[PATCH 3/4] ipa: libipa: pwl: Clean up Pwl class to match libcamera
Paul Elder
paul.elder at ideasonboard.com
Fri Apr 5 10:02:58 CEST 2024
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)
{
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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