HTML5VideoImageProcessing/edge_scale.html at master · DaisukeHirata/HTML5VideoImageProcessing · GitHub

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<!doctype html>
<html>
  <head>
    <meta charset="utf-8">
    <title>Video Frames</title>
    <link rel="stylesheet" href="style.css">
    <style>
      #movieclip {
        display: none;
      }
    </style>
  </head>
  <body>
    <header>Avoid cross domain security error. $ http-server -p 8000 </header>
    <canvas id="canvas" width="640" height="360"></canvas>
    <input id="mono" type="checkbox" name="mono"/>
    <input id="invert" type="checkbox" name="invert"/>
    <input id="r_weight" type="range" value="0.4" min="0.0" max="3" step="0.1"/>
    <input id="g_weight" type="range" value="1.0" min="0.0" max="3" step="0.1"/>
    <input id="b_weight" type="range" value="1.0" min="0.0" max="3" step="0.1"/>

    <video id="movieclip" width="640" height="360" autoplay>
      <source src="./assets/movieclip.mp4" type="video/mp4"/>
      <source src="./assets/movieclip.webm" type="video/webm"/>
      <source src="./assets/movieclip.ogv" type="video/ogg"/>
    </video>

    <script src="utils.js"></script>
    <script src="Stats.js"></script>
    <script>
    window.onload = function () {

      var canvas = document.getElementById('canvas'),
          context = canvas.getContext('2d'),
          copyCanvas = createCopyCanvas(canvas),
          copyContext = copyCanvas.getContext('2d'),
          video = document.getElementById('movieclip'),
          stats = Stat.initStats();


      function createCopyCanvas (canvas) {
        var copy = document.createElement('canvas');
        copy.width = canvas.width/1.2;
        copy.height = canvas.height/1.2;
        return copy;
      }

      function edge (imageData, copiedImageData, mono, invert, rWeightNumerator, gWeightNumerator, bWeightNumerator) {

        var pixels     = imageData.data,
            pixelsCopy = copiedImageData.data,
            h  = imageData.height,
            w  = imageData.width,
            w4 = w*4,
            c  = -1/8,
            rWeight = rWeightNumerator/c,
            gWeight = gWeightNumerator/c,
            bWeight = bWeightNumerator/c;


        for (var y = h; y > 0; y--) {

          var offsetY = (y-1)*w4;

          var nextY = (y == h) ? y - 1 : y;
          var prevY = (y == 1) ? 0 : y-2;

          var offsetYPrev = prevY*w*4;
          var offsetYNext = nextY*w*4;

          for (var x = w; x > 0; x--) {

            var offset = offsetY + (x*4-4);
            var offsetPrev = offsetYPrev + ((x == 1) ? 0 : x-2) * 4;
            var offsetNext = offsetYNext + ((x == w) ? x-1 : x) * 4;

            var r = ((pixelsCopy[offsetPrev-4]
              + pixelsCopy[offsetPrev]
              + pixelsCopy[offsetPrev+4]
              + pixelsCopy[offset-4]
              + pixelsCopy[offset+4]
              + pixelsCopy[offsetNext-4]
              + pixelsCopy[offsetNext]
              + pixelsCopy[offsetNext+4]) * c
              + pixelsCopy[offset]
              )
              * rWeight;

            var g = ((pixelsCopy[offsetPrev-3]
              + pixelsCopy[offsetPrev+1]
              + pixelsCopy[offsetPrev+5]
              + pixelsCopy[offset-3]
              + pixelsCopy[offset+5]
              + pixelsCopy[offsetNext-3]
              + pixelsCopy[offsetNext+1]
              + pixelsCopy[offsetNext+5]) * c
              + pixelsCopy[offset+1])
              * gWeight;

            var b = ((pixelsCopy[offsetPrev-2]
              + pixelsCopy[offsetPrev+2]
              + pixelsCopy[offsetPrev+6]
              + pixelsCopy[offset-2]
              + pixelsCopy[offset+6]
              + pixelsCopy[offsetNext-2]
              + pixelsCopy[offsetNext+2]
              + pixelsCopy[offsetNext+6]) * c
              + pixelsCopy[offset+2])
              * bWeight;


            if (mono) {
              var brightness = (r*0.3 + g*0.59 + b*0.11)||0;
              if (invert) brightness = 255 - brightness;
              if (brightness < 0 ) brightness = 0;
              if (brightness > 255 ) brightness = 255;
              r = g = b = brightness;
            } else {
              if (invert) {
                r = 255 - r;
                g = 255 - g;
                b = 255 - b;
              }
              if (r < 0 ) r = 0;
              if (g < 0 ) g = 0;
              if (b < 0 ) b = 0;
              if (r > 255 ) r = 255;
              if (g > 255 ) g = 255;
              if (b > 255 ) b = 255;
            }

            pixels[offset] = r;
            pixels[offset+1] = g;
            pixels[offset+2] = b;
          }
        }
      }

      var callCount = 0;
      (function drawFrame () {

        stats.begin();

        window.requestAnimationFrame(drawFrame, canvas);

        copyContext.drawImage(
          video,
          0, 0, canvas.width,      canvas.height,
          0, 0, copyCanvas.width,  copyCanvas.height
        );

        var imageData       = copyContext.getImageData(0, 0, copyCanvas.width, copyCanvas.height),
            copiedImageData = copyContext.getImageData(0, 0, copyCanvas.width, copyCanvas.height),
            mono = document.getElementById('mono').checked,
            invert = document.getElementById('invert').checked,
            rWeight = parseFloat(document.getElementById('r_weight').value, 10) || 0.0,
            gWeight = parseFloat(document.getElementById('g_weight').value, 10) || 0.0,
            bWeight = parseFloat(document.getElementById('b_weight').value, 10) || 0.0;

        edge(imageData, copiedImageData, mono, invert, rWeight, gWeight, bWeight);

        context.clearRect(0,0,canvas.width,canvas.height);
        copyContext.putImageData(imageData, 0, 0);
        context.drawImage(
          copyCanvas,
          0, 0, copyCanvas.width,  copyCanvas.height,
          0, 0, canvas.width,  canvas.height
        );

        stats.end();

      }());
    };
    </script>
  </body>
</html>