CanvasRenderingContext2D: getTransform() method
Baseline
Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2020.
The CanvasRenderingContext2D.getTransform() method of the Canvas 2D API retrieves the current transformation matrix being applied to the context.
Syntax
getTransform()
Parameters
None.
Return value
A DOMMatrix object.
The transformation matrix is described by:
Note:
The returned object is not live, so updating it will not
affect the current transformation matrix, and updating the current transformation
matrix will not affect an already returned DOMMatrix.
Examples
In the following example, we have two <canvas> elements. We apply a
transform to the first one's context using
CanvasRenderingContext2D.setTransform() and draw a square on it, then
retrieve the matrix from it using getTransform().
We then apply the retrieved matrix directly to the second canvas context by passing the
DOMMatrix object directly to setTransform(), and draw a circle
on it.
HTML
<canvas width="240"></canvas> <canvas width="240"></canvas>
CSS
canvas {
border: 1px solid black;
}
JavaScript
const canvases = document.querySelectorAll("canvas");
const ctx1 = canvases[0].getContext("2d");
const ctx2 = canvases[1].getContext("2d");
ctx1.setTransform(1, 0.2, 0.8, 1, 0, 0);
ctx1.fillRect(25, 25, 50, 50);
let storedTransform = ctx1.getTransform();
console.log(storedTransform);
ctx2.setTransform(storedTransform);
ctx2.beginPath();
ctx2.arc(50, 50, 50, 0, 2 * Math.PI);
ctx2.fill();
Result
Specifications
| Specification |
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| HTML # dom-context-2d-gettransform-dev |
Browser compatibility
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getTransform
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Legend
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- Full support
- Full support
See also
- The interface defining this method:
CanvasRenderingContext2D CanvasRenderingContext2D.transform()