view include/SDL_mouse.h @ 1287:15a89a0c52bf

Date: Tue, 15 Feb 2005 21:28:48 +0900 (JST) From: "Michael Leonhard" Subject: [SDL] resize bug on Win32 and patch This is my first post to this mailing list. In this email I will detail a bug in the behavior of resizable SDL windows on Win32. Then I will explain the solution and provide a patch. Symptoms: Under Windows, an SDL display created with the SDL_RESIZABLE flag exhibits quirky behavior when being maximized. The window is resized to the proper size, but it is shifted upwards about half the height of the title bar. Similarly, a window whose origin is above the top of the screen will spontaneously move its upper-left origin upon being resized. After two such resize-induced moves, the title bar will be entirely off the top edge of the screen. Subsequently, when the mouse is clicked and released on the window border, the window will shrink its height spontaneously. This height shrinkage occurs even if the user did not resize the border. To observe this curious situation, please invoke: SDL-1.2.8/test/testwm.exe -resize Cause: A pair of integers, SDL_windowX and SDL_windowY, are defined in video/wincommon/SDL_sysevents.c. They are used by the DirectX video driver and the DIB video driver: video/windx5/SDL_dx5video.c video/windib/SDL_dibvideo.c As I understand the source code, the primary use of these variables is to create a rectangle that represents the surface area in CLIENT SPACE. Client space refers to a coordinate system that originates at the upper left corner of a Win32 Window's drawable area. This is just inside the window border and title bar. This client space rectangle, called bounds, is subsequently converted to screen space with a call to AdjustWindowRectEx. The problem is found in SDL's handling of the WM_WINDOWPOSCHANGED message. According to MSDN, "The WM_WINDOWPOSCHANGED message is sent to a window whose size, position, or place in the Z order has changed as a result of a call to the SetWindowPos function or another window-management function." I have confirmed that this message is indeed being sent to the SDL window when the mouse is clicked on the window border, even if the window border is not dragged. In video/wincommon/SDL_sysevents.c, on line 464, in response to the WM_WINDOWPOSCHANGED message, the (potentially) new client rectangle is obtained. This rectangle is translated into screen coordinates and THEN assigned to the SDL_windowX and Y variables. Thus screen coordinates are being assigned to client coordinate variables. Once this is understood, the solution is apparent: assign SDL_windowX and Y before translating the rectangle to screen coordinates. This is accomplished by the following patch. -Mike_L
author Sam Lantinga <slouken@libsdl.org>
date Sun, 29 Jan 2006 08:50:06 +0000
parents f09d5edfc7a3
children c9b51268668f
line wrap: on
line source

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2004 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
    License as published by the Free Software Foundation; either
    version 2 of the License, or (at your option) any later version.

    This library 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
    Library General Public License for more details.

    You should have received a copy of the GNU Library General Public
    License along with this library; if not, write to the Free
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

    Sam Lantinga
    slouken@libsdl.org
*/

#ifdef SAVE_RCSID
static char rcsid =
 "@(#) $Id$";
#endif

/* Include file for SDL mouse event handling */

#ifndef _SDL_mouse_h
#define _SDL_mouse_h

#include "SDL_types.h"
#include "SDL_video.h"

#include "begin_code.h"
/* Set up for C function definitions, even when using C++ */
#ifdef __cplusplus
extern "C" {
#endif

typedef struct WMcursor WMcursor;	/* Implementation dependent */
typedef struct SDL_Cursor {
	SDL_Rect area;			/* The area of the mouse cursor */
	Sint16 hot_x, hot_y;		/* The "tip" of the cursor */
	Uint8 *data;			/* B/W cursor data */
	Uint8 *mask;			/* B/W cursor mask */
	Uint8 *save[2];			/* Place to save cursor area */
	WMcursor *wm_cursor;		/* Window-manager cursor */
} SDL_Cursor;

/* Function prototypes */
/*
 * Retrieve the current state of the mouse.
 * The current button state is returned as a button bitmask, which can
 * be tested using the SDL_BUTTON(X) macros, and x and y are set to the
 * current mouse cursor position.  You can pass NULL for either x or y.
 */
extern DECLSPEC Uint8 SDLCALL SDL_GetMouseState(int *x, int *y);

/*
 * Retrieve the current state of the mouse.
 * The current button state is returned as a button bitmask, which can
 * be tested using the SDL_BUTTON(X) macros, and x and y are set to the
 * mouse deltas since the last call to SDL_GetRelativeMouseState().
 */
extern DECLSPEC Uint8 SDLCALL SDL_GetRelativeMouseState(int *x, int *y);

/*
 * Set the position of the mouse cursor (generates a mouse motion event)
 */
extern DECLSPEC void SDLCALL SDL_WarpMouse(Uint16 x, Uint16 y);

/*
 * Create a cursor using the specified data and mask (in MSB format).
 * The cursor width must be a multiple of 8 bits.
 *
 * The cursor is created in black and white according to the following:
 * data  mask    resulting pixel on screen
 *  0     1       White
 *  1     1       Black
 *  0     0       Transparent
 *  1     0       Inverted color if possible, black if not.
 *
 * Cursors created with this function must be freed with SDL_FreeCursor().
 */
extern DECLSPEC SDL_Cursor * SDLCALL SDL_CreateCursor
		(Uint8 *data, Uint8 *mask, int w, int h, int hot_x, int hot_y);

/*
 * Set the currently active cursor to the specified one.
 * If the cursor is currently visible, the change will be immediately 
 * represented on the display.
 */
extern DECLSPEC void SDLCALL SDL_SetCursor(SDL_Cursor *cursor);

/*
 * Returns the currently active cursor.
 */
extern DECLSPEC SDL_Cursor * SDLCALL SDL_GetCursor(void);

/*
 * Deallocates a cursor created with SDL_CreateCursor().
 */
extern DECLSPEC void SDLCALL SDL_FreeCursor(SDL_Cursor *cursor);

/*
 * Toggle whether or not the cursor is shown on the screen.
 * The cursor start off displayed, but can be turned off.
 * SDL_ShowCursor() returns 1 if the cursor was being displayed
 * before the call, or 0 if it was not.  You can query the current
 * state by passing a 'toggle' value of -1.
 */
extern DECLSPEC int SDLCALL SDL_ShowCursor(int toggle);

/* Used as a mask when testing buttons in buttonstate
   Button 1:	Left mouse button
   Button 2:	Middle mouse button
   Button 3:	Right mouse button
   Button 4:	Mouse wheel up	 (may also be a real button)
   Button 5:	Mouse wheel down (may also be a real button)
 */
#define SDL_BUTTON(X)		(SDL_PRESSED << ((X)-1))
#define SDL_BUTTON_LEFT		1
#define SDL_BUTTON_MIDDLE	2
#define SDL_BUTTON_RIGHT	3
#define SDL_BUTTON_WHEELUP	4
#define SDL_BUTTON_WHEELDOWN	5
#define SDL_BUTTON_LMASK	SDL_BUTTON(SDL_BUTTON_LEFT)
#define SDL_BUTTON_MMASK	SDL_BUTTON(SDL_BUTTON_MIDDLE)
#define SDL_BUTTON_RMASK	SDL_BUTTON(SDL_BUTTON_RIGHT)


/* Ends C function definitions when using C++ */
#ifdef __cplusplus
}
#endif
#include "close_code.h"

#endif /* _SDL_mouse_h */