mouse_handler_base.hpp

/*
   Copyright (C) 2006 - 2018 by Joerg Hinrichs <joerg.hinrichs@alice-dsl.de>
   wesnoth playturn Copyright (C) 2003 by David White <dave@whitevine.net>
   Part of the Battle for Wesnoth Project https://www.wesnoth.org/

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY.

   See the COPYING file for more details.
*/

#pragma once

#include "map/location.hpp"

#include <SDL_events.h>

class display;

namespace events
{
struct command_disabler
{
	command_disabler();
	~command_disabler();
};

extern int commands_disabled;

class mouse_handler_base
{
public:
	mouse_handler_base();

	virtual ~mouse_handler_base()
	{
	}

	/**
	 * Reference to the used display objects. Derived classes should ensure
	 * this is always valid. Note the constructor of this class cannot use this.
	 */
	virtual display& gui() = 0;

	/** Const version of @ref gui */
	virtual const display& gui() const = 0;
	
	/** If mouse/finger has moved far enough to consider it move/swipe, and not a click/touch */
	bool dragging_started() const;

	/**
	 * @return true when the class in the "dragging" state.
	 */
	bool is_dragging() const;

	/** Minimum dragging distance to fire the drag&drop */
	virtual int drag_threshold() const
	{
		return 0;
	}

	void mouse_motion_event(const SDL_MouseMotionEvent& event, const bool browse);

	void touch_motion_event(const SDL_TouchFingerEvent& event, const bool browse);

	/** Update the mouse with a fake mouse motion */
	void mouse_update(const bool browse, map_location loc);

	bool get_show_menu() const
	{
		return show_menu_;
	}

	/**
	 * This handles minimap scrolling and click-drag.
	 * @returns true when the caller should not process the mouse motion
	 * further (i.e. should return), false otherwise.
	 */
	bool mouse_motion_default(int x, int y, bool update);

	/**
	 * Called when a mouse motion event takes place. Derived classes must provide an
	 * implementation, possibly using mouse_motion_default().
	 */
	virtual void mouse_motion(
			int x, int y, const bool browse, bool update = false, map_location new_loc = map_location::null_location())
			= 0;

	virtual void touch_motion(
			int x, int y, const bool browse, bool update = false, map_location new_loc = map_location::null_location())
			= 0;

	virtual void mouse_press(const SDL_MouseButtonEvent& event, const bool browse);
	bool is_left_click(const SDL_MouseButtonEvent& event) const;
	bool is_middle_click(const SDL_MouseButtonEvent& event) const;
	bool is_right_click(const SDL_MouseButtonEvent& event) const;
	bool is_touch_click(const SDL_MouseButtonEvent& event) const;

	/** Called when scrolling with the mouse wheel. */
	virtual void mouse_wheel(int xscroll, int yscroll, bool browse);

	/**
	 * Derived classes can override this to disable mousewheel scrolling under
	 * some circumstances, e.g. when the mouse wheel controls something else,
	 * but the event is also received by this class
	 */
	virtual bool allow_mouse_wheel_scroll(int /*x*/, int /*y*/)
	{
		return true;
	}

	/**
	 * Overridden in derived classes, called on a left click (mousedown).
	 * Defaults to process (initiate) minimap scrolling.
	 *
	 * @returns true when the click should not process the event further.
	 * This means do not treat the call as a start of drag movement.
	 * FIXME: This return value is currently ignored
	 */
	virtual bool left_click(int x, int y, const bool browse);

	/** Overridden in derived class. Called on drag + drop movements. */
	virtual void move_action(bool /*browse*/)
	{
		// Overridden with unit move code elsewhere
	}

	virtual void touch_action(const map_location hex, bool browse);

	/** Called whenever the left mouse drag has "ended". */
	virtual void left_drag_end(int /*x*/, int /*y*/, const bool /*browse*/);

	/** Called when the left mouse button is up */
	virtual void left_mouse_up(int /*x*/, int /*y*/, const bool /*browse*/)
	{
	}

	/**
	 * Overridden in derived classes, called on a right click (mousedown).
	 * Defaults to displaying the menu (by setting the appropriate flag)
	 * if right_click_show_menu returns true.
	 *
	 * @returns true when the click should not process the event further.
	 * This means do not treat the call as a start of drag movement.
	 */
	virtual bool right_click(int x, int y, const bool browse)
	{
		return right_click_show_menu(x, y, browse);
	}

	/**
	 * Called in the default right_click when the context menu is about to
	 * be shown, can be used for preprocessing and preventing the menu from
	 * being displayed without rewriting the right click function.
	 *
	 * @returns true when the menu should be displayed and false otherwise
	 * FIXME: This return value is currently ignored
	 */
	virtual bool right_click_show_menu(int /*x*/, int /*y*/, const bool /*browse*/)
	{
		return true;
	}

	/** Called whenever the right mouse drag has "ended". */
	virtual void right_drag_end(int /*x*/, int /*y*/, const bool /*browse*/)
	{
		// FIXME: This is called when we select an option in context-menu,
		//       which is bad because that was not a real dragging
	}

	/** Called when the right mouse button is up. */
	virtual void right_mouse_up(int /*x*/, int /*y*/, const bool /*browse*/);

	/** Called when the mouse wheel is scrolled up. */
	virtual void mouse_wheel_up(int /*x*/, int /*y*/, const bool /*browse*/)
	{
	}

	/** Called when the mouse wheel is scrolled down. */
	virtual void mouse_wheel_down(int /*x*/, int /*y*/, const bool /*browse*/)
	{
	}

	/** Called when the mouse wheel is scrolled left. */
	virtual void mouse_wheel_left(int /*x*/, int /*y*/, const bool /*browse*/)
	{
	}

	/** Called when the mouse wheel is scrolled right. */
	virtual void mouse_wheel_right(int /*x*/, int /*y*/, const bool /*browse*/)
	{
	}

	/** Called when the middle click scrolling. */
	void set_scroll_start(int x, int y)
	{
		scroll_start_x_ = x;
		scroll_start_y_ = y;
	}

	const SDL_Point get_scroll_start() const
	{
		return {scroll_start_x_, scroll_start_y_};
	}

	bool scroll_started() const
	{
		return scroll_started_;
	}

protected:
	void cancel_dragging();
	void clear_dragging(const SDL_MouseButtonEvent& event, bool browse);
	void init_dragging(bool& dragging_flag);

	/** MMB click (on game map) state flag */
	bool simple_warp_;

	/** minimap scrolling (scroll-drag) state flag */
	bool minimap_scrolling_;

	/** LMB drag init flag */
	bool dragging_left_;

	/** Finger drag init flag */
	bool dragging_touch_;

	/** Actual drag flag */
	bool dragging_started_;

	/** RMB drag init flag */
	bool dragging_right_;

	/** Drag start position x */
	int drag_from_x_;

	/** Drag start position y */
	int drag_from_y_;

	/** Drag start map location */
	map_location drag_from_hex_;

	/** last highlighted hex */
	map_location last_hex_;

	/** Show context menu flag */
	bool show_menu_;

	/** Relative to middle click scrolling */
	int scroll_start_x_;
	int scroll_start_y_;
	bool scroll_started_;
};

} // end namespace events