d3.js Delaunay.trianglePolygons()用法及代码示例

D3.js是一个强大的数据可视化 JavaScript 框架，其模块之一 Delaunay 支持 Delaunay 三角剖分。这德劳奈.trianglePolygons()方法按顺序返回每个三角形的多边形上的可迭代对象。

用法:

Delaunay.trianglePolygons()

参数：

该方法不带参数。

返回值：

此方法返回多边形上的 Iterable。

示例 1：下面的代码示例显示了使用德劳奈.trianglePolygons()方法。

HTML


<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <script src=
"https://d3js.org/d3.v5.min.js">
    </script>
</head>
<body>
    <h1 style="text-align: center; 
        color: green;">
        GeeksforGeeks
    </h1>
    <h3 style="text-align: center;">
        D3.js | d3.trianglePolygons() Method
    </h3>
    <div id="app" style="text-align: center; 
            margin-top: 20px; 
            font-size: 18px;">
    </div>
    <script type="module">
        import * as d3 from "https://cdn.skypack.dev/d3@7";
        const canvasWidth = 400;
        const canvasHeight = 300;
        const canvas =
            document.createElement("canvas");
        const context =
            canvas.getContext("2d");
        canvas.width = canvasWidth;
        canvas.height = canvasHeight;
        const data = Array(50)
            .fill()
            .map((_, i) => ({
                x: (i * canvasWidth) / 50,
                y: Math.random() * canvasHeight
            }));
        const voronoi = d3.Delaunay.from(
            data,
            (d) => d.x,
            (d) => d.y
        ).voronoi([0, 0, canvasWidth, canvasHeight]);
        context.clearRect(0, 0, canvasWidth, canvasHeight);
        context.fillStyle = "black";
        context.beginPath();
        voronoi.delaunay.renderPoints(context, 1);
        context.fill();
        context.lineWidth = 1.5;
        const segments =
            voronoi.render().split(/M/).slice(1);
        for (const e of segments) {
            context.beginPath();
            context.strokeStyle =
                d3.hsl(360 * Math.random(), 0.7, 0.5);
            context.stroke(new Path2D("M" + e));
        }
        const trianglePolygons =
            voronoi.delaunay.trianglePolygons();
        console.log(trianglePolygons)
        document.querySelector("#app").
            appendChild(canvas);
    </script>
</body>
</html>

输出：

resize-1709472822368222932Screenshot202403031859001-(1)

示例 2：下面的代码使用d3.德劳奈.trianglePolygons()在画布上渲染 Delaunay 三角剖分的各个三角形的方法。

HTML


<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <script src="https://d3js.org/d3.v7.min.js"></script>
</head>
<body style="text-align: center;">
    <h1 style="text-align: center; color: green;">
        GeeksforGeeks
    </h1>
    <h3 style="text-align: center;">
        D3.js | Delaunay Triangles with trianglePolygons()
    </h3>
    <div id="app" style=
        "text-align: center; 
        margin-top: 20px;">
    </div>
    <script type="module">
        import * as d3 from "https://cdn.skypack.dev/d3@7";
        const width = 600;
        const height = 400;
        const points = Array.from({ length: 50 }, 
            () => [Math.random() * width, 
                Math.random() * height]);
        const delaunay = d3.Delaunay.from(points);
        const triangles = delaunay.trianglePolygons();
        const canvas = d3.select("#app")
            .append("canvas")
            .attr("width", width)
            .attr("height", height);
        const context = 
            canvas.node().getContext("2d");
        context.beginPath();
        delaunay.renderPoints(context);
        context.fillStyle = "black";
        context.fill();
        context.lineWidth = 2;
        for (const triangle of triangles) {
            context.beginPath();
            context.strokeStyle = "blue";
            context.moveTo(triangle[0][0], triangle[0][1]);
            for (const point of triangle) {
                context.lineTo(point[0], point[1]);
            }
            context.closePath();
            context.stroke();
        }
    </script>
</body>
</html>

输出：

Screenshot-2024-03-04-214856

相关用法

注：本文由纯净天空筛选整理自kirandeepkaurguler大神的英文原创作品 D3.js Delaunay.trianglePolygons() Method。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。