norm_diverging.hpp

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#ifndef GENESIS_UTILS_COLOR_NORM_DIVERGING_H_
#define GENESIS_UTILS_COLOR_NORM_DIVERGING_H_
 
/*
    Genesis - A toolkit for working with phylogenetic data.
    Copyright (C) 2014-2023 Lucas Czech
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.
 
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
 
    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
    Contact:
    Lucas Czech <lczech@carnegiescience.edu>
    Department of Plant Biology, Carnegie Institution For Science
    260 Panama Street, Stanford, CA 94305, USA
*/
 
#include "genesis/utils/color/color.hpp"
#include "genesis/utils/color/functions.hpp"
#include "genesis/utils/color/norm_linear.hpp"
 
#include <cmath>
#include <limits>
#include <vector>
 
namespace genesis {
namespace utils {
 
// =================================================================================================
//     Color Normalization Diverging
// =================================================================================================
 
class ColorNormalizationDiverging
    : public ColorNormalizationLinear
{
public:
 
    // -------------------------------------------------------------------------
    //     Constructors and Rule of Five
    // -------------------------------------------------------------------------
 
    ColorNormalizationDiverging()
        : ColorNormalizationLinear( -1.0, 1.0 )
        , mid_value_( 0.0 )
    {}
 
    ColorNormalizationDiverging( double min, double max )
        : ColorNormalizationDiverging( min, ( min + max ) / 2.0, max )
    {}
 
    ColorNormalizationDiverging( double min, double mid, double max )
        : ColorNormalizationLinear( min, max )
        , mid_value_( mid )
    {
        ColorNormalizationDiverging::is_valid_or_throw_();
    }
 
    explicit ColorNormalizationDiverging( std::vector<double> const& values )
    {
        autoscale( values.begin(), values.end() );
    }
 
    template <class ForwardIterator>
    ColorNormalizationDiverging( ForwardIterator first, ForwardIterator last )
    {
        autoscale( first, last );
    }
 
    virtual ~ColorNormalizationDiverging() override = default;
 
    ColorNormalizationDiverging(ColorNormalizationDiverging const&) = default;
    ColorNormalizationDiverging(ColorNormalizationDiverging&&)      = default;
 
    ColorNormalizationDiverging& operator= (ColorNormalizationDiverging const&) = default;
    ColorNormalizationDiverging& operator= (ColorNormalizationDiverging&&)      = default;
 
    // -------------------------------------------------------------------------
    //     Accessors
    // -------------------------------------------------------------------------
 
    double mid_value() const
    {
        return mid_value_;
    }
 
    // -------------------------------------------------------------------------
    //     Modificators
    // -------------------------------------------------------------------------
 
    ColorNormalizationDiverging& make_centric( double center = 0.0 )
    {
        // Set the min and max so that they are symmetric around center.
        auto const dist = std::max(
            std::fabs( center - min_value() ),
            std::fabs( center - max_value() )
        );
        min_value( center - dist );
        max_value( center + dist );
        mid_value_ = center;
 
        return *this;
    }
 
    ColorNormalizationDiverging& mid_value( double value )
    {
        mid_value_ = value;
        return *this;
    }
 
    // -------------------------------------------------------------------------
    //     Virtual Functions
    // -------------------------------------------------------------------------
 
protected:
 
    virtual bool is_valid_() const override
    {
        return min_value() < mid_value_ && mid_value_ < max_value();
    }
 
    virtual void is_valid_or_throw_() const override
    {
        if( min_value() >= max_value() ) {
            throw std::runtime_error( "Invalid Color Normalization with min >= max." );
        }
        if( min_value() >= mid_value() ) {
            throw std::runtime_error( "Invalid Color Normalization with min >= mid." );
        }
        if( mid_value() >= max_value() ) {
            throw std::runtime_error( "Invalid Color Normalization with mid >= max." );
        }
    }
 
    virtual double normalize_( double value ) const override
    {
        // Already checked by base class.
        assert( min_value() <= value && value <= max_value() );
        assert( is_valid_() );
 
        // Bring value into the range [ 0.0, 1.0 ].
        double pos = 0.0;
        if( value < mid_value_ ) {
            pos = ( value - min_value() ) / ( mid_value_ - min_value() );
            pos /= 2.0;
        } else {
            pos = ( value - mid_value_ ) / ( max_value() - mid_value_ );
            pos /= 2.0;
            pos += 0.5;
        }
        return pos;
    }
 
    virtual void update_hook_( double min, double max ) override
    {
        mid_value_ = ( min + max ) / 2.0;
    }
 
    // -------------------------------------------------------------------------
    //     Data Members
    // -------------------------------------------------------------------------
 
private:
 
    double mid_value_ = 0.0;
 
};
 
} // namespace utils
} // namespace genesis
 
#endif // include guard