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

x

The x-axis coordinate of the point to check, unaffected by the current transformation of the context.

y

The y-axis coordinate of the point to check, unaffected by the current transformation of the context.

fillRule

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

nonzero

The non-zero winding rule. Default rule.

evenodd

The even-odd winding rule.

path

A Path2D path to check against. If unspecified, the current path is used.

A boolean value

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

This example uses the isPointInPath() method to check if a point is within the current path.

HTML

<canvas id="canvas"></canvas>
<p>In path: <code id="result">false</code></p>

JavaScript

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

ctx.rect(10, 10, 100, 100);
ctx.fill();
result.innerText = ctx.isPointInPath(30, 70);

Result

Whenever you move the mouse, this example checks whether the cursor is in a circular Path2D path. If yes, the circle becomes green, otherwise it is red.

HTML

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

JavaScript

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

// Create circle
const circle = new Path2D();
circle.arc(150, 75, 50, 0, 2 * Math.PI);
ctx.fillStyle = "red";
ctx.fill(circle);

// Listen for mouse moves
canvas.addEventListener("mousemove", (event) => {
  // Check whether point is inside circle
  const isPointInPath = ctx.isPointInPath(circle, event.offsetX, event.offsetY);
  ctx.fillStyle = isPointInPath ? "green" : "red";

  // Draw circle
  ctx.clearRect(0, 0, canvas.width, canvas.height);
  ctx.fill(circle);
});

Result

• 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.

• The interface defining this method: CanvasRenderingContext2D