mirror of https://github.com/SixLabors/ImageSharp
winscripter
4 weeks ago
2 changed files with 142 additions and 54 deletions
@ -1,54 +0,0 @@ |
|||||
// Copyright (c) Six Labors.
|
|
||||
// Licensed under the Six Labors Split License.
|
|
||||
|
|
||||
namespace SixLabors.ImageSharp.Formats.Jxl.Cms.TransferFunctions; |
|
||||
|
|
||||
/// <summary>
|
|
||||
/// Base class for PQ transfer function.
|
|
||||
/// </summary>
|
|
||||
internal abstract class JxlPerceptualQuantizationTransferFunctionBase |
|
||||
{ |
|
||||
private const double M1 = 2610.0 / 16384; |
|
||||
private const double M2 = (2523.0 / 4096) * 128; |
|
||||
private const double C1 = 3424.0 / 4096; |
|
||||
private const double C2 = (2413.0 / 4096) * 32; |
|
||||
private const double C3 = (2392.0 / 4096) * 32; |
|
||||
|
|
||||
protected static double DisplayFromEncoded(float displayIntensityTarget, double e) |
|
||||
{ |
|
||||
if (e == 0.0) |
|
||||
{ |
|
||||
return 0.0; |
|
||||
} |
|
||||
|
|
||||
double originalSign = e; |
|
||||
|
|
||||
e = Math.Abs(e); |
|
||||
|
|
||||
double xp = Math.Pow(e, 1.0 / M2); |
|
||||
double num = Math.Max(xp - C1, 0.0); |
|
||||
double den = C2 - (C3 * xp); |
|
||||
double d = Math.Pow(num / den, 1.0 / M1); |
|
||||
|
|
||||
return Math.CopySign(d * (10000.0 / displayIntensityTarget), originalSign); |
|
||||
} |
|
||||
|
|
||||
protected static double EncodedFromDisplay(float displayIntensityTarget, double d) |
|
||||
{ |
|
||||
if (d == 0.0) |
|
||||
{ |
|
||||
return 0.0; |
|
||||
} |
|
||||
|
|
||||
double originalSign = d; |
|
||||
|
|
||||
d = Math.Abs(d); |
|
||||
|
|
||||
double xp = Math.Pow(d * (displayIntensityTarget * (1 / 10000)), M1); |
|
||||
double num = C1 + (xp * C2); |
|
||||
double den = 1.0 + (xp * C3); |
|
||||
double e = Math.Pow(num / den, M2); |
|
||||
|
|
||||
return Math.CopySign(e, originalSign); |
|
||||
} |
|
||||
} |
|
||||
@ -0,0 +1,142 @@ |
|||||
|
// Copyright (c) Six Labors.
|
||||
|
// Licensed under the Six Labors Split License.
|
||||
|
|
||||
|
using System.Numerics; |
||||
|
|
||||
|
namespace SixLabors.ImageSharp.Formats.Jxl.Cms.TransferFunctions; |
||||
|
|
||||
|
/// <summary>
|
||||
|
/// Perceptual Quantization transfer function.
|
||||
|
/// </summary>
|
||||
|
internal struct JxlPqTransferFunction(float displayIntensityTarget = DefaultIntensityTarget) |
||||
|
{ |
||||
|
private const double M1 = 2610.0 / 16384; |
||||
|
private const double M2 = (2523.0 / 4096) * 128; |
||||
|
private const double C1 = 3424.0 / 4096; |
||||
|
private const double C2 = (2413.0 / 4096) * 32; |
||||
|
private const double C3 = (2392.0 / 4096) * 32; |
||||
|
|
||||
|
private readonly float scaleFactorTo10000Nits = displayIntensityTarget * (1.0f / 10000.0f); |
||||
|
private readonly float scaleFactorFrom10000Nits = 10000.0f / displayIntensityTarget; |
||||
|
|
||||
|
private static ReadOnlySpan<float> DisplayP => |
||||
|
[ |
||||
|
2.62975656e-04f, 2.62975656e-04f, 2.62975656e-04f, 2.62975656e-04f, |
||||
|
-6.23553089e-03f, -6.23553089e-03f, -6.23553089e-03f, -6.23553089e-03f, |
||||
|
7.38602301e-01f, 7.38602301e-01f, 7.38602301e-01f, 7.38602301e-01f, |
||||
|
2.64553172e+00f, 2.64553172e+00f, 2.64553172e+00f, 2.64553172e+00f, |
||||
|
5.50034862e-01f, 5.50034862e-01f, 5.50034862e-01f, 5.50034862e-01f |
||||
|
]; |
||||
|
|
||||
|
private static ReadOnlySpan<float> DisplayQ => |
||||
|
[ |
||||
|
4.21350107e+02f, 4.21350107e+02f, 4.21350107e+02f, 4.21350107e+02f, |
||||
|
-4.28736818e+02f, -4.28736818e+02f, -4.28736818e+02f, -4.28736818e+02f, |
||||
|
1.74364667e+02f, 1.74364667e+02f, 1.74364667e+02f, 1.74364667e+02f, |
||||
|
-3.39078883e+01f, -3.39078883e+01f, -3.39078883e+01f, -3.39078883e+01f, |
||||
|
2.67718770e+00f, 2.67718770e+00f, 2.67718770e+00f, 2.67718770e+00f |
||||
|
]; |
||||
|
|
||||
|
private static ReadOnlySpan<float> EncodedP => |
||||
|
[ |
||||
|
1.351392e-02f, 1.351392e-02f, 1.351392e-02f, 1.351392e-02f, |
||||
|
-1.095778e+00f, -1.095778e+00f, -1.095778e+00f, -1.095778e+00f, |
||||
|
5.522776e+01f, 5.522776e+01f, 5.522776e+01f, 5.522776e+01f, |
||||
|
1.492516e+02f, 1.492516e+02f, 1.492516e+02f, 1.492516e+02f, |
||||
|
4.838434e+01f, 4.838434e+01f, 4.838434e+01f, 4.838434e+01f |
||||
|
]; |
||||
|
|
||||
|
private static ReadOnlySpan<float> EncodedQ => |
||||
|
[ |
||||
|
1.012416e+00f, 1.012416e+00f, 1.012416e+00f, 1.012416e+00f, |
||||
|
2.016708e+01f, 2.016708e+01f, 2.016708e+01f, 2.016708e+01f, |
||||
|
9.263710e+01f, 9.263710e+01f, 9.263710e+01f, 9.263710e+01f, |
||||
|
1.120607e+02f, 1.120607e+02f, 1.120607e+02f, 1.120607e+02f, |
||||
|
2.590418e+01f, 2.590418e+01f, 2.590418e+01f, 2.590418e+01f |
||||
|
]; |
||||
|
|
||||
|
private static ReadOnlySpan<float> EncodedPLo => |
||||
|
[ |
||||
|
9.863406e-06f, 9.863406e-06f, 9.863406e-06f, 9.863406e-06f, |
||||
|
3.881234e-01f, 3.881234e-01f, 3.881234e-01f, 3.881234e-01f, |
||||
|
1.352821e+02f, 1.352821e+02f, 1.352821e+02f, 1.352821e+02f, |
||||
|
6.889862e+04f, 6.889862e+04f, 6.889862e+04f, 6.889862e+04f, |
||||
|
-2.864824e+05f, -2.864824e+05f, -2.864824e+05f, -2.864824e+05f |
||||
|
]; |
||||
|
|
||||
|
private static ReadOnlySpan<float> EncodedQLo => |
||||
|
[ |
||||
|
3.371868e+01f, 3.371868e+01f, 3.371868e+01f, 3.371868e+01f, |
||||
|
1.477719e+03f, 1.477719e+03f, 1.477719e+03f, 1.477719e+03f, |
||||
|
1.608477e+04f, 1.608477e+04f, 1.608477e+04f, 1.608477e+04f, |
||||
|
-4.389884e+04f, -4.389884e+04f, -4.389884e+04f, -4.389884e+04f, |
||||
|
-2.072546e+05f, -2.072546e+05f, -2.072546e+05f, -2.072546e+05f |
||||
|
]; |
||||
|
|
||||
|
public static double DisplayFromEncoded(float displayIntensityTarget, double e) |
||||
|
{ |
||||
|
if (e == 0.0) |
||||
|
{ |
||||
|
return 0.0; |
||||
|
} |
||||
|
|
||||
|
double originalSign = e; |
||||
|
|
||||
|
e = Math.Abs(e); |
||||
|
|
||||
|
double xp = Math.Pow(e, 1.0 / M2); |
||||
|
double num = Math.Max(xp - C1, 0.0); |
||||
|
double den = C2 - (C3 * xp); |
||||
|
double d = Math.Pow(num / den, 1.0 / M1); |
||||
|
|
||||
|
return Math.CopySign(d * (10000.0 / displayIntensityTarget), originalSign); |
||||
|
} |
||||
|
|
||||
|
public static double EncodedFromDisplay(float displayIntensityTarget, double d) |
||||
|
{ |
||||
|
if (d == 0.0) |
||||
|
{ |
||||
|
return 0.0; |
||||
|
} |
||||
|
|
||||
|
double originalSign = d; |
||||
|
|
||||
|
d = Math.Abs(d); |
||||
|
|
||||
|
double xp = Math.Pow(d * (displayIntensityTarget * (1 / 10000)), M1); |
||||
|
double num = C1 + (xp * C2); |
||||
|
double den = 1.0 + (xp * C3); |
||||
|
double e = Math.Pow(num / den, M2); |
||||
|
|
||||
|
return Math.CopySign(e, originalSign); |
||||
|
} |
||||
|
|
||||
|
public Vector<float> DisplayFromEncoded(Vector<float> x) |
||||
|
{ |
||||
|
Vector<float> sign = Vector.Create(0x80000000u).As<uint, float>(); |
||||
|
Vector<float> originalSign = x & sign; |
||||
|
x = Vector.AndNot(sign, x); |
||||
|
|
||||
|
Vector<float> xpxx = (x * x) + x; |
||||
|
Vector<float> magnitude = EvaluateRationalPolynomial(xpxx, DisplayP, DisplayQ); |
||||
|
|
||||
|
return Vector.AndNot(sign, magnitude * Vector.Create(this.scaleFactorFrom10000Nits)) | originalSign; |
||||
|
} |
||||
|
|
||||
|
public Vector<float> EncodedFromDisplay(Vector<float> x) |
||||
|
{ |
||||
|
Vector<float> sign = Vector.Create(0x80000000u).As<uint, float>(); |
||||
|
Vector<float> originalSign = x & sign; |
||||
|
x = Vector.AndNot(sign, x); |
||||
|
|
||||
|
|
||||
|
Vector<float> xto025 = Vector.SquareRoot(Vector.SquareRoot(x * Vector.Create(this.scaleFactorTo10000Nits))); |
||||
|
|
||||
|
Vector<float> magnitude = Vector.ConditionalSelect( |
||||
|
Vector.LessThan(x, Vector.Create(1e-4f)), |
||||
|
EvaluateRationalPolynomial(xto025, EncodedPLo, EncodedQLo), |
||||
|
EvaluateRationalPolynomial(xto025, EncodedP, EncodedQ)); |
||||
|
|
||||
|
return Vector.AndNot(sign, magnitude) | originalSign; |
||||
|
} |
||||
|
} |
||||
Loading…
Reference in new issue