public static RgbValue YuvToRgb(YuvValue yuv)
{
RgbValue rgb = new RgbValue();
rgb.r = (byte)Clip(yuv.y + (91881 * yuv.v >> 16) - 179);
rgb.g = (byte)Clip(yuv.y - ((22544 * yuv.u + 46793 * yuv.v) >> 16) + 135);
rgb.b = (byte)Clip(yuv.y + (116129 * yuv.u >> 16) - 226);
return(rgb);
}
// https://stackoverflow.com/questions/1737726/how-to-perform-rgb-yuv-conversion-in-c-c
public static YuvValue RgbToYuv(RgbValue rgb)
{
YuvValue yuv = new YuvValue();
yuv.y = Clip((19595 * rgb.r + 38470 * rgb.g + 7471 * rgb.b) >> 16);
yuv.u = Clip((36962 * (rgb.b - Clip((19595 * rgb.r + 38470 * rgb.g + 7471 * rgb.b) >> 16)) >> 16) + 128);
yuv.v = Clip((46727 * (rgb.r - Clip((19595 * rgb.r + 38470 * rgb.g + 7471 * rgb.b) >> 16)) >> 16) + 128);
return(yuv);
}
/// Borrowed from Microprose: Magic The Gathering (1997)
/// (can't identify if its borrowed from somewhere else :-))
/// Buggy.
public static YuvValue RgbToYuv2(RgbValue rgb)
{
YuvValue yuv = new YuvValue();
yuv.y = (64 * rgb.g + 8 * rgb.r + 5 * rgb.b) / 28;
yuv.u = (4 * rgb.b - yuv.y + 0x400) / 2;
yuv.v = (32 * rgb.r - 8 * yuv.y + 0x1998) / 13;
return(yuv);
}
public static RgbValue YuvToRgb2(YuvValue yuv)
{
RgbValue rgb = new RgbValue();
int r = yuv.y + yuv.v + yuv.v / 2 + yuv.v / 8 - 0x333;
int b = yuv.y + yuv.u * 2 - 0x400;
int g = yuv.y * 2 - yuv.y / 4 - r / 2 - b / 4 - b / 16;
rgb.r = (byte)Clip(r / 4);
rgb.g = (byte)Clip(g / 4);
rgb.b = (byte)Clip(b / 4);
return(rgb);
}
public byte [] Compress(Image image, int iterations = 3)
{
int width = image.Width;
int height = image.Height;
YuvValue [] yuvSurface = new YuvValue[width * height];
/// RGB -> Yuv
Bitmap bitmap = new Bitmap(image);
for (int y = 0; y < height; y++)
{
for (int x = 0; x < width; x++)
{
Color color = bitmap.GetPixel(x, y);
RgbValue rgb = new RgbValue();
rgb.r = color.R;
rgb.g = color.G;
rgb.b = color.B;
yuvSurface[y * width + x] = Yuv.RgbToYuv(rgb);
}
}
/// Lerp U/V
/// Seems doesnt't affect compression ratio much...
//LerpUV(width, height, yuvSurface);
/// Extract components and align on power of 2
int alignedSize = UpperPowerOfTwo(Math.Max(width, height));
Int32[] yvalues = new Int32[alignedSize * alignedSize];
Int32[] uvalues = new Int32[alignedSize * alignedSize];
Int32[] vvalues = new Int32[alignedSize * alignedSize];
for (int y = 0; y < alignedSize; y++)
{
for (int x = 0; x < alignedSize; x++)
{
if (y >= height || x >= width)
{
yvalues[y * alignedSize + x] = -1;
uvalues[y * alignedSize + x] = -1;
vvalues[y * alignedSize + x] = -1;
}
else
{
yvalues[y * alignedSize + x] = yuvSurface[y * width + x].y;
uvalues[y * alignedSize + x] = yuvSurface[y * width + x].u;
vvalues[y * alignedSize + x] = yuvSurface[y * width + x].v;
}
}
}
/// Adjust border pixels by last color, to avoid edge glitching
if ((width & 1) != 0)
{
for (int y = 0; y < height; y++)
{
yvalues[y * alignedSize + width] = yvalues[y * alignedSize + width - 1];
uvalues[y * alignedSize + width] = uvalues[y * alignedSize + width - 1];
vvalues[y * alignedSize + width] = vvalues[y * alignedSize + width - 1];
}
}
if ((height & 1) != 0)
{
for (int x = 0; x < width; x++)
{
yvalues[height * alignedSize + x] = yvalues[(height - 1) * alignedSize + x];
uvalues[height * alignedSize + x] = uvalues[(height - 1) * alignedSize + x];
vvalues[height * alignedSize + x] = vvalues[(height - 1) * alignedSize + x];
}
}
/// Wavelet
Wavelet.FWT(yvalues, alignedSize, alignedSize, iterations);
Wavelet.FWT(uvalues, alignedSize, alignedSize, iterations);
Wavelet.FWT(vvalues, alignedSize, alignedSize, iterations);
/// Gzip
byte[] ycomp = Gzip.Compress(ToByteArray(yvalues));
byte[] ucomp = Gzip.Compress(ToByteArray(uvalues));
byte[] vcomp = Gzip.Compress(ToByteArray(vvalues));
/// Header
Int32[] header = new Int32[8];
header[0] = alignedSize;
header[1] = width;
header[2] = height;
header[3] = iterations;
header[4] = ycomp.Length;
header[5] = ucomp.Length;
header[6] = vcomp.Length;
header[7] = WayaSignature;
/// Waya Image
byte[] headerByte = ToByteArray(header);
byte[] waveImage = new byte[headerByte.Length + ycomp.Length + ucomp.Length + vcomp.Length];
headerByte.CopyTo(waveImage, 0);
ycomp.CopyTo(waveImage, headerByte.Length);
ucomp.CopyTo(waveImage, headerByte.Length + ycomp.Length);
vcomp.CopyTo(waveImage, headerByte.Length + ycomp.Length + ucomp.Length);
return(waveImage);
}
public Image Decompress(byte [] data)
{
byte[] headerByte = new byte[8 * 4];
Array.Copy(data, 0, headerByte, 0, headerByte.Length);
Int32[] header = ToIntArray(headerByte);
int alignedSize = header[0];
int width = header[1];
int height = header[2];
int iterations = header[3];
int ycompSize = header[4];
int ucompSize = header[5];
int vcompSize = header[6];
int signature = header[7];
if (signature != WayaSignature)
{
return(null);
}
Bitmap bitmap = new Bitmap(width, height);
YuvValue[] yuvSurface = new YuvValue[width * height];
byte[] ycomp = new byte[ycompSize];
byte[] ucomp = new byte[ucompSize];
byte[] vcomp = new byte[vcompSize];
Array.Copy(data, headerByte.Length, ycomp, 0, ycompSize);
Array.Copy(data, headerByte.Length + ycompSize, ucomp, 0, ucompSize);
Array.Copy(data, headerByte.Length + ycompSize + ucompSize, vcomp, 0, vcompSize);
/// Gzip
Int32[] yvalues = ToIntArray(Gzip.Decompress(ycomp));
Int32[] uvalues = ToIntArray(Gzip.Decompress(ucomp));
Int32[] vvalues = ToIntArray(Gzip.Decompress(vcomp));
/// Wavelet
Wavelet.IWT(yvalues, alignedSize, alignedSize, iterations);
Wavelet.IWT(uvalues, alignedSize, alignedSize, iterations);
Wavelet.IWT(vvalues, alignedSize, alignedSize, iterations);
/// Extract components
for (int y = 0; y < height; y++)
{
for (int x = 0; x < width; x++)
{
yuvSurface[y * width + x] = new YuvValue();
yuvSurface[y * width + x].y = yvalues[y * alignedSize + x];
yuvSurface[y * width + x].u = uvalues[y * alignedSize + x];
yuvSurface[y * width + x].v = vvalues[y * alignedSize + x];
}
}
/// Yuv -> RGB
for (int y = 0; y < height; y++)
{
for (int x = 0; x < width; x++)
{
RgbValue rgb = Yuv.YuvToRgb(yuvSurface[y * width + x]);
Color color = Color.FromArgb(rgb.r, rgb.g, rgb.b);
bitmap.SetPixel(x, y, color);
}
}
return(bitmap);
}