CanvasRenderingContext2D.resetTransform() - Web APIs 编辑

Experimental

This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The CanvasRenderingContext2D.resetTransform() method of the Canvas 2D API resets the current transform to the identity matrix.

Syntax

void ctx.resetTransform();

Examples

Resetting the matrix

This example draws a rotated rectangle after modifying the matrix, and then resets the matrix using the resetTransform() method.

HTML

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

JavaScript

The rotate() method rotates the transformation matrix by 45°. The fillRect() method draws a filled rectangle, adjusted according to that matrix.

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

// Draw a rotated rectangle
ctx.rotate(45 * Math.PI / 180);
ctx.fillRect(60, 0, 100, 30);

// Reset transformation matrix to the identity matrix
ctx.resetTransform();

Result

Continuing with a regular matrix

Whenever you're done drawing transformed shapes, you should call resetTransform() before rendering anything else. In this example, the first two shapes are drawn with a skew transformation, and the last two are drawn with the identity (regular) transformation.

HTML

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

JavaScript

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

// Skewed rectangles
ctx.transform(1, 0, 1.7, 1, 0, 0);
ctx.fillStyle = 'gray';
ctx.fillRect(40, 40, 50, 20);
ctx.fillRect(40, 90, 50, 20);

// Non-skewed rectangles
ctx.resetTransform();
ctx.fillStyle = 'red';
ctx.fillRect(40, 40, 50, 20);
ctx.fillRect(40, 90, 50, 20);

Result

The skewed rectangles are gray, and the non-skewed rectangles are red.

Polyfill

You can also use the setTransform() method to reset the current transform to the identity matrix, like so:

ctx.setTransform(1, 0, 0, 1, 0, 0);

Specifications

Browser compatibility

BCD tables only load in the browser

See also

• The interface defining this method: CanvasRenderingContext2D