域的问题

simple-mind-map/src/plugins/MiniMap.js

@@ -55,19 +55,28 @@ class MiniMap {
       bottom: 0
     }
     viewBoxStyle.left =
-      Math.max(0, (-_rectX / _rectWidth) * actWidth) + miniMapBoxLeft + 'px'
+      Math.max(0, (-_rectX / _rectWidth) * actWidth) + miniMapBoxLeft
     viewBoxStyle.right =
       Math.max(0, ((_rectX2 - origWidth) / _rectWidth) * actWidth) +
-      miniMapBoxLeft +
-      'px'
+      miniMapBoxLeft
 
     viewBoxStyle.top =
-      Math.max(0, (-_rectY / _rectHeight) * actHeight) + miniMapBoxTop + 'px'
+      Math.max(0, (-_rectY / _rectHeight) * actHeight) + miniMapBoxTop
     viewBoxStyle.bottom =
       Math.max(0, ((_rectY2 - origHeight) / _rectHeight) * actHeight) +
-      miniMapBoxTop +
-      'px'
-    
+      miniMapBoxTop
+
+    if (viewBoxStyle.top > miniMapBoxTop + actHeight) {
+      viewBoxStyle.top = miniMapBoxTop + actHeight
+    }
+    if (viewBoxStyle.left > miniMapBoxLeft + actWidth) {
+      viewBoxStyle.left = miniMapBoxLeft + actWidth
+    }
+
+    Object.keys(viewBoxStyle).forEach((key) => {
+      viewBoxStyle[key] = viewBoxStyle[key] + 'px'
+    })
+
     this.removeNodeContent(svg)
     return {
       svgHTML: svg.svg(), // 小地图html