code: function() {
          var context;
          if (this.cacheImageRecord) {
              context = this.cacheImageRecord.getRenderedContext();
          } else if (this.context2D) {
              context = this.context2D;
          } else {
              $.console.warn(
                  '[Tile.drawCanvas] attempting to get tile scale %s when tile\'s not cached',
                  this.toString());
              return 1;
          }
          return context.canvas.width / (this.size.x * $.pixelDensityRatio);
      }
docs: Get the ratio between current and original size.
  @function
  @return {Float}