CanvasPattern: setTransform() method

Note: This feature is available in Web Workers.

The CanvasPattern.setTransform() method uses a DOMMatrix object as the pattern's transformation matrix and invokes it on the pattern.

Syntax

setTransform(matrix)

Parameters

matrix: A DOMMatrix to use as the pattern's transformation matrix.

This is just a simple code snippet which uses the setTransform method to create a CanvasPattern with the specified pattern transformation from a DOMMatrix. The pattern gets applied if you set it as the current fillStyle and gets drawn onto the canvas when using the fillRect() method, for example.

HTML

html

<canvas id="canvas"></canvas>

JavaScript

const canvas = document.getElementById("canvas");
const ctx = canvas.getContext("2d");

const matrix = new DOMMatrix([1, 0.2, 0.8, 1, 0, 0]);

const img = new Image();
img.src = "canvas_createpattern.png";

img.onload = () => {
  const pattern = ctx.createPattern(img, "repeat");
  pattern.setTransform(matrix.rotate(-45).scale(1.5));
  ctx.fillStyle = pattern;
  ctx.fillRect(0, 0, 400, 400);
};

Editable demo

Here's an editable demo of the code snippet above. Try changing the argument to SetTransform() to see the effect it had.

<canvas id="canvas" width="400" height="200" class="playable-canvas"></canvas>
<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">
const img = new Image();
img.src = 'canvas_createpattern.png';
img.onload = () => {
  const pattern = ctx.createPattern(img, 'repeat');
  pattern.setTransform(matrix.rotate(-45).scale(1.5));
  ctx.fillStyle = pattern;
  ctx.fillRect(0, 0, 400, 400);
};
</textarea>

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

const matrix = new DOMMatrix([1, 0.2, 0.8, 1, 0, 0]);

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

reset.addEventListener("click", () => {
  textarea.value = code;
  drawCanvas();
});

edit.addEventListener("click", () => {
  textarea.focus();
});

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

Specifications

Specification
HTML Standard # dom-canvaspattern-settransform-dev

Browser compatibility

BCD tables only load in the browser

CanvasPattern: setTransform() method

Syntax

Parameters

Return value

Examples

Using the `setTransform` method

HTML

JavaScript

Editable demo

Specifications

Browser compatibility

See also