[修正] 修正背景图缩放问题

src/app/ui/collection-tools/collection-tools.component.ts

@@ -950,14 +950,15 @@ export class CollectionToolsComponent implements OnInit {
     img.src = this.selectingSitePlan.imageUrl;  
     img.onload = function(){
       if (img.height > dadHeight && img.width > imgWidth) {
-        let number = (dadHeight/img.height + imgWidth/img.width) / 2
-        that.canvas.setBackgroundScale(number-0.015)
+        let width = imgWidth/img.width
+        let height = dadHeight/img.height
+        that.canvas.setBackgroundScale((width>height? height : width)-0.005)
         return
       } else if (img.height > dadHeight) {
-        that.canvas.setBackgroundScale((dadHeight/img.height)-0.01)
+        that.canvas.setBackgroundScale((dadHeight/img.height)-0.005)
         return
       } else if (img.width > imgWidth) {
-        that.canvas.setBackgroundScale((imgWidth/img.width)-0.01)
+        that.canvas.setBackgroundScale((imgWidth/img.width)-0.005)
         return
       }
     };