• 自动画心线条(网页)


      1 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
      2 <HTML>
      3  <HEAD>
      4   <TITLE> New Document </TITLE>
      5   <META NAME="Generator" CONTENT="EditPlus">
      6   <META NAME="Author" CONTENT="">
      7   <META NAME="Keywords" CONTENT="">
      8   <META NAME="Description" CONTENT="">
      9   <style>
     10   body {
     11     background-color: rgb(29,32,32);    
     12     margin: 0;
     13     overflow: hidden;
     14   
     15 }
     16 .label {
     17     position: absolute;
     18     top: 0;
     19     left: 0;
     20     padding: 5px 15px;
     21     color: #eee;
     22     font-size: 13px;
     23     background-color: rgba(0, 0, 0, .15);
     24 }
     25 .instructions {
     26     position: absolute;
     27     bottom: 0%;
     28     left: 0;
     29     padding: 5px 15px;
     30     color: #eee;
     31     font-size: 13px;
     32     background-color: rgba(0, 0, 0, .15);
     33 }
     34 .label {
     35     position: absolute;
     36     top: 0;
     37     left: 0;
     38     padding: 5px 15px;
     39     color: #eee;
     40     font-size: 13px;
     41     background-color: rgba(0, 0, 0, .15);
     42 }
     43 canvas { display:block; }
     44   </style>
     45  </HEAD>
     46 
     47  <BODY>
     48  <head>
     49   <meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=no, maximum-scale=1, shrink-to-fit=no">
     50 </head>
     51 <body>
     52 <canvas id=canvas></canvas>
     53 <div class="label">SPARED THE MISERY OF HOPE</div>
     54 <div class="instructions">MOVE MOUSE AROUND </div>
     55 
     56   </body>
     57   <script>
     58   var ctx = canvas.getContext("2d");
     59 var body = [];
     60 canvas.width = window.innerWidth;
     61 canvas.height = window.innerHeight;
     62 
     63 var mouse_pos_x = canvas.width/2;
     64 var mouse_pos_y = canvas.height/2;
     65 var delta = 1;
     66 var step = 0;
     67 var loop = 0;
     68 var line = 0;
     69 var lineMax = 20;
     70 var lineMin = 5;
     71 var TWO_PI = 2 * Math.PI;
     72 var t = 0;
     73 var animate = true;
     74 var op = 1;
     75 
     76 var bodyLength = 20;
     77 
     78 canvas.addEventListener('mouseleave', mouse_leave);
     79 
     80 canvas.addEventListener('mousemove', mouse_track);
     81 
     82 function mouse_leave(){
     83   animate = true;
     84 }
     85 
     86 
     87 function mouse_track(event) {
     88   animate = false;
     89   if((Math.abs(mouse_pos_x - event.clientX) > delta) || (Math.abs(mouse_pos_y - event.clientY) > delta)){
     90     mouse_pos_x = event.clientX;
     91     mouse_pos_y = event.clientY;
     92   }
     93 }
     94 
     95 
     96 //Colours from:
     97 //https://krazydad.com/tutorials/makecolors.php
     98 
     99 var red = [];
    100 var grn = [];
    101 var blu = [];
    102 
    103 center = 128;
    104 width = 127;
    105 frequency1 = 0.3;
    106 frequency2 = 0.3;
    107 frequency3 = 0.3;
    108 
    109 phase1 = 0;
    110 phase2 = 2;
    111 phase3 = 4;
    112 
    113 for (s = 0; s < bodyLength; s++) {
    114   red[s] = Math.round(Math.sin(frequency1*s + phase1) * width + center);
    115   grn[s] = Math.round(Math.sin(frequency2*s + phase2) * width + center);
    116   blu[s] = Math.round(Math.sin(frequency3*s + phase3) * width + center);
    117 }
    118 
    119 size = Math.min(canvas.width, canvas.height)/50;
    120 //See below
    121 var startX = canvas.width/2 + size * (16 * Math.sin(0) * Math.sin(0) * Math.sin(0));
    122 var startY = canvas.height - (canvas.height/2 + ( size *( 13 * Math.cos(0)  - 5 * Math.cos(0) - 2 * Math.cos(0) - Math.cos(0))));
    123 
    124 for (i = 0; i < bodyLength; i++) {
    125   var b = {
    126     x: startX,
    127     y: startY
    128   };
    129   body.push(b);
    130 }
    131 
    132 //****** DRAW ******//
    133 
    134 function draw() {
    135   
    136   t += 0.08;
    137   t = t % TWO_PI;
    138 
    139     if(line <= lineMin){
    140       op = 1;
    141       line = lineMin+1;
    142     }
    143     if(line >= lineMax){
    144       op = -1;
    145       line = lineMax-1;
    146     }
    147     loop++;
    148     if(loop == 5){
    149       step++;
    150       step = step % bodyLength;
    151       loop = 0;
    152     }
    153   
    154   line = op + line;
    155   
    156   if(animate){
    157     size = Math.min(canvas.width, canvas.height)/50;
    158     //Heart curve from:
    159     //http://mathworld.wolfram.com/HeartCurve.html
    160     mouse_pos_x = canvas.width/2 + size * (16 * Math.sin(t) * Math.sin(t) * Math.sin(t));
    161     mouse_pos_y = canvas.height - (canvas.height/2 + ( size * ( 13 * Math.cos(t)  - 5 * Math.cos(2*t) - 2 * Math.cos(3*t) - Math.cos(4*t))));
    162   }
    163 
    164   canvas.width = window.innerWidth;
    165   canvas.height = window.innerHeight;
    166 
    167   for (i = (body.length-1); i > 0; i--) {
    168     body[i].x = body[i-1].x;
    169     body[i].y = body[i-1].y;
    170   } 
    171   body[0].x = mouse_pos_x;
    172   body[0].y = mouse_pos_y;
    173 
    174   ctx.lineWidth = line; 
    175   ctx.strokeStyle = "rgb("+red[step]+","+grn[step]+","+blu[step]+")";
    176   ctx.fillStyle = "rgb("+red[step]+","+grn[step]+","+blu[step]+")";
    177   
    178   //Draw leading circle
    179   ctx.beginPath();
    180   ctx.arc((body[0].x), (body[0].y), line/2, 0, TWO_PI);
    181   ctx.fill();
    182   
    183   //Draw line
    184   ctx.beginPath();
    185   ctx.moveTo(body[0].x, body[0].y);
    186 
    187   for(s = 0; s < body.length - 2; s++){
    188 
    189     //Bezier curve along points taken from: 
    190     //http://stackoverflow.com/questions/7054272/how-to-draw-smooth-curve-through-n-points-using-javascript-html5-canvas
    191 
    192     var xc = (body[s].x + body[s+1].x) / 2;
    193     var yc = (body[s].y + body[s+1].y) / 2;
    194     ctx.quadraticCurveTo(body[s].x, body[s].y, xc, yc);
    195   }
    196   ctx.stroke();
    197   
    198   //Draw trailing circle
    199   ctx.beginPath();
    200   ctx.arc(xc, yc, line/2, 0, TWO_PI);
    201   ctx.fill();
    202 
    203   window.requestAnimationFrame(draw);
    204 }
    205 window.requestAnimationFrame(draw);
    206   </script>
    207  </BODY>
    208 </HTML>
    诚者,君子之所守也。
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  • 原文地址:https://www.cnblogs.com/SkystarX/p/12180929.html
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