function app() {
    var R = 0x0000c0;
    var G = 0x00c000;
    var B = 0xc00000;
    var YR = 0x0000ff;
    var YG = 0x00ff00;
    var YB = 0xff0000;
    var palette = [
        0, B, R, B | R, G, G | B, G | R, G | B | R,
        0, YB, YR, YB | YR, YG, YG | YB, YG | YR, YG | YB | YR,
    ];
    var colorTab = new Uint32Array(256 * 256 * 8);
    var colorTabFlash = new Uint32Array(256 * 256 * 8);
    var canvasElement = document.getElementById("canv");
    var context = canvasElement.getContext("2d");
    var image = context.getImageData(0, 0, 256, 192);
    var imageData = new Uint32Array(image.data.buffer);
    var lineOffsets = new Array(192);
    var attrOffsets = new Array(6144);
    function precalc() {
        var inkTab = new Uint32Array(256);
        var paperTab = new Uint32Array(256);
        var inkTabFlash = new Uint32Array(256);
        var paperTabFlash = new Uint32Array(256);
        function getInkColor(attr, flashed) {
            var bright = !!(attr & 0x40);
            var flash = !!(attr & 0x80);
            if (flashed && flash)
                var cindex = ((attr >>> 3) & 7);
            else
                var cindex = ((attr >>> 0) & 7);
            return 0xff000000 | palette[cindex + (bright ? 8 : 0)];
        }
        function getPaperColor(attr, flashed) {
            var bright = !!(attr & 0x40);
            var flash = !!(attr & 0x80);
            if (flashed && flash)
                var cindex = ((attr >>> 0) & 7);
            else
                var cindex = ((attr >>> 3) & 7);
            return 0xff000000 | palette[cindex + (bright ? 8 : 0)];
        }
        for (var aval = 0; aval < 256; aval++) {
            inkTab[aval] = getInkColor(aval, false);
            paperTab[aval] = getPaperColor(aval, false);
            inkTabFlash[aval] = getInkColor(aval, true);
            paperTabFlash[aval] = getPaperColor(aval, true);
        }
        for (var bval = 0; bval < 256; bval++) {
            for (var aval = 0; aval < 256; aval++) {
                var index = (bval * 256 + aval) * 8;
                for (var bit = 0; bit < 8; bit++) {
                    if (bval & (1 << (7 - bit))) {
                        colorTab[index + bit] = inkTab[aval];
                        colorTabFlash[index + bit] = inkTabFlash[aval];
                    }
                    else {
                        colorTab[index + bit] = paperTab[aval];
                        colorTabFlash[index + bit] = paperTabFlash[aval];
                    }
                }
            }
        }
        for (var line = 0; line < 192; line++) {
            var part = line >> 6;
            var charLine = line & 7;
            var scanLine = (line >> 3) & 7;
            var realLine = part * 64 + charLine * 8 + scanLine;
            lineOffsets[line] = realLine;
            var attrBase = 6144 + (realLine >> 3) * 32;
            for (var boffs = 0; boffs < 32; boffs++) {
                attrOffsets[line * 32 + boffs] = attrBase + boffs;
            }
        }
    }
    function render(fileContent) {
        if (fileContent.byteLength != 6912)
            return;
        var index = 0;
        var data = new Uint8Array(fileContent);
        for (var line = 0; line < 192; line++) {
            var dstIndex = lineOffsets[line] * 256;
            var attrIndex = attrOffsets[index];
            for (var bcnt = 0; bcnt < 32; bcnt++) {
                var attr = data[attrIndex++];
                var byte = data[index++];
                var srcIndex = (byte * 256 + attr) * 8;
                imageData.set(colorTab.subarray(srcIndex, srcIndex + 8), dstIndex);
                dstIndex += 8;
            }
        }
        context.putImageData(image, 0, 0);
    }
    var request = new XMLHttpRequest();
    request.overrideMimeType('text\/plain; charset=x-user-defined');
    request.open('GET', "/test.scr", true);
    request.responseType = "arraybuffer";
    request.onload = function () {
        var t0 = performance.now();
        for (var cnt = 0; cnt < 1000; cnt++)
            render(request.response);
        var t1 = performance.now();
        console.log('time: ', (t1 - t0).toFixed(4), 'milliseconds');
    };
    precalc();
    request.send(null);
}
app();