--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libmlk-rpg/rpg/message.h	Sat Nov 28 22:37:30 2020 +0100
@@ -0,0 +1,225 @@
+/*
+ * message.h -- message dialog
+ *
+ * Copyright (c) 2020 David Demelier <markand@malikania.fr>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#ifndef MOLKO_RPG_MESSAGE_H
+#define MOLKO_RPG_MESSAGE_H
+
+/**
+ * \file message.h
+ * \brief Message dialog.
+ * \ingroup actions
+ * \ingroup drawing
+ *
+ * This module's purpose is to show a dialog box into the screen to show text
+ * and optionally ask the user a question. It is similar to what you're used to
+ * see in many RPGs.
+ *
+ * To use it use the following procedure:
+ *
+ * 1. Create a struct message object and set required properties,
+ * 2. Call \ref message_start to reset the state,
+ * 3. Call \ref message_handle and \ref message_update with appropriate values,
+ * 4. Call \ref message_draw to render the dialog.
+ *
+ * Depending on message flags or user input, step 3 may return true in this
+ * case you should stop using the message as it has completed rendering.
+ *
+ * \note All properties must exist until the object is no longer used.
+ *
+ * \code
+ * struct message msg = {
+ * 	// You can show up to 6 lines.
+ * 	.text = {
+ * 		"Hello, what's up?"
+ * 	},
+ * 	// This indicates this message is a question.
+ * 	.flags = MESSAGE_FLAGS_QUESTION
+ * };
+ * \endcode
+ *
+ * For performance reasons, flexibility and simplicity, the message box does
+ * not try to be clever about positions of lines. It will simply create an
+ * animation for opening the box, drawing the lines to the position according
+ * to the theme padding and spacing and interact with user. For convenience
+ * though, the \ref message_query can be used to determine dimensions required
+ * for a better final result.
+ *
+ * ## Example, computing the dimensions:
+ *
+ * \code
+ * // We create a message that we put on the center of the screen.
+ * struct message msg = {
+ *     .text = {
+ *         "Hi, have you tried turning it off and on again?"
+ *     }
+ * };
+ *
+ * message_query(&msg, &msg.w, &msg.h);
+ * align(ALIGN_CENTER, &msg.x, &msg.y, msg.w, msg.h, 0, 0, window.w, window.h);
+ * \endcode
+ */
+
+#include <stdbool.h>
+
+#include <core/texture.h>
+
+struct action;
+struct font;
+struct theme;
+
+union event;
+
+/**
+ * \brief Default animation speed in milliseconds.
+ */
+#define MESSAGE_DELAY_DEFAULT   (150)
+
+/**
+ * \brief Default timeout in milliseconds for automatic messages.
+ */
+#define MESSAGE_TIMEOUT_DEFAULT (5000)
+
+/**
+ * \brief Maximum number of lines allowed in the message.
+ */
+#define MESSAGE_LINES_MAX       (3)
+
+/**
+ * \brief Message flags.
+ */
+enum message_flags {
+	MESSAGE_FLAGS_AUTOMATIC         = (1 << 0),     /*!< Will automatically change state by itself. */
+	MESSAGE_FLAGS_QUESTION          = (1 << 1),     /*!< The message is a question. */
+	MESSAGE_FLAGS_FADEIN            = (1 << 2),     /*!< Animate opening. */
+	MESSAGE_FLAGS_FADEOUT           = (1 << 3)      /*!< Animate closing. */
+};
+
+/**
+ * \brief Message state.
+ */
+enum message_state {
+	MESSAGE_STATE_NONE,             /*!< Message hasn't start yet or is finished */
+	MESSAGE_STATE_OPENING,          /*!< Message animation is opening */
+	MESSAGE_STATE_SHOWING,          /*!< Message is displaying */
+	MESSAGE_STATE_HIDING            /*!< Message animation for hiding */
+};
+
+/**
+ * \brief Message object.
+ */
+struct message {
+	int x;                                  /*!< (+) Position in x. */
+	int y;                                  /*!< (+) Position in y. */
+	unsigned int w;                         /*!< (+) Width. */
+	unsigned int h;                         /*!< (+) Height. */
+	unsigned int spacing;                   /*!< (+) Spacing between lines. */
+	unsigned int delay;                     /*!< (+) Delay for animations. */
+	unsigned int timeout;                   /*!< (+) Timeout in milliseconds. */
+	const char *text[MESSAGE_LINES_MAX];    /*!< (+) Lines of text to show. */
+	unsigned int index;                     /*!< (+) Line selected */
+	enum message_flags flags;               /*!< (+) Message flags */
+	enum message_state state;               /*!< (-) Current state */
+	const struct theme *theme;              /*!< (+&?) Theme to use. */
+	unsigned int elapsed;                   /*!< (-) Time elapsed. */
+	double scale;                           /*!< (-) Current scale [0-1]. */
+};
+
+/**
+ * Start opening the message. This function will reset the message state and
+ * elapsed time.
+ *
+ * \pre msg != NULL
+ * \pre msg->delay > 0 if msg->flags contains MESSAGE_FLAGS_FADEIN or
+ *      MESSAGE_FLAGS_FADEOUT
+ * \param msg the message
+ */
+void
+message_start(struct message *msg);
+
+/**
+ * Compute the minimal message dimensions required.
+ *
+ * \pre msg != NULL
+ * \param msg the message to query
+ * \param w the pointer to width (may be NULL)
+ * \param h the pointer to height (may be NULL)
+ */
+void
+message_query(const struct message *msg, unsigned int *w, unsigned int *h);
+
+/**
+ * Handle input events.
+ *
+ * This function will alter state of the message and change its selection in
+ * case of question.
+ *
+ * \pre msg != NULL
+ * \pre ev != NULL
+ * \param msg the message
+ * \param ev the event which occured
+ */
+void
+message_handle(struct message *msg, const union event *ev);
+
+/**
+ * Update the message state and elapsed time..
+ *
+ * \pre msg != NULL
+ * \param msg the message
+ * \param ticks the elapsed delay since last frame
+ * \return true if it has finished
+ */
+bool
+message_update(struct message *msg, unsigned int ticks);
+
+/**
+ * Draw the message into the screen.
+ *
+ * \pre msg != NULL
+ * \param msg the message
+ */
+void
+message_draw(const struct message *msg);
+
+/**
+ * Start hiding the message.
+ *
+ * \pre msg != NULL
+ * \param msg the message
+ * \note You should still continue to draw the message as the animation is not
+ *       finished!
+ */
+void
+message_hide(struct message *msg);
+
+/**
+ * Convert message into an action.
+ *
+ * \pre msg != NULL
+ * \pre act != NULL
+ * \param msg the message to reference
+ * \param act the action to fill
+ * \post act->data contains msg
+ * \post act->handle invokes message_handle
+ * \post act->update invokes message_update
+ * \post act->draw invokes message_draw
+ */
+void
+message_action(struct message *msg, struct action *act);
+
+#endif /* !MOLKO_RPG_MESSAGE_H */