Neural Quantization Class
        /// <summary>
        /// Analyzes image colors and creates color map.
        /// </summary>
        private void AnalyzePixels()
        {
            int len  = _pixels.Length;
            int nPix = len / 3;

            _indexedPixels = new byte[nPix];

            //Initialize quantizer.
            var nq = new NeuQuant(_pixels, len, _sample);

            //Create reduced palette.
            _colorTab = nq.Process();

            #region BGR to RGB

            for (int i = 0; i < _colorTab.Length; i += 3)
            {
                //Only swap Red with Blue. Green stays.
                byte temp = _colorTab[i];
                _colorTab[i]      = _colorTab[i + 2];
                _colorTab[i + 2]  = temp;
                _usedEntry[i / 3] = false;
            }

            #endregion

            //Map image pixels to new palette.
            int k = 0;
            _usedEntry = new bool[256];

            for (int i = 0; i < nPix; i++)
            {
                int index = nq.Map(
                    _pixels[k++],
                    _pixels[k++],
                    _pixels[k++]);

                _usedEntry[index] = true;
                _indexedPixels[i] = (byte)index;
            }

            _colorDepth = 8;
            _palSize    = 7;

            //Get closest match to transparent color if specified.
            if (_transparent != Color.Empty)
            {
                _transIndex = nq.Map(_transparent.B, _transparent.G, _transparent.R);
            }

            _pixels = null;
        }
示例#2
0
        /// <summary>
        /// Analyzes image colors and creates color map.
        /// </summary>
        private void AnalyzePixels()
        {
            int len = _pixels.Length;
            int nPix = len / 3;
            _indexedPixels = new byte[nPix];

            //Initialize quantizer.
            var nq = new NeuQuant(_pixels, len, _sample);
            //Create reduced palette.
            _colorTab = nq.Process();

            #region BGR to RGB

            for (int i = 0; i < _colorTab.Length; i += 3)
            {
                //Only swap Red with Blue. Green stays.
                byte temp = _colorTab[i];
                _colorTab[i] = _colorTab[i + 2];
                _colorTab[i + 2] = temp;
                _usedEntry[i / 3] = false;
            }

            #endregion

            //Map image pixels to new palette.
            int k = 0;
            _usedEntry = new bool[256];

            for (int i = 0; i < nPix; i++)
            {
                int index = nq.Map(
                    _pixels[k++],
                    _pixels[k++],
                    _pixels[k++]);

                _usedEntry[index] = true;
                _indexedPixels[i] = (byte)index;
            }

            _colorDepth = 8;
            _palSize = 7;

            //Get closest match to transparent color if specified.
            if (_transparent != Color.Empty)
            {
                _transIndex = nq.Map(_transparent.B, _transparent.G, _transparent.R);
            }

            _pixels = null;
        }
示例#3
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        /// <summary>
        /// Analyzes image colors and creates color map.
        /// </summary>
        private void AnalyzePixels()
        {
            var len  = _pixels.Length;
            var nPix = len / 3;

            _indexedPixels = new byte[nPix];

            var colorTable = _colorList.GroupBy(x => x)         //Grouping based on its value
                             .OrderByDescending(g => g.Count()) //Order by most frequent values
                             .Select(g => g.FirstOrDefault())   //take the first among the group
                             .ToList();                         //Could use .Take(256)

            _usedEntry = new bool[256];

            if (colorTable.Count <= 256)
            {
                #region No quantitizer needed

                _colorTab = new byte[768];

                int indexAux = 0;
                foreach (var color in colorTable)
                {
                    _colorTab[indexAux++] = color.R;
                    _colorTab[indexAux++] = color.G;
                    _colorTab[indexAux++] = color.B;
                }

                //var grouped = _pixels.Select((x, i) => new { x, i })
                //    .GroupBy(x => x.i / 3)
                //    .Select(g => g.ToList())
                //    .Select(g => new { R = g[0], G = g[1], B = g[2] })
                //    .Distinct();

                var k = 0;
                for (var i = 0; i < nPix; i++)
                {
                    var b = _pixels[k++];
                    var g = _pixels[k++];
                    var r = _pixels[k++];

                    var pos = colorTable.IndexOf(Color.FromArgb(r, g, b));

                    if (pos == -1 || pos > 255)
                    {
                        pos = 0;
                    }

                    _usedEntry[pos]   = true;
                    _indexedPixels[i] = (byte)pos;
                }

                //Get closest match to transparent color if specified.
                if (_transparent != Color.Empty)
                {
                    _transIndex = colorTable.IndexOf(Color.FromArgb(_transparent.R, _transparent.G, _transparent.B));

                    if (_transIndex == -1)
                    {
                        _transIndex = 0;
                    }
                }

                #endregion
            }
            else
            {
                #region Quantitizer needed

                //Neural quantitizer.
                var nq = new NeuQuant(_pixels, len, _sample);

                //Create reduced palette.
                _colorTab = nq.Process();

                //Map image pixels to new palette.
                var k = 0;
                for (var i = 0; i < nPix; i++)
                {
                    var index = nq.Map(
                        _pixels[k++],
                        _pixels[k++],
                        _pixels[k++]);

                    _usedEntry[index] = true;
                    _indexedPixels[i] = (byte)index;
                }

                //Get closest match to transparent color if specified.
                if (_transparent != Color.Empty)
                {
                    _transIndex = nq.Map(_transparent.B, _transparent.G, _transparent.R);
                }

                #endregion
            }

            _colorDepth = 8;
            _palSize    = 7;
            _pixels     = null;
        }