static SignedColor CalculateError(SignedColor delta, int x, int y, DitherPattern pattern)
{
if (y == 0)
{
x--;
}
else
{
x -= pattern.KernelMinX;
}
int mul = pattern.Kernel[y][x];
if (mul == 0)
{
return(new SignedColor());
}
else
{
int div = pattern.Divisor;
SignedColor c = new SignedColor();
c.R = (delta.R * mul) / div;
c.G = (delta.G * mul) / div;
c.B = (delta.B * mul) / div;
c.A = (delta.A * mul) / div;
return(c);
}
}
public Color Dither(int x, int y, Color c, DitherPattern pattern)
{
// Get the existing error at this pixel
SignedColor e = GetError(x, y);
// Get the quantized color
Color q = QuantizeColor(c, e);
// Calculate the difference
SignedColor delta = Diff(c, q);
// Kernel may be zero size (so we should ignore it)
if (pattern.KernelHeight > 0)
{
// First row handled differently
for (int i = 1; i <= pattern.KernelMaxX; ++i)
{
AddError(x + i, y, CalculateError(delta, i, 0, pattern));
}
// Process subsequent rows
for (int j = 1; j < pattern.KernelHeight; ++j)
{
for (int i = pattern.KernelMinX; i <= pattern.KernelMaxX; ++i)
{
AddError(x + i, y + j, CalculateError(delta, i, j, pattern));
}
}
}
_totalError += delta.RGBError;
return(q);
}
static float DitherOneImage(Bitmap srcData, Bitmap dstData, DitherPattern pattern, Color transparentColorKey)
{
Ditherer ditherer = new Ditherer(srcData.Width, srcData.Height);
for (int x = 0; x < srcData.Width; x++)
{
for (int y = 0; y < srcData.Height; y++)
{
Color c = srcData.GetPixel(x, y);
if (c == transparentColorKey || c.A == 0)
{
dstData.SetPixel(x, y, Color.FromArgb(0));
}
else
{
dstData.SetPixel(x, y, ditherer.Dither(x, y, c, pattern));
}
}
}
return(ditherer.RootMeanSquaredError);
}
public static bool OrderedDither(Bitmap bmp, DitherPattern dp, ErrorDiffusion ed,
bool fStretch, Color dark, Color bright, out Bitmap bmp1)
{
bmp1 = null;
if (bmp.PixelFormat != PixelFormat.Format24bppRgb)
return false;
int w = bmp.Width;
int h = bmp.Height;
Bitmap tmp = (Bitmap)bmp.Clone();
ImageUtils.GrayScale(ref tmp);
if (fStretch) ImageUtils.HistoStretch(ref tmp);
byte[,] od22 = { { 51, 204},
{153, 102} };
byte[,] od33 = { {131, 182, 105},
{157, 236, 26},
{ 79, 210, 52} };
byte[,] od332 = { { 64, 128, 64},
{128, 196, 128},
{ 64, 128, 64} };
byte[,] od44 = { { 15, 195, 60, 240},
{135, 75, 180, 120},
{ 45, 225, 30, 210},
{165, 105, 150, 90} };
byte[,] od442 = { { 51, 102, 204, 153},
{ 204, 153, 51, 102},
{ 153, 204, 102, 51},
{ 102, 51, 153, 204} };
byte[,] od443 = { { 51, 102, 204, 153},
{ 204, 153, 51, 102},
{ 102, 51, 153, 204},
{ 153, 204, 102, 51} };
byte[,] msk = od22;
switch (dp)
{
case DitherPattern.od22: msk = od22; break;
case DitherPattern.od33: msk = od33; break;
case DitherPattern.od332: msk = od332; break;
case DitherPattern.od44: msk = od44; break;
case DitherPattern.od442: msk = od442; break;
case DitherPattern.od443: msk = od443; break;
}
double[,] fs = { { -1, -1, 7.0/16.0},
{ 3.0/16.0, 5.0/16.0, 1.0/16.0} };
double[,] st = { {-1, -1, -1, 8.0/42.0, 4.0/42.0},
{2.0/42.0, 4.0/42.0, 8.0/42.0, 4.0/42.0, 2.0/42.0},
{1.0/42.0, 2.0/42.0, 4.0/42.0, 2.0/42.0, 1.0/42.0} };
double[,] sr = { {-1, -1, -1, 5.0/32.0, 3.0/32.0},
{2.0/32.0, 4.0/32.0, 5.0/32.0, 4.0/32.0, 2.0/32.0},
{-1, 2.0/32.0, 3.0/32.0, 2.0/32.0, -1} };
double[,] jjn = { {-1, -1, -1, 7.0/48.0, 5.0/48.0},
{3.0/48.0, 5.0/48.0, 7.0/48.0, 5.0/48.0, 3.0/48.0},
{1.0/48.0, 3.0/48.0, 5.0/48.0, 3.0/48.0, 1.0/48.0} };
double[,] df = st;
switch (ed)
{
case ErrorDiffusion.FloydSteinberg: df = fs; break;
case ErrorDiffusion.Stucci: df = st; break;
case ErrorDiffusion.Sierra: df = sr; break;
case ErrorDiffusion.JaJuNi: df = jjn; break;
}
byte d8;
bool d;
double err;
int xx, yy;
int row = df.GetLength(0);
int col = df.GetLength(1);
int xrange = (col - 1) / 2;
bmp1 = new Bitmap(w, h, PixelFormat.Format1bppIndexed);
int dm = msk.GetLength(0);
BmpProc8 src = new BmpProc8(tmp);
BmpProc1 dst = new BmpProc1(bmp1);
for (int y = 0; y < h; y++)
for (int x = 0; x < w; x++)
{
d8 = src[x, y];
d = (d8 > msk[y % dm, x % dm]);
dst[x, y] = d;
if (d) { err = d8 - 255; } else { err = d8; }
for (int iy = 0; iy < row; iy++)
for (int ix = -xrange; ix <= xrange; ix++)
{
xx = x + ix; if ((xx < 0) | (xx > w - 1)) continue;
yy = y + iy; if (yy > h - 1) continue;
if (df[iy, ix + xrange] < 0) continue;
src[xx, yy] = ImageUtils.AdjustByte(src[xx, yy] +
err * df[iy, ix + xrange]);
}
}
CallDispose(dst, src, tmp);
ColorPalette cp = bmp1.Palette;
cp.Entries[0] = dark;
cp.Entries[1] = bright;
bmp1.Palette = cp;
return true;
}
