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JS Achieves Particle Shuttle

  • Last update:  2021-02-23
  • I. Overview

    1. Expected effect

    In the large screen scene, add a cool particle shuttle background to the decision report, and the effect is shown in the following figure:

    1.gif


    2. Implementation ideas

    Set initialization JS event to generate dynamic background.


    II. Example

    1. Design report

    Click the body component to add after initialization events, as shown in the figure below:

    2.png

    The JavaScript code is as follows:

    $("body").prepend('<canvas id="mycanvas" style="position:absolute;z-index:-2; background-color:black;"></canvas>');
    var canvas = mycanvas; 
    var w = window.innerWidth;
    var h = window.innerHeight;
    canvas.width = w;
    canvas.height = h;
    canvas.backgroundColor = "#000";
    var ctx = canvas.getContext('2d');
     
    function Build() {
        this.ctx = ctx;
        this.counts = 3000;  
        this.maxSize = 4;  
        this.halfWidth = w / 2,
            this.halfHeight = h / 2;
        this.arr = [];  
    }
    Build.prototype.add = function(coor) {
        var grd = this.ctx.createRadialGradient(coor.x, coor.y, coor.size / 2, coor.x, coor.y, coor.size);
        grd.addColorStop(0, "white");
        grd.addColorStop(1, coor.color);
        this.ctx.fillStyle = grd;
        this.ctx.beginPath();
        this.ctx.arc(coor.x, coor.y, coor.size, 0, Math.PI * 2, true);
        this.ctx.transform(1, 0, 0, 1, 0, coor.z);
        this.ctx.closePath();
        this.ctx.fill();
    }
    Build.prototype.init = function() {
        this.run();
        this.render();
        this.animate();
    }
    Build.prototype.run = function() {
        var nums = 0;
        while (nums < this.counts) {
            var coor = {
                x: Math.ceil(Math.random() * w),
                y: Math.ceil(Math.random() * h),
                posx: Math.random() * w - this.halfWidth,
                posy: Math.random() * h - this.halfHeight,
                fl: 100,
                speed: Math.random() * 2,
                posz: Math.random() * 250,
                r: Math.ceil(Math.random() * this.maxSize),
                color: "rgba(" + Math.ceil(Math.random() * 255) + "," + Math.ceil(Math.random() * 255) + "," + Math.ceil(Math.random() * 255) + "," + Math.random() + ")"
            };
            this.arr.push(coor);
            nums++;
        }
    }
    Build.prototype.clear = function() {
        ctx.clearRect(0, 0, w, h);
    }
    Build.prototype.render = function() {
        this.clear();
        for (var item of this.arr) {
            this.draw(item);
        }
    }
    Build.prototype.animate = function() {
            var _this = this;
            this.render(); 
            window.requestAnimationFrame(function() {
                _this.animate();
            });
        },
        Build.prototype.draw = function(item) {
            if (item.posz > -item.fl) { 
                var scale = item.fl / (item.fl + item.posz); 
                item.x = this.halfWidth + item.posx * scale;
                item.y = this.halfHeight + item.posy * scale;
                item.size = item.r * scale;
                item.posz -= item.speed;
            } else { 
                item.posz = Math.random() * 250;
            }
            this.add(item);
        }
    var app = new Build();
    app.init();
    window.addEventListener('resize', function() {
        canvas.width = w = window.innerWidth;
        canvas.height = h = window.innerHeight;
    }, false); 


    2. Effect preview

    Save the template, click dashboard preview, the effect is as shown in I.1 expected effect.


    III. Template download

    For completed templates, please refer to:

    %fr_HOME%\webapps\webroot\WEB-INF\reportlets\doc-EN\JS\JS_particle_shuttle.frm

    Click to download the template:JS_particle_shuttle.frm



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