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Diffstat (limited to 'src/color-map.cpp')
| -rw-r--r-- | src/color-map.cpp | 150 |
1 files changed, 150 insertions, 0 deletions
diff --git a/src/color-map.cpp b/src/color-map.cpp new file mode 100644 index 0000000..d3d4e49 --- /dev/null +++ b/src/color-map.cpp @@ -0,0 +1,150 @@ +/* + * Copyright (c) 2020-2021 Vasile Vilvoiu <vasi.vilvoiu@gmail.com> + * + * specgram is free software; you can redistribute it and/or modify + * it under the terms of the MIT license. See LICENSE for details. + */ +#include "color-map.hpp" + +#include <cmath> +#include <cassert> + +std::unique_ptr<ColorMap> +ColorMap::FromType(ColorMapType type, + const sf::Color& bg_color, + const sf::Color& custom_color) +{ + /* colormaps are not allowed to be translucent */ + sf::Color opaque_bg_color(bg_color.r, bg_color.g, bg_color.b, 255); + sf::Color opaque_custom_color(custom_color.r, custom_color.g, custom_color.b, 255); + + switch (type) { + case ColorMapType::kJet: + return std::make_unique<JetColorMap>(); + + case ColorMapType::kGray: + return std::make_unique<TwoColorMap>(sf::Color::Black, sf::Color::White); + + case ColorMapType::kPurple: + return std::make_unique<ThreeColorMap>(sf::Color::Black, sf::Color(204, 51, 255, 255), sf::Color::White); + + case ColorMapType::kBlue: + return std::make_unique<ThreeColorMap>(sf::Color::Black, sf::Color(51, 51, 255, 255), sf::Color::White); + + case ColorMapType::kGreen: + return std::make_unique<ThreeColorMap>(sf::Color::Black, sf::Color(0, 150, 0, 255), sf::Color::White); + + case ColorMapType::kOrange: + return std::make_unique<ThreeColorMap>(sf::Color::Black, sf::Color(255, 102, 0, 255), sf::Color::White); + + case ColorMapType::kRed: + return std::make_unique<ThreeColorMap>(sf::Color::Black, sf::Color(230, 0, 0, 255), sf::Color::White); + + case ColorMapType::kCustom: + return std::make_unique<TwoColorMap>(opaque_bg_color, opaque_custom_color); + + default: + throw std::runtime_error("unknown color map"); + } +} + +std::vector<uint8_t> +ColorMap::Gradient(std::size_t width) const +{ + RealWindow values; + values.resize(width); + for (std::size_t i = 0; i < width; i++) { + values[i] = (double) i / (double) (width-1); + } + return this->Map(values); +} + +InterpolationColorMap::InterpolationColorMap(const std::vector<sf::Color>& colors, + const std::vector<double>& vals) : colors_(colors), values_(vals) +{ + /* respect boundaries */ + if (vals.size() != colors.size()) { + throw std::runtime_error("number of boundaries and number of colors differ"); + } + if (vals.size() < 2) { + throw std::runtime_error("at least two colors needed in a colormap"); + } + if (vals[0] != 0.0f) { + throw std::runtime_error("first colormap boundary must be 0.0"); + } + if (vals[vals.size()-1] != 1.0f) { + throw std::runtime_error("last colormap boundary must be 1.0"); + } + for (std::size_t i = 0; i < vals.size()-1; i++) { + if (vals[i] >= vals[i+1]) { + throw std::runtime_error("boundaries must be ascending"); + } + } +} + +std::vector<uint8_t> +InterpolationColorMap::GetColor(double value) const +{ + if ((value < 0.0f) || (value > 1.0f)) { + throw std::runtime_error("input value outside of colormap domain"); + } + + std::size_t k = 0; + while (value > this->values_[k+1]) { + k++; + assert(k < (this->values_.size()-1)); + } + + double fu = (value - this->values_[k]) / (this->values_[k+1] - this->values_[k]); + double fl = 1.0f - fu; + + return { + static_cast<uint8_t>(std::round(fl * this->colors_[k].r + fu * this->colors_[k+1].r)), + static_cast<uint8_t>(std::round(fl * this->colors_[k].g + fu * this->colors_[k+1].g)), + static_cast<uint8_t>(std::round(fl * this->colors_[k].b + fu * this->colors_[k+1].b)), + static_cast<uint8_t>(std::round(fl * this->colors_[k].a + fu * this->colors_[k+1].a)), + }; +} + +std::vector<uint8_t> +InterpolationColorMap::Map(const RealWindow& input) const +{ + std::vector<uint8_t> output; + output.resize(input.size() * 4); + + for (std::size_t i = 0; i < input.size(); i++) { + auto color = this->GetColor(input[i]); + assert(color.size() == 4); + output[i * 4 + 0] = color[0]; + output[i * 4 + 1] = color[1]; + output[i * 4 + 2] = color[2]; + output[i * 4 + 3] = color[3]; + } + + return output; +} + +TwoColorMap::TwoColorMap(const sf::Color& c1, const sf::Color& c2) + : InterpolationColorMap({ c1, c2 }, { 0.0f, 1.0f }) +{ +} + +ThreeColorMap::ThreeColorMap(const sf::Color& c1, const sf::Color& c2, const sf::Color& c3) + : InterpolationColorMap({ c1, c2, c3 }, { 0.0f, 0.5f, 1.0f }) +{ +} + +JetColorMap::JetColorMap() : InterpolationColorMap( + { /* MATLAB jet colormap */ + sf::Color(0, 0, 143, 255), + sf::Color(0, 0, 255, 255), + sf::Color(0, 255, 255, 255), + sf::Color(255, 255, 0, 255), + sf::Color(255, 127, 0, 255), + sf::Color(255, 0, 0, 255), + sf::Color(127, 0, 0, 255), + }, + { 0.0f, 1.0f / 9.0f, 23.0f / 63.0f, 13.0f / 21.0f, 47.0f / 63.0f, 55.0 / 63.0, 1.0f } + ) +{ +}
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