diff --git a/src/drawer.js b/src/drawer.js
index 614e6cbe..3534577e 100644
--- a/src/drawer.js
+++ b/src/drawer.js
@@ -130,6 +130,10 @@ $.Drawer = function( options ) {
     // explicit left-align
     this.container.style.textAlign = "left";
     this.container.appendChild( this.canvas );
+
+    // Image smoothing for canvas rendering (only if canvas is used).
+    // Canvas default is "true", so this will only be changed if user specified "false".
+    this._imageSmoothingEnabled = true;
 };
 
 /** @lends OpenSeadragon.Drawer.prototype */
@@ -254,6 +258,7 @@ $.Drawer.prototype = {
                     this.sketchCanvas.width = sketchCanvasSize.x;
                     this.sketchCanvas.height = sketchCanvasSize.y;
                 }
+                this._updateImageSmoothingEnabled();
             }
             this._clear();
         }
@@ -608,7 +613,6 @@ $.Drawer.prototype = {
         }
     },
 
-
     /**
      * Turns image smoothing on or off for this viewer. Note: Ignored in some (especially older) browsers that do not support this property.
      *
@@ -619,16 +623,21 @@ $.Drawer.prototype = {
      */
     setImageSmoothingEnabled: function(imageSmoothingEnabled){
         if ( this.useCanvas ) {
-            var context = this.context;
-            context.mozImageSmoothingEnabled = imageSmoothingEnabled;
-            context.webkitImageSmoothingEnabled = imageSmoothingEnabled;
-            context.msImageSmoothingEnabled = imageSmoothingEnabled;
-            context.imageSmoothingEnabled = imageSmoothingEnabled;
-
+            this._imageSmoothingEnabled = imageSmoothingEnabled;
+            this._updateImageSmoothingEnabled();
             this.viewer.forceRedraw();
         }
     },
 
+    // private
+    _updateImageSmoothingEnabled: function(){
+        var context = this.context;
+        context.mozImageSmoothingEnabled = this._imageSmoothingEnabled;
+        context.webkitImageSmoothingEnabled = this._imageSmoothingEnabled;
+        context.msImageSmoothingEnabled = this._imageSmoothingEnabled;
+        context.imageSmoothingEnabled = this._imageSmoothingEnabled;
+    },
+
     /**
      * Get the canvas size
      * @param {Boolean} sketch If set to true return the size of the sketch canvas
@@ -686,8 +695,9 @@ $.Drawer.prototype = {
         var pixelDensityRatio = $.pixelDensityRatio;
         var viewportSize = this.viewport.getContainerSize();
         return {
-            x: viewportSize.x * pixelDensityRatio,
-            y: viewportSize.y * pixelDensityRatio
+            // canvas width and height are integers
+            x: Math.round(viewportSize.x * pixelDensityRatio),
+            y: Math.round(viewportSize.y * pixelDensityRatio)
         };
     },