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fabric.js 画圆环，圆弧，弧形区域_T甲甲T的博客

18 人参与 2022年02月15日 17:23 分类 : 《休闲阅读》评论

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="./fabric.js"></script>
    <style>
        button {
            margin: 10px 0 0 10px;

        }
    </style>
</head>

<body>
    <div style="display: flex;">
        <canvas id='c' width="1000" height="1000"></canvas>
        <div>
            <button class="btn1">画</button>
            <button class="btn2">儿子</button>
        </div>
    </div>

    <script>
        var canvas = new fabric.Canvas('c', {
            backgroundColor: '#ccc',
            selectionColor: 'white',
            selectionLineWidth: 2,
            selectionBorderColor: 'red',
            borderColor: 'red'
        });
        function addRing(angle1, angle2, x, y, r1, r2) {
            let point1 = {};
            let point2 = {};
            let point3 = {};
            let point4 = {};
            let isBig = 0
            angle1 = angle1 % 360;
            angle2 = angle2 % 360;
            if (angle2 > 180) {
                isBig = 1
            }
            if (!angle2) {
                point1.x = r1 + x;
                point1.y = y;
                point2.x = r2 + x;
                point2.y = y;
                var path = new fabric.Path(`M${point1.x},${point1.y} A${r1},${r1} 0 0,1 ${point1.x - 2 * r1},${point1.y} 
                A${r1},${r1} 0 0,1 ${point1.x},${point1.y} 
                M${point2.x},${point2.y} A${r2},${r2} 0 0,1 ${point2.x - 2 * r2},${point2.y} 
                A${r2},${r2} 0 0,1 ${point2.x},${point2.y}`, {
                    stroke: 'red',
                    fill: 'transparent',
                    hasControls: false
                })
            } else {
                point1.x = r1 * Math.cos(angle1 / 180 * Math.PI) + x;
                point1.y = r1 * Math.sin(angle1 / 180 * Math.PI) + y;
                point2.x = r2 * Math.cos(angle1 / 180 * Math.PI) + x;
                point2.y = r2 * Math.sin(angle1 / 180 * Math.PI) + y;
                point3.x = r2 * Math.cos((angle1 + angle2) / 180 * Math.PI) + x;
                point3.y = r2 * Math.sin((angle1 + angle2) / 180 * Math.PI) + y;
                point4.x = r1 * Math.cos((angle1 + angle2) / 180 * Math.PI) + x;
                point4.y = r1 * Math.sin((angle1 + angle2) / 180 * Math.PI) + y;
                var path = new fabric.Path(`M${point1.x},${point1.y} L${point2.x},${point2.y} A${r2},${r2} 0 ${isBig},1 ${point3.x},${point3.y} L${point4.x},${point4.y} A${r1},${r1} 0 ${isBig},0 ${point1.x},${point1.y}`, {
                    stroke: 'red',
                    fill: 'transparent',
                    // hasControls: false
                })
            }
            // path.parmas={
            //     angle1, angle2, x, y, r1, r2
            // }
            // canvas.loadFromJSON({
            //     objects:[ path.toJSON()]
            // })
           
            canvas.add(path)
            
            //  canvas.add( fabric.fromObject(path.toJSON()))  
        }
      
       
        addRing(0, 300, 400, 200, 30, 60);
        addRing(0, 360, 200, 200, 30, 60);
        addRing(0, 280, 600, 200, 60, 60)
       

    </script>
</body>

</html>

addPath 参数说明 angle1, angle2, x, y, r1, r2 分别对应偏转角度，弧形区域的角度，x,y是圆心，r1小圆半径，r2大圆半径。

fabric.js我是引用的本地的文件，记得修改路径。

效果图