fix the image size over the canvas

public/self/js/Director/detection.js

@@ -2676,7 +2676,7 @@ function setPage(pageData,pageSize){
 
     canvas    = document.getElementById("myCanvas");
     context   = canvas.getContext("2d");
-    maxWidth  = document.getElementById("showPic").offsetWidth;
+    maxWidth  = document.getElementById("showPic").offsetWidth-56;
     maxHeight = document.getElementById("showPic").offsetHeight-100;
     canvas.width = maxWidth;
     canvas.height = maxHeight;