canvas完成烟火的示例编码

日期：2021-02-22 类型：科技新闻我要分享

关键词：如何创建网站，免费网站建站，网站建设文章，网站建设7个基本流程，自动建站

序言：立刻过年了，我准备在后台管理里边悄悄地埋个新春祝愿+放烟火的彩蛋。新项目是根据react+typescript的，因而最终封裝变成1个组件，设定好打开時间便可以显示信息了。

文件目录构造

文件目录构造大概以下

大家将烟火分成两个环节，1个是未炸开不断升高阶段，另外一个是炸开后分散化的阶段。
在其中Vector表明1个座标，Particle表明1个烟火的亮点，Firewor表明烟火未炸开时不断升高的亮点。index.tsx便是组件了，绘图了canvas，并实行了动漫。

Vector

这个座标就很简易，后边涉及到到部位的变动都可以以应用它的add方式开展偏位实际操作

export default class Vector {
    constructor(public x: number, public y: number) {}
    add(vec2: {x: number; y: number}) {
        this.x = this.x + vec2.x;
        this.y = this.y + vec2.y;
    }
}

Particle

原始建立的情况下给个座标，后续每次升级的情况下操纵y座标着落，gravity自变量便是着落的值。timeSpan用于操纵烟火展现的时长

import Vector from './Vector';
export default class Particle {
    pos: Vector = null;
    vel: {x: number; y: number} = null;
    dead: boolean = false;
    start: number = 0;
    ctx: CanvasRenderingContext2D = null;
    constructor(pos: {x: number; y: number}, vel: {x: number; y: number}, ctx: CanvasRenderingContext2D) {
        this.pos = new Vector(pos.x, pos.y);
        this.vel = vel;
        this.dead = false;
        this.start = 0;
        this.ctx = ctx;
    }
    update(time: number, gravity: number) {
        let timeSpan = time - this.start;

        if (timeSpan > 500) {
            this.dead = true;
        }

        if (!this.dead) {
            this.pos.add(this.vel);
            this.vel.y = this.vel.y + gravity;
        }
    }

    draw() {
        if (!this.dead) {
            this.drawDot(this.pos.x, this.pos.y, Math.random() > 0.5 ? 1 : 2);
        }
    }
    drawDot(x: number, y: number, size: number) {
        this.ctx.beginPath();
        this.ctx.arc(x, y, size, 0, Math.PI * 2);
        this.ctx.fill();
        this.ctx.closePath();
    }
}

Firework

转化成任意的hsl色调，hsl(' + rndNum(360) + ', 100%, 60%);Firework每次升高的间距是1个下降的全过程，大家原始设定1个升高的间距，以后每次绘图的情况下，这个间距减gravity，当间距小于零的情况下，表明该出現烟火绽开的动漫了。

import Vector from './Vector';
import Particle from './Particle';
let rnd = Math.random;
function rndNum(num: number) {
    return rnd() * num + 1;
}
export default class Firework {
    pos: Vector = null;
    vel: Vector = null;
    color: string = null;
    size: number = 0;
    dead: boolean = false;
    start: number = 0;
    ctx: CanvasRenderingContext2D = null;
    gravity: number = null;
    exParticles: Particle[] = [];
    exPLen: number = 100;
    rootShow: boolean = true;
    constructor(x: number, y: number, gravity: number, ctx: CanvasRenderingContext2D) {
        this.pos = new Vector(x, y);
        this.vel = new Vector(0, -rndNum(10) - 3);
        this.color = 'hsl(' + rndNum(360) + ', 100%, 60%)';
        this.size = 4;
        this.dead = false;
        this.start = 0;
        this.ctx = ctx;
        this.gravity = gravity;
    }
    update(time: number, gravity: number) {
        if (this.dead) {
            return;
        }

        this.rootShow = this.vel.y < 0;

        if (this.rootShow) {
            this.pos.add(this.vel);
            this.vel.y = this.vel.y + gravity;
        } else {
            if (this.exParticles.length === 0) {
                for (let i = 0; i < this.exPLen; i++) {
                    let randomR = rndNum(5);
                    let randomX = -rndNum(Math.abs(randomR) * 2) + Math.abs(randomR);
                    let randomY =
                        Math.sqrt(Math.abs(Math.pow(randomR, 2) - Math.pow(randomX, 2))) *
                        (Math.random() > 0.5 ? 1 : ⑴);
                    this.exParticles.push(new Particle(this.pos, new Vector(randomX, randomY), this.ctx));
                    this.exParticles[this.exParticles.length - 1].start = time;
                }
            }
            let numOfDead = 0;
            for (let i = 0; i < this.exPLen; i++) {
                let p = this.exParticles[i];
                p.update(time, this.gravity);
                if (p.dead) {
                    numOfDead++;
                }
            }

            if (numOfDead === this.exPLen) {
                this.dead = true;
            }
        }
    }

    draw() {
        if (this.dead) {
            return;
        }

        this.ctx.fillStyle = this.color;
        if (this.rootShow) {
            this.drawDot(this.pos.x, this.pos.y, this.size);
        } else {
            for (let i = 0; i < this.exPLen; i++) {
                let p = this.exParticles[i];
                p.draw();
            }
        }
    }
    drawDot(x: number, y: number, size: number) {
        this.ctx.beginPath();

        this.ctx.arc(x, y, size, 0, Math.PI * 2);
        this.ctx.fill();

        this.ctx.closePath();
    }
}

FireworkComponent

组件自身就很简易了，转化成和绘图Firework。大家在这里边能够附加加1些文本

import React from 'react';
import Firework from './Firework';
import {autobind} from 'core-decorators';
let rnd = Math.random;
function rndNum(num: number) {
    return rnd() * num + 1;
}
interface PropTypes {
    onClick?: () => void;
}
@autobind
class FireworkComponent extends React.Component<PropTypes> {
    canvas: HTMLCanvasElement = null;
    ctx: CanvasRenderingContext2D = null;
    snapTime: number = 0;
    fireworks: Firework[] = [];
    gravity: number = 0.1;
    componentDidMount() {
        this.canvas = document.querySelector('#fireworks');
        this.canvas.width = window.innerWidth;
        this.canvas.height = window.innerHeight;
        this.ctx = this.canvas.getContext('2d');
        this.init();
        this.draw();
    }

    init() {
        let numOfFireworks = 20;
        for (let i = 0; i < numOfFireworks; i++) {
            this.fireworks.push(new Firework(rndNum(this.canvas.width), this.canvas.height, this.gravity, this.ctx));
        }
    }

    update(time: number) {
        for (let i = 0, len = this.fireworks.length; i < len; i++) {
            let p = this.fireworks[i];
            p.update(time, this.gravity);
        }
    }
    draw(time?: number) {
        this.update(time);

        this.ctx.fillStyle = 'rgba(0,0,0,0.3)';

        this.ctx.fillStyle = 'rgba(0,0,0,0)';
        this.ctx.clearRect(0, 0, this.canvas.width, this.canvas.height);

        this.ctx.font = 'bold 30px cursive';
        this.ctx.fillStyle = '#e91818';
        let text = 'XX新项目组给您拜个早前！';
        let textWidth = this.ctx.measureText(text);
        this.ctx.fillText(text, this.canvas.width / 2 - textWidth.width / 2, 200);
        text = '在新年到来之时，祝您：';
        textWidth = this.ctx.measureText(text);
        this.ctx.fillText(text, this.canvas.width / 2 - textWidth.width / 2, 260);
        text = '工作中圆满，新春开心!';
        this.ctx.font = 'bold 48px STCaiyun';
        this.ctx.fillStyle = 'orangered';
        textWidth = this.ctx.measureText(text);
        this.ctx.fillText(text, this.canvas.width / 2 - textWidth.width / 2, 340);
        this.ctx.fillStyle = 'gray';
        this.ctx.font = '18px Arial';
        text = '点一下随意处关掉';
        textWidth = this.ctx.measureText(text);
        this.ctx.fillText(text, this.canvas.width - 20 - textWidth.width, 60);
        this.snapTime = time;

        this.ctx.fillStyle = 'blue';
        for (let i = 0, len = this.fireworks.length; i < len; i++) {
            let p = this.fireworks[i];
            if (p.dead) {
                p = this.fireworks[i] = new Firework(
                    rndNum(this.canvas.width),
                    this.canvas.height,
                    this.gravity,
                    this.ctx
                );
                p.start = time;
            }
            p.draw();
        }

        window.requestAnimationFrame(this.draw);
    }

    render() {
        return (
            <canvas
                id="fireworks"
                onClick={this.props.onClick}
                style={{position: 'fixed', zIndex: 99, background: 'rgba(0,0,0, 0.8)'}}
                width="400"
                height="400"></canvas>
        );
    }
}
export default FireworkComponent;

大概实际效果

以上便是本文的所有內容，期待对大伙儿的学习培训有一定的协助，也期待大伙儿多多适用脚本制作之家。

上一篇：HTML5给中国汉字加拼音收起进行组件的完成编码返回下一篇：没有了