diff --git a/lib/QRCode.js b/lib/QRCode.js
index 7471f47..a8ccacf 100644
--- a/lib/QRCode.js
+++ b/lib/QRCode.js
@@ -18,7 +18,6 @@ function renderCanvas(canvas) {
     canvas.height = size;
     canvas.style.left = (window.innerWidth - size) / 2 + 'px';
     if(window.innerHeight > size) canvas.style.top = (window.innerHeight - size) / 2 + 'px';
-    ctx.fillRect(0, 0, size, size);
     var cells = this.cells;
     var cellWidth = this.size / cells.length;
     var cellHeight = this.size / cells.length;
@@ -30,6 +29,7 @@ function renderCanvas(canvas) {
             var nTop = rowIndex * cellHeight;
             ctx.fillStyle = ctx.strokeStyle = column ? bgColor : fgColor;
             ctx.lineWidth = 1;
+            ctx.clearRect(nLeft, nTop, cellWidth, cellHeight);
             ctx.fillRect(nLeft, nTop, cellWidth, cellHeight);
             ctx.strokeRect(
                 Math.floor(nLeft) + 0.5,
@@ -104,7 +104,7 @@ var QRCode = createReactClass({
                     render={renderCanvas}
                     onLoad={this.props.onLoad}
                     onLoadEnd={this.props.onLoadEnd}
-                    style={{height: size, width: size}}
+                    style={{height: size, width: size, backgroundColor: 'transparent' }}
                 />
             </View>
         );