速度表現のページ背景 左から右へ移動

/**
 * 左から右へ移動のSVG画像出力
 *
 * @author ao-system, Inc.
 * @date 2024-02-03
 */

export class LineImage {
	'use strict';
	#place;
	#color = ['rgba(100,150,255,0.1)','rgba(100,120,255,1)'];
	#filter = 'blur(3px) drop-shadow(-10px 100px 0px rgba(190,170,255,1))';
	#linearGradient;
	#rect;
	#rectX = 200;
	#rectWidth = 0;
	#speed = (Math.random() * 4 + 2);
	constructor(param) {
		if (param.place) {
			this.#place = param.place;
		}
		if (param.color) {
			this.#color = param.color;
		}
		if (param.filter) {
			this.#filter = param.filter;
		}
		this.#init();
	}
	set place(val) {
		if (this.#place instanceof Element) {
			this.#place.innerHTML = '';
		}
		this.#place = val;
		this.#createSvg();
	}
	set color(val) {
		if (this.#place instanceof Element) {
			this.#place.innerHTML = '';
		}
		this.#color = val;
		this.#createSvg();
	}
	set filter(val) {
		if (this.#place instanceof Element) {
			this.#place.innerHTML = '';
		}
		this.#filter = val;
		this.#createSvg();
	}
	#init() {
		this.#createSvg();
		setTimeout(() => {
			this.#animateSvg();
		},Math.random() * 2000);
	}
	//<svg version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" width="200px" height="50px" viewBox="0 0 200 50" preserveAspectRatio="none">
	//<linearGradient id="lg" gradientUnits="userSpaceOnUse" x1="0" y1="25" x2="200" y2="25">
	//	<stop offset="0" style="stop-color:#fff"/>
	//	<stop offset="1" style="stop-color:#aaa"/>
	//</linearGradient>
	//	<rect fill="url(#lg)" x="22" width="70" height="50"/>
	//</svg>
	#createSvg() {
		const linearGradientId = this.#generateRandomId();
		const svgElm = document.createElementNS('http://www.w3.org/2000/svg','svg');
		svgElm.setAttribute('xmlns','http://www.w3.org/2000/svg');
		svgElm.setAttribute('viewBox','0 0 200 50');
		svgElm.setAttribute('preserveAspectRatio','none');
		svgElm.style.filter = this.#filter;
		this.#linearGradient = document.createElementNS('http://www.w3.org/2000/svg','linearGradient');
		this.#linearGradient.setAttribute('id',linearGradientId);
		this.#linearGradient.setAttribute('gradientUnits','userSpaceOnUse');
		this.#linearGradient.setAttribute('x1',0);
		this.#linearGradient.setAttribute('y1',25);
		this.#linearGradient.setAttribute('x2',200);
		this.#linearGradient.setAttribute('y2',25);
		const stop1 = document.createElementNS('http://www.w3.org/2000/svg','stop');
		stop1.setAttribute('offset',0);
		stop1.setAttribute('style','stop-color:' + this.#color[0]);
		const stop2 = document.createElementNS('http://www.w3.org/2000/svg','stop');
		stop2.setAttribute('offset',1);
		stop2.setAttribute('style','stop-color:' + this.#color[1]);
		this.#rect = document.createElementNS('http://www.w3.org/2000/svg','rect');
		this.#rect.setAttribute('fill','url(#' + linearGradientId + ')');
		this.#rect.setAttribute('x',0);
		this.#rect.setAttribute('width',0);
		this.#rect.setAttribute('height',50);
		this.#linearGradient.appendChild(stop1);
		this.#linearGradient.appendChild(stop2);
		svgElm.appendChild(this.#linearGradient);
		svgElm.appendChild(this.#rect);
		this.#place?.appendChild(svgElm);
	}
	#generateRandomId(idLength = 12) {
		const characters = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
		return Array.from({length:idLength}, () => characters[Math.floor(Math.random() * characters.length)]).join('');
	}
	#animateSvg() {
		if (this.#rectX >= 200) {
			this.#rectWidth = Math.random() * 30 + 40;
			this.#rectX = -this.#rectWidth - (Math.random() * 50);
		}
		this.#rectX += this.#speed;
		this.#rect.setAttribute('x',this.#rectX);
		this.#rect.setAttribute('width',this.#rectWidth);
		this.#linearGradient.setAttribute('x1',this.#rectX);
		this.#linearGradient.setAttribute('x2',this.#rectX + this.#rectWidth);
		requestAnimationFrame(() => this.#animateSvg());
	}
}