/// <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;
}
/// <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;
}
/// <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;
}
