Improved the LayerAdapter to more accurately adjust its size downward if it renders a spritesheet, handle when a single thang is too large, and cancels in-progress async builds if a new one starts.

app/lib/surface/LayerAdapter.coffee

@@ -222,6 +222,8 @@ module.exports = LayerAdapter = class LayerAdapter extends CocoClass
     @_renderNewSpriteSheet()
     
   _renderNewSpriteSheet: (async) ->
+    @asyncBuilder.stopAsync() if @asyncBuilder
+      
     async ?= @buildAsync
     builder = new createjs.SpriteSheetBuilder()
     groups = _.groupBy(@toRenderBundles, ((bundle) -> @renderGroupingKey(bundle.thangType, '', bundle.colorConfig)), @)
@@ -259,8 +261,13 @@ module.exports = LayerAdapter = class LayerAdapter extends CocoClass
         @renderRasterThangType(thangType, builder)
         
     if async
-      builder.buildAsync()
+      try
+        builder.buildAsync()
+      catch e
+        @resolutionFactor *= 0.9
+        return @_renderNewSpriteSheet(async)
       builder.on 'complete', @onBuildSpriteSheetComplete, @, true, builder
+      @asyncBuilder = builder
     else
       sheet = builder.build()
       @onBuildSpriteSheetComplete({async:async}, builder)
@@ -268,10 +275,14 @@ module.exports = LayerAdapter = class LayerAdapter extends CocoClass
       
   onBuildSpriteSheetComplete: (e, builder) ->
     return if @initializing
+    @asyncBuilder = null
     
     if builder.spriteSheet._images.length > 1
-      @resolutionFactor *= 0.9
-      console.debug('Sprite sheet is too large... re-rendering at', @resolutionFactor.toFixed(2))
+      total = 0
+      # get a rough estimate of how much smaller the spritesheet needs to be
+      for image, index in builder.spriteSheet._images
+        total += image.height / builder.maxHeight
+      @resolutionFactor /= (Math.max(1.1, Math.sqrt(total)))
       @_renderNewSpriteSheet(e.async)
       return