>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
><P
>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
> for an explaination of how this effects your results. Colorkeying and alpha attributes also interact with surface blitting, as the following pseudo-code should hopefully explain.
<PRE
CLASS="PROGRAMLISTING"
>if (source surface has SDL_SRCALPHA set) {
if (source surface has alpha channel (that is, format->Amask != 0))
blit using per-pixel alpha, ignoring any colour key
else {
if (source surface has SDL_SRCCOLORKEY set)
blit using the colour key AND the per-surface alpha value
else
blit using the per-surface alpha value
}
} else {
if (source surface has SDL_SRCCOLORKEY set)
blit using the colour key
else
ordinary opaque rectangular blit
}</PRE
></P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN1918"
></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
