[Edit]

JavaScript - flip canvas vertically

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Created by:

Gigadude

791

In this article, we would like to show you how to flip canvas vertically using JavaScript.

Quick solution:

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var canvas = document.querySelector('#my-canvas');
var context = canvas.getContext('2d');
​
context.scale (1, -1); // <--- flip vertically
​
context.font = '55px Arial';
context.fillText('text', 10, -15);

Note:

The y-coordinates of all points inside the canvas are negative now.

Practical example

Edit

In this example, we use scale() method with negative y coordinate to flip the text on canvas vertically.

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<!doctype html>
<html>
<head>
  <style>
​
    #my-canvas { border: 1px solid gray; }
​
  </style>
</head>
<body>
  <canvas id="my-canvas" width="110" height="65"></canvas>
  <script>
​
    var canvas = document.querySelector('#my-canvas');
    var context = canvas.getContext('2d');
​
    context.scale (1, -1); // <--- flip vertically
​
    context.font = '55px Arial';
    context.fillText('text', 10, -15);
​
  </script>
</body>
</html>