Edit in JSFiddle

var canvas = document.getElementById('myCanvas');
var ctx = canvas.getContext('2d');

ctx.font = '30pt Arial';
ctx.fillText('Regular Text', 100, 50);

ctx.save();
ctx.translate(100,300);
ctx.rotate(-0.5*Math.PI);

var rText = 'Rotated Text';
ctx.fillText(rText , 0, 0);
ctx.restore();

var rWidth = ctx.measureText(rText).width;
ctx.fillText('Regular Text', 100, rWidth  + 120);

<canvas id="myCanvas" width="600" height="600" />