RulerTicks.hxx

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#ifndef RulerTicks_hxx
#define RulerTicks_hxx

#include <cmath>
namespace CLAM
{

class RulerTicks
{
                double _min;
                double _max;
                double _markGap;
                double _minGap;
                double _width;
        public:
                void setRange(double min, double max)
                {
                        _min = min;
                        _max = max;
                }
                void setWidth(double width)
                {
                        _width = width;
                }
                void setMinGap(double minGap)
                {
                        _minGap = minGap;
                }
                double markOffset() const
                {
                        double gap = markGap();
                        double ceil = std::ceil(_min/gap);
                        if (std::fabs(ceil)<1e-5) return 0.;
                        return ceil*gap;
                }
                double markGap() const
                {
                        double mappedMinGap = std::fabs(_minGap*(_max-_min)/_width);
                        double markGap=1;
                        if (mappedMinGap>=1)
                        {
                                while (true)
                                {
                                        if (markGap>=mappedMinGap) return markGap;
                                        if (markGap*2>=mappedMinGap) return markGap*2;
                                        if (markGap*5>=mappedMinGap) return markGap*5;
                                        markGap*=10;
                                }
                        }
                        else
                        {
                                while (true)
                                {
                                        if (markGap<1e-8) return 1e-8;
                                        if (markGap<mappedMinGap) return markGap;
                                        if (markGap/2<mappedMinGap) return markGap/2;
                                        if (markGap/5<mappedMinGap) return markGap/5;
                                        markGap/=10;
                                }
                        }
                        return markGap;
                }
};

} // namespace CLAM

#endif//RulerTicks_hxx

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