mathfns.h

Go to the documentation of this file.

// SPDX-License-Identifier: GPL-2.0-or-later
#ifndef INKSCAPE_HELPER_MATHFNS_H
#define INKSCAPE_HELPER_MATHFNS_H
 
#include <cmath>
#include <2geom/point.h>
 
namespace Inkscape {
namespace Util {
 
inline double round_to_nearest_multiple_plus(double x, double c1, double c0)
{
    return std::floor((x - c0) / c1 + 0.5) * c1 + c0;
}
 
inline double round_to_lower_multiple_plus(double x, double c1, double c0 = 0.0)
{
    return std::floor((x - c0) / c1) * c1 + c0;
}
 
inline double round_to_upper_multiple_plus(double x, double const c1, double const c0 = 0)
{
    return std::ceil((x - c0) / c1) * c1 + c0;
}
 
// Note: This is a naive implementation.
// Todo: (C++20) Replace with std::bit_floor.
template <typename T>
int constexpr floorlog2(T x)
{
    int n = -1;
    while (x > 0) {
        x /= 2;
        n++;
    }
    return n;
}
 
template <typename T, typename std::enable_if<std::is_integral<T>::value, bool>::type = true>
T constexpr safemod(T a, T b)
{
    a %= b;
    return a < 0 ? a + b : a;
}
 
template <typename T, typename std::enable_if<std::is_integral<T>::value, bool>::type = true>
T constexpr round_down(T a, T b)
{
    return a - safemod(a, b);
}
 
template <typename T, typename std::enable_if<std::is_integral<T>::value, bool>::type = true>
T constexpr round_up(T a, T b)
{
    return round_down(a - 1, b) + b;
}
 
template <typename T>
T safeclamp(T val, T lo, T hi)
{
    if (val < lo) return lo;
    if (val > hi) return hi;
    return val;
}
 
} // namespace Util
} // namespace Inkscape
 
#endif // INKSCAPE_HELPER_MATHFNS_H
 
/*
  Local Variables:
  mode:c++
  c-file-style:"stroustrup"
  c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
  indent-tabs-mode:nil
  fill-column:99
  End:
*/
// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 :