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view src/events/SDL_events_c.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 | 28ac87a38c17 |
| children | c9b51268668f |
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/* 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 /* Useful functions and variables from SDL_events.c */ #include "SDL_events.h" /* Start and stop the event processing loop */ extern int SDL_StartEventLoop(Uint32 flags); extern void SDL_StopEventLoop(void); extern void SDL_QuitInterrupt(void); extern void SDL_Lock_EventThread(); extern void SDL_Unlock_EventThread(); extern Uint32 SDL_EventThreadID(void); /* Event handler init routines */ extern int SDL_AppActiveInit(void); extern int SDL_KeyboardInit(void); extern int SDL_MouseInit(void); extern int SDL_QuitInit(void); /* Event handler quit routines */ extern void SDL_AppActiveQuit(void); extern void SDL_KeyboardQuit(void); extern void SDL_MouseQuit(void); extern void SDL_QuitQuit(void); /* The event filter function */ extern SDL_EventFilter SDL_EventOK; /* The array of event processing states */ extern Uint8 SDL_ProcessEvents[SDL_NUMEVENTS]; /* Internal event queueing functions (from SDL_active.c, SDL_mouse.c, SDL_keyboard.c, SDL_quit.c, SDL_events.c) */ extern int SDL_PrivateAppActive(Uint8 gain, Uint8 state); extern int SDL_PrivateMouseMotion(Uint8 buttonstate, int relative, Sint16 x, Sint16 y); extern int SDL_PrivateMouseButton(Uint8 state, Uint8 button,Sint16 x,Sint16 y); extern int SDL_PrivateKeyboard(Uint8 state, SDL_keysym *key); extern int SDL_PrivateResize(int w, int h); extern int SDL_PrivateExpose(void); extern int SDL_PrivateQuit(void); extern int SDL_PrivateSysWMEvent(SDL_SysWMmsg *message); /* Used by the activity event handler to remove mouse focus */ extern void SDL_ResetMouse(void); /* Used by the activity event handler to remove keyboard focus */ extern void SDL_ResetKeyboard(void); /* Used by the event loop to queue pending keyboard repeat events */ extern void SDL_CheckKeyRepeat(void); /* Used by the OS keyboard code to detect whether or not to do UNICODE */ #ifndef DEFAULT_UNICODE_TRANSLATION #define DEFAULT_UNICODE_TRANSLATION 0 /* Default off because of overhead */ #endif extern int SDL_TranslateUNICODE;