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CanvasRenderingContext2D.isPointInStroke

The CanvasRenderingContext2D.isPointInStroke() method of the Canvas 2D API reports whether or not the specified point is inside the area contained by the stroking of a path.

Syntax

boolean ctx.isPointInStroke(x, y);
boolean ctx.isPointInStroke(path, x, y);

Parameters

x
The X coordinate of the point to check.
y
The Y coordinate of the point to check.
path
A Path2D path to use.

Return value

Boolean
A Boolean, which is true if the point is inside the area contained by the stroking of a path, otherwise false.

Examples

Using the isPointInStroke method

This is just a simple code snippet which uses the isPointInStroke method to check if a point is inside the area contained by the stroking of a path.

HTML

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

JavaScript

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

ctx.rect(10, 10, 100, 100);
ctx.stroke();
console.log(ctx.isPointInStroke(10, 10)); // true

Edit the code below, see your changes update live in the canvas and watch for loggings in your console:

Playable code
<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">
ctx.rect(10, 10, 100, 100);
ctx.stroke();
console.log(ctx.isPointInStroke(10, 10)); // true</textarea>
var canvas = document.getElementById("canvas");
var ctx = canvas.getContext("2d");
var textarea = document.getElementById("code");
var reset = document.getElementById("reset");
var edit = document.getElementById("edit");
var code = textarea.value;

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

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

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

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

Specifications

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support (Yes) (Yes) (Yes) (Yes) (Yes)
Path parameter (Yes) 31 (31) No support (Yes) No support
Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support (Yes) (Yes) (Yes) (Yes) (Yes) (Yes)
Path parameter ? ? 31.0 (31) ? ? ?

See also

© 2005–2018 Mozilla Developer Network and individual contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D/isPointInStroke