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How to vertically center an object relative to the current viewport of the canvas in IText using FabricJS?
- 王林forward
- 2023-08-24 10:21:101350browse
In this tutorial, we will learn how to vertically center an object relative to the current viewport of a canvas in IText using FabricJS. The IText class was introduced in FabricJS version 1.4, which extends Fabric.Text and is used to create IText instances. IText instances give us the freedom to select, cut, paste or add new text without additional configuration. There are also various supported key combinations and mouse/touch combinations to make text interactive that are not available in Text.
However, IText-based Textbox allows us to resize the text rectangle and wrap it automatically. This is not the case for IText, as the height does not adjust based on line breaks. We can manipulate IText objects by using various properties. Likewise, we can use the viewportCenterV method to vertically center an object relative to the current viewport of the canvas.
grammar
viewportCenterV(): fabric.Object
Example 1
Default appearance of IText objects
Let's look at a code example to see what an IText object looks like without using the viewportCenterV method. In this case, the itext object will not be vertically centered on the canvas.
<!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 appearance of the IText object</h2>
<p>You can see that the itext object has not been centered vertically withrespect to the current viewport of canvas</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 an itext object
var itext = new fabric.IText("Add sample text here.", {
width: 300,
left: 50,
top: 70,
fill: "red",
});
// Add it to the canvas
canvas.add(itext);
</script>
</body>
</html>
Example 2
Use viewportCenterV method
Let's look at a code example to see what an IText object looks like when using the viewportCenterV method. In this case, our IText object will be centered relative to the current viewport of the canvas.
<!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 viewportCenterV method</h2>
<p>You can see that the itext object has been centered vertically with respect to the current viewport of canvas</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 an itext object
var itext = new fabric.IText("Add sample text here.", {
width: 300,
left: 50,
top: 70,
fill: "red",
});
// Add it to the canvas
canvas.add(itext);
// Using the viewportCenterV method
itext.viewportCenterV();
</script>
</body>
</html>
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