static byte FindClosestColor(Vector3f col)
{
byte closest = 0;
float closestError = float.MaxValue;
for (var i = 0; i < palVec.Length; i++)
{
var dr = col.R - palVec[i].R;
var dg = col.G - palVec[i].G;
var db = col.B - palVec[i].B;
var error = dr * dr + dg * dg + db * db;
if (error < closestError)
{
closestError = error;
closest = (byte)i;
}
}
return closest;
}
static void Main(string[] args)
{
var palette = new Image("palette.png");
palVec = new Vector3f[256];
for (uint x = 0; x < palVec.Length; x++)
{
palVec[x] = (Vector3f)palette.GetPixel(x, 0);
}
var image = new Image("test.png");
var imgVec = new Vector3f[image.Size.X, image.Size.Y];
var imgRes = new byte[image.Size.X, image.Size.Y];
for (uint y = 0; y < image.Size.Y; y++)
{
for (uint x = 0; x < image.Size.X; x++)
{
imgVec[x, y] = (Vector3f)image.GetPixel(x, y);
}
}
for (uint y = 0; y < image.Size.Y; y++)
{
for (uint x = 0; x < image.Size.X; x++)
{
if (x == 0 || y == 0 || x == image.Size.X - 1 || y == image.Size.Y - 1)
{
imgRes[x, y] = FindClosestColor(imgVec[x, y]);
continue;
}
var oldPix = imgVec[x, y];
var newCol = FindClosestColor(oldPix);
var newPix = palVec[newCol];
var error = oldPix - newPix;
imgRes[x, y] = newCol;
imgVec[x + 1, y + 0] += error * (7.0f / 16.0f);
imgVec[x - 1, y + 1] += error * (3.0f / 16.0f);
imgVec[x + 0, y + 1] += error * (5.0f / 16.0f);
imgVec[x + 1, y + 1] += error * (1.0f / 16.0f);
}
}
for (uint y = 0; y < image.Size.Y; y++)
{
for (uint x = 0; x < image.Size.X; x++)
{
image.SetPixel(x, y, (Color)palVec[imgRes[x, y]]);
}
}
image.SaveToFile("out.png");
var o = File.OpenWrite("out.pic");
for (uint y = 0; y < image.Size.Y; y++)
{
for (uint x = 0; x < image.Size.X; x++)
{
o.WriteByte(imgRes[x, y]);
}
}
o.Dispose();
}