JS realizes particle vortex background

1. Expected effect

In a big screen scenario, add a dynamic particle vortex background to the dashboard, and the effect is shown in the following figure:

2. Realization idea

Use JS code to generate dynamic background.

1. Design report

Take rich text.frm as an example, add a After Initialization event to the body, the JS code is as follows:

The JS code is as follows:

$("body").prepend('<canvas id="canvas" style="position:absolute;z-index:-2;"></canvas>');

var canvas = document.getElementById("canvas");

var ctx = canvas.getContext("2d");

canvas.width = window.innerWidth;

canvas.height = window.innerHeight;

var w = canvas.width;

var h = canvas.height;



var part_count = 600;

var P = [];

var X, Y;

var angle = 0.01;

var centerX = w * 0.5,

    centerY = h * 0.5;



var part = function(x,y,ix,iy,vx,vy,a,dist) {

  this.x = x;

  this.y = y;

this.ix = ix;

  this.iy = iy;

  this.vx = vx;

  this.vy = vy;

  this.a = a;

  this.dist = dist;

}



function init(){

  var x,y,ix,iy,vx,vy,a,dist;

  for(var i=0; i<part_count;i++){

    ix = x;

    iy = y;

    vx = random(-1,1);

    vy = random(-1,1);

    rand = random(-80,100);

    dist = part_count/10+i;

    a = 1;

    

    P.push(new part(x,y,ix,iy,vx,vy,a,dist));

  }

}

init();



function bg(){

  ctx.fillStyle = '#000000';

  ctx.globalAlpha=0.9;

  ctx.fillRect(0,0,canvas.width,canvas.height,1);

}



function distance(dx,dy){

  return Math.sqrt(dx * dx + dy * dy);

}



function draw(){

  for(var i=0; i<P.length;i++){

    var p = P[i];

    

    p.a += 0.008;

    p.x = centerX + Math.cos(i+p.a) * (p.dist*i*0.1);

    p.y = centerY + Math.sin(i+p.a) * (p.dist);

    ctx.fillStyle = '#FFFFFF';

    ctx.fillRect(p.x, p.y,2, 2);

  }

}





function loop(){

  bg();

  draw();

  window.requestAnimationFrame(loop);

}

loop();



function resize(){

  canvas.width = window.innerWidth;

  canvas.height = window.innerHeight;

  centerX = window.innerWidth * 0.5;

  centerY = window.innerHeight * 0.5;

}



function random(min, max) {

  return Math.random() * (max - min) + min;

}



window.onresize = resize;

2. Preview effect

Save the dashboard and click PC Preview. The effect is as shown in I.1 Expected effect.

Note: Mobile terminal is not supported.

Please refer to the completed template: %FR_HOME%\webapps\webroot\WEB-INF\reportlets\doc-EN\JS\Particle_vortex_background.frm

Click to download: 

Particle_vortex_background.frm