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HTML

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Adding Classes

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About the <head>

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Insecure Resource

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CSS

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CSS preprocessors help make authoring CSS easier. All of them offer things like variables and mixins to provide convenient abstractions.

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CSS Base

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JavaScript

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HTML 

              
                <table id="tb_settings">
  <tr>
    <th>Input file:</th>
    <td><input type="file" id="inFile" /></td>
  </tr>
  <tr>
    <th>Input palette:</th>
    <td><input type="file" id="inPal" /></td>
  </tr>
  <tr>
    <th>Designation:</th>
    <td><select id="palset">
      <option value=0>Background</option>
      <option value=128>Object</option>
      <option value=32>Mode 0 - BG2</option>
      <option value=64>Mode 0 - BG3</option>
      <option value=96>Mode 0 - BG4</option>
    </select></td>
  </tr>
  <tr>
    <th>Palette ID:</th>
    <td><input id="outpal" type="number" min=0 max=7 value="0"/></td>
  </tr>
  <tr>
    <th>Bit depth:</th>
    <td><select id="outbpp">
      <option value=2>2bpp</option>
      <option value=4>4bpp</option>
      <option value=8>8bpp</option>
    </select></td>
  </tr>
</table>
<div style="white-space: nowrap">
  <div id="tb_data"></div>
  <canvas id="cv_out" width=1024 height=512></canvas>
  <div id="cv_highlight"></div>
</div>
<div id="bin_data"></div>
!

CSS 

              
                #tb_settings th {
  text-align: right;
}

#tb_data {
  display: inline-block;
  vertical-align: top;
  font-family: monospace;
  height: 512px;
  width: 330px;
  overflow-y: scroll;
  border: 1px solid gray;
}

  #tb_data tr.hl, #bin_data .hl {
    background-color: lightsalmon;
  }

  #tb_data td.hl {
    background-color: darkred;
    color: white;
  }

#bin_data {
  display: inline-block;
  min-height : 1em;
  font-size: 14pt;
  font-family: monospace;
  white-space: nowrap;
}

#cv_out {
  border: 1px solid gray;
  image-rendering: optimizeSpeed;             /* Older versions of FF          */
  image-rendering: -moz-crisp-edges;          /* FF 6.0+                       */
  image-rendering: -webkit-optimize-contrast; /* Safari                        */
  image-rendering: -o-crisp-edges;            /* OS X & Windows Opera (12.02+) */
  image-rendering: pixelated;                 /* Future browsers               */
  -ms-interpolation-mode: nearest-neighbor;   /* IE                            */
}

#cv_highlight {
  position: absolute;
  display: inline-block;
  visibility: hidden;
  z-index: 1000;
  height: 8px;
  width: 8px;
  pointer-events: none;
  background-color: rgba(255, 255, 255, 0.5);
  border: 1px dotted black;
  box-sizing: border-box;
}
!

JS 

              
                var palette;
var graphics;

$(getDefPal());

$("#inPal").on("change", function() {
  var reader = new FileReader();
  reader.onload = function() {
    getPal(new Uint8Array(this.result, 0, 16384));
    if (graphics != null) fillCanvas(graphics, palette);
  }
  reader.readAsArrayBuffer(this.files[0]);
});

$("#inFile").on("change", function() {
	var reader = new FileReader();
  reader.onload = function() {
    graphics = new Uint8Array(this.result);
    fillData(graphics);
    fillCanvas(graphics, palette);
  }
  reader.readAsArrayBuffer(this.files[0]);
});

$("#outbpp").on("change", function() {
  var pal = document.getElementById("outpal");
  if (this.value == 8) {
    pal.disabled = true;
    pal.value = 0;
  } else {
    pal.disabled = false;
  }
  if (graphics != null) fillCanvas(graphics, palette);
});

$("#outpal").on("change", function() {
  if (graphics != null) fillCanvas(graphics, palette);
});

$("#palset").on("change", function() {
  var bdepth = document.getElementById("outbpp");
  document.getElementById("outpal").disabled = false;
  if (this.value == 0) {
    bdepth.disabled = false;
  } else {
    bdepth.disabled = true;
    bdepth.value = (this.value == 128 ? 4 : 2);
  }
  fillCanvas(graphics, palette);
});

function fillData(data) {
  var out = "<table><tr>";
	for (i = 0; i < data.length; i++) {
    if (i % 16 == 0 && i > 0) { out += "</tr><tr>" }
    out += "<td>" + padNum(data[i], 16, 2) + "</td>";
  }
  out += "</tr></table>";
  document.getElementById('tb_data').innerHTML = out;
}

function fillCanvas(graphics, palette) {
  var canvas = document.getElementById('cv_out');
  if (!canvas.getContext) { return; }
  var ctx = canvas.getContext('2d');
  
  var bpp = parseInt(document.getElementById('outbpp').value);
  var pal = parseInt(document.getElementById('outpal').value);
  var palset = parseInt(document.getElementById('palset').value);
  var palind = pal*(1<<bpp) + palset;
  
  var t, r, p, s, c;
  var base, ind, bp0, bp1, bp2, bp3, bp4, bp5, bp6, bp7;
  for (t = 0; t < 128; t++) { // tile loop
    base = t * bpp * 8;
    for (r = 0; r < 8; r++) {
      // fetch each of the bitplane bytes for the row
      ind = base + r*2;
      bp0 =   graphics[ind];
      bp1 =   graphics[ind + 1];
      if (bpp >= 4) {
        bp2 = graphics[ind + 16];
        bp3 = graphics[ind + 17];
      }
      if (bpp == 8) {
        bp4 = graphics[ind + 32];
        bp5 = graphics[ind + 33];
        bp6 = graphics[ind + 48];
        bp7 = graphics[ind + 49];
      }
      
      for (p = 0; p < 8; p++) {
        // fetch each of the bitplanes for the pixel
        s = 1 << p;
        c =    ((bp0 & s) >> p)
            |  ((bp1 & s) >> p) << 1;
        if (bpp >= 4)
          c |= ((bp2 & s) >> p) << 2
            |  ((bp3 & s) >> p) << 3;
        if (bpp == 8)
          c |= ((bp4 & s) >> p) << 4
            |  ((bp5 & s) >> p) << 5
            |  ((bp6 & s) >> p) << 6
            |  ((bp7 & s) >> p) << 7;
            
        // draw color
        ctx.fillStyle = 'rgb(' + palette[palind + c] + ')';
        ctx.fillRect(((t % 16)*8 + (7-p))*8, ((t >> 4)*8 + r)*8, 8, 8);
      }
    }
  }
}

$("#cv_out").mousemove(function(e) {
  if (graphics == null) { return; }
  
  var x = Math.floor((e.pageX - this.offsetLeft - 2)/8);
  var y = Math.floor((e.pageY - this.offsetTop - 2)/8);
  if (x < 0 || y < 0) { return; }
  
  var hl = document.getElementById("cv_highlight");
  hl.style.visibility = "visible";
  hl.style.left = (x*8 + this.offsetLeft + 1) + "px";
  hl.style.top  = (y*8 + this.offsetTop + 1) + "px";
  
  document.getElementById("bin_data").innerHTML = "";
  $("#tb_data .hl").removeClass("hl");
  var bpp = parseInt(document.getElementById('outbpp').value);
  var base  = (Math.floor(y/8)*16 + Math.floor(x/8))*8*bpp + (y % 8)*2;
  var rb = Math.floor(base/16), cb = base % 16;
  
  var tbData = document.getElementById("tb_data");
  var trs = tbData.getElementsByTagName("tr");
  var tds;
  var data = [];
  scrollIntoView(trs[rb], tbData);
  //trs[rb].scrollIntoView({block: "nearest"});
  for (var i = bpp; i > 0; i -= 2, rb++) {
    tds = trs[rb].getElementsByTagName("td");
    data.push(parseInt(tds[cb].innerHTML, 16));
    data.push(parseInt(tds[cb+1].innerHTML, 16));
    trs[rb].className = "hl";
    tds[cb].className = "hl";
    tds[cb+1].className = "hl";
  }
  scrollIntoView(trs[rb-1], tbData);
  //trs[rb-1].scrollIntoView({block: "nearest"});
  writeData(data, x % 8);
  
});

function writeData(data, ind) {
  var out = "$" + data.map(x => padNum(x, 16, 2)).join(" ") + " = %";
  var bout, bin = "";
  for (var i = 0; i < data.length; i++) {
    bout = padNum(data[i], 2, 8);
    bin = bout.charAt(ind) + bin;
    bout = bout.slice(0, ind) + "<span class='hl'>" + bout.charAt(ind) + "</span>" + bout.slice(ind + 1);
    out += bout + " ";
  }
  out += " 🡆 %" + bin + " = $" + padNum(parseInt(bin, 2), 16, 2);
  document.getElementById("bin_data").innerHTML = out;
}


function getPal(data) {
  palette = [];
  var c,r,g,b;
  for (var i = 0; i < 256; i++) {
    if (i > data.length) {
      palette[i] = 0x000000;
    } else {
      var i2 = i*3;
      palette[i] = data[i2] + "," + data[i2+1] + "," + data[i2+2];
    }
  }
}

function scrollIntoView(e, c) {
  if (e.offsetTop < c.scrollTop) {
    c.scrollTop = e.offsetTop;
  } else if (e.offsetTop + e.offsetHeight > c.scrollTop + c.clientHeight) {
    c.scrollTop = e.offsetTop + e.offsetHeight - c.clientHeight;
  }
}
function padNum(val, base, len) { return ("0".repeat(len) + val.toString(base)).substr(-len).toUpperCase(); }

// default palette if no file loaded
function getDefPal() {
   palette = ["0,96,184","232,240,248","16,80,112","64,128,160","112,176,208","144,192,192","168,208,208","192,224,224","152,224,224","0,0,0","216,56,24","88,248,88","152,224,224","0,0,0","232,240,248","248,88,88","0,96,184","232,240,248","16,80,112","64,128,160","112,176,208","16,80,112","64,128,160","112,176,208","152,224,224","0,0,0","88,168,240","248,248,248","152,224,224","0,0,0","216,160,56","248,216,112","0,96,184","232,240,248","0,0,0","120,104,24","200,152,88","0,120,72","224,192,80","0,200,0","0,0,0","248,248,248","0,0,0","0,200,0","176,0,0","248,0,0","248,88,0","248,160,0","0,96,184","232,240,248","0,0,0","88,88,88","120,120,120","152,152,152","192,192,192","224,224,224","0,0,0","248,248,248","0,0,0","0,200,0","232,24,104","240,64,168","248,120,200","248,192,240","0,96,184","232,240,248","112,112,112","0,0,0","192,192,192","160,200,248","168,224,248","192,248,248","0,0,0","248,248,248","0,0,0","0,200,0","0,224,0","136,248,56","200,248,0","248,248,152","0,96,184","232,240,248","0,0,0","184,168,96","216,248,200","0,128,0","0,200,0","0,248,0","0,0,0","0,0,0","0,0,0","0,0,0","0,0,0","0,0,0","0,0,0","0,0,0","0,96,184","232,240,248","0,0,0","136,88,24","248,8,248","216,160,56","248,216,32","248,248,0","0,0,0","0,0,0","0,0,0","0,0,0","0,0,0","0,0,0","0,0,0","0,0,0","0,96,184","232,240,248","0,0,0","184,0,80","248,0,128","72,72,136","104,104,176","128,128,200","0,0,0","0,0,0","0,0,0","0,0,0","0,0,0","0,0,0","0,0,0","0,0,0","0,96,184","248,248,248","0,0,0","136,88,24","216,160,56","248,216,112","248,208,192","232,0,176","80,0,0","248,64,112","32,48,136","64,128,152","128,216,200","176,40,96","248,112,104","248,248,0","0,96,184","248,248,248","0,0,0","112,112,112","160,160,160","192,192,192","224,224,224","248,16,88","0,0,0","248,248,248","0,0,0","0,200,0","176,0,0","248,0,0","248,88,0","248,160,0","0,96,184","248,248,248","0,0,0","248,120,0","248,192,0","248,248,0","184,40,0","248,136,0","0,0,0","248,248,248","0,0,0","0,200,0","232,24,104","240,64,168","248,120,200","248,192,240","0,96,184","248,248,248","0,0,0","64,64,216","104,104,216","136,136,248","184,40,0","248,136,0","0,0,0","248,248,248","0,0,0","0,200,0","0,224,0","136,248,56","200,248,0","248,248,152","0,96,184","248,248,248","0,0,0","136,0,0","184,0,0","248,0,0","184,40,0","248,136,0","0,0,0","0,0,0","0,0,0","0,0,0","0,0,0","0,0,0","0,0,0","0,0,0","0,96,184","248,248,248","0,0,0","0,120,0","0,184,0","0,248,0","184,40,0","248,136,0","0,0,0","0,0,0","0,0,0","0,0,0","0,0,0","0,0,0","0,0,0","0,0,0","0,96,184","248,248,248","0,0,0","40,48,72","72,80,88","104,104,88","152,144,64","192,192,120","0,0,0","0,0,0","0,0,0","0,0,0","0,0,0","0,0,0","0,0,0","0,0,0","0,96,184","248,248,248","24,72,72","32,112,104","40,136,120","48,160,136","56,184,152","248,0,128","0,0,0","0,0,0","0,0,0","0,0,0","0,0,0","0,0,0","0,0,0","0,0,0"];
}
!
999px

Console