HTML Canvas Image Move Color Pixel

Description

HTML Canvas Image Move Color Pixel

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<!doctype html>
<html>
  <head>
    <meta charset="utf-8">
    <title>Pixel Move</title>
  </head>/*from  w w  w.  ja v a 2  s .c o m*/
  <body>
    <canvas id="canvas" width="400" height="400"></canvas>
    <aside>Move mouse on canvas element.</aside>
  
    <script>
captureMouse = function (element) {
  var mouse = {x: 0, y: 0, event: null},
      body_scrollLeft = document.body.scrollLeft,
      element_scrollLeft = document.documentElement.scrollLeft,
      body_scrollTop = document.body.scrollTop,
      element_scrollTop = document.documentElement.scrollTop,
      offsetLeft = element.offsetLeft,
      offsetTop = element.offsetTop;
  
  element.addEventListener('mousemove', function (event) {
    var x, y;
    
    if (event.pageX || event.pageY) {
      x = event.pageX;
      y = event.pageY;
    } else {
      x = event.clientX + body_scrollLeft + element_scrollLeft;
      y = event.clientY + body_scrollTop + element_scrollTop;
    }
    x -= offsetLeft;
    y -= offsetTop;
    
    mouse.x = x;
    mouse.y = y;
    mouse.event = event;
  }, false);
  
  return mouse;
};
    window.onload = function () {
      var canvas = document.getElementById('canvas'),
          context = canvas.getContext('2d'),
          mouse = captureMouse(canvas);

      (function drawFrame () {
        window.requestAnimationFrame(drawFrame, canvas);

        //draw some stripes: red, green, and blue
        for (var i = 0; i < canvas.width; i += 10) {
          for (var j = 0; j < canvas.height; j += 10) {
            context.fillStyle = (i % 20 === 0) ? "red" : ((i % 30 === 0) ? "blue" : "pink");
            context.fillRect(i, j, 10, 10);
          }
        }

        var imagedata = context.getImageData(0, 0, canvas.width, canvas.height),
            pixels = imagedata.data;

        //pixel iteration
        for (var y = 0; y < imagedata.height; y += 1) {
          for (var x = 0; x < imagedata.width; x += 1) {

            var dx = x - mouse.x,
                dy = y - mouse.y,
                dist = Math.sqrt(dx * dx + dy * dy),
                offset = (x + y * imagedata.width) * 4,
                r = pixels[offset],
                g = pixels[offset + 1],
                b = pixels[offset + 2];

            pixels[offset]     = Math.cos(r * dist * 0.01) * 256;
            pixels[offset + 1] = Math.sin(g * dist * 0.01) * 256;
            pixels[offset + 2] = Math.cos(b * dist * 0.005) * 256;
          }
        }

        context.putImageData(imagedata, 0, 0);
      }());
    };
    </script>
  </body>
</html>



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