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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 | 355632dca928 |
| children |
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<HTML ><HEAD ><TITLE >Event Functions.</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+ "><LINK REL="HOME" TITLE="SDL Library Documentation" HREF="index.html"><LINK REL="UP" TITLE="Events" HREF="event.html"><LINK REL="PREVIOUS" TITLE="SDLKey" HREF="sdlkey.html"><LINK REL="NEXT" TITLE="SDL_PumpEvents" HREF="sdlpumpevents.html"></HEAD ><BODY CLASS="SECT1" BGCOLOR="#FFF8DC" TEXT="#000000" LINK="#0000ee" VLINK="#551a8b" ALINK="#ff0000" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" >SDL Library Documentation</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="sdlkey.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" >Chapter 8. Events</TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="sdlpumpevents.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><DIV CLASS="SECT1" ><H1 CLASS="SECT1" ><A NAME="EVENTFUNCTIONS" ></A >Event Functions.</H1 ><DIV CLASS="TOC" ><DL ><DT ><B >Table of Contents</B ></DT ><DT ><A HREF="sdlpumpevents.html" >SDL_PumpEvents</A > -- Pumps the event loop, gathering events from the input devices.</DT ><DT ><A HREF="sdlpeepevents.html" >SDL_PeepEvents</A > -- Checks the event queue for messages and optionally returns them.</DT ><DT ><A HREF="sdlpollevent.html" >SDL_PollEvent</A > -- Polls for currently pending events.</DT ><DT ><A HREF="sdlwaitevent.html" >SDL_WaitEvent</A > -- Waits indefinitely for the next available event.</DT ><DT ><A HREF="sdlpushevent.html" >SDL_PushEvent</A > -- Pushes an event onto the event queue</DT ><DT ><A HREF="sdlseteventfilter.html" >SDL_SetEventFilter</A > -- Sets up a filter to process all events before they are posted to the event queue.</DT ><DT ><A HREF="sdlgeteventfilter.html" >SDL_GetEventFilter</A > -- Retrieves a pointer to he event filter</DT ><DT ><A HREF="sdleventstate.html" >SDL_EventState</A > -- This function allows you to set the state of processing certain events.</DT ><DT ><A HREF="sdlgetkeystate.html" >SDL_GetKeyState</A > -- Get a snapshot of the current keyboard state</DT ><DT ><A HREF="sdlgetmodstate.html" >SDL_GetModState</A > -- Get the state of modifier keys.</DT ><DT ><A HREF="sdlsetmodstate.html" >SDL_SetModState</A > -- Set the current key modifier state</DT ><DT ><A HREF="sdlgetkeyname.html" >SDL_GetKeyName</A > -- Get the name of an SDL virtual keysym</DT ><DT ><A HREF="sdlenableunicode.html" >SDL_EnableUNICODE</A > -- Enable UNICODE translation</DT ><DT ><A HREF="sdlenablekeyrepeat.html" >SDL_EnableKeyRepeat</A > -- Set keyboard repeat rate.</DT ><DT ><A HREF="sdlgetmousestate.html" >SDL_GetMouseState</A > -- Retrieve the current state of the mouse</DT ><DT ><A HREF="sdlgetrelativemousestate.html" >SDL_GetRelativeMouseState</A > -- Retrieve the current state of the mouse</DT ><DT ><A HREF="sdlgetappstate.html" >SDL_GetAppState</A > -- Get the state of the application</DT ><DT ><A HREF="sdljoystickeventstate.html" >SDL_JoystickEventState</A > -- Enable/disable joystick event polling</DT ></DL ></DIV ><DIV CLASS="INFORMALTABLE" ><A NAME="AEN5312" ></A ><P ></P ><TABLE BORDER="0" CLASS="CALSTABLE" ><TBODY ><TR ><TD ALIGN="LEFT" VALIGN="TOP" ><A HREF="sdlpumpevents.html" >SDL_PumpEvents</A ></TD ><TD ALIGN="LEFT" VALIGN="TOP" >Pumps the event loop, gathering events from the input devices</TD ></TR ><TR ><TD ALIGN="LEFT" VALIGN="TOP" ><A HREF="sdlpeepevents.html" >SDL_PeepEvents</A ></TD ><TD ALIGN="LEFT" VALIGN="TOP" >Checks the event queue for messages and optionally returns them</TD ></TR ><TR ><TD ALIGN="LEFT" VALIGN="TOP" ><A HREF="sdlpollevent.html" >SDL_PollEvent</A ></TD ><TD ALIGN="LEFT" VALIGN="TOP" >Polls for currently pending events</TD ></TR ><TR ><TD ALIGN="LEFT" VALIGN="TOP" ><A HREF="sdlwaitevent.html" >SDL_WaitEvent</A ></TD ><TD ALIGN="LEFT" VALIGN="TOP" >Waits indefinitely for the next available event</TD ></TR ><TR ><TD ALIGN="LEFT" VALIGN="TOP" ><A HREF="sdlpushevent.html" >SDL_PushEvent</A ></TD ><TD ALIGN="LEFT" VALIGN="TOP" >Pushes an event onto the event queue</TD ></TR ><TR ><TD ALIGN="LEFT" VALIGN="TOP" ><A HREF="sdlseteventfilter.html" >SDL_SetEventFilter</A ></TD ><TD ALIGN="LEFT" VALIGN="TOP" >Sets up a filter to process all events</TD ></TR ><TR ><TD ALIGN="LEFT" VALIGN="TOP" ><A HREF="sdleventstate.html" >SDL_EventState</A ></TD ><TD ALIGN="LEFT" VALIGN="TOP" >Allows you to set the state of processing certain events</TD ></TR ><TR ><TD ALIGN="LEFT" VALIGN="TOP" ><A HREF="sdlgetkeystate.html" >SDL_GetKeyState</A ></TD ><TD ALIGN="LEFT" VALIGN="TOP" >Get a snapshot of the current keyboard state</TD ></TR ><TR ><TD ALIGN="LEFT" VALIGN="TOP" ><A HREF="sdlgetmodstate.html" >SDL_GetModState</A ></TD ><TD ALIGN="LEFT" VALIGN="TOP" >Get the state of modifier keys</TD ></TR ><TR ><TD ALIGN="LEFT" VALIGN="TOP" ><A HREF="sdlsetmodstate.html" >SDL_SetModState</A ></TD ><TD ALIGN="LEFT" VALIGN="TOP" >Set the state of modifier keys</TD ></TR ><TR ><TD ALIGN="LEFT" VALIGN="TOP" ><A HREF="sdlgetkeyname.html" >SDL_GetKeyName</A ></TD ><TD ALIGN="LEFT" VALIGN="TOP" >Get the name of an SDL virtual keysym</TD ></TR ><TR ><TD ALIGN="LEFT" VALIGN="TOP" ><A HREF="sdlenableunicode.html" >SDL_EnableUNICODE</A ></TD ><TD ALIGN="LEFT" VALIGN="TOP" >Enable UNICODE translation</TD ></TR ><TR ><TD ALIGN="LEFT" VALIGN="TOP" ><A HREF="sdlenablekeyrepeat.html" >SDL_EnableKeyRepeat</A ></TD ><TD ALIGN="LEFT" VALIGN="TOP" >Set keyboard repeat rate</TD ></TR ><TR ><TD ALIGN="LEFT" VALIGN="TOP" ><A HREF="sdlgetmousestate.html" >SDL_GetMouseState</A ></TD ><TD ALIGN="LEFT" VALIGN="TOP" >Retrieve the current state of the mouse</TD ></TR ><TR ><TD ALIGN="LEFT" VALIGN="TOP" ><A HREF="sdlgetrelativemousestate.html" >SDL_GetRelativeMouseState</A ></TD ><TD ALIGN="LEFT" VALIGN="TOP" >Retrieve the current state of the mouse</TD ></TR ><TR ><TD ALIGN="LEFT" VALIGN="TOP" ><A HREF="sdlgetappstate.html" >SDL_GetAppState</A ></TD ><TD ALIGN="LEFT" VALIGN="TOP" >Get the state of the application</TD ></TR ><TR ><TD ALIGN="LEFT" VALIGN="TOP" ><A HREF="sdljoystickeventstate.html" >SDL_JoystickEventState</A ></TD ><TD ALIGN="LEFT" VALIGN="TOP" >Enable/disable joystick event polling</TD ></TR ></TBODY ></TABLE ><P ></P ></DIV ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="sdlkey.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="sdlpumpevents.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >SDLKey</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="event.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >SDL_PumpEvents</TD ></TR ></TABLE ></DIV ></BODY ></HTML >