リサイズ
http://stackoverflow.com/questions/10841532/canvas-drawimage-scaling
context.drawImage(imageObj, 0, 0, 100, 100 * imageObj.height / imageObj.width)
リサイズ
http://stackoverflow.com/questions/10841532/canvas-drawimage-scaling
context.drawImage(imageObj, 0, 0, 100, 100 * imageObj.height / imageObj.width)