public void Init()
{
this.WidthInBlocks = (int)MathF.Ceiling(
MathF.Ceiling(this.Frame.SamplesPerLine / 8F) * this.HorizontalSamplingFactor / this.Frame.MaxHorizontalFactor);
this.HeightInBlocks = (int)MathF.Ceiling(
MathF.Ceiling(this.Frame.Scanlines / 8F) * this.VerticalSamplingFactor / this.Frame.MaxVerticalFactor);
int blocksPerLineForMcu = this.Frame.McusPerLine * this.HorizontalSamplingFactor;
int blocksPerColumnForMcu = this.Frame.McusPerColumn * this.VerticalSamplingFactor;
this.SizeInBlocks = new Size(blocksPerLineForMcu, blocksPerColumnForMcu);
JpegComponent c0 = this.Frame.Components[0];
this.SubSamplingDivisors = c0.SamplingFactors.DivideBy(this.SamplingFactors);
if (this.SubSamplingDivisors.Width == 0 || this.SubSamplingDivisors.Height == 0)
{
JpegThrowHelper.ThrowBadSampling();
}
int totalNumberOfBlocks = blocksPerColumnForMcu * (blocksPerLineForMcu + 1);
int width = this.WidthInBlocks + 1;
int height = totalNumberOfBlocks / width;
this.SpectralBlocks = this.memoryAllocator.Allocate2D <Block8x8>(width, height, AllocationOptions.Clean);
}
public void Init()
{
this.WidthInBlocks = (int)MathF.Ceiling(
MathF.Ceiling(this.Frame.SamplesPerLine / 8F) * this.HorizontalSamplingFactor / this.Frame.MaxHorizontalFactor);
this.HeightInBlocks = (int)MathF.Ceiling(
MathF.Ceiling(this.Frame.Scanlines / 8F) * this.VerticalSamplingFactor / this.Frame.MaxVerticalFactor);
int blocksPerLineForMcu = this.Frame.McusPerLine * this.HorizontalSamplingFactor;
int blocksPerColumnForMcu = this.Frame.McusPerColumn * this.VerticalSamplingFactor;
this.SizeInBlocks = new Size(blocksPerLineForMcu, blocksPerColumnForMcu);
// For 4-component images (either CMYK or YCbCrK), we only support two
// hv vectors: [0x11 0x11 0x11 0x11] and [0x22 0x11 0x11 0x22].
// Theoretically, 4-component JPEG images could mix and match hv values
// but in practice, those two combinations are the only ones in use,
// and it simplifies the applyBlack code below if we can assume that:
// - for CMYK, the C and K channels have full samples, and if the M
// and Y channels subsample, they subsample both horizontally and
// vertically.
// - for YCbCrK, the Y and K channels have full samples.
if (this.Index == 0 || this.Index == 3)
{
this.SubSamplingDivisors = new Size(1, 1);
}
else
{
JpegComponent c0 = this.Frame.Components[0];
this.SubSamplingDivisors = c0.SamplingFactors.DivideBy(this.SamplingFactors);
}
this.SpectralBlocks = this.memoryAllocator.Allocate2D <Block8x8>(blocksPerColumnForMcu, blocksPerLineForMcu + 1, AllocationOptions.Clean);
}
public void AllocateComponents(bool fullScan)
{
for (int i = 0; i < this.ComponentCount; i++)
{
JpegComponent component = this.Components[i];
component.AllocateSpectral(fullScan);
}
}
/// <summary>
/// Allocates the frame component blocks.
/// </summary>
public void InitComponents()
{
this.McusPerLine = (int)MathF.Ceiling(this.SamplesPerLine / 8F / this.MaxHorizontalFactor);
this.McusPerColumn = (int)MathF.Ceiling(this.Scanlines / 8F / this.MaxVerticalFactor);
for (int i = 0; i < this.ComponentCount; i++)
{
JpegComponent component = this.Components[i];
component.Init();
}
}
/// <summary>
/// Allocates the frame component blocks.
/// </summary>
/// <param name="maxSubFactorH">Maximal horizontal subsampling factor among all the components.</param>
/// <param name="maxSubFactorV">Maximal vertical subsampling factor among all the components.</param>
public void Init(int maxSubFactorH, int maxSubFactorV)
{
this.McusPerLine = (int)Numerics.DivideCeil((uint)this.PixelWidth, (uint)maxSubFactorH * 8);
this.McusPerColumn = (int)Numerics.DivideCeil((uint)this.PixelHeight, (uint)maxSubFactorV * 8);
for (int i = 0; i < this.ComponentCount; i++)
{
JpegComponent component = this.Components[i];
component.Init(maxSubFactorH, maxSubFactorV);
}
}
private void ParseBaselineDataInterleaved()
{
// Interleaved
int mcu = 0;
int mcusPerColumn = this.frame.McusPerColumn;
int mcusPerLine = this.frame.McusPerLine;
for (int j = 0; j < mcusPerColumn; j++)
{
for (int i = 0; i < mcusPerLine; i++)
{
// Scan an interleaved mcu... process components in order
for (int k = 0; k < this.componentsLength; k++)
{
int order = this.frame.ComponentOrder[k];
JpegComponent component = this.components[order];
ref HuffmanTable dcHuffmanTable = ref this.dcHuffmanTables[component.DCHuffmanTableId];
ref HuffmanTable acHuffmanTable = ref this.acHuffmanTables[component.ACHuffmanTableId];
ref short fastACRef = ref this.fastACTables.GetAcTableReference(component);
int h = component.HorizontalSamplingFactor;
int v = component.VerticalSamplingFactor;
int mcuRow = mcu / mcusPerLine;
// Scan out an mcu's worth of this component; that's just determined
// by the basic H and V specified for the component
for (int y = 0; y < v; y++)
{
int blockRow = (mcuRow * v) + y;
Span <Block8x8> blockSpan = component.SpectralBlocks.GetRowSpan(blockRow);
for (int x = 0; x < h; x++)
{
if (this.eof)
{
return;
}
int mcuCol = mcu % mcusPerLine;
int blockCol = (mcuCol * h) + x;
this.DecodeBlockBaseline(
component,
ref blockSpan[blockCol],
ref dcHuffmanTable,
ref acHuffmanTable,
ref fastACRef);
}
}
}
private unsafe void ParseBaselineDataInterleaved()
{
// Interleaved
int mcu = 0;
int mcusPerColumn = this.frame.McusPerColumn;
int mcusPerLine = this.frame.McusPerLine;
// Pre-derive the huffman table to avoid in-loop checks.
for (int i = 0; i < this.componentsLength; i++)
{
int order = this.frame.ComponentOrder[i];
JpegComponent component = this.components[order];
ref HuffmanTable dcHuffmanTable = ref this.dcHuffmanTables[component.DCHuffmanTableId];
ref HuffmanTable acHuffmanTable = ref this.acHuffmanTables[component.ACHuffmanTableId];
public ref short GetAcTableReference(JpegComponent component)
{
return(ref this.tables.GetRowSpan(component.ACHuffmanTableId)[0]);
}
