public static int Read(this Stream stream, Span <byte> buffer)
{
using var buff = new PoolArray <byte>(buffer.Length);
int cb = stream.Read(buff.Array, 0, buff.Length);
buff.Array.AsSpan(0, cb).CopyTo(buffer);
return(cb);
}
public void Quantize(Span <byte> image, Span <byte> outbuff, nint width, nint height, nint instride, nint outstride)
{
var nc = (Span <int>) stackalloc int[] { 0, 0, 0, 0, 0, 0, 0, 0 };
getNodeCounts(nc);
uint level = leafLevel;
int targetColors = maxPaletteSize - getReservedCount();
for (uint i = 1; i < leafLevel; i++)
{
if (nc[(int)i] > targetColors)
{
level = i;
break;
}
}
fixed(OctreeNode *ptree = MemoryMarshal.Cast <byte, OctreeNode>(nodeBuffer))
fixed(float *igt = &LookupTables.SrgbInverseGamma[0])
{
float ftpix = getPixelCount();
for (nuint i = 0; i < 8; i++)
{
convertNodes(ptree, igt, ptree + i, 0, level, ftpix);
}
leafLevel = level;
}
int histogramColors = nc[(int)level];
if (histogramColors > targetColors)
{
var listBuffer = BufferPool.Rent(sizeof(ReducibleNode) * histogramColors);
nuint reducibleCount = 0;
fixed(OctreeNode *ptree = MemoryMarshal.Cast <byte, OctreeNode>(nodeBuffer))
fixed(ReducibleNode * pweights = MemoryMarshal.Cast <byte, ReducibleNode>(listBuffer))
fixed(float *gt = &LookupTables.SrgbGamma[0])
{
for (nuint i = 0; i < 8; i++)
{
addReducibleNodes(ptree, pweights, gt, ptree + i, ref reducibleCount, 0, leafLevel - 1);
}
}
var weights = MemoryMarshal.Cast <byte, ReducibleNode>(listBuffer).Slice(0, (int)reducibleCount);
int reduceCount = histogramColors - targetColors;
#if SPAN_SORT
weights.Sort();
finalReduce(weights.Slice(0, reduceCount));
#else
using var buff = new PoolArray <ReducibleNode>(maxHistogramSize);
weights.CopyTo(buff.Array);
Array.Sort(buff.Array, 0, weights.Length);
finalReduce(buff.Array.AsSpan(0, reduceCount));
#endif
}
bool dither = isSubsampled || histogramColors > maxPaletteSize;
nuint nextFree = makePaletteMap(level);
var pbuff = BufferPool.Rent(((int)width + 2) * 16, true);
pbuff.AsSpan().Clear();
fixed(byte *pimage = image, poutbuff = outbuff, perrbuff = pbuff.AsSpan())
fixed(uint *pilut = &LookupTables.OctreeIndexTable[0])
fixed(uint *ppal = MemoryMarshal.Cast <byte, uint>(palBuffer))
fixed(OctreeNode * ptree = MemoryMarshal.Cast <byte, OctreeNode>(nodeBuffer))
{
for (nint y = 0; y < height; y++)
{
byte *pline = pimage + y * instride;
byte *poutline = poutbuff + y * outstride;
int * perrline = (int *)perrbuff + 4;
if (!dither)
{
remap(pline, poutline, pilut, ptree, ppal, ref nextFree, width);
}
#if HWINTRINSICS
else if (Sse2.IsSupported)
{
remapDitherSse2(pline, perrline, poutline, pilut, ptree, ppal, ref nextFree, width);
}
#endif
else
{
remapDitherScalar(pline, perrline, poutline, pilut, ptree, ppal, ref nextFree, width);
}
}
}
BufferPool.Return(pbuff);
}
