[PATCH v8 3/4] ipa: libipa: pwl: Clean up Pwl class to match libcamera
Laurent Pinchart
laurent.pinchart at ideasonboard.com
Wed Jun 12 00:14:41 CEST 2024
Hi Paul,
Thank you for the patch.
On Tue, Jun 11, 2024 at 10:24:29PM +0900, Paul Elder 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>
> Reviewed-by: Stefan Klug <stefan.klug at ideasonboard.com>
> Acked-by: David Plowman <david.plowman at raspberrypi.com>
> Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
>
> ---
> Changes in v8:
> - use the updated Vector interface
> - remove unused functions (prepend, invert, extendDomain)
> - improve class documentation
> - checkstyle
> - s/PointF/Point/
> - make inverse() return pair instead of output parameter
> - fix const order
> - fix includes
>
> No change in v7
>
> Changes in v6:
> - move adding pwl to meson here
>
> Changes in v5:
> - fix documentation order
> - fix some typos
> - add the Vector-based PointF
>
> Changes in v4:
> - update to apply to new copy of pwl
> - add documentation
> - fix doxygen
>
> No change in v3
>
> Changes in v2:
> - s/FPoint/PointF/g
> - improve documentation
> - s/matchDomain/extendDomain/
> ---
> src/ipa/libipa/meson.build | 2 +
> src/ipa/libipa/pwl.cpp | 372 ++++++++++++++++++++++++++-----------
> src/ipa/libipa/pwl.h | 133 +++++--------
> 3 files changed, 311 insertions(+), 196 deletions(-)
>
> diff --git a/src/ipa/libipa/meson.build b/src/ipa/libipa/meson.build
> index 8b0c8fff901b..3669f8939d3b 100644
> --- a/src/ipa/libipa/meson.build
> +++ b/src/ipa/libipa/meson.build
> @@ -8,6 +8,7 @@ libipa_headers = files([
> 'fc_queue.h',
> 'histogram.h',
> 'module.h',
> + 'pwl.h',
> 'vector.h',
> ])
>
> @@ -19,6 +20,7 @@ libipa_sources = files([
> 'fc_queue.cpp',
> 'histogram.cpp',
> 'module.cpp',
> + 'pwl.cpp',
> 'vector.cpp',
> ])
>
> diff --git a/src/ipa/libipa/pwl.cpp b/src/ipa/libipa/pwl.cpp
> index e39123767aa6..4dc59981708d 100644
> --- a/src/ipa/libipa/pwl.cpp
> +++ b/src/ipa/libipa/pwl.cpp
> @@ -1,19 +1,120 @@
> /* SPDX-License-Identifier: BSD-2-Clause */
> /*
> * Copyright (C) 2019, Raspberry Pi Ltd
> + * Copyright (C) 2024, Ideas on Board Oy
> *
> - * piecewise linear functions
> + * Piecewise linear functions
> */
>
> -#include <cassert>
> +#include "pwl.h"
> +
> +#include <assert.h>
> #include <cmath>
> +#include <sstream>
> #include <stdexcept>
>
> -#include "pwl.h"
> +#include <libcamera/geometry.h>
Unless I'm missing something, this isn't needed.
> +
> +/**
> + * \file pwl.h
> + * \brief Piecewise linear functions
> + */
> +
> +namespace libcamera {
> +
> +namespace ipa {
> +
> +/**
> + * \class Pwl
> + * \brief Describe a univariate piecewise linear function in two-dimensional
> + * real space
> + *
> + * A piecewise linear function is a univariate function that maps reals to
> + * reals, and it is composed of multiple straight-line segments.
> + *
> + * While a mathematical piecewise linear function would usually be defined by
> + * a list of linear functions and for which values of the domain they apply,
> + * this Pwl class is instead defined by a list of points at which these line
> + * segments intersect. These intersecting points are known as knots.
> + *
> + * https://en.wikipedia.org/wiki/Piecewise_linear_function
> + *
> + * A consequence of the Pwl class being defined by knots instead of linear
> + * functions is that the values of the piecewise linear function past the ends
> + * of the function are constants as opposed to linear functions. In a
> + * mathematical piecewise linear function that is defined by multiple linear
> + * functions, the ends of the function are also linear functions and hence grow
> + * to infinity (or negative infinity). However, since this Pwl class is defined
> + * by knots, the y-value of the leftmost and rightmost knots will hold for all
> + * x values to negative infinity and positive infinity, respectively.
Nice documentation, I especially like the part about what happens
outside of the defined segments, that was not evident.
> + */
> +
> +/**
> + * \typedef Pwl::Point
> + * \brief Describe a point in two-dimensional real space
> + */
> +
> +/**
> + * \class Pwl::Interval
> + * \brief Describe an interval in one-dimensional real space
> + */
> +
> +/**
> + * \fn Pwl::Interval::Interval(double _start, double _end)
> + * \brief Construct an interval
> + * \param _start Start of the interval
> + * \param _end End of the interval
> + */
> +
> +/**
> + * \fn Pwl::Interval::contains
> + * \brief Check if a given value falls within the interval
> + * \param value Value to check
* \return True if the value falls within the interval, including its
* bounds, or false otherwise
> + */
> +
> +/**
> + * \fn Pwl::Interval::clamp
> + * \brief Clamp a value such that it is within the interval
> + * \param value Value to clamp
* \return The clamped value
> + */
> +
> +/**
> + * \fn Pwl::Interval::length
> + * \brief Compute the length of the interval
* \return The length of the interval
> + */
> +
> +/**
> + * \var Pwl::Interval::start
> + * \brief Start of the interval
> + */
>
> -using namespace RPiController;
> +/**
> + * \var Pwl::Interval::end
> + * \brief End of the interval
> + */
>
> -int Pwl::read(const libcamera::YamlObject ¶ms)
> +/**
> + * \fn Pwl::Pwl(std::vector<Point> const &points)
> + * \brief Construct a piecewise linear function from a list of 2D points
> + * \param points Vector of points from which to construct the piecewise linear function
> + *
> + * \a points must be in ascending order of x-value.
> + */
> +
> +/**
> + * \brief Populate the piecewise linear function from yaml data
> + * \param params Yaml data to populate the piecewise linear function with
> + *
> + * Any existing points in the piecewise linear function will *not* be
> + * overwritten.
It sounds like a bit of an off behaviour, compared to clearing the PWL
first. Does anything depends on it ?
> + *
> + * The yaml data is expected to be a list with an even number of numerical
> + * elements. These will be parsed in pairs into x and y points in the piecewise
> + * linear function, and added in order. x must be monotonically increasing.
> + *
> + * \return 0 on success, negative error code otherwise
> + */
> +int Pwl::readYaml(const libcamera::YamlObject ¶ms)
> {
> if (!params.size() || params.size() % 2)
> return -EINVAL;
> @@ -24,64 +125,109 @@ int Pwl::read(const libcamera::YamlObject ¶ms)
> auto x = it->get<double>();
> if (!x)
> return -EINVAL;
> - if (it != list.begin() && *x <= points_.back().x)
> + if (it != list.begin() && *x <= points_.back().x())
> return -EINVAL;
>
> auto y = (++it)->get<double>();
> if (!y)
> return -EINVAL;
>
> - points_.push_back(Point(*x, *y));
> + points_.push_back(Point({ *x, *y }));
> }
>
> return 0;
> }
>
> +/**
> + * \brief Append a point to the end of the piecewise linear function
> + * \param x x-coordinate of the point to add to the piecewise linear function
> + * \param y y-coordinate of the point to add to the piecewise linear function
> + * \param eps Epsilon for the minimum x distance between points (optional)
> + *
> + * The point's x-coordinate must be greater than the x-coordinate of the last
> + * (= greatest) point already in the piecewise linear function.
> + */
> void Pwl::append(double x, double y, const double eps)
> {
> - if (points_.empty() || points_.back().x + eps < x)
> - points_.push_back(Point(x, y));
> + if (points_.empty() || points_.back().x() + eps < x)
> + points_.push_back(Point({ x, y }));
> }
>
> +/**
> + * \brief Prepend a point to the beginning of the piecewise linear function
> + * \param x x-coordinate of the point to add to the piecewise linear function
> + * \param y y-coordinate of the point to add to the piecewise linear function
> + * \param eps Epsilon for the minimum x distance between points (optional)
> + *
> + * The point's x-coordinate must be less than the x-coordinate of the first
> + * (= smallest) point already in the piecewise linear function.
> + */
> 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));
> + if (points_.empty() || points_.front().x() - eps > x)
> + points_.insert(points_.begin(), Point({ x, y }));
> }
>
> +/**
> + * \brief Get the domain of the piecewise linear function
> + * \return An interval representing the domain
> + */
> Pwl::Interval Pwl::domain() const
> {
> - return Interval(points_[0].x, points_[points_.size() - 1].x);
> + return Interval(points_[0].x(), points_[points_.size() - 1].x());
> }
>
> +/**
> + * \brief Get the range of the piecewise linear function
> + * \return An interval representing the range
> + */
> Pwl::Interval Pwl::range() const
> {
> - double lo = points_[0].y, hi = lo;
> + double lo = points_[0].y(), hi = lo;
> for (auto &p : points_)
> - lo = std::min(lo, p.y), hi = std::max(hi, p.y);
> + lo = std::min(lo, p.y()), hi = std::max(hi, p.y());
> return Interval(lo, hi);
> }
>
> +/**
> + * \brief Check if the piecewise linear function is empty
> + * \return True if there are no points in the function, false otherwise
> + */
> bool Pwl::empty() const
> {
> return points_.empty();
> }
>
> -double Pwl::eval(double x, int *spanPtr, bool updateSpan) const
> +/**
> + * \brief Evaluate the piecewise linear function
> + * \param[in] x The x value to input into the function
> + * \param[inout] span Initial guess for span
> + * \param[in] updateSpan Set to true to update span
> + *
> + * 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 at position \a x
> + */
> +double Pwl::eval(double x, int *span, bool updateSpan) const
> {
> - int span = findSpan(x, spanPtr && *spanPtr != -1 ? *spanPtr : points_.size() / 2 - 1);
> - if (spanPtr && updateSpan)
> - *spanPtr = span;
> - return points_[span].y +
> - (x - points_[span].x) * (points_[span + 1].y - points_[span].y) /
> - (points_[span + 1].x - points_[span].x);
> + int index = findSpan(x, span && *span != -1
> + ? *span
> + : points_.size() / 2 - 1);
> + if (span && updateSpan)
> + *span = index;
> + return points_[index].y() +
> + (x - points_[index].x()) * (points_[index + 1].y() - points_[index].y()) /
> + (points_[index + 1].x() - points_[index].x());
> }
>
> int Pwl::findSpan(double x, int span) const
> {
> /*
> * Pwls are generally small, so linear search may well be faster than
> - * binary, though could review this if large PWls start turning up.
> + * binary, though could review this if large Pwls start turning up.
> */
> int lastSpan = points_.size() - 2;
> /*
> @@ -89,65 +235,43 @@ int Pwl::findSpan(double x, int span) const
> * control point
> */
> span = std::max(0, std::min(lastSpan, span));
> - while (span < lastSpan && x >= points_[span + 1].x)
> + while (span < lastSpan && x >= points_[span + 1].x())
> span++;
> - while (span && x < points_[span].x)
> + while (span && x < points_[span].x())
> span--;
> return span;
> }
>
> -Pwl::PerpType Pwl::invert(Point const &xy, Point &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];
> - double t = ((xy - points_[span]) % spanVec) / spanVec.len2();
> - if (t < -eps) /* off the start of this span */
> - {
> - if (span == 0) {
> - perp = points_[span];
> - return PerpType::Start;
> - } else if (prevOffEnd) {
> - perp = points_[span];
> - return PerpType::Vertex;
> - }
> - } 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 */
> - {
> - perp = points_[span] + spanVec * t;
> - return PerpType::Perpendicular;
> - }
> - }
> - return PerpType::None;
> -}
> -
> -Pwl Pwl::inverse(bool *trueInverse, const double eps) const
> +/**
> + * \brief Compute the inverse function
> + * \param[in] eps Epsilon for the minimum x distance between points (optional)
> + *
> + * The output includes whether the resulting inverse function is a proper
> + * (true) inverse, or only a best effort (e.g. input was non-monotonic).
> + *
> + * \return A pair of the inverse piecewise linear function, and whether or not
> + * the result is a proper/true inverse
> + */
> +std::pair<Pwl, bool> Pwl::inverse(const double eps) const
> {
> bool appended = false, prepended = false, neither = false;
> Pwl inverse;
>
> for (Point 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)
> + 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) {
> /* do nothing */;
> - else if (p.y > inverse.points_.back().x) {
> - inverse.append(p.y, p.x, eps);
> + } 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);
> + } else if (p.y() < inverse.points_.front().x()) {
> + inverse.prepend(p.y(), p.x(), eps);
> prepended = true;
> - } else
> + } else {
> neither = true;
> + }
> }
>
> /*
> @@ -155,50 +279,58 @@ Pwl Pwl::inverse(bool *trueInverse, const double eps) const
> * onto both ends of the inverse, or if there were points that couldn't
> * go on either.
> */
> - if (trueInverse)
> - *trueInverse = !(neither || (appended && prepended));
> + bool trueInverse = !(neither || (appended && prepended));
>
> - return inverse;
> + return { inverse, trueInverse };
> }
>
> +/**
> + * \brief Compose two piecewise linear functions together
> + * \param[in] other The "other" piecewise linear function
> + * \param[in] eps Epsilon for the minimum x distance between points (optional)
> + *
> + * 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;
> + 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) } });
> + Pwl result({ Point({ 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;
> + 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
> */
> - thisX = points_[thisSpan].x +
> - (other.points_[otherSpan + 1].x -
> - points_[thisSpan].y) *
> + thisX = points_[thisSpan].x() +
> + (other.points_[otherSpan + 1].x() -
> + points_[thisSpan].y()) *
> dx / dy;
> - thisY = other.points_[++otherSpan].x;
> + thisY = other.points_[++otherSpan].x();
> } else if (std::abs(dy) > eps && otherSpan > 0 &&
> - 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 previous span in other
> */
> - thisX = points_[thisSpan].x +
> - (other.points_[otherSpan + 1].x -
> - points_[thisSpan].y) *
> + thisX = points_[thisSpan].x() +
> + (other.points_[otherSpan + 1].x() -
> + points_[thisSpan].y()) *
> dx / dy;
> - thisY = other.points_[--otherSpan].x;
> + thisY = other.points_[--otherSpan].x();
> } else {
> /* we stay in the same span in other */
> thisSpan++;
> - thisX = points_[thisSpan].x,
> - thisY = points_[thisSpan].y;
> + thisX = points_[thisSpan].x(),
> + thisY = points_[thisSpan].y();
> }
> result.append(thisX, other.eval(thisY, &otherSpan, false),
> eps);
> @@ -206,32 +338,47 @@ Pwl Pwl::compose(Pwl const &other, const double eps) const
> return result;
> }
>
> +/**
> + * \brief Apply function to (x,y) values at every control point
> + * \param f Function to be applied
> + */
> void Pwl::map(std::function<void(double x, double y)> f) const
> {
> for (auto &pt : points_)
> - f(pt.x, pt.y);
> + f(pt.x(), pt.y());
> }
>
> +/**
> + * \brief Apply function to (x, y0, y1) values wherever either Pwl has a
> + * control point.
Missing \param
> + */
> 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);
> + 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)
> - x = pwl1.points_[++span1].x;
> + x = pwl1.points_[++span1].x();
> else if (span1 == (int)pwl1.points_.size() - 1)
> - x = pwl0.points_[++span0].x;
> - else if (pwl0.points_[span0 + 1].x > pwl1.points_[span1 + 1].x)
> - x = pwl1.points_[++span1].x;
> + x = pwl0.points_[++span0].x();
> + else if (pwl0.points_[span0 + 1].x() > pwl1.points_[span1 + 1].x())
> + x = pwl1.points_[++span1].x();
> else
> - x = pwl0.points_[++span0].x;
> + x = pwl0.points_[++span0].x();
> f(x, pwl0.eval(x, &span0, false), pwl1.eval(x, &span1, false));
> }
> }
>
> +/**
> + * \brief Combine two Pwls
Missing \param
> + *
> + * Create a new Pwl where the y values are given by running f wherever either
> + * has a knot.
Missing \return
> + */
> Pwl Pwl::combine(Pwl const &pwl0, Pwl const &pwl1,
> std::function<double(double x, double y0, double y1)> f,
> const double eps)
> @@ -243,27 +390,32 @@ Pwl Pwl::combine(Pwl const &pwl0, Pwl const &pwl1,
> return result;
> }
>
> -void Pwl::matchDomain(Interval const &domain, bool clip, const double eps)
> -{
> - int span = 0;
> - prepend(domain.start, eval(clip ? points_[0].x : domain.start, &span),
> - eps);
> - span = points_.size() - 2;
> - append(domain.end, eval(clip ? points_.back().x : domain.end, &span),
> - eps);
> -}
> -
> +/**
> + * \brief Multiply the piecewise linear function
> + * \param d Scalar multiplier to multiply the function by
> + * \return This function, after it has been multiplied by \a d
> + */
> Pwl &Pwl::operator*=(double d)
> {
> for (auto &pt : points_)
> - pt.y *= d;
> + pt[1] *= d;
If you add non-const x() and y() accessors to the Vector class that
return a reference, you could use
pt.y() *= d;
Up to you.
> return *this;
> }
>
> -void Pwl::debug(FILE *fp) const
> +/**
> + * \brief Assemble and return a string describing the piecewise linear function
> + * \return A string describing the piecewise linear function
> + */
> +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 7d5e7e4d3fda..a2cbad6c1597 100644
> --- a/src/ipa/libipa/pwl.h
> +++ b/src/ipa/libipa/pwl.h
> @@ -2,126 +2,87 @@
> /*
> * Copyright (C) 2019, Raspberry Pi Ltd
> *
> - * piecewise linear functions interface
> + * Piecewise linear functions interface
> */
> #pragma once
>
> +#include <algorithm>
> +#include <cmath>
> #include <functional>
> -#include <math.h>
> +#include <string>
> +#include <utility>
> #include <vector>
>
> +#include <libcamera/geometry.h>
Unless I'm missing something, this isn't needed.
> +
> #include "libcamera/internal/yaml_parser.h"
>
> -namespace RPiController {
> +#include "vector.h"
> +
> +namespace libcamera {
> +
> +namespace ipa {
>
> class Pwl
> {
> public:
> + using Point = Vector<double, 2>;
> +
> 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)
> - {
> - return value < start ? start
> - : (value > end ? end : value);
> - }
> - double len() const { return end - start; }
> - };
> - 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
> +
> + double clamp(double value)
> {
> - return x * p.x + y * p.y;
> + return std::clamp(value, start, end);
> }
> - 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()); }
> +
> + double length() const { return end - start; }
> +
> + double start, end;
> };
> +
> Pwl() {}
Pwl() = default;
> - Pwl(std::vector<Point> const &points) : points_(points) {}
> - int read(const libcamera::YamlObject ¶ms);
> + Pwl(const std::vector<Point> &points)
> + : points_(points) {}
Pwl(const std::vector<Point> &points)
: points_(points)
{
}
but I think it would be better to not make the constructor inline. You
can move the implementation to the .cpp file. Same for the default
constructor.
> + int readYaml(const libcamera::YamlObject ¶ms);
> +
> void append(double x, double y, const double eps = 1e-6);
Is there a reason to qualify eps with const but not x and y ? I would
qualify them all, or none (likely none). Same for other functions using
eps, I think you can drop the const qualifier.
> - void prepend(double x, double y, const double eps = 1e-6);
> +
> + bool empty() const;
> 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,
> +
> + double eval(double x, int *span = 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,
> - 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. */
> +
> + std::pair<Pwl, bool> inverse(const double eps = 1e-6) const;
> + Pwl compose(const Pwl &other, const double eps = 1e-6) const;
> +
> 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,
> + combine(const Pwl &pwl0, const Pwl &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:
> + void prepend(double x, double y, const double eps = 1e-6);
> + static void map2(const Pwl &pwl0, const Pwl &pwl1,
> + std::function<void(double x, double y0, double y1)> f);
We usually put the static functions first or last, but not in the
middle.
> int findSpan(double x, int span) const;
And a blank line here to separate functions from variables.
Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> std::vector<Point> points_;
> };
>
> -} /* namespace RPiController */
> +} /* namespace ipa */
> +
> +} /* namespace libcamera */
--
Regards,
Laurent Pinchart
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