137 lines
3.8 KiB
C++
137 lines
3.8 KiB
C++
// SPDX-FileCopyrightText: 2025 Filip Leonarski, Paul Scherrer Institute <filip.leonarski@psi.ch>
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// SPDX-License-Identifier: GPL-3.0-only
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#include <cmath>
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#include "ColorScale.h"
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#include "JFJochException.h"
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static inline float Clamp01(float x) {
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return (x < 0.0f) ? 0.0f : (x > 1.0f ? 1.0f : x);
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}
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// Gamma-mapped green (recommended gamma = 0.7)
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static inline rgb GreenGamma(float f, float gamma = 0.7f) {
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f = Clamp01(f);
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const float g = std::pow(f, gamma);
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const uint8_t G = static_cast<uint8_t>(std::lround(255.0f * g));
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return {.r = 0, .g = G, .b = 0};
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}
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// Asinh-mapped green (recommended k = 8.0)
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static inline rgb GreenAsinh(float f, float k = 8.0f) {
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f = Clamp01(f);
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const float g = std::asinh(k * f) / std::asinh(k);
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const uint8_t G = static_cast<uint8_t>(std::lround(255.0f * g));
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return {.r = 0, .g = G, .b = 0};
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}
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float luminance(rgb input) {
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return 0.2126f * input.r + 0.7152f * input.g + 0.0722f * input.b;
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}
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ColorScale::ColorScale() : lut_(kLutSize) {
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CalcLUT();
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}
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void ColorScale::Select(ColorScaleEnum val) {
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current = val;
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CalcLUT();
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}
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const std::vector<rgb> &ColorScale::LUTData() const {
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return lut_;
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}
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void ColorScale::CalcLUT() const {
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const std::vector<rgb>* map = nullptr;
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switch (current) {
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case ColorScaleEnum::Viridis: map = &viridis_colormap; break;
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case ColorScaleEnum::Heat: map = &heat_colormap;
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break;
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case ColorScaleEnum::Indigo: map = &white_to_indigo_colormap;
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break;
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case ColorScaleEnum::BW: map = &white_to_black_colormap;
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break;
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case ColorScaleEnum::WB: map = &black_to_white_colormap;
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break;
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case ColorScaleEnum::Green:
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map = &green_colormap;
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break;
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case ColorScaleEnum::Magma:
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map = &magma_colormap; break;
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case ColorScaleEnum::Inferno:
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map = &inferno_colormap; break;
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default:
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throw JFJochException(JFJochExceptionCategory::InputParameterInvalid,
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"Color scale unknown");
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}
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for (size_t i = 0; i < kLutSize; ++i) {
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const float f = static_cast<float>(i) / static_cast<float>(kLutSize - 1);
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lut_[i] = Apply(f, *map);
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}
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}
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rgb ColorScale::Apply(float input, const std::vector<rgb> &map) {
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size_t num_colors = map.size();
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if (num_colors < 2) {
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throw std::invalid_argument("Colormap must have at least two colors.");
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}
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float scaled_value = input * (num_colors - 1);
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size_t lower_idx = static_cast<size_t>(scaled_value);
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size_t upper_idx = std::min(lower_idx + 1, num_colors - 1);
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float t = scaled_value - lower_idx; // Fraction for interpolation
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rgb lower = map[lower_idx];
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rgb upper = map[upper_idx];
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return {
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.r = static_cast<uint8_t>(lower.r + t * (upper.r - lower.r)),
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.g = static_cast<uint8_t>(lower.g + t * (upper.g - lower.g)),
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.b = static_cast<uint8_t>(lower.b + t * (upper.b - lower.b))
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};
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}
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rgb ColorScale::Apply(ColorScaleSpecial input) const {
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switch (input) {
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case ColorScaleSpecial::Gap:
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return gap;
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default:
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case ColorScaleSpecial::BadPixel:
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return bad;
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}
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}
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rgb ColorScale::Apply(float input, float min, float max) const {
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if (!std::isfinite(input))
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return gap;
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float f;
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if (input <= min)
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f = 0.0f;
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else if (input >= max)
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f = 1.0f;
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else
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f = (input - min) / (max - min);
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const size_t idx = static_cast<size_t>(f * static_cast<float>(kLutSize - 1));
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return lut_[idx];
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}
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rgb ColorScale::ApplyLUTIndex(size_t idx) const {
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if (idx >= kLutSize)
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return lut_[kLutSize-1];
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return lut_[idx];
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}
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ColorScale &ColorScale::Gap(rgb input) {
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gap = input;
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return *this;
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}
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ColorScale &ColorScale::BadPixel(rgb input) {
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bad = input;
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return *this;
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}
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