canvas绘制六芒星

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如何使用canvas绘制六芒星呢？它是由由两个正三角形组成 ，这里封装了一个函数regulaPolygon(cxt, n, dx, dy, R, angle, djs_fillColor, djs_strokeColor)，可以设定两个正三边形，两个相差角度为60度。六芒星(Star of David) 又称大卫之星、大卫星、六角星等 六芒星象征着男女合一,孕育生命,代表着融合、圆满、吉祥,是护族符号。

示例效果图

示例源代码（共91行）

/*
* @Author: 大剑师兰特（xiaozhuanlan），还是大剑师兰特（CSDN）
* @此源代码版权归大剑师兰特所有，可供学习或商业项目中借鉴，未经授权，不得重复地发表到博客、论坛，问答，git等公共空间或网站中。
* @Email: [e-mail]
* @weixin: gis-dajianshi
* @First published in CSDN
* @First published time: 2024-01-22
*/
<template>
	<div class="djs_container">
		<div class="top">
			<h3>canvas绘制六芒星</h3>
			<div>大剑师兰特, 还是大剑师兰特，gis-dajianshi</div>
			<h4>
				<el-button type="primary" size="mini" @click="draw()">绘制</el-button>
				<el-button type="danger" size="mini" @click="clearCanvas()">清除</el-button>
			</h4>
		</div>
		<div class="dajianshi ">
			<canvas id="dajianshi" ref="mycanvas" width="980" height="490"></canvas>
		</div>
	</div>
</template>
<script>
	export default {
		data() {
			return {
				ctx: null,
				canvas: null,
			}
		},
		mounted() {
			this.setCanvas()
		},
		methods: {
			clearCanvas() {
				this.ctx.clearRect(0, 0, this.canvas.width, this.canvas.height);
			},
			setCanvas() {
				this.canvas = document.getElementById('dajianshi');
				if (!this.canvas.getContext) return;
				this.ctx = this.canvas.getContext("2d");
			},
			draw() {
				this.regulaPolygon(this.ctx, 3, 490, 245, 200, 30, 'transparent', 'red');
				this.regulaPolygon(this.ctx, 3, 490, 245, 200, 90, 'transparent', 'red');
			},

			//边数n中心点dx,中心点dy,半径R,旋转角度angle
			regulaPolygon(cxt, n, dx, dy, R, angle, djs_fillColor, djs_strokeColor) {
				cxt.beginPath();
				let degree = (2 * Math.PI) / n;
				let rangle = (angle * 2 * Math.PI) / 360;
				for (let i = 0; i < n; i++) {
					let x = Math.cos(i * degree - rangle);
					let y = Math.sin(i * degree - rangle);
					cxt.lineTo(x * R + dx, y * R + dy);
				}
				cxt.closePath();
				cxt.fillStyle = djs_fillColor;
				cxt.fill();
				cxt.strokeStyle = djs_strokeColor;
				cxt.stroke();
			}
		}
	}
</script>
<style scoped>
	.djs_container {
		width: 1000px;
		height: 680px;
		margin: 50px auto;
		border: 1px solid #991188;
		position: relative;
	}

	.top {
		margin: 0 auto 0px;
		padding: 10px 0;
		background: #991188;
		color: #fff;
	}

	.dajianshi {
		margin: 5px auto 0;
		border: 1px solid #ccc;
		width: 980px;
		height: 490px;
		background-color: #f9f9f9;
	}
</style>

canvas基本属性

canvas基础方法