我們可以透過建立fabric.Polygon的實例來建立一個Polygon物件。多邊形物件的特徵可以是由一組連接的直線段組成的任何閉合形狀。由於它是 FabricJS 的基本元素之一，我們也可以透過應用角度、不透明度等屬性輕鬆自訂它。為了找到表示目前變換的變換矩陣，我們使用 calcOwnMatrix 方法。
calcOwnMatrix(): Array
讓我們來看一個程式碼範例，了解如何使用 calcOwnMatrix 方法找到表示多邊形目前變換的變換矩陣。您可以從開發工具開啟控制台來查看正在顯示的陣列值。
<!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 calcOwnMatrix method</h2>
<p>
You can open console from dev tools and see that the logged output contains the transform matrix of the polygon instance
</p>
<canvas id="canvas"></canvas>
<script>
// Initiate a canvas instance
var canvas = new fabric.Canvas("canvas");
canvas.setWidth(document.body.scrollWidth);
canvas.setHeight(250);
// Initiating a polygon object
var polygon = new fabric.Polygon(
[
{ x: 200, y: 10 },
{ x: 250, y: 50 },
{ x: 250, y: 180 },
{ x: 150, y: 180 },
{ x: 150, y: 50 },
{ x: 200, y: 10 },
],
{
fill: "green",
stroke: "blue",
strokeWidth: 20,
skewX: 15,
}
);
// Adding it to the canvas
canvas.add(polygon);
// Using calcOwnMatrix method
console.log(
"The transform matrix which represents current transformation of the polygon instance is: ",
polygon.calcOwnMatrix()
);
</script>
</body>
</html>
讓我們看一個程式碼範例，以了解當我們對多邊形物件應用水平縮放時，傳回數組的值是如何受到影響的。在這裡，我們向scaleX屬性傳遞了值2。這確保了我們的多邊形物件在水平方向上縮放2倍。我們也可以在控制台中看到傳回數組的第0個索引值發生了變化。這是因為第 0 個索引表示scaleX 值。
<!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 calcOwnMatrix method along with scaleX property</h2>
<p>
You can open console from dev tools and see that the logged output has changed
</p>
<canvas id="canvas"></canvas>
<script>
// Initiate a canvas instance
var canvas = new fabric.Canvas("canvas");
canvas.setWidth(document.body.scrollWidth);
canvas.setHeight(250);
// Initiating a polygon object
var polygon = new fabric.Polygon(
[
{ x: 200, y: 10 },
{ x: 250, y: 50 },
{ x: 250, y: 180 },
{ x: 150, y: 180 },
{ x: 150, y: 50 },
{ x: 200, y: 10 },
],
{
fill: "green",
stroke: "blue",
strokeWidth: 20,
skewX: 15,
scaleX: 2,
}
);
// Adding it to the canvas
canvas.add(polygon);
// Using calcOwnMatrix method
console.log(
"The transform matrix which represents current transformation of the polygon instance is: ",
polygon.calcOwnMatrix()
);
</script>
</body>
</html>
在本教學中，我們使用兩個簡單的範例來示範如何使用 FabricJS 找到表示 Polygon 物件目前變換的變換矩陣。
以上是FabricJS – 找出表示多邊形物件目前變換的變換矩陣？的詳細內容。更多資訊請關注PHP中文網其他相關文章！
