// Converts the specified image into an AllRGB version by looping
// randomly through the source pixels and choosing the 'nearest'
// remaining color to map it to. The number of color bits per channel
// used dictates the size of the output image ([image]_allRGBv2.png).
// Uses the specified color space for coordinate locations.
static void allRGBify(string path, string maskPath, int bitsPerChannel, ColorSpace cs)
{
if ((bitsPerChannel & 1) != 0) {
Console.Out.WriteLine("bitsPerChannel must be divisible by 2");
return;
} else if (bitsPerChannel > 8) {
Console.Out.WriteLine("Only up to 8 bits per channel are supported");
return;
}
DateTime startTime = DateTime.Now;
// imageSize = 2^(3*bitsPerChannel/2)
int imageSize = 1 << (3 * bitsPerChannel >> 1);
int numPixels = imageSize * imageSize;
Bitmap bitmap = new Bitmap(Image.FromFile(path), imageSize, imageSize);
BitmapData bitmapData = bitmap.LockBits(
new Rectangle(0, 0, imageSize, imageSize),
ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb);
// Load the raw pixel data, BGRBGRBGR..... Note that it may contain
// padding at the end of rows; need to be very careful when indexing!
int pixelBytes = bitmapData.Stride * bitmapData.Height;
Debug.Assert(pixelBytes >= numPixels * 3);
byte[] pixels = new byte[pixelBytes];
System.Runtime.InteropServices.Marshal.Copy(
bitmapData.Scan0, pixels, 0, pixelBytes);
// If available, load the pixel mask as well
// True is high priority, false is low.
bool[,] maskFlags = new bool[imageSize, imageSize];
if (maskPath != null && maskPath != "") {
Bitmap mask = new Bitmap(Image.FromFile(maskPath), imageSize, imageSize);
for (int y = 0; y < imageSize; ++y) {
for (int x = 0; x < imageSize; ++x) {
if (mask.GetPixel(x, y).R == 0) {
maskFlags[y, x] = true;
}
}
}
}
// Set up error diffusion, if it is turned on. At the same time,
// calculate the average color of the image for the initial error
// term.
float[, ,] pixelError = null; // To be added to the corresponding
// pixel's color to get the target
// color for lookup.
// Note: Order is y,x,{R,G,B}.
bool[,] donePixels = null;
if (USE_ERROR_DIFFUSION) {
donePixels = new bool[imageSize, imageSize];
pixelError = new float[imageSize, imageSize, 3];
initializeErrorDiffusion(pixelError, pixels, bitmapData.Stride, imageSize);
}
// A random ordering of the pixels to process.
Pair<int, int>[] coords = getRandomPixelOrdering(maskFlags, imageSize, imageSize);
// A KDTree of all the candidate colors the pixels can be mapped to.
// We periodically need to rebuild this tree to keep it from getting
// unbalanced.
KDTree kd = buildKDTreeOfColors(bitsPerChannel, cs);
int pixelsTillRebuild = coords.Length * 1 / 4;
pixelsTillRebuild = Math.Min(pixelsTillRebuild, 1 << 19);
// Actually look up the colours, writing back to the pixel array as
// we go.
for (int i = 0; i < coords.Length; ++i) {
if ((i & ((1 << 7) - 1)) == 0) {
Console.Out.WriteLine("Done " + i + " pixels");
// If 'r' is caught, rebuild spatial index immediately.
if (Console.KeyAvailable) {
ConsoleKeyInfo key = Console.ReadKey(true);
switch (key.KeyChar) {
case 'r':
pixelsTillRebuild = 0;
break;
default:
break;
}
}
}
if (pixelsTillRebuild == 0) {
rebuildKDTree(ref kd);
pixelsTillRebuild = Math.Max((coords.Length - i) * 1 / 4, 1000);
pixelsTillRebuild = Math.Min(pixelsTillRebuild, 1 << 19);
}
pixelsTillRebuild--;
Pair<int, int> coord = coords[i];
int x = coord.First;
int y = coord.Second;
int pixelIndex = y * bitmapData.Stride + 3 * x;
byte oldR;
byte oldG;
byte oldb;
if (USE_ERROR_DIFFUSION) {
oldR = capToByte(pixels[pixelIndex + 2] +
pixelError[y, x, 0]);
oldG = capToByte(pixels[pixelIndex + 1] +
pixelError[y, x, 1]);
oldb = capToByte(pixels[pixelIndex + 0] +
pixelError[y, x, 2]);
} else {
oldR = pixels[pixelIndex + 2];
oldG = pixels[pixelIndex + 1];
oldb = pixels[pixelIndex + 0];
}
ColorLocation oldColor = new ColorLocation(oldR, oldG, oldb, cs);
ColorLocation newColor = (ColorLocation)kd.nearest(oldColor.Location);
kd.delete(newColor.Location);
if (USE_ERROR_DIFFUSION) {
pixelError[y, x, 0] += pixels[pixelIndex + 2] - newColor.R;
pixelError[y, x, 1] += pixels[pixelIndex + 1] - newColor.G;
pixelError[y, x, 2] += pixels[pixelIndex + 0] - newColor.B;
markPixelDoneAndSpreadError(donePixels, pixelError, imageSize, x, y);
}
pixels[pixelIndex + 2] = newColor.R;
pixels[pixelIndex + 1] = newColor.G;
pixels[pixelIndex + 0] = newColor.B;
}
// Finally, load the pixels back into the bitmap and save out.
System.Runtime.InteropServices.Marshal.Copy(pixels, 0, bitmapData.Scan0, pixelBytes);
bitmap.UnlockBits(bitmapData);
string newFileName =
Path.GetDirectoryName(path) +
Path.DirectorySeparatorChar +
Path.GetFileNameWithoutExtension(path) +
"_allRGBv2.png";
bitmap.Save(newFileName, ImageFormat.Png);
TimeSpan totalTime = DateTime.Now - startTime;
Console.Out.WriteLine("Generating " + Path.GetFileName(newFileName) +
" took " + totalTime.ToString());
}
// Build a KDTree of all the possible colors, indexed by location in the
// chosen color space. When fewer than 8 bits per pixel are used, the
// low order bits are skipped within each channel.
static KDTree buildKDTreeOfColors(int bitsPerChannel, ColorSpace cs)
{
int colorsPerChannel = 1 << bitsPerChannel;
int shift = 8 - bitsPerChannel;
ColorLocation[] colors = new ColorLocation[colorsPerChannel * colorsPerChannel * colorsPerChannel];
int colorIndex = 0;
for (int r = 0; r < colorsPerChannel; ++r) {
for (int g = 0; g < colorsPerChannel; ++g) {
for (int b = 0; b < colorsPerChannel; ++b) {
ColorLocation c = new ColorLocation((byte)(r << shift),
(byte)(g << shift),
(byte)(b << shift),
cs);
colors[colorIndex] = c;
colorIndex++;
}
}
}
colors.Shuffle();
KDTree kd = new KDTree();
for (int i = 0; i < colors.Length; ++i) {
ColorLocation c = colors[i];
kd.insert(c.Location, c);
}
colors = null;
return kd;
}
