view docs/html/sdllocksurface.html @ 4393:9afe12fb4c41 SDL-1.2

Fixed bug #901 Tim Angus 2009-12-11 11:45:46 PST Disable mouse event generation when state is not SDL_APPMOUSEFOCUS If a Windows SDL application is minimised by using alt-tab, SDL_APPMOUSEFOCUS is lost as part of the minimisation. Unfortunately, the directx driver doesn't pay any attention to this state when generating mouse button events, so clicking on the Desktop can cause mouse clicks in the SDL application, while it's still minimised. The attached patch fixes this. It looks much more complicated than it actually is due to indentation; here it is ignoring whitespace: tma@abraxas:~/sources/SDL-1.2-svn$ svn diff -x -b Index: src/video/windx5/SDL_dx5events.c =================================================================== --- src/video/windx5/SDL_dx5events.c (revision 5376) +++ src/video/windx5/SDL_dx5events.c (working copy) @@ -374,10 +374,9 @@ if ( !(SDL_GetAppState() & SDL_APPMOUSEFOCUS) ) { mouse_lost = 1; ClipCursor(NULL); - } - + } else { /* If the mouse was lost, regain some sense of mouse state */ - if ( mouse_lost && (SDL_GetAppState() & SDL_APPMOUSEFOCUS) ) { + if ( mouse_lost ) { POINT mouse_pos; Uint8 old_state; Uint8 new_state; @@ -548,6 +547,7 @@ if ( xrel || yrel ) { post_mouse_motion(1, xrel, yrel); } + } } /* The main Win32 event handler */
author Sam Lantinga <slouken@libsdl.org>
date Mon, 14 Dec 2009 22:41:31 +0000
parents 355632dca928
children
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><H1
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>SDL_LockSurface</H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN1919"
></A
><H2
>Name</H2
>SDL_LockSurface&nbsp;--&nbsp;Lock a surface for directly access.</DIV
><DIV
CLASS="REFSYNOPSISDIV"
><A
NAME="AEN1922"
></A
><H2
>Synopsis</H2
><DIV
CLASS="FUNCSYNOPSIS"
><A
NAME="AEN1923"
></A
><P
></P
><PRE
CLASS="FUNCSYNOPSISINFO"
>#include "SDL.h"</PRE
><P
><CODE
><CODE
CLASS="FUNCDEF"
>int <B
CLASS="FSFUNC"
>SDL_LockSurface</B
></CODE
>(SDL_Surface *surface);</CODE
></P
><P
></P
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><DIV
CLASS="REFSECT1"
><A
NAME="AEN1929"
></A
><H2
>Description</H2
><P
><TT
CLASS="FUNCTION"
>SDL_LockSurface</TT
> sets up a surface for directly 
accessing the pixels.  Between calls to <TT
CLASS="FUNCTION"
>SDL_LockSurface</TT
>
and <TT
CLASS="FUNCTION"
>SDL_UnlockSurface</TT
>, you can write to and read from 
<TT
CLASS="PARAMETER"
><I
>surface-&#62;<TT
CLASS="STRUCTFIELD"
><I
>pixels</I
></TT
></I
></TT
>, using the pixel format stored in
<TT
CLASS="PARAMETER"
><I
>surface-&#62;<TT
CLASS="STRUCTFIELD"
><I
>format</I
></TT
></I
></TT
>.  Once you are done accessing the
surface, you should use <TT
CLASS="FUNCTION"
>SDL_UnlockSurface</TT
> to release it.</P
><P
>Not all surfaces require locking.  
If <TT
CLASS="LITERAL"
>SDL_MUSTLOCK</TT
>(<TT
CLASS="PARAMETER"
><I
>surface</I
></TT
>)
evaluates to <SPAN
CLASS="RETURNVALUE"
>0</SPAN
>, then you can read and write to the 
surface at any time, and the pixel format of the surface will not change. </P
><P
>No operating system or library calls should be made between lock/unlock
pairs, as critical system locks may be held during this time.</P
><P
>It should be noted, that since SDL 1.1.8 surface locks are recursive. This means that you can lock a surface multiple times, but each lock must have a match unlock.
<PRE
CLASS="PROGRAMLISTING"
>    .
    .
    SDL_LockSurface( surface );
    .
    /* Surface is locked */
    /* Direct pixel access on surface here */
    .
    SDL_LockSurface( surface );
    .
    /* More direct pixel access on surface */
    .
    SDL_UnlockSurface( surface );
    /* Surface is still locked */
    /* Note: Is versions &#60; 1.1.8, the surface would have been */
    /* no longer locked at this stage                         */
    .
    SDL_UnlockSurface( surface );
    /* Surface is now unlocked */
    .
    .</PRE
></P
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><A
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></A
><H2
>Return Value</H2
><P
><TT
CLASS="FUNCTION"
>SDL_LockSurface</TT
> returns <SPAN
CLASS="RETURNVALUE"
>0</SPAN
>, 
or <SPAN
CLASS="RETURNVALUE"
>-1</SPAN
> if the surface couldn't be locked.</P
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><A
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></A
><H2
>See Also</H2
><P
><A
HREF="sdlunlocksurface.html"
><TT
CLASS="FUNCTION"
>SDL_UnlockSurface</TT
></A
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