Meziantou.FrameworkHdrToneMappingOperator Enum
Selects the curve that compresses the highlights of high dynamic range samples into a standard dynamic range (HdrToneMappingOptions).
public enum HdrToneMappingOperatorRemarks
Every curve is applied to the largest of the red, green and blue components of a color, in linear display light divided by the target white, and the three components are scaled by the same factor: the hue and the saturation of the color are kept, and its brightest component never exceeds the white. In what follows x is that largest component and p the peak of the source in the same unit (at least 1).
Fields
| Name | Value | Description |
|---|---|---|
Bt2390 | 0 | The electrical-electrical transfer function of Report ITU-R BT.2390 (section 5.4.1), evaluated on PQ values: light up to a knee is kept as it is, and the light above it follows a Hermite spline that reaches the white at the peak of the source. This is the default. |
Clip | 1 | Keeps the light up to the white and clips what is above: min(x, 1). Highlights lose their detail. |
Reinhard | 2 | The operator of Reinhard et al. ("Photographic Tone Reproduction for Digital Images", 2002, equation 4) with the peak of the source as its white point: x (1 + x / p^2) / (1 + x). It compresses every tone, the dark ones the least. |
Hable | 3 | The filmic curve of John Hable ("Filmic Tonemapping Operators", 2010), h(x) / h(p) with h(x) = (x (A x + C B) + D E) / (x (A x + B) + D F) - E / F and A = 0.15, B = 0.50, C = 0.10, D = 0.20, E = 0.02, F = 0.30: a toe that darkens the shadows and a long shoulder. |
Mobius | 4 | A straight line up to 0.3, continued by the Möbius function s (x + a) / (x + b) that has the same value and the same slope there and reaches the white at the peak of the source: the tones below the knee are kept exactly. |