Brought the canvas size down again because it halves the FPS in Firefox at least.

app/lib/surface/RegionChooser.coffee

@@ -33,7 +33,7 @@ module.exports = class RegionChooser extends CocoClass
     @options.camera.dragDisabled = false
 
   restrictRegion: ->
-    RATIO = 1.56876  # 1848 / 1178
+    RATIO = 1.56876  # 924 / 589
     rect = @options.camera.normalizeBounds([@firstPoint, @secondPoint])
     currentRatio = rect.width / rect.height
     if currentRatio > RATIO

app/templates/editor/level/modal/world_select.jade

@@ -27,7 +27,7 @@ block modal-body-content
     div.alert.alert-info 
       strong Enter
       |  to confirm
-  canvas(width=1848, height=1178)
+  canvas(width=924, height=589)
 
 block modal-footer-content
   a.btn.btn-primary#done-button Done

app/templates/editor/level/thangs_tab.jade

@@ -27,7 +27,7 @@ button.navbar-toggle.toggle.btn-primary#thangs-palette-toggle(type="button", dat
         a(data-i18n="editor.delete") Delete
       li#duplicate
         a(data-i18n="editor.duplicate") Duplicate
-    canvas(width=1848, height=1178)#surface
+    canvas(width=924, height=589)#surface
     #canvas-left-gradient.gradient
     #canvas-top-gradient.gradient
 

app/templates/play/level.jade

@@ -8,7 +8,7 @@
     #tome-view
   
   #canvas-wrapper
-    canvas(width=1848, height=1178)#surface
+    canvas(width=924, height=589)#surface
     #canvas-left-gradient.gradient
     #canvas-top-gradient.gradient
   

app/templates/play/spectate.jade

@@ -3,7 +3,7 @@
 .level-content
   #control-bar-view
   #canvas-wrapper
-    canvas(width=1848, height=1178)#surface
+    canvas(width=924, height=589)#surface
     #canvas-left-gradient.gradient
     #canvas-top-gradient.gradient
   #gold-view.secret.expanded

app/views/editor/level/modal/world_select.coffee

@@ -78,8 +78,8 @@ module.exports = class WorldSelectModal extends View
 
   showZoomRegion: ->
     d = @defaultFromZoom
-    canvasWidth = 1848  # Dimensions for canvas player. Need these somewhere.
-    canvasHeight = 1178
+    canvasWidth = 924  # Dimensions for canvas player. Need these somewhere.
+    canvasHeight = 589
     dimensions = {x: canvasWidth/d.zoom, y: canvasHeight/d.zoom}
     dimensions = @surface.camera.surfaceToWorld(dimensions)
     width = dimensions.x

app/views/editor/level/treema_nodes.coffee

@@ -3,7 +3,7 @@ ThangType = require '/models/ThangType'
 
 makeButton = -> $('<a class="btn btn-primary btn-xs treema-map-button"><span class="glyphicon glyphicon-screenshot"></span></a>')
 shorten = (f) -> parseFloat(f.toFixed(1))
-WIDTH = 1848
+WIDTH = 924
 
 module.exports.WorldPointNode = class WorldPointNode extends TreemaNode.nodeMap.point2d
   constructor: (args...) ->