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view src/SDL_error_c.h @ 1212:7663bb0f52c7
To: sdl@libsdl.org
From: Christian Walther <cwalther@gmx.ch>
Date: Thu, 15 Dec 2005 21:19:53 +0100
Subject: [SDL] More mouse enhancements for Mac OS X
The attached patch brings two more enhancements to mouse handling on Mac
OS X (Quartz):
1. Currently, after launching an SDL application, SDL's notion of the
mouse position is stuck in the top left corner (0,0) until the first
time the mouse is moved. That's because the UpdateMouse() function isn't
implemented in the Quartz driver. This patch adds it.
2. When grabbing input while the mouse cursor is hidden, the function
CGAssociateMouseAndMouseCursorPosition(0) is called, which prevents the
system's notion of the mouse location from moving (and therefore leaving
the SDL window) even when the mouse is moved. However, apparently the
Wacom tablet driver (and maybe other special pointing device drivers)
doesn't care about that setting and still allows the mouse location to
go outside of the window. Interestingly, the system cursor, which is
made visible by the existing code in SDL in that case, does not follow
the mouse location, but appears in the middle of the SDL window. The
mouse location being outside of the window however means that mouse
button events go to background applications (or the dock or whatever is
there), which is very confusing to the user who sees no cursor outside
of the SDL window.
I have not found any way of intercepting these events (and that's
probably by design, as "normal" applications shouldn't prevent the user
from bringing other applications' windows to the front by clicking on
them). An idea would be placing a fully transparent, screen-filling
window in front of everything, but I fear that this might affect
rendering performance (by doing unnecessary compositing, using up
memory, or whatever).
The deluxe solution to the problem would be talking to the tablet
driver using AppleEvents to tell it to constrain its mapped area to the
window (see Wacom's "TabletEventDemo" sample app,
http://www.wacomeng.com/devsupport/mac/downloads.html), but I think that
the bloat that solution would add to SDL would outweigh its usefulness.
What I did instead in my patch is reassociating mouse and cursor when
the mouse leaves the window while an invisible grab is in effect, and
restoring the grab when the window is entered. That way, the grab can
still be effectively broken by a tablet, but at least it's obvious to
the user that it is broken. That change is minimal - it doesn't affect
operation with a mouse (or a trackpad), and the code that it adds is not
executed on every PumpEvents() call, only when entering and leaving the
window.
Unless there are any concerns about the patch, please apply. Feel free
to shorten the lengthy comment in SDL_QuartzEvents.m if you think it's
too verbose.
Thanks
-Christian
author | Ryan C. Gordon <icculus@icculus.org> |
---|---|
date | Mon, 02 Jan 2006 00:31:00 +0000 |
parents | 04a403e4ccf5 |
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 /* This file defines a structure that carries language-independent error messages */ #ifndef _SDL_error_c_h #define _SDL_error_c_h #define ERR_MAX_STRLEN 128 #define ERR_MAX_ARGS 5 typedef struct SDL_error { /* This is a numeric value corresponding to the current error */ int error; /* This is a key used to index into a language hashtable containing internationalized versions of the SDL error messages. If the key is not in the hashtable, or no hashtable is available, the key is used directly as an error message format string. */ unsigned char key[ERR_MAX_STRLEN]; /* These are the arguments for the error functions */ int argc; union { void *value_ptr; #if 0 /* What is a character anyway? (UNICODE issues) */ unsigned char value_c; #endif int value_i; double value_f; unsigned char buf[ERR_MAX_STRLEN]; } args[ERR_MAX_ARGS]; } SDL_error; #endif /* _SDL_error_c_h */