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#ifndef COLOR_RAMP_H
#define COLOR_RAMP_H
class Color_ramp
{
typedef std::array<unsigned char, 3> Color;
typedef std::pair<double, Color> Step;
std::vector<Step> m_steps;
public:
Color_ramp()
{
m_steps.push_back (std::make_pair (0, Color{ 192, 192, 255}));
m_steps.push_back (std::make_pair (0.2, Color{ 0, 0, 255}));
m_steps.push_back (std::make_pair (0.4, Color{ 0, 255, 0}));
m_steps.push_back (std::make_pair (0.6, Color{ 255, 255, 0}));
m_steps.push_back (std::make_pair (0.8, Color{ 255, 0, 0}));
m_steps.push_back (std::make_pair (1.0, Color{ 128, 0, 0}));
}
Color get (double value) const
{
std::size_t idx = 0;
while (m_steps[idx+1].first < value)
++ idx;
double v0 = m_steps[idx].first;
double v1 = m_steps[idx+1].first;
const Color& c0 = m_steps[idx].second;
const Color& c1 = m_steps[idx+1].second;
double ratio = (value - v0) / (v1 - v0);
Color out;
for (std::size_t i = 0; i < 3; ++ i)
out[i] = static_cast<unsigned char>((1 - ratio) * c0[i] + ratio * c1[i]);
return out;
}
};
#endif // COLOR_RAMP_H
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