CanvasPattern.setTransform()

Playable code

<canvas id="canvas" width="400" height="200" class="playable-canvas"></canvas>
<svg id="svg1" style="display:none"></svg>
<div class="playable-buttons">
  <input id="edit" type="button" value="Edit" />
  <input id="reset" type="button" value="Reset" />
</div>
<textarea id="code" class="playable-code" style="height:120px">
var img = new Image();
img.src = 'https://mdn.mozillademos.org/files/222/Canvas_createpattern.png';
img.onload = function() {
  var pattern = ctx.createPattern(img, 'repeat');
  pattern.setTransform(matrix.rotate(-45).scale(1.5));
  ctx.fillStyle = pattern;
  ctx.fillRect(0, 0, 400, 400);
};</textarea>

var canvas = document.getElementById('canvas');
var ctx = canvas.getContext('2d');
var textarea = document.getElementById('code');
var reset = document.getElementById('reset');
var edit = document.getElementById('edit');
var code = textarea.value;

var svg1 = document.getElementById('svg1');
var matrix = svg1.createSVGMatrix();

function drawCanvas() {
  ctx.clearRect(0, 0, canvas.width, canvas.height);
  eval(textarea.value);
}

reset.addEventListener('click', function() {
  textarea.value = code;
  drawCanvas();
});

edit.addEventListener('click', function() {
  textarea.focus();
})

textarea.addEventListener('input', drawCanvas);
window.addEventListener('load', drawCanvas);