WIP: think I got zoom working?

index.html

@@ -101,10 +101,6 @@
       </p>
     </template>
 
-    <div>
-      debug margin
-    </div>
-
     <svg viewbox="-100 -100 3450 2400" xmlns="http://www.w3.org/2000/svg">
       <defs>
         <pattern id="inch-mark" x="0" y="0" width="2in" height="2in" patternUnits="userSpaceOnUse">
@@ -131,8 +127,7 @@
       <image id="img2" href="scans/map1.jpg" width="2284" height="1518" />
       <g id="firing-arcs"></g>
       <rect id="map" x="0" y="0" width="34in" height="23in" />
-      <rect id="view-box" x="-100" y="-100" width="3450" height="2400" />
-      <!-- <rect id="view-box" x1="-100" y1="-100" x2="3450" y2="2400" /> -->
+      <!-- <rect id="debug-view-box" x="-100" y="-100" width="3450" height="2400" /> -->
     </svg>
 
     <div id="content">