[PATCH 3/4] ipa: libipa: pwl: Clean up Pwl class to match libcamera
Paul Elder
paul.elder at ideasonboard.com
Fri Apr 5 16:37:06 CEST 2024
Hi Naush,
On Fri, Apr 05, 2024 at 10:56:58AM +0100, Naushir Patuck wrote:
> 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.
I was under the impression that the interval itself made up the min and max
range values, which is why I changed it to clamp. I started seeing clip
used elsewhere too though and I suppose it's not that big of a deal so
I'll change it back to clip (except I have patches coming in a few
minutes that depend on this so they'll still have clamp).
Thanks,
Paul
>
>
> > {
> > 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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