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How to Rotate an Image In Canvas?

3 minutes read

To rotate an image in a canvas, you can use the context.rotate() method in JavaScript. First, select the image you want to rotate using its source or ID. Then, specify the angle by which you want to rotate the image in radians. Next, you need to set the rotation point using the context.translate() method to ensure the rotation occurs around a specific point. Finally, apply the rotation transformation to the canvas context using the context.rotate() method with the specified angle. This will rotate the image in the canvas by the desired angle.


How to rotate an image in canvas using HTML5?

You can rotate an image in an HTML5 canvas using the canvas element and the ctx.rotate() method. Here's an example code snippet:

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<!DOCTYPE html>
<html>
  <head>
    <title>Rotate Image in Canvas</title>
  </head>
  <body>
    <canvas id="myCanvas" width="400" height="400"></canvas>
    <script>
      var canvas = document.getElementById('myCanvas');
      var ctx = canvas.getContext('2d');

      var image = new Image();
      image.src = 'image.jpg';

      image.onload = function() {
        ctx.translate(canvas.width / 2, canvas.height / 2);
        ctx.rotate(Math.PI / 4); // Rotate by 45 degrees
        ctx.drawImage(image, -image.width / 2, -image.height / 2);
      };
    </script>
  </body>
</html>


In this example, we first create a canvas element with an ID of myCanvas and dimensions of 400x400. We then get the canvas context ctx and load an image using the Image object.


Once the image is loaded, we use the ctx.translate() method to move the origin to the center of the canvas, then use ctx.rotate() to rotate the canvas context by a specified angle (in radians). Lastly, we draw the image on the canvas at the new rotated position.


How to rotate an image in canvas counterclockwise?

To rotate an image in a canvas counterclockwise, you can use the transform() method in HTML5 canvas.


Here is an example code snippet to rotate an image counterclockwise by 90 degrees:

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// Get the canvas element and its context
var canvas = document.getElementById('myCanvas');
var ctx = canvas.getContext('2d');

// Create an image object and load an image into it
var img = new Image();
img.src = 'image.jpg';

// Once the image is loaded, draw it on the canvas and rotate it counterclockwise by 90 degrees
img.onload = function() {
  // Clear the canvas
  ctx.clearRect(0, 0, canvas.width, canvas.height);
  
  // Translate the canvas center to the image center
  ctx.translate(canvas.width / 2, canvas.height / 2);
  
  // Rotate the canvas counterclockwise by 90 degrees
  ctx.rotate(-Math.PI / 2);
  
  // Draw the image at the new rotated position
  ctx.drawImage(img, -img.width / 2, -img.height / 2);
};


This code will rotate the image counterclockwise by 90 degrees and draw it on the canvas. You can modify the rotation angle and other parameters to achieve the desired rotation effect.


How to rotate an image in canvas clockwise?

To rotate an image in a canvas clockwise, you can use the rotate() method of the canvas 2D rendering context. Here is an example code snippet to rotate an image by 90 degrees clockwise:

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// Get the canvas element and its 2D rendering context
const canvas = document.getElementById('myCanvas');
const ctx = canvas.getContext('2d');

// Create an image object
const img = new Image();
img.onload = function() {
  // Rotate the image by 90 degrees clockwise
  ctx.save(); // Save the current state of the context
  ctx.translate(canvas.width / 2, canvas.height / 2); // Translate the origin to the center of the canvas
  ctx.rotate(Math.PI / 2); // Rotate by 90 degrees (PI/2 radians) clockwise
  ctx.drawImage(img, -img.width / 2, -img.height / 2); // Draw the rotated image
  ctx.restore(); // Restore the saved state of the context
};
img.src = 'image.jpg';


In this code snippet, we first create an image object and set its onload event handler to rotate the image once it is loaded. Inside the event handler, we use the translate() method to move the origin of the canvas context to the center of the canvas, rotate the canvas context by 90 degrees using the rotate() method, and then draw the image at the correct position. Finally, we restore the saved state of the context using the restore() method.

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