public static KernelMap <T> GetOrAdd(int isize, int osize, InterpolationSettings interpolator, int ichannels, double offset)
{
if (!(interpolator.WeightingFunction is IUniquelyIdentifiable iwf))
{
return(KernelMap <T> .create(isize, osize, interpolator, ichannels, offset));
}
var hasher = Blake2b.CreateIncrementalHasher(Unsafe.SizeOf <Guid>());
hasher.Update(isize);
hasher.Update(osize);
hasher.Update(ichannels);
hasher.Update(offset);
hasher.Update(iwf.UniqueID);
hasher.Update(interpolator.Blur);
Span <byte> hash = stackalloc byte[Unsafe.SizeOf <Guid>()];
hasher.Finish(hash);
var key = MemoryMarshal.Read <Guid>(hash);
if (lruCache.TryGet(key, out var map))
{
return(map);
}
return(lruCache.GetOrAdd(key, KernelMap <T> .create(isize, osize, interpolator, ichannels, offset)));
}
unsafe public static KernelMap MakeScaleMap(uint isize, uint osize, InterpolationSettings interpolator)
{
double offs = interpolator.WeightingFunction.Support <= 0.1 ? 0.5 : 0.0;
double blur = interpolator.Blur;
if (interpolator.WeightingFunction.Support <= 0.5)
{
blur = 1d;
}
double wfactor = Math.Min((double)osize / isize, 1d);
double wdist = Math.Min(interpolator.WeightingFunction.Support / wfactor * blur, isize / 2d);
int wsize = (int)Math.Ceiling(wdist * 2d);
var map = new KernelMap((int)isize, (int)osize, wsize);
fixed(int *mapstart = map.Map)
{
double *wp = stackalloc double[wsize];
int * mp = mapstart;
double inc = (double)isize / osize;
double midpoint = ((double)isize - osize) / (osize * 2d) + offs;
for (int i = 0; i < osize; i++)
{
int end = (int)(midpoint + wdist);
int start = end - wsize + 1;
*mp++ = start;
double weightsum = 0d;
for (int j = 0; j < wsize; j++)
{
double weight = interpolator.WeightingFunction.GetValue(Math.Abs(((double)start + j - midpoint) * wfactor / blur));
weightsum += weight;
wp[j] = weight;
}
for (int j = 0; j < wsize; j++)
{
*mp++ = MathUtil.ScaleToInt32(wp[j] / weightsum);
}
midpoint += inc;
}
}
return(map.clamp());
}
unsafe public static KernelMap <T> CreateResample(int isize, int osize, InterpolationSettings interpolator, int ichannels, bool subsampleOffset, bool vectored)
{
double offs = interpolator.WeightingFunction.Support < 0.1 ? 0.5 : subsampleOffset ? 0.25 : 0.0;
double ratio = Math.Min((double)osize / isize, 1d);
double cscale = ratio / interpolator.Blur;
double support = Math.Min(interpolator.WeightingFunction.Support / cscale, isize / 2d);
int channels = vectored ? ichannels : 1;
int ksize = (int)Math.Ceiling(support * 2d);
int kpad = vectored ? getPadding(isize, ksize, channels) : 0;
var map = new KernelMap <T>(osize, ksize + kpad, channels);
fixed(byte *mstart = map.Map)
{
int * mp = (int *)mstart;
double inc = (double)isize / osize;
double spoint = ((double)isize - osize) / (osize * 2d) + offs;
Span <float> kernel = stackalloc float[ksize];
for (int i = 0; i < osize; i++)
{
int start = (int)(spoint + support) - ksize + 1;
fillWeights(kernel, interpolator.WeightingFunction, start, spoint, cscale);
spoint += inc;
*mp++ = start;
for (int j = 0; j < kernel.Length; j++)
{
var w = convertWeight(kernel[j]);
for (int k = 0; k < channels; k++)
{
Unsafe.Write(mp++, w);
}
}
mp += kpad * channels;
}
}
return(map.clamp(isize));
}
unsafe public static KernelMap <T> MakeScaleMap(uint isize, uint osize, int colorChannels, bool alphaChannel, bool vectored, InterpolationSettings interpolator)
{
var ainterpolator = interpolator.WeightingFunction.Support > 1d ? InterpolationSettings.Hermite : interpolator;
double offs = interpolator.WeightingFunction.Support < 0.1 ? 0.5 : 0.0;
double wfactor = Math.Min((double)osize / isize, 1d);
double wscale = wfactor / interpolator.Blur;
double awscale = wfactor / ainterpolator.Blur;
double wdist = Math.Min(interpolator.WeightingFunction.Support / wscale, isize / 2d);
int channels = colorChannels + (alphaChannel ? 1 : 0);
int wsize = (int)Math.Ceiling(wdist * 2d);
if (vectored && wsize * channels % (Vector <T> .Count * channels) >= (Vector <T> .Count * channels) / 2)
{
wsize = (wsize * channels + (Vector <T> .Count * channels - 1) & ~(Vector <T> .Count * channels - 1)) / channels;
}
wsize = Math.Min(wsize, (int)isize);
var map = new KernelMap <T>((int)isize, (int)osize, wsize, channels);
fixed(byte *mapstart = map.Map.Array)
{
double *wp = stackalloc double[wsize];
double *awp = stackalloc double[wsize];
int * mp = (int *)mapstart;
double inc = (double)isize / osize;
double spoint = ((double)isize - osize) / (osize * 2d) + offs;
for (int i = 0; i < osize; i++)
{
int start = (int)(spoint + wdist) - wsize + 1;
*mp++ = start;
double weightsum = 0d;
for (int j = 0; j < wsize; j++)
{
double weight = interpolator.WeightingFunction.GetValue(Math.Abs(((double)start + j - spoint) * wscale));
weightsum += weight;
wp[j] = weight;
}
weightsum = 1d / weightsum;
for (int j = 0; j < wsize; j++)
{
wp[j] *= weightsum;
}
if (alphaChannel)
{
double aweightsum = 0d;
for (int j = 0; j < wsize; j++)
{
double weight = ainterpolator.WeightingFunction.GetValue(Math.Abs(((double)start + j - spoint) * awscale));
aweightsum += weight;
awp[j] = weight;
}
aweightsum = 1d / aweightsum;
for (int j = 0; j < wsize; j++)
{
awp[j] *= aweightsum;
}
}
for (int j = 0; j < wsize; j++)
{
T w = convertWeight(wp[j]);
for (int k = 0; k < colorChannels; k++)
{
Unsafe.Write(mp++, w);
}
if (alphaChannel)
{
Unsafe.Write(mp++, convertWeight(awp[j]));
}
}
spoint += inc;
}
}
return(map.clamp());
}
unsafe public static KernelMap <T> MakeScaleMap(uint isize, uint osize, int colorChannels, bool alphaChannel, bool vectored, InterpolationSettings interpolator)
{
double offs = interpolator.WeightingFunction.Support < 0.1 ? 0.5 : 0.0;
double ratio = Math.Min((double)osize / isize, 1d);
double cscale = ratio / interpolator.Blur;
double support = Math.Min(interpolator.WeightingFunction.Support / cscale, isize / 2d);
int channels = colorChannels + (alphaChannel ? 1 : 0);
int ksize = (int)Math.Ceiling(support * 2d);
int kpad = vectored ? getKernelPadding((int)isize, ksize, channels) : 0;
var map = new KernelMap <T>((int)isize, (int)osize, ksize + kpad, channels);
fixed(byte *mstart = &map.Map.Array[0])
{
int * mp = (int *)mstart;
double *kp = stackalloc double[ksize];
double inc = (double)isize / osize;
double spoint = ((double)isize - osize) / (osize * 2d) + offs;
for (int i = 0; i < osize; i++)
{
int start = (int)(spoint + support) - ksize + 1;
fillKernelWeights(interpolator.WeightingFunction, kp, ksize, start, spoint, cscale);
spoint += inc;
*mp++ = start;
for (int j = 0; j < ksize; j++)
{
var w = convertWeight(kp[j]);
for (int k = 0; k < channels; k++)
{
Unsafe.Write(mp++, w);
}
}
mp += kpad * channels;
}
}
return(map.clamp());
}