/**
* Analyzes image colors and creates color map.
*/
protected void AnalyzePixels()
{
int len = pixels.Length;
int nPix = len / 3;
indexedPixels = new byte[nPix];
NeuQuant nq = new NeuQuant(pixels, len, sample);
// initialize quantizer
colorTab = nq.Process(); // create reduced palette
// map image pixels to new palette
int k = 0;
for (int i = 0; i < nPix; i++)
{
int index =
nq.Map(pixels[k++] & 0xff,
pixels[k++] & 0xff,
pixels[k++] & 0xff);
usedEntry[index] = true;
indexedPixels[i] = (byte)index;
}
pixels = null;
colorDepth = 8;
palSize = 7;
// get closest match to transparent color if specified
if (transparent != Color.Empty)
{
transIndex = FindClosest(transparent);
}
}
/**
* Initiates writing of a GIF file with the specified name.
*
* @param file String containing output file name.
* @return false if open or initial write failed.
*/
/*public bool Start(String file)
* {
* bool ok = true;
* try
* {
* // bw = new BinaryWriter( new MemoryStream( file, FileMode.OpenOrCreate, FileAccess.Write, FileShare.None ) );
* fs = new MemoryStream( file, FileMode.OpenOrCreate, FileAccess.Write, FileShare.None );
* ok = Start(fs);
* closeStream = true;
* }
* catch (IOException e)
* {
* ok = false;
* }
* return started = ok;
* }*/
/**
* Analyzes image colors and creates color map.
*/
protected void AnalyzePixels()
{
int len = pixels.Length;
int nPix = len / 3;
indexedPixels = new byte[nPix];
NeuQuant nq = new NeuQuant(pixels, len, sample);
// initialize quantizer
colorTab = nq.Process(); // create reduced palette
// convert map from BGR to RGB
// for (int i = 0; i < colorTab.Length; i += 3)
// {
// byte temp = colorTab[i];
// colorTab[i] = colorTab[i + 2];
// colorTab[i + 2] = temp;
// usedEntry[i / 3] = false;
// }
// map image pixels to new palette
int k = 0;
for (int i = 0; i < nPix; i++)
{
int index =
nq.Map(pixels[k++] & 0xff,
pixels[k++] & 0xff,
pixels[k++] & 0xff);
/*int index =
* nq.Map(pixels[k+2] & 0xff,
* pixels[k+1] & 0xff,
* pixels[k] & 0xff);
* k += 3;*/
usedEntry[index] = true;
indexedPixels[i] = (byte)index;
}
pixels = null;
colorDepth = 8;
palSize = 7;
// get closest match to transparent color if specified
if (transparent != Color.Empty)
{
transIndex = FindClosest(transparent);
}
}
/**
* Analyzes image colors and creates color map.
*/
protected void AnalyzePixels()
{
int len = pixels.Length;
int nPix = len / 3;
indexedPixels = new byte[nPix];
NeuQuant nq = new NeuQuant(pixels, len, sample);
// initialize quantizer
colorTab = nq.Process(); // create reduced palette
// convert map from BGR to RGB
// for (int i = 0; i < colorTab.Length; i += 3)
// {
// byte temp = colorTab[i];
// colorTab[i] = colorTab[i + 2];
// colorTab[i + 2] = temp;
// usedEntry[i / 3] = false;
// }
// map image pixels to new palette
int k = 0;
for (int i = 0; i < nPix; i++)
{
int index =
nq.Map(pixels[k++] & 0xff,
pixels[k++] & 0xff,
pixels[k++] & 0xff);
usedEntry[index] = true;
indexedPixels[i] = (byte) index;
}
pixels = null;
colorDepth = 8;
palSize = 7;
// get closest match to transparent color if specified
if (transparent != Color.Empty )
{
transIndex = FindClosest(transparent);
}
}
private void CreatePalette(byte[] pixels, out byte[] pixelindexes, out byte[] colorpalette, out bool[] usedpalette, out int alphaindex)
{
if (this.HQMode) {
int len = pixels.Length;
int nPix = len / 3;
NeuQuant nq = new NeuQuant(pixels, len, this.PaletteSample);
pixelindexes = new byte[nPix];
usedpalette = new bool[256];
colorpalette = nq.Process(); // thy shal cast blackmagic upon us.
// map image pixels to new palette
int k = 0;
for (int i = 0; i < nPix; i++) {
int index = nq.Map(pixels[k++] & 0xff, pixels[k++] & 0xff, pixels[k++] & 0xff);
usedpalette[index] = true;
pixelindexes[i] = (byte)index;
}
} else {
GifEncoderLQ lq = new GifEncoderLQ();
colorpalette = lq.GetColorBytes();
pixelindexes = new byte[pixels.Length / 3];
usedpalette = null;
alphaindex = 0;
// map image pixels to new palette
for (int i = 0; i < pixelindexes.Length; i++) {
long leastDistance = long.MaxValue;
int result = 0;
int r = pixels[i * 3 + 2];
int g = pixels[i * 3 + 1];
int b = pixels[i * 3 + 0];
for (int index = 0; index < 256; index++) {
int ra = r - colorpalette[index * 3 + 0];
int rg = g - colorpalette[index * 3 + 1];
int rb = b - colorpalette[index * 3 + 2];
long distance = ra * ra + rg * rg + rb * rb;
// if a difference is zero, we're good because it won't get better
if (distance == 0) {
result = index;
break;
}
// if a difference is the best so far, stores it as our best candidate
if (distance < leastDistance) {
leastDistance = distance;
result = index;
}
}
pixelindexes[i] = (byte)result;
}
}
alphaindex = this.AlphaColor != Color.Empty ? this.FindClosest(this.AlphaColor, colorpalette) : 0;
}
