CanvasRenderingContext2D.isPointInPath()

The CanvasRenderingContext2D.isPointInPath() method of the Canvas 2D API reports whether or not the specified point is contained in the current path.

SyntaxEdit

boolean ctx.isPointInPath(x, y);
boolean ctx.isPointInPath(x, y, fillRule);

boolean ctx.isPointInPath(path, x, y);
boolean ctx.isPointInPath(path, x, y, fillRule);

Parameters

x

The X coordinate of the point to check.

y

The Y coordinate of the point to check.

fillRule

The algorithm by which to determine if a point is inside a path or outside a path.
Possible values:

• "nonzero": The non-zero winding rule, which is the default rule.
• "evenodd": The even-odd winding rule.

path

A Path2D path to use.

Return value

Boolean

A Boolean, which is true if the specified point is contained in the current or specified path, otherwise false.

ExamplesEdit

Using the isPointInPath method

This is just a simple code snippet which uses the isPointinPath method to check if a point is in the current 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.isPointInPath(10, 10)); // true 
 

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

<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.isPointInPath(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);

SpecificationsEdit

Browser compatibilityEdit

Compatibility notesEdit

• Prior to Gecko 7.0 (Firefox 7.0 / Thunderbird 7.0 / SeaMonkey 2.4), this method incorrectly failed to multiply the specified point's coordinates by the current transformation matrix before comparing it to the path. Now this method works correctly even if the context is rotated, scaled, or otherwise transformed.

See alsoEdit

• The interface defining it, CanvasRenderingContext2D.