gaspargergo.github.io/curvedPatterns.html at master · gaspargergo/gaspargergo.github.io · GitHub

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<!doctype HTML>
<html>

<head>
  <title>instant Art</title>
  <link href="https://fonts.googleapis.com/css?family=Alfa+Slab+One&display=swap" rel="stylesheet">

  <style>
    #title {
      font-family: 'Alfa Slab One', sans-serif;
      font-size: 50px;
      color: black;
      background-color: white;
      letter-spacing: -2px;
      margin-top: 1000px;
    }

    span{
      transition: all 0.5s ease-in-out;
    }

    a:hover{
      cursor: pointer;
    }

    center{
      margin-top: 50px;
    }

    canvas{
      visibility:hidden;
    }

    #pic{
      position: fixed;
    }

  </style>
</head>

<body>
  <center><a id="title" onClick="colorPixels()">instant patterns</a>

  <div id="container"><canvas id="canvas" height="600px" width="600px"></canvas></div>

  <canvas id="pic" height="600px" width="600px"></canvas>

</center>


  <script>

  document.addEventListener('mousedown', function (event) {
    if (event.detail > 1) {
      event.preventDefault();
      }
    }, false);

  var c=document.getElementById("canvas");
  var ctx=c.getContext("2d");
  ctx.clearRect(0, 0, c.width, c.height);

  function colorPixels(){

    var x = 0;
    var y = 0;
    ctx.clearRect(0, 0, c.width, c.height);
    var numOfPoints = Math.floor(Math.random() * (8 - 4 + 1)) + 4;

    var points = [];

    //first point
    points.push(0); //x coordinate
    points.push(Math.floor(Math.random() * (c.height + 1))); //y coordinate

    for(var i = 0; i < numOfPoints-2;i++){ //adding points to the array
      points.push(Math.floor(Math.random() * (c.width + 1))); //x coordinate
      points.push(Math.floor(Math.random() * (c.height + 1))); //y coordinate
    }

    //last point
    points.push(c.width); //x coordinate
    points.push(Math.floor(Math.random() * (c.height + 1))); //y coordinate

    ctx.lineWidth = 10;

    ctx.fillStyle = '#'+ Math.random().toString(16).slice(-6); //filling background
    ctx.fillRect(0,0,c.width,c.height);

    ctx.fillStyle = '#'+ Math.random().toString(16).slice(-6); //random color for the drawing
    ctx.strokeStyle = ctx.fillStyle;

    drawCurve(ctx, points);

    ctx.lineTo(c.width,c.height); //in order to fill, closing the borders
    ctx.lineTo(0,c.height);
    ctx.lineTo(points[0],points[1]);

    ctx.stroke(); //drawing
    ctx.fill();

    var temp = document.getElementById("pic");
    var tempContext = temp.getContext("2d");

    //drawing the pattern block in anther canvas
    switch(Math.floor(Math.random()*4)){
      case 0:
        //normal, no flip
        tempContext.drawImage(c,0,0,c.width/2,c.width/2);
        tempContext.drawImage(c,c.width/2,0,c.width/2,c.width/2);
        tempContext.drawImage(c,0,c.width/2,c.width/2,c.width/2);
        tempContext.drawImage(c,c.width/2,c.width/2,c.width/2,c.width/2);
        break;
      case 1:
        //simple horizontal flip
        tempContext.save();
        tempContext.drawImage(c, 0,0,temp.width/2,temp.width/2);
        tempContext.scale(-1, 1);
        tempContext.drawImage(c, -temp.width,0,temp.width/2,temp.width/2);

        tempContext.drawImage(c, -temp.width,temp.width/2,temp.width/2,temp.width/2);
        tempContext.scale(-1, 1);
        tempContext.drawImage(c, 0,temp.width/2,temp.width/2,temp.width/2);
        tempContext.restore();
        break;
      case 2:
        //simple horizontal flip & slide
        tempContext.save();
        tempContext.drawImage(c, 0,0,temp.width/2,temp.width/2);
        tempContext.scale(-1, 1);
        tempContext.drawImage(c, -temp.width,0,temp.width/2,temp.width/2);

        tempContext.drawImage(c, -temp.width/2,temp.width/2,temp.width/2,temp.width/2);
        tempContext.scale(-1, 1);
        tempContext.drawImage(c, temp.width/2,temp.width/2,temp.width/2,temp.width/2);
        tempContext.restore();
        break;
      case 3:
        //horizontal & vertical flip
        tempContext.save();
        tempContext.drawImage(c, 0,0,temp.width/2,temp.width/2);
        tempContext.scale(-1, 1);
        tempContext.drawImage(c, -temp.width,0,temp.width/2,temp.width/2);

        tempContext.scale(-1,-1);
        tempContext.drawImage(c, 0,-temp.width,temp.width/2,temp.width/2);

        tempContext.scale(-1,1);
        tempContext.drawImage(c, -temp.width,-temp.width,temp.width/2,temp.width/2);
        tempContext.restore();
    }


    ctx.clearRect(0,0,c.height,c.width);
    for(var k = 0; k < 2; k++){
      for(var i = 0; i < 2;i++){
        ctx.drawImage(temp,300*i,k*300,300,300);
      }
    }

    setBackground();

  }

  function setBackground(){
    var img = c.toDataURL();
    document.body.style.background = "url(" +img+ ")";
  }


  function drawCurve(ctx, ptsa, tension, isClosed, numOfSegments, showPoints) {

    showPoints  = showPoints ? showPoints : false;

    ctx.beginPath();

    drawLines(ctx, getCurvePoints(ptsa, tension, isClosed, numOfSegments));

    if (showPoints) {
        ctx.stroke();
        ctx.beginPath();
        for(var i=0;i<ptsa.length-1;i+=2) {
                ctx.rect(ptsa[i] - 2, ptsa[i+1] - 2, 4, 4);
        }

    }
  }

  function getCurvePoints(pts, tension, isClosed, numOfSegments) {

    // use input value if provided, or use a default value
    tension = (typeof tension != 'undefined') ? tension : 0.5;
    isClosed = isClosed ? isClosed : false;
    numOfSegments = numOfSegments ? numOfSegments : 16;

    var _pts = [], res = [],    // clone array
        x, y,           // our x,y coords
        t1x, t2x, t1y, t2y, // tension vectors
        c1, c2, c3, c4,     // cardinal points
        st, t, i;       // steps based on num. of segments

    // clone array so we don't change the original
    //
    _pts = pts.slice(0);

    // The algorithm require a previous and next point to the actual point array.
    // Check if we will draw closed or open curve.
    // If closed, copy end points to beginning and first points to end
    // If open, duplicate first points to befinning, end points to end
    if (isClosed) {
        _pts.unshift(pts[pts.length - 1]);
        _pts.unshift(pts[pts.length - 2]);
        _pts.unshift(pts[pts.length - 1]);
        _pts.unshift(pts[pts.length - 2]);
        _pts.push(pts[0]);
        _pts.push(pts[1]);
    }
    else {
        _pts.unshift(pts[1]);   //copy 1. point and insert at beginning
        _pts.unshift(pts[0]);
        _pts.push(pts[pts.length - 2]); //copy last point and append
        _pts.push(pts[pts.length - 1]);
    }

    // ok, lets start..

    // 1. loop goes through point array
    // 2. loop goes through each segment between the 2 pts + 1e point before and after
    for (i=2; i < (_pts.length - 4); i+=2) {
        for (t=0; t <= numOfSegments; t++) {

            // calc tension vectors
            t1x = (_pts[i+2] - _pts[i-2]) * tension;
            t2x = (_pts[i+4] - _pts[i]) * tension;

            t1y = (_pts[i+3] - _pts[i-1]) * tension;
            t2y = (_pts[i+5] - _pts[i+1]) * tension;

            // calc step
            st = t / numOfSegments;

            // calc cardinals
            c1 =   2 * Math.pow(st, 3)  - 3 * Math.pow(st, 2) + 1;
            c2 = -(2 * Math.pow(st, 3)) + 3 * Math.pow(st, 2);
            c3 =       Math.pow(st, 3)  - 2 * Math.pow(st, 2) + st;
            c4 =       Math.pow(st, 3)  -     Math.pow(st, 2);

            // calc x and y cords with common control vectors
            x = c1 * _pts[i]    + c2 * _pts[i+2] + c3 * t1x + c4 * t2x;
            y = c1 * _pts[i+1]  + c2 * _pts[i+3] + c3 * t1y + c4 * t2y;

            //store points in array
            res.push(x);
            res.push(y);

        }
    }

    return res;
  }

  function drawLines(ctx, pts) {
    ctx.moveTo(pts[0], pts[1]);
    for(i=2;i<pts.length-1;i+=2) ctx.lineTo(pts[i], pts[i+1]);
  }


  function download(){
    saveAsPNG(c,'stripes');
  }

  function saveAsPNG(image, filename){ // No IE <11 support. Chrome URL bug for large images may crash
    var anchorElement, event, blob;
    function image2Canvas(image){  // converts an image to canvas
        function createCanvas(width, height){  // creates a canvas of width height
            var can = document.createElement("canvas");
            can.width = width;
            can.height = height;
            return can;
        };
        var newImage = canvas(img.width, img.height); // create new image
        newImage.ctx = newImage.getContext("2d");  // get image context
        newImage.ctx.drawImage(image, 0, 0); // draw the image onto the canvas
        return newImage;  // return the new image
    }
    if(image.toDataURL === undefined){    // does the image have the toDataURL function
        image = image2Canvas(image);  // No then convert to canvas
    }
    // if msToBlob and msSaveBlob then use them to save. IE >= 10
    // As suggested by Kaiido
    if(image.msToBlob !== undefined && navigator.msSaveBlob !== undefined){
       blob = image.msToBlob();
       navigator.msSaveBlob(blob, filename + ".png");
       return;
    }
    anchorElement = document.createElement('a');  // Create a download link
    anchorElement.href = image.toDataURL();   // attach the image data URL
    // check for download attribute
    if ( anchorElement.download !== undefined ) {
        anchorElement.download = filename + ".png";  // set the download filename
        if (typeof MouseEvent === "function") {   // does the browser support the object MouseEvent
            event = new MouseEvent(   // yes create a new mouse click event
                "click", {
                    view        : window,
                    bubbles     : true,
                    cancelable  : true,
                    ctrlKey     : false,
                    altKey      : false,
                    shiftKey    : false,
                    metaKey     : false,
                    button      : 0,
                    buttons     : 1,
                }
            );
            anchorElement.dispatchEvent(event); // simulate a click on the download link.
        } else
        if (anchorElement.fireEvent) {    // if no MouseEvent object try fireEvent
            anchorElement.fireEvent("onclick");
        }
    }
}

  </script>
</body>

</html>