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view src/thread/linux/clone.S @ 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 | 974ba6ae0fa3 |
| children | c9b51268668f |
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/* Taken with thanks from LinuxThreads 0.6 */ /* This is no longer necessary with glibc-2.1, which has its own clone() */ #ifdef linux /* Look to see if glibc is available, and if so, what version */ #include <features.h> #if (__GLIBC__ > 2) || ((__GLIBC__ == 2) && (__GLIBC_MINOR__ >= 1)) #define HAVE_CLONE #endif /* glibc 2.1 or newer */ #endif /* linux */ #if defined(linux) && !defined(SDL_USE_PTHREADS) && !defined(HAVE_CLONE) #if defined(__i386__) /************************************************************************/ /* Copyright (C) 1996, 1997 Free Software Foundation, Inc. Contributed by Richard Henderson (rth@tamu.edu) The GNU C 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. The GNU C 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 the GNU C Library; see the file COPYING.LIB. If not, write to the Free Software Foundation, Inc., 675 Mass Ave, #ifdef SAVE_RCSID static char rcsid = "@(#) $Id$"; #endif Cambridge, MA 02139, USA. */ /* clone() is even more special than fork() as it mucks with stacks and invokes a function in the right context after its all over. */ #include <asm/errno.h> #include <asm/unistd.h> /* int clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg); */ .text .align 4 .globl __clone .type __clone,@function .weak clone clone = __clone __clone: /* Sanity check arguments. */ movl $-EINVAL,%eax movl 4(%esp),%ecx /* no NULL function pointers */ testl %ecx,%ecx jz syscall_error movl 8(%esp),%ecx /* no NULL stack pointers */ testl %ecx,%ecx jz syscall_error /* Insert the argument onto the new stack. */ subl $8,%ecx movl 16(%esp),%eax movl %eax,4(%ecx) /* Save the function pointer as the zeroth argument. */ /* It will be popped off in the child in the ebx frobbing below. */ movl 4(%esp),%eax movl %eax,0(%ecx) /* Do the system call */ pushl %ebx movl 16(%esp),%ebx movl $__NR_clone,%eax int $0x80 popl %ebx test %eax,%eax jl syscall_error jz thread_start ret syscall_error: negl %eax pushl %eax #ifdef __PIC__ call __errno_location@PLT #else call __errno_location #endif popl 0(%eax) movl $-1, %eax ret thread_start: subl %ebp,%ebp /* terminate the stack frame */ call *%ebx pushl %eax #ifdef __PIC__ call _exit@PLT #else call _exit #endif /************************************************************************/ #elif defined(sparc) /************************************************************************/ /* Copyright (C) 1996, 1997 Free Software Foundation, Inc. Contributed by Miguel de Icaza (miguel@nuclecu.unam.mx) Based on code written for the Intel by Richard Henderson (rth@tamu.edu) The GNU C 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. The GNU C 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 the GNU C Library; see the file COPYING.LIB. If not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ /* clone() is even more special than fork() as it mucks with stacks and invokes a function in the right context after its all over. */ #include <asm/errno.h> #include <asm/unistd.h> /* int clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg); */ .text .align 4 .globl __clone .type __clone,@function .weak clone clone = __clone __clone: save %sp,-96,%sp /* sanity check arguments */ tst %i0 be __clone_syscall_error tst %i1 be __clone_syscall_error nop /* Do the system call */ mov %i1,%o1 mov %i2,%o0 set __NR_clone,%g1 ta 0x10 bcs __clone_syscall_error tst %o1 bne __thread_start nop mov %o0,%i0 ret restore __clone_syscall_error: call __errno_location set EINVAL,%i0 st %i0,[%o0] mov -1,%i0 ret restore __thread_start: call %i0 mov %i3,%o0 call _exit,0 nop /************************************************************************/ #else #error "Unknown Linux architecture" #endif #endif /* Linux && ! SDL_USE_PTHREADS */