所属分类：web前端开发
我们可以通过创建fabric.Polygon的实例来创建一个Polygon对象。多边形对象的特征可以是由一组连接的直线段组成的任何闭合形状。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。为了添加收缩和展开动画，我们可以使用 scaleX 和 scaleY 属性与 animate 方法结合使用。
animate(property: String | Object, value: Number | Object): fabric.Object | fabric.AnimationContext | Array.<fabric.AnimationContext>
property - 该属性接受一个String或Object值来确定我们想要哪些属性制作动画。
value - 此属性接受 Number 或 Object 值，用于确定要设置动画的值特性。
scaleX：此属性接受 Number 值。分配的值决定水平对象比例因子。它的默认值为 1。
scaleY：此属性接受 Number 值。分配的值决定垂直对象比例因子。它的默认值为 1。
让我们看一个代码示例，看看如何使用 animate 方法添加收缩动画。我们向scaleX和scaleY属性传递一个值0.5，这使得多边形从水平和垂直方向都是原始大小的一半。
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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>Adding shrink animation to the polygon</h2>
<p>You can see that shrink animation has been added to the polygon</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 polygon object
var polygon = new fabric.Polygon(
[
{ x: 60, y: 0 },
{ x: 60, y: 60 },
{ x: 0, y: 60 },
{ x: 0, y: 0 },
],
{
fill: "#ffe4e1",
stroke: "green",
strokeWidth: 5,
top: 90,
left: 100,
}
);
// Adding it to the canvas
canvas.add(polygon);
// Using the animate method and passing scaleX property
polygon.animate("scaleX", "0.5", {
onChange: canvas.renderAll.bind(canvas),
easing: fabric.util.ease.easeInCubic,
duration: 1000,
});
// Using the animate method and passing scaleY property
polygon.animate("scaleY", "0.5", {
onChange: canvas.renderAll.bind(canvas),
easing: fabric.util.ease.easeInCubic,
duration: 1000,
});
</script>
</body>
</html>
在此示例中，我们将了解如何使用 animate 方法添加 expand 动画。由于我们向scaleX和scaleY属性传递的值为1.5，因此多边形对象将在水平和垂直方向上缩放1.5倍。
<!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>Adding expand animation to the polygon</h2>
<p>You can see that expand animation has been added to the polygon</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 polygon object
var polygon = new fabric.Polygon(
[
{ x: 60, y: 0 },
{ x: 60, y: 60 },
{ x: 0, y: 60 },
{ x: 0, y: 0 },
],
{
fill: "#ffe4e1",
stroke: "green",
strokeWidth: 5,
top: 90,
left: 100,
}
);
// Adding it to the canvas
canvas.add(polygon);
// Using the animate method and passing scaleX property
polygon.animate("scaleX", "1.5", {
onChange: canvas.renderAll.bind(canvas),
easing: fabric.util.ease.easeInCubic,
duration: 1000,
});
// Using the animate method and passing scaleY property
polygon.animate("scaleY", "1.5", {
onChange: canvas.renderAll.bind(canvas),
easing: fabric.util.ease.easeInCubic,
duration: 1000,
});
</script>
</body>
</html>
在本教程中，我们使用两个简单的示例来演示如何使用 FabricJS 将收缩和展开动画添加到 Polygon 对象
