CanvasRenderingContext2D.closePath() - Web APIs 编辑

The CanvasRenderingContext2D.closePath() method of the Canvas 2D API attempts to add a straight line from the current point to the start of the current sub-path. If the shape has already been closed or has only one point, this function does nothing.

This method doesn't draw anything to the canvas directly. You can render the path using the stroke() or fill() methods.

Syntax

void ctx.closePath();

Examples

Closing a triangle

This example creates the first two (diagonal) sides of a triangle using the lineTo() method. After that, the triangle's base is created with the closePath() method, which automatically connects the shape's first and last points.

HTML

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

JavaScript

The triangle's corners are at (20, 140), (120, 10), and (220, 140).

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

ctx.beginPath();
ctx.moveTo(20, 140);   // Move pen to bottom-left corner
ctx.lineTo(120, 10);   // Line to top corner
ctx.lineTo(220, 140);  // Line to bottom-right corner
ctx.closePath();       // Line to bottom-left corner
ctx.stroke();

Result

Closing just one sub-path

This example draws a smiley face consisting of three disconnected sub-paths.

Note: Although closePath() is called after all the arcs have been created, only the last arc (sub-path) gets closed.

HTML

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

JavaScript

The first two arcs create the face's eyes. The last arc creates the mouth.

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

ctx.beginPath();
ctx.arc(240, 20, 40, 0, Math.PI);
ctx.moveTo(100, 20);
ctx.arc(60, 20, 40, 0, Math.PI);
ctx.moveTo(215, 80);
ctx.arc(150, 80, 65, 0, Math.PI);
ctx.closePath();
ctx.lineWidth = 6;
ctx.stroke();

Result

Specifications

Browser compatibility

BCD tables only load in the browser

See also

• The interface defining this method: CanvasRenderingContext2D
• CanvasRenderingContext2D.beginPath()