/* LICENSE BLOCK
Part of mde: a Modular D game-oriented Engine
Copyright © 2007-2008 Diggory Hardy

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;
without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>. */

/** Contains the IGui interface and some basic types used by the gui package. */
module mde.gui.IGui;

/** Window coordinate and dimension/size type (int).
 *
 * Used to disambiguate between general integers and coordinates; all widget positions/sizes should
 * use this type (or one of the aliases below). */
typedef int		wdim;

/** Aliases of wdim providing extra information about what their contents hold: absolute position,
 * position relative to the containing widget (wdrel should not be used if relative to anything
 * else), or size. Their use instead of wdim is optional (and in some cases wdim values aren't of
 * any of these types). Also don't use these aliases for variables which may also be used to other
 * effects, e.g. if they can have special values with special meanings. */
alias wdim	wdabs;
alias wdim	wdrel;	/// ditto
alias wdim	wdsize;	/// ditto

/** A pair of wdim variables, and strictly no other data (methods may be added if deemed useful).
 *
 * Potentially usable to return two wdim variables, e.g. width and height, from a function.
 * However, the current usage of out variables looks like it's better. */
struct wdimPair {
    wdim x, y;	/// data
}

/** The Gui interface.
*
* This contains the functions for use by Windows, not those for external use (use Gui directly for
* that). */
interface IGui
{
    /**  Get the GUI's rendererName for creating a renderer (may be overridden by the window). */
    char[] rendererName ();
    
    /** Called by a sub-widget when a redraw is necessary (since drawing may sometimes be done on
    * event.
    *
    * Currently forces the whole Gui to be redrawn. */
    void requestRedraw ();
    
    /** Add a mouse click callback: delegate will be called for all mouse click events recieved.
     *
     * The delegate should return true if it accepts the event and no further processing is
     * required (i.e. the event should not be handled by anything else), false otherwise.
     * Note that this is not a mechanism to prevent unwanted event handling, and in the future may
     * be removed (so event handling cannot be cut short). */
    void addClickCallback (bool delegate (wdabs cx, wdabs cy, ubyte b, bool state) dg);
    /** Add a mouse motion callback: delegate will be called for all motion events recieved. */
    void addMotionCallback (void delegate (wdabs cx, wdabs cy) dg);
    /** Remove all event callbacks with _frame pointer frame. */
    void removeCallbacks (void* frame);
}