所属分类：web前端开发
在本教程中，我们将学习如何使用 FabricJS 获取图像的对象比例因子。我们可以通过创建fabric.Image的实例来创建一个Image对象。由于它是 FabricJS 的基本元素之一，我们还可以通过应用角度、不透明度等属性轻松自定义它。为了获取 Image 的对象比例因子，我们使用 getObjectScaling 方法。
getObjectScaling(): Object
让我们看一个代码示例，以查看使用 getObjectScaling 方法时记录的输出。在这种情况下，控制台中将显示默认的scaleX和scaleY值为1。
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<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 getObjectscaling method</h2>
<p>
You can open console from dev tools and see that the logged value is being displayed in the console
</p>
<canvas id="canvas"></canvas>
<img src="https://img.zzsucai.com/202310/07/CRUR7195599104125.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 an Image object
var image = new fabric.Image(imageElement, {
top: 50,
left: 110,
});
// Add it to the canvas
canvas.add(image);
// Using getObjectScaling method
console.log("The scale factor is", image.getObjectScaling());
</script>
</body>
</html>
让我们看一个代码示例，以查看当 getObjectScaling 方法与 scaleX 属性结合使用时记录的输出。在这种情况下，图像对象的scaleX值将显示为2，而scaleY值将保持不变。
<!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 getObjectScaling method and passing the scaleX property</h2>
<p>
You can open console from dev tools and see that the logged value is being displayed in the console
</p>
<canvas id="canvas"></canvas>
<img src="https://img.zzsucai.com/202310/07/CRUR7195599104125.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 an Image object
var image = new fabric.Image(imageElement, {
top: 50,
left: 110,
scaleX: 2,
});
// Add it to the canvas
canvas.add(image);
// Using getObjectScaling method
console.log("The scale factor is", image.getObjectScaling());
</script>
</body>
</html>
