How to set a multiplier to scale a cloned image using FabricJS?

In this tutorial, we are going to learn how to set a multiplier to scale the cloned image using FabricJS. We can create an Image object by creating an instance of fabric.Image. Since it is one of the basic elements of FabricJS, we can also easily customize it by applying properties like angle, opacity etc. In order to set a multiplier to scale the cloned image, we use the multiplier property.

Syntax

cloneAsImage( callback: function, { multiplier: Number}: Object): fabric.Object

Parameters

  • callback (optional) − This parameter is a function which is to be invoked with a cloned image instance as the first argument.

  • options (optional) − This parameter is an optional Object which provides additional customizations to our clone image. Using this parameter we can set a multiplier, crop the clone image, remove the current object transform or a lot of properties can be changed of which multiplier is a property.

Options Keys

  • multiplier − This property accepts a Number value which denotes the multiplier to scale the final output image by. The default value is 1.

Without using the multiplier property

Example

Let’s see a code example of how the cloned Image object appears when the multiplier property is not used. In this case, the default multiplier value will be used, which is 1.

<!DOCTYPE html>
<html>
<head>
   <!-- Adding the Fabric JS Library-->
   <script src="https://cdnjs.cloudflare.com/ajax/libs/fabric.js/510/fabric.min.js"></script>
</head>
<body>
   <h2>Without using the multiplier property</h2> 
   <p>You can see that the clone image uses the default multiplier</p>
   <canvas id="canvas"></canvas>
   <img src="https://www.tutorialspoint.com/images/logo.png" id="img1" style="display: none" />
   <script>
      // Initiate a canvas instance
      var canvas = new fabric.Canvas("canvas");
      canvas.setWidth(document.body.scrollWidth);
      canvas.setHeight(250);
      
      // Initiating the image element
      var imageElement = document.getElementById("img1");
      
      // Initiate a shadow object
      var shadow = new fabric.Shadow({
         color: "#308080",
         blur: 3,
      });
      
      // Initiate an Image object
      var image = new fabric.Image(imageElement, {
         top: 50,
         left: 110,
         skewX: 20,
         shadow: shadow,
      });
      
      // Using cloneAsImage method
      image.cloneAsImage(function (Img) {
         canvas.add(Img);
      });
   </script>
</body>
</html>

Using the multiplier property

Example

In this example, we have used the multiplier property and passed it a value 2 to demonstrate that the final cloned image will be scaled by twice in both x and y directions.

<!DOCTYPE html>
<html>
<head>
   <!-- Adding the Fabric JS Library-->
   <script src="https://cdnjs.cloudflare.com/ajax/libs/fabric.js/510/fabric.min.js"></script>
</head>
<body>
   <h2>Using the multiplier property</h2>
   <p>You can see that the clone image has been scaled</p>
   <canvas id="canvas"></canvas>
   <img src="https://www.tutorialspoint.com/images/logo.png" id="img1" style="display: none" />
   <script>
      // Initiate a canvas instance
      var canvas = new fabric.Canvas("canvas");
      canvas.setWidth(document.body.scrollWidth);
      canvas.setHeight(250);
      // Initiating the image element
      var imageElement = document.getElementById("img1");
      // Initiate a shadow object
      var shadow = new fabric.Shadow({
         color: "#308080",
         blur: 3,
      });
      // Initiate an Image object
      var image = new fabric.Image(imageElement, {
         top: 50,
         left: 110,
         skewX: 20,
         shadow: shadow,
      });
      // Using cloneAsImage method
      image.cloneAsImage(
         function (Img) {
            Img.set("top", 90);
            canvas.add(Img);
         },
         {
            multiplier: 2,
         }
      );
   </script>
</body>
</html>

Updated on: 27-Oct-2022

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