RmlUi/Include/RmlUi/Core/Tween.h

/*
 * This source file is part of RmlUi, the HTML/CSS Interface Middleware
 *
 * For the latest information, see http://github.com/mikke89/RmlUi
 *
 * Copyright (c) 2019-2023 The RmlUi Team, and contributors
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 */

#ifndef RMLUI_CORE_TWEEN_H
#define RMLUI_CORE_TWEEN_H

#include "Header.h"
#include "Types.h"

namespace Rml {

class RMLUICORE_API Tween {
public:
	enum Type { None, Back, Bounce, Circular, Cubic, Elastic, Exponential, Linear, Quadratic, Quartic, Quintic, Sine, Callback, Count };
	enum Direction { In = 1, Out = 2, InOut = 3 };
	using CallbackFnc = float (*)(float);

	Tween(Type type = Linear, Direction direction = Out);
	Tween(Type type_in, Type type_out);
	Tween(CallbackFnc callback, Direction direction = In);

	// Evaluate the Tweening function at point t in [0, 1].
	float operator()(float t) const;

	// Reverse direction of the tweening function.
	void reverse();

	bool operator==(const Tween& other) const;
	bool operator!=(const Tween& other) const;

	String to_string() const;

private:
	float tween(Type type, float t) const;
	float in(float t) const;
	float out(float t) const;
	float in_out(float t) const;

	Type type_in = None;
	Type type_out = None;
	CallbackFnc callback = nullptr;
};

} // namespace Rml
#endif