private static void UndoGray16Bit(Span <byte> pixelBytes, int width, bool isBigEndian)
{
int rowBytesCount = width * 2;
int height = pixelBytes.Length / rowBytesCount;
if (isBigEndian)
{
for (int y = 0; y < height; y++)
{
int offset = 0;
Span <byte> rowBytes = pixelBytes.Slice(y * rowBytesCount, rowBytesCount);
ushort pixelValue = TiffUtils.ConvertToUShortBigEndian(rowBytes.Slice(offset, 2));
offset += 2;
for (int x = 1; x < width; x++)
{
Span <byte> rowSpan = rowBytes.Slice(offset, 2);
ushort diff = TiffUtils.ConvertToUShortBigEndian(rowSpan);
pixelValue += diff;
BinaryPrimitives.WriteUInt16BigEndian(rowSpan, pixelValue);
offset += 2;
}
}
}
else
{
for (int y = 0; y < height; y++)
{
int offset = 0;
Span <byte> rowBytes = pixelBytes.Slice(y * rowBytesCount, rowBytesCount);
ushort pixelValue = TiffUtils.ConvertToUShortLittleEndian(rowBytes.Slice(offset, 2));
offset += 2;
for (int x = 1; x < width; x++)
{
Span <byte> rowSpan = rowBytes.Slice(offset, 2);
ushort diff = TiffUtils.ConvertToUShortLittleEndian(rowSpan);
pixelValue += diff;
BinaryPrimitives.WriteUInt16LittleEndian(rowSpan, pixelValue);
offset += 2;
}
}
}
}
/// <inheritdoc/>
public override void Decode(ReadOnlySpan <byte> data, Buffer2D <TPixel> pixels, int left, int top, int width, int height)
{
// Note: due to an issue with netcore 2.1 and default values and unpredictable behavior with those,
// we define our own defaults as a workaround. See: https://github.com/dotnet/runtime/issues/55623
Rgba64 rgba = TiffUtils.Rgba64Default;
var color = default(TPixel);
color.FromVector4(TiffUtils.Vector4Default);
int offset = 0;
for (int y = top; y < top + height; y++)
{
Span <TPixel> pixelRow = pixels.GetRowSpan(y).Slice(left, width);
if (this.isBigEndian)
{
for (int x = 0; x < pixelRow.Length; x++)
{
ulong r = TiffUtils.ConvertToUShortBigEndian(data.Slice(offset, 2));
offset += 2;
ulong g = TiffUtils.ConvertToUShortBigEndian(data.Slice(offset, 2));
offset += 2;
ulong b = TiffUtils.ConvertToUShortBigEndian(data.Slice(offset, 2));
offset += 2;
pixelRow[x] = TiffUtils.ColorFromRgba64(rgba, r, g, b, color);
}
}
else
{
int byteCount = pixelRow.Length * 6;
PixelOperations <TPixel> .Instance.FromRgb48Bytes(
this.configuration,
data.Slice(offset, byteCount),
pixelRow,
pixelRow.Length);
offset += byteCount;
}
}
}
