d3.js Delaunay.find()用法及代碼示例

D3.js 是一個強大的數據可視化 JavaScript 框架，其模塊之一 Delaunay 支持 Delaunay 三角剖分。這德勞奈.find()方法返回最接近指定點 (x, y) 的輸入點的索引。

用法:

 delaunay.find(x, y[, i])

參數：

x: 要查找索引點的點的 x 坐標。
y：要查找索引點的點的 y 坐標。
我(可選)：它是一個可選參數，指示搜索的起始三角形索引。如果提供，則搜索從指定的三角形索引開始。

返回值：

Delaunay 三角形的索引包含指定點 (x, y)。

例子：此示例顯示 delaunay.find() 方法的使用。

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.Delaunay.find() 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;
        // Generating a set of random points
        const data = Array(50)  // Reduced number of points
            .fill()
            .map((_, i) => ({
                x: (i * canvasWidth) / 50,
                y: Math.random() * canvasHeight
            }));
        // Creating a Delaunay triangulation from the data
        const voronoi = d3.Delaunay.from(
            data,
            (d) => d.x,
            (d) => d.y
        ).voronoi([0, 0, canvasWidth, canvasHeight]);
        // Clearing the canvas
        context.clearRect(0, 0, canvasWidth, canvasHeight);
        // Rendering the Delaunay points on the canvas
        context.fillStyle = "black";
        context.beginPath();
        voronoi.delaunay.renderPoints(context, 1);
        context.fill();
        // Styling the Voronoi diagram
        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));
        }
        // Using the find() method to locate 
        // the Delaunay triangle for the point (2, 3)
        const findResult = voronoi.delaunay.find(2, 3);
        // Displaying the result on the HTML page
        document.querySelector("#app").innerHTML =
            `Index of Delaunay Triangle 
            containing (2, 3): ${findResult}`;
        document.querySelector("#app").appendChild(canvas);
    </script>
</body>
</html>

輸出：

MicrosoftTeams-image-(3)-(1)

相關用法

注：本文由純淨天空篩選整理自taran910大神的英文原創作品 D3.js Delaunay.find() Method。非經特殊聲明，原始代碼版權歸原作者所有，本譯文未經允許或授權，請勿轉載或複製。