/// <summary>
/// 誤差拡散しつつ減色
/// </summary>
/// <param name="bmp"></param>
/// <returns>変換結果</returns>
private BlockColor[,] Convert(Bitmap bmp)
{
using (var accessor = new BitmapAccessor((Bitmap)bmp.Clone()))
{
var w = bmp.Width;
var h = bmp.Height;
var result = new BlockColor[w, h];
int[][] ditherData = { new int[w * 3], new int[w * 3] };
for (var y = 0; y < h; y++)
{
// Recycle
var shift = ditherData[0];
Array.Copy(ditherData, 1, ditherData, 0, ditherData.Length - 1);
for (var i = 0; i < shift.Length; i++)
{
shift[i] = 0;
}
ditherData[ditherData.Length - 1] = shift;
for (var x = 0; x < w; x++)
{
var color = accessor.GetPixel(x, y);
var r = Math.Max(0, Math.Min(255, color.R + ditherData[0][x * 3 + 0]));
var g = Math.Max(0, Math.Min(255, color.G + ditherData[0][x * 3 + 1]));
var b = Math.Max(0, Math.Min(255, color.B + ditherData[0][x * 3 + 2]));
var nearestMatch = FindNearest(r, g, b);
result[x, y] = nearestMatch;
bmp.SetPixel(x, y, Color.FromArgb(nearestMatch.R, nearestMatch.G, nearestMatch.B));
var rDiff = r - nearestMatch.R;
var gDiff = g - nearestMatch.G;
var bDiff = b - nearestMatch.B;
for (var k = 0; k < DitherX.Length; k++)
{
var tmpX = DitherX[k] + x;
var tmpY = DitherY[k];
if ((tmpY < h) && (tmpX < w) && (tmpX > 0))
{
ditherData[tmpY][tmpX * 3 + 0] += (int)Math.Floor(DitherErr[k] * rDiff);
ditherData[tmpY][tmpX * 3 + 1] += (int)Math.Floor(DitherErr[k] * gDiff);
ditherData[tmpY][tmpX * 3 + 2] += (int)Math.Floor(DitherErr[k] * bDiff);
}
}
}
convertFile.Complete++;
}
return(result);
}
}
/// <summary>
/// 最も近い色を持つ BlockColor を返す
/// </summary>
/// <param name="r">R</param>
/// <param name="g">G</param>
/// <param name="b">B</param>
/// <returns>BlockColor</returns>
private BlockColor FindNearest(int r, int g, int b)
{
var bestDiff = double.MaxValue;
var bestMatch = new BlockColor();
double diff;
foreach (var block in blockColors)
{
var rDiff = block.R - r;
var gDiff = block.G - g;
var bDiff = block.B - b;
if ((diff = Math.Sqrt(rDiff * rDiff + gDiff * gDiff + bDiff * bDiff)) < bestDiff)
{
bestDiff = diff;
bestMatch = block;
}
}
return(bestMatch);
}
/// <summary>
/// 近似色のみで減色
/// </summary>
/// <param name="bmp"></param>
/// <returns>変換結果</returns>
private BlockColor[,] Convert(Bitmap bmp)
{
using (var accessor = new BitmapAccessor((Bitmap)bmp.Clone()))
{
var w = bmp.Width;
var h = bmp.Height;
var result = new BlockColor[w, h];
int[][] ditherData = { new int[w * 3], new int[w * 3] };
for (var y = 0; y < h; y++)
{
// Recycle
var shift = ditherData[0];
Array.Copy(ditherData, 1, ditherData, 0, ditherData.Length - 1);
for (var i = 0; i < shift.Length; i++)
{
shift[i] = 0;
}
ditherData[ditherData.Length - 1] = shift;
for (var x = 0; x < w; x++)
{
var color = accessor.GetPixel(x, y);
var nearestMatch = FindNearest(color.R, color.G, color.B);
result[x, y] = nearestMatch;
bmp.SetPixel(x, y, Color.FromArgb(nearestMatch.R, nearestMatch.G, nearestMatch.B));
}
convertFile.Complete++;
}
return(result);
}
}