/// <summary>
/// Decodes the raw pixel data row by row
/// </summary>
/// <typeparam name="TPixel">The pixel format.</typeparam>
/// <param name="compressedStream">The compressed pixel data stream.</param>
/// <param name="pixels">The image pixel accessor.</param>
private void DecodePixelData <TPixel>(Stream compressedStream, PixelAccessor <TPixel> pixels)
where TPixel : struct, IPixel <TPixel>
{
while (this.currentRow < this.header.Height)
{
int bytesRead = compressedStream.Read(this.scanline, this.currentRowBytesRead, this.bytesPerScanline - this.currentRowBytesRead);
this.currentRowBytesRead += bytesRead;
if (this.currentRowBytesRead < this.bytesPerScanline)
{
return;
}
this.currentRowBytesRead = 0;
FilterType filterType = (FilterType)this.scanline[0];
switch (filterType)
{
case FilterType.None:
NoneFilter.Decode(this.scanline);
break;
case FilterType.Sub:
SubFilter.Decode(this.scanline, this.bytesPerScanline, this.bytesPerPixel);
break;
case FilterType.Up:
UpFilter.Decode(this.scanline, this.previousScanline, this.bytesPerScanline);
break;
case FilterType.Average:
AverageFilter.Decode(this.scanline, this.previousScanline, this.bytesPerScanline, this.bytesPerPixel);
break;
case FilterType.Paeth:
PaethFilter.Decode(this.scanline, this.previousScanline, this.bytesPerScanline, this.bytesPerPixel);
break;
default:
throw new ImageFormatException("Unknown filter type.");
}
this.ProcessDefilteredScanline(this.scanline, pixels);
Swap(ref this.scanline, ref this.previousScanline);
this.currentRow++;
}
}
/// <summary>
/// Decodes the raw pixel data row by row
/// </summary>
/// <typeparam name="TColor">The pixel format.</typeparam>
/// <typeparam name="TPacked">The packed format. <example>uint, long, float.</example></typeparam>
/// <param name="compressedStream">The compressed pixel data stream.</param>
/// <param name="pixels">The image pixel accessor.</param>
private void DecodePixelData <TColor, TPacked>(Stream compressedStream, PixelAccessor <TColor, TPacked> pixels)
where TColor : struct, IPackedPixel <TPacked>
where TPacked : struct
{
// TODO: ArrayPool<byte>.Shared.Rent(this.bytesPerScanline)
byte[] previousScanline = new byte[this.bytesPerScanline];
byte[] scanline = new byte[this.bytesPerScanline];
for (int y = 0; y < this.header.Height; y++)
{
compressedStream.Read(scanline, 0, this.bytesPerScanline);
FilterType filterType = (FilterType)scanline[0];
byte[] defilteredScanline;
// TODO: It would be good if we can reduce the memory usage here. Each filter is creating a new row.
switch (filterType)
{
case FilterType.None:
defilteredScanline = NoneFilter.Decode(scanline);
break;
case FilterType.Sub:
defilteredScanline = SubFilter.Decode(scanline, this.bytesPerPixel);
break;
case FilterType.Up:
defilteredScanline = UpFilter.Decode(scanline, previousScanline);
break;
case FilterType.Average:
defilteredScanline = AverageFilter.Decode(scanline, previousScanline, this.bytesPerPixel);
break;
case FilterType.Paeth:
defilteredScanline = PaethFilter.Decode(scanline, previousScanline, this.bytesPerPixel);
break;
default:
throw new ImageFormatException("Unknown filter type.");
}
previousScanline = defilteredScanline;
this.ProcessDefilteredScanline(defilteredScanline, y, pixels);
}
}
/// <summary>
/// Decodes the raw pixel data row by row
/// </summary>
/// <typeparam name="TColor">The pixel format.</typeparam>
/// <typeparam name="TPacked">The packed format. <example>uint, long, float.</example></typeparam>
/// <param name="pixelData">The pixel data.</param>
/// <param name="pixels">The image pixels.</param>
private void DecodePixelData <TColor, TPacked>(byte[] pixelData, TColor[] pixels)
where TColor : struct, IPackedPixel <TPacked>
where TPacked : struct
{
byte[] previousScanline = new byte[this.bytesPerScanline];
for (int y = 0; y < this.header.Height; y++)
{
byte[] scanline = new byte[this.bytesPerScanline];
Array.Copy(pixelData, y * this.bytesPerScanline, scanline, 0, this.bytesPerScanline);
FilterType filterType = (FilterType)scanline[0];
byte[] defilteredScanline;
switch (filterType)
{
case FilterType.None:
defilteredScanline = NoneFilter.Decode(scanline);
break;
case FilterType.Sub:
defilteredScanline = SubFilter.Decode(scanline, this.bytesPerPixel);
break;
case FilterType.Up:
defilteredScanline = UpFilter.Decode(scanline, previousScanline);
break;
case FilterType.Average:
defilteredScanline = AverageFilter.Decode(scanline, previousScanline, this.bytesPerPixel);
break;
case FilterType.Paeth:
defilteredScanline = PaethFilter.Decode(scanline, previousScanline, this.bytesPerPixel);
break;
default:
throw new ImageFormatException("Unknown filter type.");
}
previousScanline = defilteredScanline;
this.ProcessDefilteredScanline <TColor, TPacked>(defilteredScanline, y, pixels);
}
}
/// <summary>
/// Decodes the raw interlaced pixel data row by row
/// <see href="https://github.com/juehv/DentalImageViewer/blob/8a1a4424b15d6cc453b5de3f273daf3ff5e3a90d/DentalImageViewer/lib/jiu-0.14.3/net/sourceforge/jiu/codecs/PNGCodec.java"/>
/// </summary>
/// <typeparam name="TColor">The pixel format.</typeparam>
/// <param name="compressedStream">The compressed pixel data stream.</param>
/// <param name="pixels">The image pixel accessor.</param>
private void DecodeInterlacedPixelData <TColor>(Stream compressedStream, PixelAccessor <TColor> pixels)
where TColor : struct, IPixel <TColor>
{
byte[] previousScanline = ArrayPool <byte> .Shared.Rent(this.bytesPerScanline);
byte[] scanline = ArrayPool <byte> .Shared.Rent(this.bytesPerScanline);
try
{
for (int pass = 0; pass < 7; pass++)
{
// Zero out the scanlines, because the bytes that are rented from the arraypool may not be zero.
Array.Clear(scanline, 0, this.bytesPerScanline);
Array.Clear(previousScanline, 0, this.bytesPerScanline);
int y = Adam7FirstRow[pass];
int numColumns = this.ComputeColumnsAdam7(pass);
if (numColumns == 0)
{
// This pass contains no data; skip to next pass
continue;
}
int bytesPerInterlaceScanline = this.CalculateScanlineLength(numColumns) + 1;
while (y < this.header.Height)
{
compressedStream.Read(scanline, 0, bytesPerInterlaceScanline);
FilterType filterType = (FilterType)scanline[0];
switch (filterType)
{
case FilterType.None:
NoneFilter.Decode(scanline);
break;
case FilterType.Sub:
SubFilter.Decode(scanline, bytesPerInterlaceScanline, this.bytesPerPixel);
break;
case FilterType.Up:
UpFilter.Decode(scanline, previousScanline, bytesPerInterlaceScanline);
break;
case FilterType.Average:
AverageFilter.Decode(scanline, previousScanline, bytesPerInterlaceScanline, this.bytesPerPixel);
break;
case FilterType.Paeth:
PaethFilter.Decode(scanline, previousScanline, bytesPerInterlaceScanline, this.bytesPerPixel);
break;
default:
throw new ImageFormatException("Unknown filter type.");
}
this.ProcessInterlacedDefilteredScanline(scanline, y, pixels, Adam7FirstColumn[pass], Adam7ColumnIncrement[pass]);
Swap(ref scanline, ref previousScanline);
y += Adam7RowIncrement[pass];
}
}
}
finally
{
ArrayPool <byte> .Shared.Return(previousScanline);
ArrayPool <byte> .Shared.Return(scanline);
}
}
/// <summary>
/// Decodes the raw pixel data row by row
/// </summary>
/// <typeparam name="TColor">The pixel format.</typeparam>
/// <param name="compressedStream">The compressed pixel data stream.</param>
/// <param name="pixels">The image pixel accessor.</param>
private void DecodePixelData <TColor>(Stream compressedStream, PixelAccessor <TColor> pixels)
where TColor : struct, IPixel <TColor>
{
byte[] previousScanline = ArrayPool <byte> .Shared.Rent(this.bytesPerScanline);
byte[] scanline = ArrayPool <byte> .Shared.Rent(this.bytesPerScanline);
// Zero out the scanlines, because the bytes that are rented from the arraypool may not be zero.
Array.Clear(scanline, 0, this.bytesPerScanline);
Array.Clear(previousScanline, 0, this.bytesPerScanline);
try
{
for (int y = 0; y < this.header.Height; y++)
{
compressedStream.Read(scanline, 0, this.bytesPerScanline);
FilterType filterType = (FilterType)scanline[0];
switch (filterType)
{
case FilterType.None:
NoneFilter.Decode(scanline);
break;
case FilterType.Sub:
SubFilter.Decode(scanline, this.bytesPerScanline, this.bytesPerPixel);
break;
case FilterType.Up:
UpFilter.Decode(scanline, previousScanline, this.bytesPerScanline);
break;
case FilterType.Average:
AverageFilter.Decode(scanline, previousScanline, this.bytesPerScanline, this.bytesPerPixel);
break;
case FilterType.Paeth:
PaethFilter.Decode(scanline, previousScanline, this.bytesPerScanline, this.bytesPerPixel);
break;
default:
throw new ImageFormatException("Unknown filter type.");
}
this.ProcessDefilteredScanline(scanline, y, pixels);
Swap(ref scanline, ref previousScanline);
}
}
finally
{
ArrayPool <byte> .Shared.Return(previousScanline);
ArrayPool <byte> .Shared.Return(scanline);
}
}
/// <summary>
/// Decodes the raw interlaced pixel data row by row
/// <see href="https://github.com/juehv/DentalImageViewer/blob/8a1a4424b15d6cc453b5de3f273daf3ff5e3a90d/DentalImageViewer/lib/jiu-0.14.3/net/sourceforge/jiu/codecs/PNGCodec.java"/>
/// </summary>
/// <typeparam name="TPixel">The pixel format.</typeparam>
/// <param name="compressedStream">The compressed pixel data stream.</param>
/// <param name="image">The current image.</param>
private void DecodeInterlacedPixelData <TPixel>(Stream compressedStream, Image <TPixel> image)
where TPixel : struct, IPixel <TPixel>
{
while (true)
{
int numColumns = this.ComputeColumnsAdam7(this.pass);
if (numColumns == 0)
{
this.pass++;
// This pass contains no data; skip to next pass
continue;
}
int bytesPerInterlaceScanline = this.CalculateScanlineLength(numColumns) + 1;
while (this.currentRow < this.header.Height)
{
int bytesRead = compressedStream.Read(this.scanline.Array, this.currentRowBytesRead, bytesPerInterlaceScanline - this.currentRowBytesRead);
this.currentRowBytesRead += bytesRead;
if (this.currentRowBytesRead < bytesPerInterlaceScanline)
{
return;
}
this.currentRowBytesRead = 0;
Span <byte> scanSpan = this.scanline.Slice(0, bytesPerInterlaceScanline);
Span <byte> prevSpan = this.previousScanline.Slice(0, bytesPerInterlaceScanline);
var filterType = (FilterType)scanSpan[0];
switch (filterType)
{
case FilterType.None:
break;
case FilterType.Sub:
SubFilter.Decode(scanSpan, this.bytesPerPixel);
break;
case FilterType.Up:
UpFilter.Decode(scanSpan, prevSpan);
break;
case FilterType.Average:
AverageFilter.Decode(scanSpan, prevSpan, this.bytesPerPixel);
break;
case FilterType.Paeth:
PaethFilter.Decode(scanSpan, prevSpan, this.bytesPerPixel);
break;
default:
throw new ImageFormatException("Unknown filter type.");
}
Span <TPixel> rowSpan = image.GetRowSpan(this.currentRow);
this.ProcessInterlacedDefilteredScanline(this.scanline.Array, rowSpan, Adam7FirstColumn[this.pass], Adam7ColumnIncrement[this.pass]);
Swap(ref this.scanline, ref this.previousScanline);
this.currentRow += Adam7RowIncrement[this.pass];
}
this.pass++;
this.previousScanline.Clear();
if (this.pass < 7)
{
this.currentRow = Adam7FirstRow[this.pass];
}
else
{
this.pass = 0;
break;
}
}
}
