[PATCH 3/4] ipa: libipa: pwl: Clean up Pwl class to match libcamera
Naushir Patuck
naush at raspberrypi.com
Fri Apr 5 11:56:58 CEST 2024
Hi Paul,
On Fri, 5 Apr 2024 at 09:03, Paul Elder <paul.elder at ideasonboard.com> wrote:
>
> Clean up the Pwl class copied from the Raspberry Pi IPA to align it more
> with the libcamera style.
>
> Signed-off-by: Paul Elder <paul.elder at ideasonboard.com>
> ---
> src/ipa/libipa/pwl.cpp | 135 +++++++++++++++++++++++++++++++++--------
> src/ipa/libipa/pwl.h | 113 ++++++++++++++--------------------
> 2 files changed, 154 insertions(+), 94 deletions(-)
>
> diff --git a/src/ipa/libipa/pwl.cpp b/src/ipa/libipa/pwl.cpp
> index 09f5d65c..58925d83 100644
> --- a/src/ipa/libipa/pwl.cpp
> +++ b/src/ipa/libipa/pwl.cpp
> @@ -5,13 +5,40 @@
> * pwl.cpp - piecewise linear functions
> */
>
> +#include "pwl.h"
> +
> #include <cassert>
> #include <cmath>
> +#include <sstream>
> #include <stdexcept>
>
> -#include "pwl.h"
> +#include <libcamera/geometry.h>
> +
> +namespace libcamera {
> +
> +namespace ipa {
>
> -int Pwl::read(const libcamera::YamlObject ¶ms)
> +/*
> + * \enum Pwl::PerpType
> + * \brief Type of perpendicular found when inverting a piecewise linear function
> + *
> + * \var None
> + * \brief no perpendicular found
> + *
> + * \var Start
> + * \brief start of Pwl is closest point
> + *
> + * \var End
> + * \brief end of Pwl is closest point
> + *
> + * \var Vertex
> + * \brief vertex of Pwl is closest point
> + *
> + * \var Perpendicular
> + * \brief true perpendicular found
> + */
> +
> +int Pwl::readYaml(const libcamera::YamlObject ¶ms)
> {
> if (!params.size() || params.size() % 2)
> return -EINVAL;
> @@ -29,7 +56,7 @@ int Pwl::read(const libcamera::YamlObject ¶ms)
> if (!y)
> return -EINVAL;
>
> - points_.push_back(Point(*x, *y));
> + points_.push_back(FPoint(*x, *y));
> }
>
> return 0;
> @@ -38,13 +65,13 @@ int Pwl::read(const libcamera::YamlObject ¶ms)
> void Pwl::append(double x, double y, const double eps)
> {
> if (points_.empty() || points_.back().x + eps < x)
> - points_.push_back(Point(x, y));
> + points_.push_back(FPoint(x, y));
> }
>
> void Pwl::prepend(double x, double y, const double eps)
> {
> if (points_.empty() || points_.front().x - eps > x)
> - points_.insert(points_.begin(), Point(x, y));
> + points_.insert(points_.begin(), FPoint(x, y));
> }
>
> Pwl::Interval Pwl::domain() const
> @@ -65,6 +92,19 @@ bool Pwl::empty() const
> return points_.empty();
> }
>
> +/*
> + * \brief Evaluate the piecewise linear function
> + * \param[in] x The x value to input into the function
> + * \param[inout] spanPtr Initial guess for span
> + * \param[in] updateSpan Set to true to update spanPtr
> + *
> + * Evaluate Pwl, optionally supplying an initial guess for the
> + * "span". The "span" may be optionally be updated. If you want to know
> + * the "span" value but don't have an initial guess you can set it to
> + * -1.
> + *
> + * \return The result of evaluating the piecewise linear function with input \a x
> + */
> double Pwl::eval(double x, int *spanPtr, bool updateSpan) const
> {
> int span = findSpan(x, spanPtr && *spanPtr != -1 ? *spanPtr : points_.size() / 2 - 1);
> @@ -94,16 +134,22 @@ int Pwl::findSpan(double x, int span) const
> return span;
> }
>
> -Pwl::PerpType Pwl::invert(Point const &xy, Point &perp, int &span,
> +/*
> + * Find perpendicular closest to xy, starting from span+1 so you can
> + * call it repeatedly to check for multiple closest points (set span to
> + * -1 on the first call). Also returns "pseudo" perpendiculars; see
> + * PerpType enum.
> + */
> +Pwl::PerpType Pwl::invert(FPoint const &xy, FPoint &perp, int &span,
> const double eps) const
> {
> assert(span >= -1);
> bool prevOffEnd = false;
> for (span = span + 1; span < (int)points_.size() - 1; span++) {
> - Point spanVec = points_[span + 1] - points_[span];
> + FPoint spanVec = points_[span + 1] - points_[span];
> double t = ((xy - points_[span]) % spanVec) / spanVec.len2();
> - if (t < -eps) /* off the start of this span */
> - {
> + if (t < -eps) {
> + /* off the start of this span */
> if (span == 0) {
> perp = points_[span];
> return PerpType::Start;
> @@ -111,15 +157,15 @@ Pwl::PerpType Pwl::invert(Point const &xy, Point &perp, int &span,
> perp = points_[span];
> return PerpType::Vertex;
> }
> - } else if (t > 1 + eps) /* off the end of this span */
> - {
> + } else if (t > 1 + eps) {
> + /* off the end of this span */
> if (span == (int)points_.size() - 2) {
> perp = points_[span + 1];
> return PerpType::End;
> }
> prevOffEnd = true;
> - } else /* a true perpendicular */
> - {
> + } else {
> + /* a true perpendicular */
> perp = points_[span] + spanVec * t;
> return PerpType::Perpendicular;
> }
> @@ -127,25 +173,34 @@ Pwl::PerpType Pwl::invert(Point const &xy, Point &perp, int &span,
> return PerpType::None;
> }
>
> +/*
> + * \brief Compute the inverse function
> + * \param[out] trueInverse True of the resulting inverse is a proper/true inverse
> + * \param[in] eps Epsilon (optional)
> + * Indicate if it is a proper (true) inverse, or only a best effort (e.g.
> + * input was non-monotonic).
> + * \return The inverse piecewise linear function
> + */
> Pwl Pwl::inverse(bool *trueInverse, const double eps) const
> {
> bool appended = false, prepended = false, neither = false;
> Pwl inverse;
>
> - for (Point const &p : points_) {
> - if (inverse.empty())
> + for (FPoint const &p : points_) {
> + if (inverse.empty()) {
> inverse.append(p.y, p.x, eps);
> - else if (std::abs(inverse.points_.back().x - p.y) <= eps ||
> - std::abs(inverse.points_.front().x - p.y) <= eps)
> + } else if (std::abs(inverse.points_.back().x - p.y) <= eps ||
> + std::abs(inverse.points_.front().x - p.y) <= eps) {
> /* do nothing */;
> - else if (p.y > inverse.points_.back().x) {
> + } else if (p.y > inverse.points_.back().x) {
> inverse.append(p.y, p.x, eps);
> appended = true;
> } else if (p.y < inverse.points_.front().x) {
> inverse.prepend(p.y, p.x, eps);
> prepended = true;
> - } else
> + } else {
> neither = true;
> + }
> }
>
> /*
> @@ -159,18 +214,25 @@ Pwl Pwl::inverse(bool *trueInverse, const double eps) const
> return inverse;
> }
>
> +/*
> + * \brief Compose two piecewise linear functions together
> + * \param[in] other The "other" piecewise linear function
> + * \param[in] eps Epsilon (optiona)
> + * The "this" function is done first, and "other" after.
> + * \return The composed piecewise linear function
> + */
> Pwl Pwl::compose(Pwl const &other, const double eps) const
> {
> double thisX = points_[0].x, thisY = points_[0].y;
> int thisSpan = 0, otherSpan = other.findSpan(thisY, 0);
> Pwl result({ { thisX, other.eval(thisY, &otherSpan, false) } });
> +
> while (thisSpan != (int)points_.size() - 1) {
> double dx = points_[thisSpan + 1].x - points_[thisSpan].x,
> dy = points_[thisSpan + 1].y - points_[thisSpan].y;
> if (std::abs(dy) > eps &&
> otherSpan + 1 < (int)other.points_.size() &&
> - points_[thisSpan + 1].y >=
> - other.points_[otherSpan + 1].x + eps) {
> + points_[thisSpan + 1].y >= other.points_[otherSpan + 1].x + eps) {
> /*
> * next control point in result will be where this
> * function's y reaches the next span in other
> @@ -204,18 +266,24 @@ Pwl Pwl::compose(Pwl const &other, const double eps) const
> return result;
> }
>
> +/* \brief Apply function to (x,y) values at every control point. */
> void Pwl::map(std::function<void(double x, double y)> f) const
> {
> for (auto &pt : points_)
> f(pt.x, pt.y);
> }
>
> +/*
> + * \brief Apply function to (x, y0, y1) values wherever either Pwl has a
> + * control point.
> + */
> void Pwl::map2(Pwl const &pwl0, Pwl const &pwl1,
> std::function<void(double x, double y0, double y1)> f)
> {
> int span0 = 0, span1 = 0;
> double x = std::min(pwl0.points_[0].x, pwl1.points_[0].x);
> f(x, pwl0.eval(x, &span0, false), pwl1.eval(x, &span1, false));
> +
> while (span0 < (int)pwl0.points_.size() - 1 ||
> span1 < (int)pwl1.points_.size() - 1) {
> if (span0 == (int)pwl0.points_.size() - 1)
> @@ -230,6 +298,12 @@ void Pwl::map2(Pwl const &pwl0, Pwl const &pwl1,
> }
> }
>
> +/*
> + * \brief Combine two Pwls
> + *
> + * Create a new Pwl where the y values are given by running f wherever either
> + * has a knot.
> + */
> Pwl Pwl::combine(Pwl const &pwl0, Pwl const &pwl1,
> std::function<double(double x, double y0, double y1)> f,
> const double eps)
> @@ -241,6 +315,11 @@ Pwl Pwl::combine(Pwl const &pwl0, Pwl const &pwl1,
> return result;
> }
>
> +/*
> + * \brief Make "this" match (at least) the given domain.
> + *
> + * Any extension my be clipped or linear.
> + */
> void Pwl::matchDomain(Interval const &domain, bool clip, const double eps)
> {
> int span = 0;
> @@ -258,10 +337,16 @@ Pwl &Pwl::operator*=(double d)
> return *this;
> }
>
> -void Pwl::debug(FILE *fp) const
> +std::string Pwl::toString() const
> {
> - fprintf(fp, "Pwl {\n");
> + std::stringstream ss;
> + ss << "Pwl { ";
> for (auto &p : points_)
> - fprintf(fp, "\t(%g, %g)\n", p.x, p.y);
> - fprintf(fp, "}\n");
> + ss << "(" << p.x << ", " << p.y << ") ";
> + ss << "}";
> + return ss.str();
> }
> +
> +} /* namespace ipa */
> +
> +} /* namespace libcamera */
> diff --git a/src/ipa/libipa/pwl.h b/src/ipa/libipa/pwl.h
> index 7a6a6452..ef49e302 100644
> --- a/src/ipa/libipa/pwl.h
> +++ b/src/ipa/libipa/pwl.h
> @@ -8,116 +8,91 @@
>
> #include <functional>
> #include <math.h>
> +#include <string>
> #include <vector>
>
> +#include <libcamera/geometry.h>
> +
> #include "libcamera/internal/yaml_parser.h"
>
> +namespace libcamera {
> +
> +namespace ipa {
> +
> class Pwl
> {
> public:
> + enum class PerpType {
> + None,
> + Start,
> + End,
> + Vertex,
> + Perpendicular,
> + };
> +
> struct Interval {
> Interval(double _start, double _end)
> - : start(_start), end(_end)
> - {
> - }
> - double start, end;
> + : start(_start), end(_end) {}
> +
> bool contains(double value)
> {
> return value >= start && value <= end;
> }
> - double clip(double value)
> +
> + double clamp(double value)
Typically clamp implies a min/max range value. Since we are only
using a singular value here, IMO this should still be called clip.
Thanks,
Naush
> {
> return value < start ? start
> : (value > end ? end : value);
> }
> +
> double len() const { return end - start; }
> +
> + double start, end;
> };
> - struct Point {
> - Point() : x(0), y(0) {}
> - Point(double _x, double _y)
> - : x(_x), y(_y) {}
> - double x, y;
> - Point operator-(Point const &p) const
> - {
> - return Point(x - p.x, y - p.y);
> - }
> - Point operator+(Point const &p) const
> - {
> - return Point(x + p.x, y + p.y);
> - }
> - double operator%(Point const &p) const
> - {
> - return x * p.x + y * p.y;
> - }
> - Point operator*(double f) const { return Point(x * f, y * f); }
> - Point operator/(double f) const { return Point(x / f, y / f); }
> - double len2() const { return x * x + y * y; }
> - double len() const { return sqrt(len2()); }
> - };
> +
> Pwl() {}
> - Pwl(std::vector<Point> const &points) : points_(points) {}
> - int read(const libcamera::YamlObject ¶ms);
> + Pwl(std::vector<FPoint> const &points)
> + : points_(points) {}
> + int readYaml(const libcamera::YamlObject ¶ms);
> +
> void append(double x, double y, const double eps = 1e-6);
> void prepend(double x, double y, const double eps = 1e-6);
> +
> Interval domain() const;
> Interval range() const;
> +
> bool empty() const;
> - /*
> - * Evaluate Pwl, optionally supplying an initial guess for the
> - * "span". The "span" may be optionally be updated. If you want to know
> - * the "span" value but don't have an initial guess you can set it to
> - * -1.
> - */
> +
> double eval(double x, int *spanPtr = nullptr,
> bool updateSpan = true) const;
> - /*
> - * Find perpendicular closest to xy, starting from span+1 so you can
> - * call it repeatedly to check for multiple closest points (set span to
> - * -1 on the first call). Also returns "pseudo" perpendiculars; see
> - * PerpType enum.
> - */
> - enum class PerpType {
> - None, /* no perpendicular found */
> - Start, /* start of Pwl is closest point */
> - End, /* end of Pwl is closest point */
> - Vertex, /* vertex of Pwl is closest point */
> - Perpendicular /* true perpendicular found */
> - };
> - PerpType invert(Point const &xy, Point &perp, int &span,
> +
> + PerpType invert(FPoint const &xy, FPoint &perp, int &span,
> const double eps = 1e-6) const;
> - /*
> - * Compute the inverse function. Indicate if it is a proper (true)
> - * inverse, or only a best effort (e.g. input was non-monotonic).
> - */
> Pwl inverse(bool *trueInverse = nullptr, const double eps = 1e-6) const;
> - /* Compose two Pwls together, doing "this" first and "other" after. */
> Pwl compose(Pwl const &other, const double eps = 1e-6) const;
> - /* Apply function to (x,y) values at every control point. */
> +
> void map(std::function<void(double x, double y)> f) const;
> - /*
> - * Apply function to (x, y0, y1) values wherever either Pwl has a
> - * control point.
> - */
> +
> static void map2(Pwl const &pwl0, Pwl const &pwl1,
> std::function<void(double x, double y0, double y1)> f);
> - /*
> - * Combine two Pwls, meaning we create a new Pwl where the y values are
> - * given by running f wherever either has a knot.
> - */
> +
> static Pwl
> combine(Pwl const &pwl0, Pwl const &pwl1,
> std::function<double(double x, double y0, double y1)> f,
> const double eps = 1e-6);
> - /*
> - * Make "this" match (at least) the given domain. Any extension my be
> - * clipped or linear.
> - */
> +
> void matchDomain(Interval const &domain, bool clip = true,
> const double eps = 1e-6);
> +
> Pwl &operator*=(double d);
> - void debug(FILE *fp = stdout) const;
> +
> + std::string toString() const;
>
> private:
> int findSpan(double x, int span) const;
> - std::vector<Point> points_;
> + std::vector<FPoint> points_;
> };
> +
> +} /* namespace ipa */
> +
> +} /* namespace libcamera */
> --
> 2.39.2
>
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