How to lock the vertical skewing of a Triangle using FabricJS?


<p>In this tutorial, we are going to learn how to lock the vertical skewing of a Triangle using FabricJS. Just as we can specify the position, colour, opacity and dimension of a triangle object in the canvas, we can also specify whether we want to stop skewing an object vertically. This can be done by using the <em>lockSkewingY</em> property.</p><h2>Syntax</h2><pre class="just-code notranslate language-javascript" data-lang="javascript">new fabric.Triangle({ lockSkewingY : Boolean }: Object)</pre><h2>Parameters</h2><ul class="list"><li><p><strong>Options</strong><strong> (optional)</strong> − This parameter is an <em>Object</em> which provides additional customizations to our triangle. Using this parameter, properties such as colour, cursor, stroke width, and a lot of other properties can be changed related to the object of which <em>lockSkewingY</em> is a property.</p></li></ul><h2>Options Keys</h2><ul class="list"><li><p><strong>lockSkewingY</strong> − This property accepts a <strong>Boolean</strong> value. If we assign it a 'true' value, then the object's vertical skewing will be locked.</p></li></ul><h2>Example 1</h2><p><strong>Default behaviour of a Triangle object in the canvas</strong></p><p>Let's see a code example to understand the default behaviour of a Triangle object when <em>lockSkewingY</em> property is not used. Skewing the object in both horizontal and vertical directions is feasible by pressing the <strong>shift key</strong> and then dragging along the horizontal or vertical direction.</p><pre class="demo-code notranslate language-javascript" data-lang="javascript"><!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>Default behaviour of a Triangle object in the canvas</h2>    <p>You can press the shift-key and drag the edge along the X or Y-axis to see that skewing is possible in both directions.</p>    <canvas id="canvas"></canvas>    <script>       // Initiate a canvas instance       var canvas = new fabric.Canvas("canvas");       canvas.setWidth(document.body.scrollWidth);       canvas.setHeight(250);       // Initiate a triangle object       var triangle = new fabric.Triangle({          left: 105,          top: 70,          width: 90,          height: 80,          fill: "#746cc0",          stroke: "#967bb6",          strokeWidth: 5,       });       // Add it to the canvas       canvas.add(triangle);    </script> </body> </html></pre><h2>Example 2</h2><p><strong>Passing <em>lockSkewingY</em> as key with 'true' value</strong></p><p>In this example, we will see how we can cease the ability of a triangle object to skew vertically using the <em>lockSkewingY</em> property. As we can see, although we can skew the triangle object horizontally, we are not allowed to perform the same action vertically.</p><pre class="demo-code notranslate language-javascript" data-lang="javascript"><!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>Passing lockSkewingY as key with 'true' value</h2>    <p>You can see that skewing along the y-axis is no longer feasible</p>    <canvas id="canvas"></canvas>    <script>       // Initiate a canvas instance       var canvas = new fabric.Canvas("canvas");       canvas.setWidth(document.body.scrollWidth);       canvas.setHeight(250);       // Initiate a triangle object       var triangle = new fabric.Triangle({          left: 105,          top: 70,          width: 90,          height: 80,          fill: "#746cc0",          stroke: "#967bb6",          strokeWidth: 5,          lockSkewingY: true,       });       // Add it to the canvas       canvas.add(triangle);    </script> </body> </html></pre>

Updated on: 27-Jun-2022

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