view docs/html/sdlblitsurface.html @ 4:4f6c5f021323

Date: Thu, 26 Apr 2001 10:46:23 +0200 From: Alexander Pipelka <pipelka@bms-austria.com> Subject: SDL ELO driver bugfix Hi Sam! We noticed that the ELO serial touchscreen controller is quite sensitive in terms of correct protocol handling. The current implementation cause some controllers to hangup after some time (> 24h). I think the attached patch should fix this (I ran my device more than 3 days without any hangups).
author Sam Lantinga <slouken@lokigames.com>
date Thu, 26 Apr 2001 16:54:56 +0000
parents 74212992fb08
children 55f1f1b3e27d
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<HTML
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>SDL_BlitSurface</TITLE
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><H1
><A
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>SDL_BlitSurface</A
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><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN1806"
></A
><H2
>Name</H2
>SDL_BlitSurface&nbsp;--&nbsp;This performs a fast blit from the source surface to the destination surface.</DIV
><DIV
CLASS="REFSYNOPSISDIV"
><A
NAME="AEN1809"
></A
><H2
>Synopsis</H2
><DIV
CLASS="FUNCSYNOPSIS"
><A
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></A
><P
></P
><PRE
CLASS="FUNCSYNOPSISINFO"
>#include "SDL.h"</PRE
><P
><CODE
><CODE
CLASS="FUNCDEF"
>int <B
CLASS="FSFUNC"
>SDL_BlitSurface</B
></CODE
>(SDL_Surface *src, SDL_Rect *srcrect, SDL_Surface *dst, SDL_Rect *dstrect);</CODE
></P
><P
></P
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN1816"
></A
><H2
>Description</H2
><P
>This performs a fast blit from the source surface to the destination surface.</P
><P
>Only the position is used in the <TT
CLASS="PARAMETER"
><I
>dstrect</I
></TT
> (the
width and height are ignored).</P
><P
>If either <TT
CLASS="PARAMETER"
><I
>srcrect</I
></TT
> or
<TT
CLASS="PARAMETER"
><I
>dstrect</I
></TT
> are <TT
CLASS="LITERAL"
>NULL</TT
>, the entire
surface (<TT
CLASS="PARAMETER"
><I
>src</I
></TT
> or <TT
CLASS="PARAMETER"
><I
>dst</I
></TT
>) is
copied.</P
><P
>The final blit rectangle is saved in
<TT
CLASS="PARAMETER"
><I
>dstrect</I
></TT
> after all clipping is performed
(<TT
CLASS="PARAMETER"
><I
>srcrect</I
></TT
> is not modified).</P
><P
>The blit function should not be called on a locked surface.</P
><DIV
CLASS="NOTE"
><BLOCKQUOTE
CLASS="NOTE"
><P
><B
>Note: </B
>The results of blitting operations vary greatly depending on whether <TT
CLASS="LITERAL"
>SDL_SRCAPLHA</TT
> is set or not. See <A
HREF="sdlsetalpha.html"
>SDL_SetAlpha</A
>.</P
></BLOCKQUOTE
></DIV
></DIV
><DIV
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><A
NAME="AEN1835"
></A
><H2
>Return Value</H2
><P
>If the blit is successful, it returns <SPAN
CLASS="RETURNVALUE"
>0</SPAN
>,
otherwise it returns <SPAN
CLASS="RETURNVALUE"
>-1</SPAN
>.</P
><P
>If either of the surfaces were in video memory, and the blit returns
<SPAN
CLASS="RETURNVALUE"
>-2</SPAN
>, the video memory was lost, so it should be
reloaded with artwork and re-blitted:
<PRE
CLASS="PROGRAMLISTING"
>        while ( SDL_BlitSurface(image, imgrect, screen, dstrect) == -2 ) {
                while ( SDL_LockSurface(image)) &#60; 0 )
                        Sleep(10);
                -- Write image pixels to image-&#62;pixels --
                SDL_UnlockSurface(image);
        }</PRE
>
This happens under DirectX 5.0 when the system switches away from your
fullscreen application.  Locking the surface will also fail until you
have access to the video memory again.</P
></DIV
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><A
NAME="AEN1843"
></A
><H2
>See Also</H2
><P
><A
HREF="sdllocksurface.html"
><TT
CLASS="FUNCTION"
>SDL_LockSurface</TT
></A
>,
<A
HREF="sdlfillrect.html"
><TT
CLASS="FUNCTION"
>SDL_FillRect</TT
></A
>,
<A
HREF="sdlsurface.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_Surface</SPAN
></A
>,
<A
HREF="sdlrect.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_Rect</SPAN
></A
></P
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