CanvasRenderingContext2D.strokeRect() - Web APIs 编辑

The CanvasRenderingContext2D.strokeRect() method of the Canvas 2D API draws a rectangle that is stroked (outlined) according to the current strokeStyle and other context settings.

This method draws directly to the canvas without modifying the current path, so any subsequent fill() or stroke() calls will have no effect on it.

Syntax

void ctx.strokeRect(x, y, width, height);

The strokeRect() method draws a stroked rectangle whose starting point is at (x, y) and whose size is specified by width and height.

Parameters

x

The x-axis coordinate of the rectangle's starting point.

y

The y-axis coordinate of the rectangle's starting point.

width

The rectangle's width. Positive values are to the right, and negative to the left.

height

The rectangle's height. Positive values are down, and negative are up.

Examples

A simple stroked rectangle

This example draws a rectangle with a green outline using the strokeRect() method.

HTML

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

JavaScript

The rectangle's top-left corner is at (20, 10). It has a width of 160 and a height of 100.

const canvas = document.getElementById('canvas');
const ctx = canvas.getContext('2d');
ctx.strokeStyle = 'green';
ctx.strokeRect(20, 10, 160, 100);

Result

Applying various context settings

This example draws a rectangle with a drop shadow and thick, beveled outlines.

HTML

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

JavaScript

const canvas = document.getElementById('canvas');
const ctx = canvas.getContext('2d');
ctx.shadowColor = '#d53';
ctx.shadowBlur = 20;
ctx.lineJoin = 'bevel';
ctx.lineWidth = 15;
ctx.strokeStyle = '#38f';
ctx.strokeRect(30, 30, 160, 90);

Result

Specifications

Browser compatibility

BCD tables only load in the browser

See also

• The interface defining this method: CanvasRenderingContext2D
• CanvasRenderingContext2D.strokeStyle
• CanvasRenderingContext2D.clearRect()
• CanvasRenderingContext2D.fillRect()