在本教學中，我們將學習如何使用 FabricJS 來尋找 Image 物件的真實中心座標。我們可以透過建立fabric.Image的實例來建立一個Image物件。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 Image 物件的真實中心座標，我們使用 getCenterPoint方法。
getCenterPoint(): fabric.Point
讓我們看一個程式碼範例，以查看使用 getCenterPoint 方法時記錄的輸出。 getCenterPoint 方法傳回物件的真實中心座標。在本例中，記錄的輸出為 x= 256.5 和 y= 91，它們是中心點。
<!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 getCenterPoint method</h2>
<p>
You can open console from dev tools and see that the logged output contains the center points
</p>
<canvas id="canvas"></canvas>
<img
src="https://www.tutorialspoint.com/images/logo.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 the getCenterPoint method
console.log(
"The center point of Image object is: ",
image.getCenterPoint()
);
</script>
</body>
</html>
在此範例中，我們使用了 getCenterPoint 方法和cropX 方法來證明記錄的中心點值將保持不變。
<!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 getCenterPoint method along with cropX method</h2>
<p>
You can open console from dev tools and see that the logged output contains the center points
</p>
<canvas id="canvas"></canvas>
<img
src="https://www.tutorialspoint.com/images/logo.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,
cropX: 70,
});
// Add it to the canvas
canvas.add(image);
// Using the getCenterPoint method
console.log(
"The center point of Image object is: ",
image.getCenterPoint()
);
</script>
</body>
</html>
以上是FabricJS – 如何找到 Image 物件的真實中心座標？的詳細內容。更多資訊請關注PHP中文網其他相關文章！
