image.hpp

/*
   Copyright (C) 2003 - 2017 by David White <dave@whitevine.net>
   Part of the Battle for Wesnoth Project http://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 "terrain/translation.hpp"
#include "game_config.hpp"

#include <SDL.h>
#include <unordered_map>

class surface;
class texture;

///this module manages the cache of images. With an image name, you can get
///the surface corresponding to that image.
//
namespace image {
	template<typename T>
	class cache_type;

	//a generic image locator. Abstracts the location of an image.
	class locator
	{
	public:
		enum type { NONE, FILE, SUB_FILE };
	private:
		// Called by each constructor after actual construction to
		// initialize the index_ field
		void init_index();
		void parse_arguments();
		struct value {
			value();
			value(const value &a);
			value(const char *filename);
			value(const std::string& filename);
			value(const std::string& filename, const std::string& modifications);
			value(const std::string& filename, const map_location& loc, int center_x, int center_y, const std::string& modifications);

			bool operator==(const value& a) const;
			bool operator<(const value& a) const;

			type type_;
			std::string filename_;
			map_location loc_;
			std::string modifications_;
			int center_x_;
			int center_y_;
		};

		friend struct std::hash<value>;

	public:

		typedef std::unordered_map<value, int> locator_finder_t;

		// Constructing locators is somewhat slow, accessing image
		// through locators is fast. The idea is that calling functions
		// should store locators, and not strings to construct locators
		// (the second will work, of course, but will be slower)
		locator();
		locator(const locator &a, const std::string &mods ="");
		locator(const char *filename);
		locator(const std::string& filename);
		locator(const std::string& filename, const std::string& modifications);
		locator(const std::string &filename, const map_location &loc,
		int center_x, int center_y, const std::string& modifications = "");

		locator& operator=(const locator &a);
		bool operator==(const locator &a) const { return index_ == a.index_; }
		bool operator!=(const locator &a) const { return index_ != a.index_; }
		bool operator<(const locator &a) const { return index_ < a.index_; }

		const std::string &get_filename() const { return val_.filename_; }
		const map_location& get_loc() const { return val_.loc_ ; }
		int get_center_x() const { return val_.center_x_; }
		int get_center_y() const { return val_.center_y_; }
		const std::string& get_modifications() const {return val_.modifications_;}
		type get_type() const { return val_.type_; }
		// const int get_index() const { return index_; };

		// returns true if the locator does not correspond to any
		// actual image
		bool is_void() const { return val_.type_ == NONE; }

		/**
		 * Tests whether the file the locater points at exists.
		 *
		 * is_void doesn't seem to work before the image is loaded and also in
		 * debug mode a placeholder is returned. So it's not possible to test
		 * for the existence of a file. So this function does that. (Note it
		 * tests for existence not whether or not it's a valid image.)
		 *
		 * @return                Whether or not the file exists.
		 */
		bool file_exists() const;

		template <typename T>
		bool in_cache(cache_type<T> &cache) const;
		template <typename T>
		T &access_in_cache(cache_type<T> &cache) const;
		template <typename T>
		const T &locate_in_cache(cache_type<T> &cache) const;
		template <typename T>
		void add_to_cache(cache_type<T> &cache, const T &data) const;

	private:

		int index_;
		value val_;
	};

	surface load_from_disk(const locator &loc);

	typedef cache_type<surface> image_cache;
	typedef cache_type<texture> texture_cache;
	typedef cache_type<bool> bool_cache;

	typedef std::map<t_translation::terrain_code, surface> mini_terrain_cache_map;
	extern mini_terrain_cache_map mini_terrain_cache;
	extern mini_terrain_cache_map mini_fogged_terrain_cache;
	extern mini_terrain_cache_map mini_highlighted_terrain_cache;

	///light_string store colors info of central and adjacent hexes.
	///The structure is one or several 4 chars blocks (L,R,G,B)
	///where RGB is the color and L is the lightmap to use:
    ///   -1: none
    ///    0: full hex
    ///  1-6: concave corners
    /// 7-12: convex half-corners 1
    ///13-19: convex half-corners 2
	typedef std::basic_string<signed char> light_string;
	///return light_string of one light operation(see above)
	light_string get_light_string(int op, int r, int g, int b);

	// pair each light possibility with its lighted surface
	typedef std::map<light_string, surface> lit_variants;
	// lighted variants for each locator
	typedef cache_type<lit_variants> lit_cache;

	void flush_cache();

	///the image manager is responsible for setting up images, and destroying
	///all images when the program exits. It should probably
	///be created once for the life of the program
	struct manager
	{
		manager();
		~manager();
	};

	///will make all scaled images have these rgb values added to all
	///their pixels. i.e. add a certain color hint to images. useful
	///for representing day/night. Invalidates all scaled images.
	void set_color_adjustment(int r, int g, int b);

	///set the team colors used by the TC image modification
	///use a vector with one string for each team
	///using nullptr will reset to default TC
	void set_team_colors(const std::vector<std::string>* colors = nullptr);

	const std::vector<std::string>& get_team_colors();

	///sets the pixel format used by the images. Is called every time the
	///video mode changes. Invalidates all images.
	void set_pixel_format(SDL_PixelFormat* format);

	///sets the amount scaled images should be scaled. Invalidates all
	///scaled images.
	void set_zoom(unsigned int zoom);

	/// UNSCALED : image will be drawn "as is" without changing size, even in case of redraw
	/// SCALED_TO_ZOOM : image will be scaled taking zoom into account
	/// HEXED : the hex mask is applied on the image
	/// SCALED_TO_HEX : image will be scaled to fit into a hex, taking zoom into account
	/// TOD_COLORED : same as SCALED_TO_HEX but ToD coloring is also applied
	/// BRIGHTENED  : same as TOD_COLORED but also brightened
	enum TYPE { UNSCALED, SCALED_TO_ZOOM, HEXED, SCALED_TO_HEX, TOD_COLORED, BRIGHTENED};

	///function to get the surface corresponding to an image.
	surface get_image(const locator& i_locator, TYPE type=UNSCALED);

	texture get_texture(const image::locator& i_locator);

	///function to get the surface corresponding to an image.
	///after applying the lightmap encoded in ls
	///type should be HEXED or SCALED_TO_HEX
	surface get_lighted_image(const image::locator& i_locator, const light_string& ls, TYPE type);

	///function to get the standard hex mask
	surface get_hexmask();

	///function to check if an image fit into an hex
	///return false if the image has not the standard size.
	bool is_in_hex(const locator& i_locator);

	///function to check if an image is empty after hex cut
	///should be only used on terrain image (cache the hex cut version)
	bool is_empty_hex(const locator& i_locator);

	///function to reverse an image. The image MUST have originally been returned from
	///an image:: function. Returned images have the same semantics as for get_image()
	surface reverse_image(const surface &surf);

	///returns true if the given image actually exists, without loading it.
	bool exists(const locator& i_locator);

	/// precache the existence of files in the subdir (ex: "terrain/")
	void precache_file_existence(const std::string& subdir = "");
	bool precached_file_exists(const std::string& file);

	/// initialize any private data, e.g. algorithm choices from preferences
	bool update_from_preferences();

	bool save_image(const locator& i_locator, const std::string& outfile);
	bool save_image(const surface& surf, const std::string& outfile);
}