public void EncodeImage( Bitmap inp, Stream outs )
{
if ( inp == null ||
outs == null ) return;
int width = inp.Width;
int height = inp.Height;
if ( width < 1 || height < 1 ) return;
// !!!{{ TODO: add the encoding code here
DeflateStream ds = new BufferedDeflateStream( 16384, outs, CompressionMode.Compress, true );
// file header: [ MAGIC, width, height ]
ds.WriteByte( (byte)((MAGIC >> 24) & 0xff) );
ds.WriteByte( (byte)((MAGIC >> 16) & 0xff) );
ds.WriteByte( (byte)((MAGIC >> 8) & 0xff) );
ds.WriteByte( (byte)( MAGIC & 0xff) );
ds.WriteByte( (byte)((width >> 8) & 0xff) );
ds.WriteByte( (byte)( width & 0xff) );
ds.WriteByte( (byte)((height >> 8) & 0xff) );
ds.WriteByte( (byte)( height & 0xff) );
for ( int y = 0; y < height; y++ )
for ( int x = 0; x < width; x++ )
{
byte gr = (byte)(inp.GetPixel( x, y ).GetBrightness() * 255.0f);
ds.WriteByte( gr );
}
ds.Close();
// !!!}}
}
public void EncodeImage(Bitmap inputImage, Stream outputStream)
{
if (inputImage == null ||
outputStream == null) return;
int width = inputImage.Width;
int height = inputImage.Height;
if (width < 1 || height < 1) return;
int backgroundColor = ComputeDominantColor(inputImage);
Bitmap copyImage = new Bitmap(inputImage);
DeflateStream ds = new BufferedDeflateStream(16384, outputStream, CompressionMode.Compress, true);
try
{
// file header: [ MAGIC, width, height, dominant color ]
ds.WriteByte((byte)((MAGIC >> 24) & 0xff));
ds.WriteByte((byte)((MAGIC >> 16) & 0xff));
ds.WriteByte((byte)((MAGIC >> 8) & 0xff));
ds.WriteByte((byte)(MAGIC & 0xff));
ds.WriteByte((byte)((width >> 8) & 0xff));
ds.WriteByte((byte)(width & 0xff));
ds.WriteByte((byte)((height >> 8) & 0xff));
ds.WriteByte((byte)(height & 0xff));
// dominant color
ds.WriteByte((byte)(backgroundColor & 0x01));
// debug counters:
int totalPixels = width * height;
if (InfoEnabled)
{
Console.WriteLine("Total pixels: {0}, [{1}, {2}]", totalPixels, width, height);
}
int totalLinePixels = GetTotalLinePixels(inputImage, backgroundColor);
if (InfoEnabled)
{
Console.WriteLine("Total line pixels: {0} ({1} %)", totalLinePixels, 100.0 * totalLinePixels / totalPixels);
}
int firstLinePixels = 0;
int neighborhoodLinePixels = 0;
int totalStartPixelBits = 0;
Point previousStartingPoint = new Point();
int longestLine = 0;
List<int> lineDirections = new List<int>();
if (TraceEnabled)
{
Console.WriteLine("Encoding.");
}
for (int y = 0; y < height; y++)
{
for (int x = 0; x < width; x++)
{
int bwIntensity = BWImageHelper.GetBWPixel(copyImage, x, y);
if (IsBackground(backgroundColor, bwIntensity))
{
continue;
}
// now we have found the first unprocessed non-background pixel
if (TraceEnabled)
{
Console.WriteLine("First pixel: [{0}, {1}]", x, y);
}
BWImageHelper.SetBWPixel(copyImage, x, y, backgroundColor);
// write position of line's starting pixel
// X and Y as two-byte numbers
int diffX = x - previousStartingPoint.X;
int diffY = y - previousStartingPoint.Y;
firstLinePixels++;
int currentX = x;
int currentY = y;
previousStartingPoint.X = x;
previousStartingPoint.Y = y;
bool lineContinues = true;
int lineLength = 1;
while (lineContinues && (lineLength < 256))
//while (lineContinues)
{
lineContinues = false;
for (int directionIndex = 0; directionIndex < neighborhood.Directions.Count; directionIndex++)
{
Point direction = neighborhood.Directions[directionIndex];
int nextX = currentX + direction.X;
int nextY = currentY + direction.Y;
if (!BWImageHelper.IsInside(copyImage, nextX, nextY))
{
continue;
}
int nextIntensity = BWImageHelper.GetBWPixel(copyImage, nextX, nextY);
if (!IsBackground(backgroundColor, nextIntensity))
{
currentX = nextX;
currentY = nextY;
if (TraceEnabled)
{
Console.WriteLine("Neighbor pixel: [{0}, {1}]", nextX, nextY);
Console.WriteLine(" Direction: {0} ({1})", direction, directionIndex);
}
lineDirections.Add(directionIndex);
lineContinues = true;
neighborhoodLinePixels++;
lineLength++;
BWImageHelper.SetBWPixel(copyImage, nextX, nextY, backgroundColor);
break;
}
}
}
// store diffX and diffY as two signed 15-bit numbers in 4 bytes
// |1-bit X sign|15-bit abs(diffX)|1-bit Y sign|15-bit abs(diffY)|
// sign: 0 = positive or zero, 1 = negative
if (TraceEnabled)
{
Console.WriteLine("Diff: [{0}, {1}]", diffX, diffY);
}
// X sign
int buffer = (diffX < 0) ? 1 : 0;
// diff X
buffer <<= 15;
buffer |= Math.Abs(diffX) & 0x1fff;
// Y sign
buffer <<= 1;
buffer |= (diffY < 0) ? 1 : 0;
// diff Y
buffer <<= 15;
buffer |= Math.Abs(diffY) & 0x1fff;
ds.WriteByte((byte)((buffer >> 24) & 0xff));
ds.WriteByte((byte)((buffer >> 16) & 0xff));
ds.WriteByte((byte)((buffer >> 8) & 0xff));
ds.WriteByte((byte)(buffer & 0xff));
totalStartPixelBits += CountBits(buffer);
// write the number of following directions
ds.WriteByte((byte)((lineLength - 1) & 0xff));
// write the list of following directions
buffer = 0;
int bufferLength = 0;
foreach (int directionIndex in lineDirections)
{
buffer = (buffer << neighborhood.SignificantBits) + directionIndex;
bufferLength += neighborhood.SignificantBits;
int remainingBits = bufferLength - 8; // free space in the byte
if ((bufferLength >= 8) && (remainingBits < neighborhood.SignificantBits))
{
int writtenByte = (buffer >> remainingBits) & 0xff;
ds.WriteByte((byte)(writtenByte & 0xff));
buffer -= writtenByte << remainingBits;
bufferLength -= 8;
}
}
if (bufferLength > 0)
{
// shift the remaining bits completely to the left
// (so that the rest of the byte is filled with zeros only)
buffer <<= 8 - bufferLength;
ds.WriteByte((byte)(buffer & 0xff));
buffer = 0;
bufferLength = 0;
}
lineDirections.Clear();
longestLine = Math.Max(longestLine, lineLength);
}
}
if (InfoEnabled)
{
Console.WriteLine("Total first pixels: {0} ({1} %) ({2} %)", firstLinePixels, 100.0 * firstLinePixels / totalPixels, 100.0 * firstLinePixels / totalLinePixels);
Console.WriteLine("Total neighborhood pixels: {0} ({1} %) ({2} %)", neighborhoodLinePixels, 100.0 * neighborhoodLinePixels / totalPixels, 100.0 * neighborhoodLinePixels / totalLinePixels);
Console.WriteLine("First + neighborhood: {0}", firstLinePixels + neighborhoodLinePixels);
Console.WriteLine("Total start pixel bits: {0}", totalStartPixelBits);
Console.WriteLine("Longest line: {0}", longestLine);
Console.WriteLine();
}
}
finally
{
if (ds != null)
{
ds.Close();
}
}
}
