/// <summary>
/// Initializes static members of the <see cref="JpegEncoderCore"/> class.
/// </summary>
static JpegEncoderCore()
{
// Initialize the Huffman tables
for (int i = 0; i < TheHuffmanSpecs.Length; i++)
{
TheHuffmanLut[i] = new HuffmanLut(TheHuffmanSpecs[i]);
}
}
/// <summary>
/// Initializes static members of the <see cref="HuffmanLut"/> struct.
/// </summary>
static HuffmanLut()
{
// Initialize the Huffman tables
for (int i = 0; i < HuffmanSpec.TheHuffmanSpecs.Length; i++)
{
TheHuffmanLut[i] = new HuffmanLut(HuffmanSpec.TheHuffmanSpecs[i]);
}
}
public void Encode(ImageBase image, Stream stream, int quality, JpegSubsample sample)
{
if (image == null || stream == null){
throw new ArgumentNullException();
}
ushort max = JpegConstants.MaxLength;
if (image.Width >= max || image.Height >= max){
throw new Exception($"Image is too large to encode at {image.Width}x{image.Height}.");
}
outputStream = stream;
subsample = sample;
for (int i = 0; i < theHuffmanSpec.Length; i++){
theHuffmanLut[i] = new HuffmanLut(theHuffmanSpec[i]);
}
for (int i = 0; i < nQuantIndex; i++){
quant[i] = new byte[Block.blockSize];
}
if (quality < 1){
quality = 1;
}
if (quality > 100){
quality = 100;
}
int scale;
if (quality < 50){
scale = 5000/quality;
} else{
scale = 200 - quality*2;
}
for (int i = 0; i < nQuantIndex; i++){
for (int j = 0; j < Block.blockSize; j++){
int x = unscaledQuant[i, j];
x = (x*scale + 50)/100;
if (x < 1){
x = 1;
}
if (x > 255){
x = 255;
}
quant[i][j] = (byte) x;
}
}
int componentCount = 3;
double densityX = ((Image2) image).HorizontalResolution;
double densityY = ((Image2) image).VerticalResolution;
WriteApplicationHeader((short) densityX, (short) densityY);
WriteDqt();
WriteSof0(image.Width, image.Height, componentCount);
WriteDht(componentCount);
using (IPixelAccessor pixels = image.Lock()){
WriteSos(pixels);
}
buffer[0] = 0xff;
buffer[1] = 0xd9;
stream.Write(buffer, 0, 2);
stream.Flush();
}
public void Encode(ImageBase image, Stream stream, int quality, JpegSubsample sample)
{
if (image == null || stream == null){
throw new ArgumentNullException();
}
ushort max = JpegConstants.MaxLength;
if (image.Width >= max || image.Height >= max){
throw new Exception($"Image is too large to encode at {image.Width}x{image.Height}.");
}
outputStream = stream;
subsample = sample;
for (int i = 0; i < theHuffmanSpec.Length; i++){
theHuffmanLut[i] = new HuffmanLut(theHuffmanSpec[i]);
}
for (int i = 0; i < nQuantIndex; i++){
quant[i] = new byte[Block.blockSize];
}
if (quality < 1){
quality = 1;
}
if (quality > 100){
quality = 100;
}
int scale;
if (quality < 50){
scale = 5000/quality;
} else{
scale = 200 - quality*2;
}
for (int i = 0; i < nQuantIndex; i++){
for (int j = 0; j < Block.blockSize; j++){
int x = unscaledQuant[i, j];
x = (x*scale + 50)/100;
if (x < 1){
x = 1;
}
if (x > 255){
x = 255;
}
quant[i][j] = (byte) x;
}
}
int componentCount = 3;
double densityX = ((Image2) image).HorizontalResolution;
double densityY = ((Image2) image).VerticalResolution;
WriteApplicationHeader((short) densityX, (short) densityY);
WriteDqt();
WriteSof0(image.Width, image.Height, componentCount);
WriteDht(componentCount);
using (IPixelAccessor pixels = image.Lock()){
WriteSos(pixels);
}
buffer[0] = 0xff;
buffer[1] = 0xd9;
stream.Write(buffer, 0, 2);
stream.Flush();
}
