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How to set the minimum scale value allowed for a Circle using FabricJS?

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2023-09-05 15:25:09953browse

How to set the minimum scale value allowed for a Circle using FabricJS?

In this tutorial, we will learn how to set the minimum allowed ratio of a Circle using FabricJS. Circles are one of the various shapes provided by FabricJS. In order to create a circle, we must create an instance of the Fabric.Circle class and add it to the canvas. We can customize the circular object by adding a fill color, removing its borders, and even changing its dimensions. Likewise, we can also use the minScaleLimit property to set its minimum allowed scale.

Syntax

new fabric.Circle({ minScaleLimit : Number }: Object)

Parameters

  • Options (optional) - This parameter is a Object Provides additional customization for our circles. Using this parameter, you can change the color, cursor, border width, and many other properties associated with the object for which minScaleLimit is a property.

Option Key

  • ##minScaleLimit - This property accepts numbers strong> As a value that allows us to control the minimum allowed proportion of the circle.

Example 1

Appearance of the default circle object

Let's take a look at the code to see what happens when # is not used ##minScaleLimit

property, what the circular object looks like. In this case we will be able to scale the object freely since no minimum limit is set. 

<!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>Setting the minimum allowed scale value of circle using FabricJS</h2>
      <p>Select the object and scale it down by dragging one of its controlling corners. Here you can scale down the object freely since there is no minimum limit set.</p>
      <canvas id="canvas"></canvas>

      <script>
         // Initiate a canvas instance
         var canvas = new fabric.Canvas("canvas");
         var circle = new fabric.Circle({
            left: 115,
            top: 50,
            radius: 50,
            fill: "#ff1493"
         });

         // Adding it to the canvas
         canvas.add(circle);
         canvas.setWidth(document.body.scrollWidth);
         canvas.setHeight(250);
      </script>
   </body>
</html>
Example 2

Passing the

minScaleLimit attribute as a key with a custom value In this example, We'll see how assigning a value to the

minScaleLimit

property changes the minimum allowed scale value for a circular object in the canvas. Here we are using 0.8 as the value, which means that we will not be able to shrink the object to a radius smaller than 64 pixels, which is calculated by radius * limit (0.8 * 80 = 64 pixels). 

<!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>Setting the minimum allowed scale value of circle using FabricJS</h2>
      <p>Select the object and try to scale it down by dragging one of its controlling corners. You cannot scale down the object freely, as we have set <b>minScaleLimit</b> at 0.8. So, the minimum scale of the circle must be at least 80% of the original radius, beyond which you cannot scale it down any further. </p>
      <canvas id="canvas"></canvas>

      <script>
         // Initiate a canvas instance
         var canvas = new fabric.Canvas("canvas");
         var circle = new fabric.Circle({
            left: 115,
            top: 50,
            radius: 80,
            fill: "#ff1493",
            minScaleLimit: 0.8
         });

         // Adding it to the canvas
         canvas.add(circle);
         canvas.setWidth(document.body.scrollWidth);
         canvas.setHeight(250);
      </script>
   </body>
</html>

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