<?xml version="1.0" encoding="UTF-8"?>
<!-- -*- Mode: HTML; tab-width: 2; indent-tabs-mode: nil; -*- -->
<!-- vim: set shiftwidth=2 tabstop=2 autoindent expandtab: -->
<!-- This Source Code Form is subject to the terms of the Mozilla Public
   - License, v. 2.0. If a copy of the MPL was not distributed with this
   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
<!--

Features to add:
* make the left and right parts of the viewer independently scrollable
* make the test list filterable
** default to only showing unexpecteds
* add other ways to highlight differences other than circling?
* add zoom/pan to images
* Add ability to load log via XMLHttpRequest (also triggered via URL param)
* color the test list based on pass/fail and expected/unexpected/random/skip
* ability to load multiple logs ?
** rename them by clicking on the name and editing
** turn the test list into a collapsing tree view
** move log loading into popup from viewer UI

-->
<!DOCTYPE html>
<html lang="en-US" xml:lang="en-US" xmlns="http://www.w3.org/1999/xhtml">
<head>
  <title>Reftest analyzer</title>
  <style type="text/css"><![CDATA[

  html, body { margin: 0; }
  html { padding: 0; }
  body { padding: 4px; }

  #pixelarea, #itemlist, #images { position: absolute; }
  #itemlist, #images { overflow: auto; }
  #pixelarea { top: 0; left: 0; width: 320px; height: 84px; overflow: visible }
  #itemlist { top: 84px; left: 0; width: 320px; bottom: 0; }
  #images { top: 0; bottom: 0; left: 320px; right: 0; }

  #leftpane { width: 320px; }
  #images { position: fixed; top: 10px; left: 340px; }

  form#imgcontrols { margin: 0; display: block; }

  #itemlist > table { border-collapse: collapse; }
  #itemlist > table > tbody > tr > td { border: 1px solid; padding: 1px; }
  #itemlist td.activeitem { background-color: yellow; }

  /*
  #itemlist > table > tbody > tr.pass > td.url { background: lime; }
  #itemlist > table > tbody > tr.fail > td.url { background: red; }
  */

  #magnification > svg { display: block; width: 84px; height: 84px; }

  #pixelinfo { font: small sans-serif; position: absolute; width: 200px; left: 84px; }
  #pixelinfo table { border-collapse: collapse; }
  #pixelinfo table th { white-space: nowrap; text-align: left; padding: 0; }
  #pixelinfo table td { font-family: monospace; padding: 0 0 0 0.25em; }

  #pixelhint { display: inline; color: #88f; cursor: help; }
  #pixelhint > * { display: none; position: absolute; margin: 8px 0 0 8px; padding: 4px; width: 400px; background: #ffa; color: black; box-shadow: 3px 3px 2px #888; z-index: 1; }
  #pixelhint:hover { color: #000; }
  #pixelhint:hover > * { display: block; }
  #pixelhint p { margin: 0; }
  #pixelhint p + p { margin-top: 1em; }

  ]]></style>
  <script type="text/javascript"><![CDATA[

var XLINK_NS = "http://www.w3.org/1999/xlink";
var SVG_NS = "http://www.w3.org/2000/svg";
var IMAGE_NOT_AVAILABLE = "data:image/png;base64,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";

var gPhases = null;

var gIDCache = {};

var gMagPixPaths = [];     // 2D array of array-of-two <path> objects used in the pixel magnifier
var gMagWidth = 5;         // number of zoomed in pixels to show horizontally
var gMagHeight = 5;        // number of zoomed in pixels to show vertically
var gMagZoom = 16;         // size of the zoomed in pixels
var gImage1Data;           // ImageData object for the reference image
var gImage2Data;           // ImageData object for the test output image
var gFlashingPixels = [];  // array of <path> objects that should be flashed due to pixel color mismatch
var gParams;

function ID(id) {
  if (!(id in gIDCache))
    gIDCache[id] = document.getElementById(id);
  return gIDCache[id];
}

function hash_parameters() {
  var result = { };
  var params = window.location.hash.substr(1).split(/[&;]/);
  for (var i = 0; i < params.length; i++) {
    var parts = params[i].split("=");
    result[parts[0]] = unescape(unescape(parts[1]));
  }
  return result;
}

function load() {
  gPhases = [ ID("entry"), ID("loading"), ID("viewer") ];
  build_mag();
  gParams = hash_parameters();
  if (gParams.log) {
    show_phase("loading");
    process_log(gParams.log);
  } else if (gParams.logurl) {
    show_phase("loading");
    var req = new XMLHttpRequest();
    req.onreadystatechange = function() {
      if (req.readyState === 4) {
        process_log(req.responseText);
      }
    };
    req.open('GET', gParams.logurl, true);
    req.send();
  }
  window.addEventListener('keypress', handle_keyboard_shortcut, false);
  ID("image1").addEventListener('error', image_load_error, false);
  ID("image2").addEventListener('error', image_load_error, false);
}

function image_load_error(e) {
  e.target.setAttributeNS(XLINK_NS, "xlink:href", IMAGE_NOT_AVAILABLE);
}

function build_mag() {
  var mag = ID("mag");

  var r = document.createElementNS(SVG_NS, "rect");
  r.setAttribute("x", gMagZoom * -gMagWidth / 2);
  r.setAttribute("y", gMagZoom * -gMagHeight / 2);
  r.setAttribute("width", gMagZoom * gMagWidth);
  r.setAttribute("height", gMagZoom * gMagHeight);
  mag.appendChild(r);

  mag.setAttribute("transform", "translate(" + (gMagZoom * (gMagWidth / 2) + 1) + "," + (gMagZoom * (gMagHeight / 2) + 1) + ")");

  for (var x = 0; x < gMagWidth; x++) {
    gMagPixPaths[x] = [];
    for (var y = 0; y < gMagHeight; y++) {
      var p1 = document.createElementNS(SVG_NS, "path");
      p1.setAttribute("d", "M" + ((x - gMagWidth / 2) + 1) * gMagZoom + "," + (y - gMagHeight / 2) * gMagZoom + "h" + -gMagZoom + "v" + gMagZoom);
      p1.setAttribute("stroke", "black");
      p1.setAttribute("stroke-width", "1px");
      p1.setAttribute("fill", "#aaa");

      var p2 = document.createElementNS(SVG_NS, "path");
      p2.setAttribute("d", "M" + ((x - gMagWidth / 2) + 1) * gMagZoom + "," + (y - gMagHeight / 2) * gMagZoom + "v" + gMagZoom + "h" + -gMagZoom);
      p2.setAttribute("stroke", "black");
      p2.setAttribute("stroke-width", "1px");
      p2.setAttribute("fill", "#888");

      mag.appendChild(p1);
      mag.appendChild(p2);
      gMagPixPaths[x][y] = [p1, p2];
    }
  }

  var flashedOn = false;
  setInterval(function() {
    flashedOn = !flashedOn;
    flash_pixels(flashedOn);
  }, 500);
}

function show_phase(phaseid) {
  for (var i in gPhases) {
    var phase = gPhases[i];
    phase.style.display = (phase.id == phaseid) ? "" : "none";
  }

  if (phase == "viewer")
    ID("images").style.display = "none";
}

function fileentry_changed() {
  show_phase("loading");
  var input = ID("fileentry");
  var files = input.files;
  if (files.length > 0) {
    // Only handle the first file; don't handle multiple selection.
    // The parts of the log we care about are ASCII-only.  Since we
    // can ignore lines we don't care about, best to read in as
    // iso-8859-1, which guarantees we don't get decoding errors.
    var fileReader = new FileReader();
    fileReader.onload = function(e) {
      var log = null;

      log = e.target.result;

      if (log)
        process_log(log);
      else
        show_phase("entry");
    }
    fileReader.readAsText(files[0], "iso-8859-1");
  }
  // So the user can process the same filename again (after
  // overwriting the log), clear the value on the form input so we
  // will always get an onchange event.
  input.value = "";
}

function log_pasted() {
  show_phase("loading");
  var entry = ID("logentry");
  var log = entry.value;
  entry.value = "";
  process_log(log);
}

var gTestItems;

function process_log(contents) {
  var lines = contents.split(/[\r\n]+/);
  gTestItems = [];
  for (var j in lines) {
    var line = lines[j];
    try {
      var data = JSON.parse(line);
    } catch(e) {
      continue;
    }
    // Ignore duplicated output in logcat.
    if (!data.action == "test_end" && data.status != "FAIL")
      continue;

    if (!data.hasOwnProperty("extra") ||
        !data.extra.hasOwnProperty("reftest_screenshots")) {
      continue;
    }

    var url = data.test;
    var screenshots = data.extra.reftest_screenshots;
    gTestItems.push(
      {
        pass: data.status === "PASS",
        // only one of the following three should ever be true
        unexpected: data.hasOwnProperty("expected"),
        random: false,
        skip: data.status == "SKIP",
        url: url,
        images: [],
        imageLabels: []
      });

    var item = gTestItems[gTestItems.length - 1];
    item.images.push("data:image/png;base64," + screenshots[0].screenshot);
    item.imageLabels.push(screenshots[0].url);
    if (screenshots.length > 1) {
      item.images.push("data:image/png;base64," + screenshots[2].screenshot);
      item.imageLabels.push(screenshots[2].url);
    }
  }
  build_viewer();
}

function build_viewer() {
  if (gTestItems.length == 0) {
    show_phase("entry");
    return;
  }

  var cell = ID("itemlist");
  while (cell.childNodes.length > 0)
    cell.removeChild(cell.childNodes[cell.childNodes.length - 1]);

  var table = document.createElement("table");
  var tbody = document.createElement("tbody");
  table.appendChild(tbody);

  for (var i in gTestItems) {
    var item = gTestItems[i];

    // optional url filter for only showing unexpected results
    if (parseInt(gParams.only_show_unexpected) && !item.unexpected)
      continue;

    // XXX regardless skip expected pass items until we have filtering UI
    if (item.pass && !item.unexpected)
      continue;

    var tr = document.createElement("tr");
    var rowclass = item.pass ? "pass" : "fail";
    var td;
    var text;

    td = document.createElement("td");
    text = "";
    if (item.unexpected) { text += "!"; rowclass += " unexpected"; }
    if (item.random) { text += "R"; rowclass += " random"; }
    if (item.skip) { text += "S"; rowclass += " skip"; }
    td.appendChild(document.createTextNode(text));
    tr.appendChild(td);

    td = document.createElement("td");
    td.id = "item" + i;
    td.className = "url";
    // Only display part of URL after "/mozilla/".
    var match = item.url.match(/\/mozilla\/(.*)/);
    text = document.createTextNode(match ? match[1] : item.url);
    if (item.images.length > 0) {
      var a = document.createElement("a");
      a.href = "javascript:show_images(" + i + ")";
      a.appendChild(text);
      td.appendChild(a);
    } else {
      td.appendChild(text);
    }
    tr.appendChild(td);

    tbody.appendChild(tr);
  }

  cell.appendChild(table);

  show_phase("viewer");
}

function get_image_data(src, whenReady) {
  var img = new Image();
  img.onload = function() {
    var canvas = document.createElement("canvas");
    canvas.width = img.naturalWidth;
    canvas.height = img.naturalHeight;

    var ctx = canvas.getContext("2d");
    ctx.drawImage(img, 0, 0);

    whenReady(ctx.getImageData(0, 0, img.naturalWidth, img.naturalHeight));
  };
  img.src = src;
}

function sync_svg_size(imageData) {
  // We need the size of the 'svg' and its 'image' elements to match the size
  // of the ImageData objects that we're going to read pixels from or else our
  // magnify() function will be very broken.
  ID("svg").setAttribute("width", imageData.width);
  ID("svg").setAttribute("height", imageData.height);
}

function show_images(i) {
  var item = gTestItems[i];
  var cell = ID("images");

  // Remove activeitem class from any existing elements
  var activeItems = document.querySelectorAll(".activeitem");
  for (var activeItemIdx = activeItems.length; activeItemIdx-- != 0;) {
    activeItems[activeItemIdx].classList.remove("activeitem");
  }

  ID("item" + i).classList.add("activeitem");
  ID("image1").style.display = "";
  ID("image2").style.display = "none";
  ID("diffrect").style.display = "none";
  ID("imgcontrols").reset();

  ID("image1").setAttributeNS(XLINK_NS, "xlink:href", item.images[0]);
  // Making the href be #image1 doesn't seem to work
  ID("feimage1").setAttributeNS(XLINK_NS, "xlink:href", item.images[0]);
  if (item.images.length == 1) {
    ID("imgcontrols").style.display = "none";
  } else {
    ID("imgcontrols").style.display = "";

    ID("image2").setAttributeNS(XLINK_NS, "xlink:href", item.images[1]);
    // Making the href be #image2 doesn't seem to work
    ID("feimage2").setAttributeNS(XLINK_NS, "xlink:href", item.images[1]);

    ID("label1").textContent = 'Image ' + item.imageLabels[0];
    ID("label2").textContent = 'Image ' + item.imageLabels[1];
  }

  cell.style.display = "";

  get_image_data(item.images[0], function(data) { gImage1Data = data; sync_svg_size(gImage1Data); });
  get_image_data(item.images[1], function(data) { gImage2Data = data });
}

function show_image(i) {
  if (i == 1) {
    ID("image1").style.display = "";
    ID("image2").style.display = "none";
  } else {
    ID("image1").style.display = "none";
    ID("image2").style.display = "";
  }
}

function handle_keyboard_shortcut(event) {
  switch (event.charCode) {
  case 49: // "1" key
    document.getElementById("radio1").checked = true;
    show_image(1);
    break;
  case 50: // "2" key
    document.getElementById("radio2").checked = true;
    show_image(2);
    break;
  case 100: // "d" key
    document.getElementById("differences").click();
    break;
  case 112: // "p" key
    shift_images(-1);
    break;
  case 110: // "n" key
    shift_images(1);
    break;
  }
}

function shift_images(dir) {
  var activeItem = document.querySelector(".activeitem");
  if (!activeItem) {
    return;
  }
  for (var elm = activeItem; elm; elm = elm.parentElement) {
    if (elm.tagName != "tr") {
      continue;
    }
    elm = dir > 0 ? elm.nextElementSibling : elm.previousElementSibling;
    if (elm) {
      elm.getElementsByTagName("a")[0].click();
    }
    return;
  }
}

function show_differences(cb) {
  ID("diffrect").style.display = cb.checked ? "" : "none";
}

function flash_pixels(on) {
  var stroke = on ? "red" : "black";
  var strokeWidth = on ? "2px" : "1px";
  for (var i = 0; i < gFlashingPixels.length; i++) {
    gFlashingPixels[i].setAttribute("stroke", stroke);
    gFlashingPixels[i].setAttribute("stroke-width", strokeWidth);
  }
}

function cursor_point(evt) {
  var m = evt.target.getScreenCTM().inverse();
  var p = ID("svg").createSVGPoint();
  p.x = evt.clientX;
  p.y = evt.clientY;
  p = p.matrixTransform(m);
  return { x: Math.floor(p.x), y: Math.floor(p.y) };
}

function hex2(i) {
  return (i < 16 ? "0" : "") + i.toString(16);
}

function canvas_pixel_as_hex(data, x, y) {
  var offset = (y * data.width + x) * 4;
  var r = data.data[offset];
  var g = data.data[offset + 1];
  var b = data.data[offset + 2];
  return "#" + hex2(r) + hex2(g) + hex2(b);
}

function hex_as_rgb(hex) {
  return "rgb(" + [parseInt(hex.substring(1, 3), 16), parseInt(hex.substring(3, 5), 16), parseInt(hex.substring(5, 7), 16)] + ")";
}

function magnify(evt) {
  var { x: x, y: y } = cursor_point(evt);
  var centerPixelColor1, centerPixelColor2;

  var dx_lo = -Math.floor(gMagWidth / 2);
  var dx_hi = Math.floor(gMagWidth / 2);
  var dy_lo = -Math.floor(gMagHeight / 2);
  var dy_hi = Math.floor(gMagHeight / 2);

  flash_pixels(false);
  gFlashingPixels = [];
  for (var j = dy_lo; j <= dy_hi; j++) {
    for (var i = dx_lo; i <= dx_hi; i++) {
      var px = x + i;
      var py = y + j;
      var p1 = gMagPixPaths[i + dx_hi][j + dy_hi][0];
      var p2 = gMagPixPaths[i + dx_hi][j + dy_hi][1];
      // Here we just use the dimensions of gImage1Data since we expect test
      // and reference to have the same dimensions.
      if (px < 0 || py < 0 || px >= gImage1Data.width || py >= gImage1Data.height) {
        p1.setAttribute("fill", "#aaa");
        p2.setAttribute("fill", "#888");
      } else {
        var color1 = canvas_pixel_as_hex(gImage1Data, x + i, y + j);
        var color2 = canvas_pixel_as_hex(gImage2Data, x + i, y + j);
        p1.setAttribute("fill", color1);
        p2.setAttribute("fill", color2);
        if (color1 != color2) {
          gFlashingPixels.push(p1, p2);
          p1.parentNode.appendChild(p1);
          p2.parentNode.appendChild(p2);
        }
        if (i == 0 && j == 0) {
          centerPixelColor1 = color1;
          centerPixelColor2 = color2;
        }
      }
    }
  }
  flash_pixels(true);
  show_pixelinfo(x, y, centerPixelColor1, hex_as_rgb(centerPixelColor1), centerPixelColor2, hex_as_rgb(centerPixelColor2));
}

function show_pixelinfo(x, y, pix1rgb, pix1hex, pix2rgb, pix2hex) {
  var pixelinfo = ID("pixelinfo");
  ID("coords").textContent = [x, y];
  ID("pix1hex").textContent = pix1hex;
  ID("pix1rgb").textContent = pix1rgb;
  ID("pix2hex").textContent = pix2hex;
  ID("pix2rgb").textContent = pix2rgb;
}

  ]]></script>

</head>
<body onload="load()">

<div id="entry">

<h1>Reftest analyzer: load raw structured log</h1>

<p>Either paste your log into this textarea:<br />
<textarea cols="80" rows="10" id="logentry"/><br/>
<input type="button" value="Process pasted log" onclick="log_pasted()" /></p>

<p>... or load it from a file:<br/>
<input type="file" id="fileentry" onchange="fileentry_changed()" />
</p>
</div>

<div id="loading" style="display:none">Loading log...</div>

<div id="viewer" style="display:none">
  <div id="pixelarea">
    <div id="pixelinfo">
      <table>
        <tbody>
          <tr><th>Pixel at:</th><td colspan="2" id="coords"/></tr>
          <tr><th>Image 1:</th><td id="pix1rgb"></td><td id="pix1hex"></td></tr>
          <tr><th>Image 2:</th><td id="pix2rgb"></td><td id="pix2hex"></td></tr>
        </tbody>
      </table>
      <div>
        <div id="pixelhint">★
          <div>
            <p>Move the mouse over the reftest image on the right to show
            magnified pixels on the left.  The color information above is for
            the pixel centered in the magnified view.</p>
            <p>Image 1 is shown in the upper triangle of each pixel and Image 2
            is shown in the lower triangle.</p>
          </div>
        </div>
      </div>
    </div>
    <div id="magnification">
      <svg xmlns="http://www.w3.org/2000/svg" width="84" height="84" shape-rendering="optimizeSpeed">
        <g id="mag"/>
      </svg>
    </div>
  </div>
  <div id="itemlist"></div>
  <div id="images" style="display:none">
    <form id="imgcontrols">
    <input id="radio1" type="radio" name="which" value="0" onchange="show_image(1)" checked="checked" /><label id="label1" title="1" for="radio1">Image 1</label>
    <input id="radio2" type="radio" name="which" value="1" onchange="show_image(2)"                   /><label id="label2" title="2" for="radio2">Image 2</label>
    <label><input id="differences" type="checkbox" onchange="show_differences(this)" />Circle differences</label>
    </form>
    <svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" version="1.1" width="800" height="1000" id="svg">
      <defs>
        <!-- use sRGB to avoid loss of data -->
        <filter id="showDifferences" x="0%" y="0%" width="100%" height="100%"
                style="color-interpolation-filters: sRGB">
          <feImage id="feimage1" result="img1" xlink:href="#image1" />
          <feImage id="feimage2" result="img2" xlink:href="#image2" />
          <!-- inv1 and inv2 are the images with RGB inverted -->
          <feComponentTransfer result="inv1" in="img1">
            <feFuncR type="linear" slope="-1" intercept="1" />
            <feFuncG type="linear" slope="-1" intercept="1" />
            <feFuncB type="linear" slope="-1" intercept="1" />
          </feComponentTransfer>
          <feComponentTransfer result="inv2" in="img2">
            <feFuncR type="linear" slope="-1" intercept="1" />
            <feFuncG type="linear" slope="-1" intercept="1" />
            <feFuncB type="linear" slope="-1" intercept="1" />
          </feComponentTransfer>
          <!-- w1 will have non-white pixels anywhere that img2
               is brighter than img1, and w2 for the reverse.
               It would be nice not to have to go through these
               intermediate states, but feComposite
               type="arithmetic" can't transform the RGB channels
               and leave the alpha channel untouched. -->
          <feComposite result="w1" in="img1" in2="inv2" operator="arithmetic" k2="1" k3="1" />
          <feComposite result="w2" in="img2" in2="inv1" operator="arithmetic" k2="1" k3="1" />
          <!-- c1 will have non-black pixels anywhere that img2
               is brighter than img1, and c2 for the reverse -->
          <feComponentTransfer result="c1" in="w1">
            <feFuncR type="linear" slope="-1" intercept="1" />
            <feFuncG type="linear" slope="-1" intercept="1" />
            <feFuncB type="linear" slope="-1" intercept="1" />
          </feComponentTransfer>
          <feComponentTransfer result="c2" in="w2">
            <feFuncR type="linear" slope="-1" intercept="1" />
            <feFuncG type="linear" slope="-1" intercept="1" />
            <feFuncB type="linear" slope="-1" intercept="1" />
          </feComponentTransfer>
          <!-- c will be nonblack (and fully on) for every pixel+component where there are differences -->
          <feComposite result="c" in="c1" in2="c2" operator="arithmetic" k2="255" k3="255" />
          <!-- a will be opaque for every pixel with differences and transparent for all others -->
          <feColorMatrix result="a" type="matrix" values="0 0 0 0 0  0 0 0 0 0  0 0 0 0 0  1 1 1 0 0" />

          <!-- a, dilated by 1 pixel -->
          <feMorphology result="dila1" in="a" operator="dilate" radius="1" />
          <!-- a, dilated by 2 pixels -->
          <feMorphology result="dila2" in="dila1" operator="dilate" radius="1" />

          <!-- all the pixels in the 2-pixel dilation of a but not in the 1-pixel dilation, to highlight the diffs -->
          <feComposite result="highlight" in="dila2" in2="dila1" operator="out" />

          <feFlood result="red" flood-color="red" />
          <feComposite result="redhighlight" in="red" in2="highlight" operator="in" />
          <feFlood result="black" flood-color="black" flood-opacity="0.5" />
          <feMerge>
            <feMergeNode in="black" />
            <feMergeNode in="redhighlight" />
          </feMerge>
        </filter>
      </defs>
      <g onmousemove="magnify(evt)">
        <image x="0" y="0" width="100%" height="100%" id="image1" />
        <image x="0" y="0" width="100%" height="100%" id="image2" />
      </g>
      <rect id="diffrect" filter="url(#showDifferences)" pointer-events="none" x="0" y="0" width="100%" height="100%" />
    </svg>
  </div>
</div>

</body>
</html>