index : libcamera/vivid.git	pobrn/rebase vivid
	libcamera pipeline handler for VIVID	git repository hosting on libcamera.org

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path: root/src/ipa/libipa

Mode	Name	Size
-rw-r--r--	algorithm.cpp	6618	logplain
-rw-r--r--	algorithm.h	2456	logplain
-rw-r--r--	camera_sensor_helper.cpp	15850	logplain
-rw-r--r--	camera_sensor_helper.h	2098	logplain
-rw-r--r--	fc_queue.cpp	5574	logplain
-rw-r--r--	fc_queue.h	2802	logplain
-rw-r--r--	histogram.cpp	4437	logplain
-rw-r--r--	histogram.h	807	logplain
-rw-r--r--	meson.build	536	logplain
-rw-r--r--	module.cpp	3899	logplain
-rw-r--r--	module.h	2697	logplain

generated by cgit v1.2.1 (git 2.18.0) at 2025-01-13 06:24:37 +0000

/* SPDX-License-Identifier: BSD-2-Clause */
/*
 * Copyright (C) 2019, Raspberry Pi Ltd
 *
 * piecewise linear functions
 */

#include <cassert>
#include <cmath>
#include <stdexcept>

#include "pwl.h"

using namespace RPiController;

int Pwl::read(const libcamera::YamlObject &params)
{
	if (!params.size() || params.size() % 2)
		return -EINVAL;

	const auto &list = params.asList();

	for (auto it = list.begin(); it != list.end(); it++) {
		auto x = it->get<double>();
		if (!x)
			return -EINVAL;
		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));
	}

	return 0;
}

void Pwl::append(double x, double y, const double eps)
{
	if (points_.empty() || points_.back().x + eps < x)
		points_.push_back(Point(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));
}

Pwl::Interval Pwl::domain() const
{
	return Interval(points_[0].x, points_[points_.size() - 1].x);
}

Pwl::Interval Pwl::range() const
{
	double lo = points_[0].y, hi = lo;
	for (auto &p : points_)
		lo = std::min(lo, p.y), hi = std::max(hi, p.y);
	return Interval(lo, hi);
}

bool Pwl::empty() const
{
	return points_.empty();
}

double Pwl::eval(double x, int *spanPtr, 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 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.
	 */
	int lastSpan = points_.size() - 2;
	/*
	 * some algorithms may call us with span pointing directly at the last
	 * control point
	 */
	span = std::max(0, std::min(lastSpan, span));
	while (span < lastSpan && x >= points_[span + 1].x)
		span++;
	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
{
	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)
			/* do nothing */;
		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
			neither = true;
	}

	/*
	 * This is not a proper inverse if we found ourselves putting points
	 * onto both ends of the inverse, or if there were points that couldn't
	 * go on either.
	 */
	if (trueInverse)