JavaScript - is point in path on canvas

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Created by:

Violetd

865

In this article, we would like to show you how to check if point is in the path on canvas using JavaScript.

Quick solution:

var canvas = document.querySelector('#my-canvas');

var context = canvas.getContext('2d');

context.isPointInPath(10, 10); // isPointInPath(x, y)

Practical example

In this example, we present how to use isPointInPath() method to check if a point is within the current path (square).

// ONLINE-RUNNER:browser;

<!doctype html>
<html>
<head>
  <style>

    #my-canvas { border: 1px solid gray; }

  </style>
</head>
<body>
  <canvas id="my-canvas" width="200" height="200"></canvas>
  <script>

    var canvas = document.querySelector('#my-canvas');
    var context = canvas.getContext('2d');
    
    context.strokeStyle = '#28a745';
    context.rect(20, 20, 100, 100); // rect(x, y, width, height)
    context.stroke();

    // point A
    console.log(context.isPointInPath(50, 50)); // true
    
    // point B
    console.log(context.isPointInPath(90, 90)); // true
    
    // point C
    console.log(context.isPointInPath(150, 150)); // false

  </script>
</body>
</html>

Visualization of the points we check: