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232 lines
4.3 KiB
HTML
232 lines
4.3 KiB
HTML
<HTML
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><HEAD
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><TITLE
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>Initializing SDL</TITLE
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><META
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NAME="GENERATOR"
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CONTENT="Modular DocBook HTML Stylesheet Version 1.64
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"><LINK
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REL="HOME"
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TITLE="SDL Library Documentation"
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HREF="index.html"><LINK
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REL="UP"
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TITLE="The Basics"
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HREF="guidethebasics.html"><LINK
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REL="PREVIOUS"
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TITLE="The Basics"
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HREF="guidethebasics.html"><LINK
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REL="NEXT"
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TITLE="Graphics and Video"
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HREF="guidevideo.html"></HEAD
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BGCOLOR="#FFF8DC"
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CELLSPACING="0"
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><TR
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><TH
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COLSPAN="3"
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ALIGN="center"
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>SDL Library Documentation</TH
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></TR
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><TR
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><TD
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WIDTH="10%"
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ALIGN="left"
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VALIGN="bottom"
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><A
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HREF="guidethebasics.html"
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>Prev</A
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></TD
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><TD
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WIDTH="80%"
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ALIGN="center"
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VALIGN="bottom"
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>Chapter 1. The Basics</TD
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><TD
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WIDTH="10%"
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ALIGN="right"
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VALIGN="bottom"
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><A
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HREF="guidevideo.html"
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>Next</A
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></TD
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></TR
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></TABLE
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><HR
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ALIGN="LEFT"
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WIDTH="100%"></DIV
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><DIV
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CLASS="SECT1"
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><H1
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CLASS="SECT1"
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><A
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NAME="GUIDEBASICSINIT"
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>Initializing SDL</A
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></H1
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><P
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>SDL is composed of eight subsystems - Audio, CDROM, Event Handling, File I/O, Joystick Handling, Threading, Timers and Video. Before you can use any of these subsystems they must be initialized by calling <A
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HREF="sdlinit.html"
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><TT
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CLASS="FUNCTION"
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>SDL_Init</TT
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></A
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> (or <A
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HREF="sdlinitsubsystem.html"
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><TT
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CLASS="FUNCTION"
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>SDL_InitSubSystem</TT
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></A
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>. <TT
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CLASS="FUNCTION"
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>SDL_Init</TT
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> must be called before any other SDL function. It automatically initializes the Event Handling, File I/O and Threading subsystems and it takes a parameter specifying which other subsystems to initialize. So, to initialize the default subsystems and the Video subsystems you would call:
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<PRE
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CLASS="PROGRAMLISTING"
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> SDL_Init ( SDL_INIT_VIDEO );</PRE
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>
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To initialize the default subsystems, the Video subsystem and the Timers subsystem you would call:
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<PRE
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CLASS="PROGRAMLISTING"
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> SDL_Init ( SDL_INIT_VIDEO | SDL_INIT_TIMER );</PRE
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></P
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><P
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><TT
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CLASS="FUNCTION"
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>SDL_Init</TT
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> is complemented by <A
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HREF="sdlquit.html"
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><TT
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CLASS="FUNCTION"
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>SDL_Quit</TT
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></A
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> (and <A
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HREF="sdlquitsubsystem.html"
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><TT
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CLASS="FUNCTION"
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>SDL_QuitSubSystem</TT
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></A
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>). <TT
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CLASS="FUNCTION"
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>SDL_Quit</TT
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> shuts down all subsystems, including the default ones. It should always be called before a SDL application exits.</P
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><P
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>With <TT
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CLASS="FUNCTION"
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>SDL_Init</TT
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> and <TT
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CLASS="FUNCTION"
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>SDL_Quit</TT
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> firmly embedded in your programmers toolkit you can write your first and most basic SDL application. However, we must be prepare to handle errors. Many SDL functions return a value and indicates whether the function has succeeded or failed, <TT
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CLASS="FUNCTION"
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>SDL_Init</TT
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>, for instance, returns -1 if it could not initialize a subsystem. SDL provides a useful facility that allows you to determine exactly what the problem was, every time an error occurs within SDL an error message is stored which can be retrieved using <TT
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CLASS="FUNCTION"
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>SDL_GetError</TT
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>. Use this often, you can never know too much about an error.</P
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><DIV
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CLASS="EXAMPLE"
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><A
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NAME="AEN60"
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></A
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><P
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><B
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>Example 1-1. Initializing SDL</B
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></P
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><PRE
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CLASS="PROGRAMLISTING"
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>#include "SDL.h" /* All SDL App's need this */
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#include <stdio.h>
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int main() {
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printf("Initializing SDL.\n");
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/* Initialize defaults, Video and Audio */
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if((SDL_Init(SDL_INIT_VIDEO|SDL_INIT_AUDIO)==-1)) {
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printf("Could not initialize SDL: %s.\n", SDL_GetError());
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exit(-1);
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}
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printf("SDL initialized.\n");
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printf("Quiting SDL.\n");
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/* Shutdown all subsystems */
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SDL_Quit();
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printf("Quiting....\n");
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exit(0);
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} </PRE
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></DIV
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></DIV
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><DIV
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CLASS="NAVFOOTER"
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><HR
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ALIGN="LEFT"
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WIDTH="100%"><TABLE
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CELLSPACING="0"
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><TR
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WIDTH="33%"
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ALIGN="left"
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VALIGN="top"
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><A
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HREF="guidethebasics.html"
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>Prev</A
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></TD
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><TD
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WIDTH="34%"
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ALIGN="center"
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VALIGN="top"
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><A
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HREF="index.html"
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>Home</A
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></TD
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><TD
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WIDTH="33%"
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ALIGN="right"
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VALIGN="top"
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><A
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HREF="guidevideo.html"
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>Next</A
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></TD
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></TR
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><TR
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><TD
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WIDTH="33%"
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ALIGN="left"
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VALIGN="top"
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>The Basics</TD
|
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><TD
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WIDTH="34%"
|
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ALIGN="center"
|
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VALIGN="top"
|
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><A
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HREF="guidethebasics.html"
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>Up</A
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></TD
|
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><TD
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WIDTH="33%"
|
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ALIGN="right"
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VALIGN="top"
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>Graphics and Video</TD
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></TR
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></TABLE
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></BODY
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> |