[fix] tweaks

docker-compose.yml

@@ -41,5 +41,5 @@ services:
     image: teamlaser/laser-app:latest
     depends_on:
       - db
-    command:  bash -c "while true; do python ./worker.py; sleep 30; done"
+    command:  bash -c "while true; do python ./worker.py; sleep 3; done"
 

index.html

@@ -10,6 +10,7 @@
     video { border: 1px solid #ccc; display: block; margin: 0 0 20px 0; }
     #canvas { margin-top: 20px; border: 1px solid #ccc; display: block; }
     span.ui-slider-handle.ui-corner-all.ui-state-default {    background: dodgerblue;}
+    canvas#simuCanvas {background: #333;}
   </style>
   <link rel="stylesheet" type="text/css" href="css/bootstrap/css/bootstrap.min.css" />
   <link rel="stylesheet" type="text/css" href="js/jquery-ui/jquery-ui.css" />
@@ -67,7 +68,7 @@
       </div>
     </div>
   </div>
-  <div class="row" id="result">
+  <div class="row" id="preview">
     <div class="col-sm">
       <canvas id="simuCanvas" width="640" height="480"></canvas>
     </div>

js/canvas.js

@@ -255,6 +255,13 @@ $(document).ready(function(){
   }
   function refreshImageList(){
     var imageList = localStorage.getItem("imageList") ? JSON.parse(localStorage.getItem("imageList"))  : []
+
+    if( 0 == imageList.length){
+      $("#preview").hide()
+      return
+    }
+    $("#preview").show()
+
     html = ''
     for( id in imageList){
       hash_name = imageList[id]