public static void CompressData(int[,] dataMatrix, BitWriter writer)
{
// Write compressed file variables
ArithmeticCoder coder = new ArithmeticCoder(writer);
var size = (int)Math.Sqrt(dataMatrix.Length);
for (int i = 0; i < size; i++)
{
for (int j = 0; j < size; j++)
{
uint symbol = (uint)(dataMatrix[i, j] + 255);
// For each symbol and update the model statistics
coder.EncodeSymbol(symbol);
coder.arithmeticModel.UpdateModel(symbol);
}
}
coder.EncodeSymbol(EOF);
coder.FlushEncoder();
writer.WriteNBits(1, 7);
writer.Dispose();
}
private void btnSaveEncodedImage_Click(object sender, EventArgs e)
{
try
{
var headerBmpFile = bmpObject.GetBmpHeader();
var compressedDataMatrix = nlEngine.GetErrorPredictedQuantizedMatrix();
var dataMatrixSize = (int)Math.Sqrt(compressedDataMatrix.Length);
var compressedFileName = Path.GetFileNameWithoutExtension(inputFilePathEncoder);
var fileExtension = ".k" + userKMaxReconstructionError + "p" + userPredictorSelection;
if (userKMaxReconstructionError != numericUpDownKValue.Value)
{
throw new NullReferenceException();
}
if (userPredictorSelection != comboBoxPredictorSelection.SelectedIndex)
{
throw new NullReferenceException();
}
if (String.IsNullOrEmpty(compressedFileName) || isFileEncoded == false)
{
throw new NullReferenceException();
}
using (var fbd = new FolderBrowserDialog())
{
var result = fbd.ShowDialog();
if (result == DialogResult.OK && !string.IsNullOrWhiteSpace(fbd.SelectedPath))
{
var compressedFilePath = fbd.SelectedPath;
switch (comboBoxSaveMode.SelectedIndex)
{
case 0: // Fixed Saving Mode (F)
{
fileExtension += "F.nlp";
compressedFilePath += "\\" + compressedFileName + fileExtension;
// Building the bmp compressed file format
BitWriter writer = new BitWriter(compressedFilePath);
// [1-F] writing the specific header byte by byte
for (int i = 0; i < headerBmpFile.Length; i++)
{
writer.WriteNBits(headerBmpFile[i], 8);
}
// [2-F] writing the predictor used (on 4 bits)
writer.WriteNBits((uint)userPredictorSelection, 4);
// [3-F] writing the k value used (on 4 bits)
writer.WriteNBits((uint)userKMaxReconstructionError, 4);
// [4-F] writing the save mode used (on 2 bits)
writer.WriteNBits((uint)comboBoxSaveMode.SelectedIndex, 2);
// [5-F] writing bmp data matrix elements (on 9 bits each)
for (int i = 0; i < dataMatrixSize; i++)
{
for (int j = 0; j < dataMatrixSize; j++)
{
writer.WriteNBits((uint)compressedDataMatrix[i, j] + 255, 9);
}
}
writer.WriteNBits(1, 7);
writer.Dispose();
break;
}
case 1: // Jpeg Table Saving Mode (T)
{
fileExtension += "T.nlp";
compressedFilePath += "\\" + compressedFileName + fileExtension;
// Building the bmp compressed file format
BitWriter writer = new BitWriter(compressedFilePath);
// [1-T] writing the specific header byte by byte
for (int i = 0; i < headerBmpFile.Length; i++)
{
writer.WriteNBits(headerBmpFile[i], 8);
}
// [2-T] writing the predictor used (on 4 bits)
writer.WriteNBits((uint)userPredictorSelection, 4);
// [3-T] writing the k value used (on 4 bits)
writer.WriteNBits((uint)userKMaxReconstructionError, 4);
// [4-T] writing the save mode used (on 2 bits)
writer.WriteNBits((uint)comboBoxSaveMode.SelectedIndex, 2);
// [5-T] writing bmp data matrix elements encoded with JPEG Table
for (int i = 0; i < dataMatrixSize; i++)
{
for (int j = 0; j < dataMatrixSize; j++)
{
Helpers.WriteValueUsingJPEGTable(writer, compressedDataMatrix[i, j]);
}
}
writer.WriteNBits(1, 7);
writer.Dispose();
break;
}
case 2: // Arithmetic Saving Mode (Entropic Coder) (A)
{
fileExtension += "A.nlp";
compressedFilePath += "\\" + compressedFileName + fileExtension;
// Building the bmp compressed file format
BitWriter writer = new BitWriter(compressedFilePath);
// [1-A] writing the specific header byte by byte
for (int i = 0; i < headerBmpFile.Length; i++)
{
writer.WriteNBits(headerBmpFile[i], 8);
}
// [2-A] writing the predictor used (on 4 bits)
writer.WriteNBits((uint)userPredictorSelection, 4);
// [3-A] writing the k value used (on 4 bits)
writer.WriteNBits((uint)userKMaxReconstructionError, 4);
// [4-A] writing the save mode used (on 2 bits)
writer.WriteNBits((uint)comboBoxSaveMode.SelectedIndex, 2);
// [5-A] writing bmp data matrix elements encoded with Arithmetic CODER
ArithmeticCoder.CompressData(compressedDataMatrix, writer);
break;
}
default: break;
}
}
}
isFileEncoded = false;
MessageBox.Show("Encoded image succesfully saved!");
}
catch (NullReferenceException)
{
MessageBox.Show("Warning: You forgot to load/encode the image. (Other causes: encoding settings are changed)");
}
}
