view docs/html/sdlkeysym.html @ 2321:c5feceb0395e

SetupWindowData in SDL_X11window.c was realloc()ing the display window list and incrementing numwindows even though those are being updated in functions that call this function. The result is that it is possible to get the same window added to the list twice.
author Bob Pendleton <bob@pendleton.com>
date Tue, 04 Mar 2008 23:09:28 +0000
parents 355632dca928
children
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<HTML
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>SDL_keysym</TITLE
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><H1
><A
NAME="SDLKEYSYM"
></A
>SDL_keysym</H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN4659"
></A
><H2
>Name</H2
>SDL_keysym&nbsp;--&nbsp;Keysym structure</DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN4662"
></A
><H2
>Structure Definition</H2
><PRE
CLASS="PROGRAMLISTING"
>typedef struct{
  Uint8 scancode;
  SDLKey sym;
  SDLMod mod;
  Uint16 unicode;
} SDL_keysym;</PRE
></DIV
><DIV
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><A
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></A
><H2
>Structure Data</H2
><DIV
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><A
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></A
><P
></P
><TABLE
BORDER="0"
CLASS="CALSTABLE"
><TBODY
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="STRUCTFIELD"
><I
>scancode</I
></TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Hardware specific scancode</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="STRUCTFIELD"
><I
>sym</I
></TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>SDL virtual keysym</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="STRUCTFIELD"
><I
>mod</I
></TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Current key modifiers</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="STRUCTFIELD"
><I
>unicode</I
></TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Translated character</TD
></TR
></TBODY
></TABLE
><P
></P
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><DIV
CLASS="REFSECT1"
><A
NAME="AEN4686"
></A
><H2
>Description</H2
><P
>The <SPAN
CLASS="STRUCTNAME"
>SDL_keysym</SPAN
> structure is used by reporting key presses and releases since it is a part of the <A
HREF="sdlkeyboardevent.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_KeyboardEvent</SPAN
></A
>.</P
><P
>The <TT
CLASS="STRUCTFIELD"
><I
>scancode</I
></TT
> field should generally be left alone, it is the hardware dependent scancode returned by the keyboard. The <TT
CLASS="STRUCTFIELD"
><I
>sym</I
></TT
> field is extremely useful. It is the SDL-defined value of the key (see <A
HREF="sdlkey.html"
>SDL Key Syms</A
>. This field is very useful when you are checking for certain key presses, like so:
<PRE
CLASS="PROGRAMLISTING"
>.
.
while(SDL_PollEvent(&#38;event)){
  switch(event.type){
    case SDL_KEYDOWN:
      if(event.key.keysym.sym==SDLK_LEFT)
        move_left();
      break;
    .
    .
    .
  }
}
.
.</PRE
>
<TT
CLASS="STRUCTFIELD"
><I
>mod</I
></TT
> stores the current state of the keyboard modifiers as explained in <A
HREF="sdlgetmodstate.html"
><TT
CLASS="FUNCTION"
>SDL_GetModState</TT
></A
>. The <TT
CLASS="STRUCTFIELD"
><I
>unicode</I
></TT
> is only used when UNICODE translation is enabled with <A
HREF="sdlenableunicode.html"
><TT
CLASS="FUNCTION"
>SDL_EnableUNICODE</TT
></A
>. If <TT
CLASS="STRUCTFIELD"
><I
>unicode</I
></TT
> is non-zero then this a the UNICODE character corresponding to the keypress. If the high 9 bits of the character are 0, then this maps to the equivalent ASCII character:
<PRE
CLASS="PROGRAMLISTING"
>char ch;
if ( (keysym.unicode &#38; 0xFF80) == 0 ) {
  ch = keysym.unicode &#38; 0x7F;
}
else {
  printf("An International Character.\n");
}</PRE
>
UNICODE translation does have a slight overhead so don't enable it unless its needed.</P
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><H2
>See Also</H2
><P
><A
HREF="sdlkey.html"
><SPAN
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>SDLKey</SPAN
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