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-rw-r--r--src/ipa/libipa/pwl.h86
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diff --git a/src/ipa/libipa/pwl.h b/src/ipa/libipa/pwl.h
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+/* SPDX-License-Identifier: BSD-2-Clause */
+/*
+ * Copyright (C) 2019, Raspberry Pi Ltd
+ *
+ * Piecewise linear functions interface
+ */
+#pragma once
+
+#include <algorithm>
+#include <cmath>
+#include <functional>
+#include <string>
+#include <utility>
+#include <vector>
+
+#include "libcamera/internal/yaml_parser.h"
+
+#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) {}
+
+ bool contains(double value)
+ {
+ return value >= start && value <= end;
+ }
+
+ double clamp(double value)
+ {
+ return std::clamp(value, start, end);
+ }
+
+ double length() const { return end - start; }
+
+ double start, end;
+ };
+
+ Pwl();
+ Pwl(const std::vector<Point> &points);
+ int readYaml(const libcamera::YamlObject &params);
+
+ void append(double x, double y, double eps = 1e-6);
+
+ bool empty() const;
+ Interval domain() const;
+ Interval range() const;
+
+ double eval(double x, int *span = nullptr,
+ bool updateSpan = true) const;
+
+ std::pair<Pwl, bool> inverse(double eps = 1e-6) const;
+ Pwl compose(const Pwl &other, double eps = 1e-6) const;
+
+ void map(std::function<void(double x, double y)> f) const;
+
+ static Pwl
+ combine(const Pwl &pwl0, const Pwl &pwl1,
+ std::function<double(double x, double y0, double y1)> f,
+ double eps = 1e-6);
+
+ Pwl &operator*=(double d);
+
+ std::string toString() const;
+
+private:
+ static void map2(const Pwl &pwl0, const Pwl &pwl1,
+ std::function<void(double x, double y0, double y1)> f);
+ void prepend(double x, double y, double eps = 1e-6);
+ int findSpan(double x, int span) const;
+
+ std::vector<Point> points_;
+};
+
+} /* namespace ipa */
+
+} /* namespace libcamera */