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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
>SDL_Surface</TITLE
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><H1
><A
NAME="SDLSURFACE"
></A
>SDL_Surface</H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN3263"
></A
><H2
>Name</H2
>SDL_Surface&nbsp;--&nbsp;Graphical Surface Structure</DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN3266"
></A
><H2
>Structure Definition</H2
><PRE
CLASS="PROGRAMLISTING"
>typedef struct SDL_Surface {
        Uint32 flags;                           /* Read-only */
        SDL_PixelFormat *format;                /* Read-only */
        int w, h;                               /* Read-only */
        Uint16 pitch;                           /* Read-only */
        void *pixels;                           /* Read-write */

        /* clipping information */
        SDL_Rect clip_rect;                     /* Read-only */

        /* Reference count -- used when freeing surface */
        int refcount;                           /* Read-mostly */

	/* This structure also contains private fields not shown here */
} SDL_Surface;</PRE
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN3269"
></A
><H2
>Structure Data</H2
><DIV
CLASS="INFORMALTABLE"
><A
NAME="AEN3271"
></A
><P
></P
><TABLE
BORDER="0"
CLASS="CALSTABLE"
><TBODY
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="STRUCTFIELD"
><I
>flags</I
></TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Surface flags</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="STRUCTFIELD"
><I
>format</I
></TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Pixel <A
HREF="sdlpixelformat.html"
>format</A
></TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="STRUCTFIELD"
><I
>w, h</I
></TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Width and height of the surface</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="STRUCTFIELD"
><I
>pitch</I
></TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Length of a surface scanline in bytes</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="STRUCTFIELD"
><I
>pixels</I
></TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Pointer to the actual pixel data</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="STRUCTFIELD"
><I
>clip_rect</I
></TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>surface clip <A
HREF="sdlrect.html"
>rectangle</A
></TD
></TR
></TBODY
></TABLE
><P
></P
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN3300"
></A
><H2
>Description</H2
><P
><SPAN
CLASS="STRUCTNAME"
>SDL_Surface</SPAN
>'s represent areas of "graphical"
memory, memory that can be drawn to. The video framebuffer is returned
as a <SPAN
CLASS="STRUCTNAME"
>SDL_Surface</SPAN
> by
<A
HREF="sdlsetvideomode.html"
><TT
CLASS="FUNCTION"
>SDL_SetVideoMode</TT
></A
>
and <A
HREF="sdlgetvideosurface.html"
><TT
CLASS="FUNCTION"
>SDL_GetVideoSurface</TT
></A
>.
Most of the fields should be pretty obvious.
<TT
CLASS="STRUCTFIELD"
><I
>w</I
></TT
> and <TT
CLASS="STRUCTFIELD"
><I
>h</I
></TT
> are the
width and height of the surface in pixels.
<TT
CLASS="STRUCTFIELD"
><I
>pixels</I
></TT
> is a pointer to the actual pixel data,
the surface should be <A
HREF="sdllocksurface.html"
>locked</A
>
before accessing this field. The <TT
CLASS="STRUCTFIELD"
><I
>clip_rect</I
></TT
> field
is the clipping rectangle as set by
<A
HREF="sdlsetcliprect.html"
><TT
CLASS="FUNCTION"
>SDL_SetClipRect</TT
></A
>.</P
><P
>The following are supported in the
<TT
CLASS="STRUCTFIELD"
><I
>flags</I
></TT
> field.</P
><DIV
CLASS="INFORMALTABLE"
><A
NAME="AEN3318"
></A
><P
></P
><TABLE
BORDER="1"
CLASS="CALSTABLE"
><TBODY
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_SWSURFACE</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Surface is stored in system memory</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_HWSURFACE</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Surface is stored in video memory</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_ASYNCBLIT</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Surface uses asynchronous blits if possible</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_ANYFORMAT</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Allows any pixel-format (Display surface)</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_HWPALETTE</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Surface has exclusive palette</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_DOUBLEBUF</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Surface is double buffered (Display surface)</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_FULLSCREEN</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Surface is full screen (Display Surface)</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_OPENGL</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Surface has an OpenGL context (Display Surface)</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_OPENGLBLIT</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Surface supports OpenGL blitting (Display Surface)</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_RESIZABLE</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Surface is resizable (Display Surface)</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_HWACCEL</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Surface blit uses hardware acceleration</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_SRCCOLORKEY</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Surface use colorkey blitting</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_RLEACCEL</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Colorkey blitting is accelerated with RLE</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_SRCALPHA</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Surface blit uses alpha blending</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_PREALLOC</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Surface uses preallocated memory</TD
></TR
></TBODY
></TABLE
><P
></P
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN3381"
></A
><H2
>See Also</H2
><P
><A
HREF="sdlpixelformat.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_PixelFormat</SPAN
></A
></P
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