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1 <HTML
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2 ><HEAD
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3 ><TITLE
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4 >Initializing SDL</TITLE
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5 ><META
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6 NAME="GENERATOR"
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7 CONTENT="Modular DocBook HTML Stylesheet Version 1.61
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8 "><LINK
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9 REL="HOME"
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10 TITLE="SDL Library Documentation"
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11 HREF="index.html"><LINK
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12 REL="UP"
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13 TITLE="The Basics"
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14 HREF="guidethebasics.html"><LINK
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15 REL="PREVIOUS"
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16 TITLE="The Basics"
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17 HREF="guidethebasics.html"><LINK
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18 REL="NEXT"
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19 TITLE="Graphics and Video"
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20 HREF="guidevideo.html"></HEAD
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21 ><BODY
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22 CLASS="SECT1"
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23 BGCOLOR="#FFF8DC"
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24 TEXT="#000000"
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25 LINK="#0000ee"
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26 VLINK="#551a8b"
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27 ALINK="#ff0000"
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28 ><DIV
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29 CLASS="NAVHEADER"
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30 ><TABLE
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31 WIDTH="100%"
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32 BORDER="0"
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33 CELLPADDING="0"
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34 CELLSPACING="0"
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35 ><TR
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36 ><TH
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37 COLSPAN="3"
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38 ALIGN="center"
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39 >SDL Library Documentation</TH
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40 ></TR
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41 ><TR
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42 ><TD
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43 WIDTH="10%"
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44 ALIGN="left"
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45 VALIGN="bottom"
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46 ><A
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47 HREF="guidethebasics.html"
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48 >Prev</A
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49 ></TD
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50 ><TD
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51 WIDTH="80%"
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52 ALIGN="center"
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53 VALIGN="bottom"
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54 >Chapter 1. The Basics</TD
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55 ><TD
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56 WIDTH="10%"
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57 ALIGN="right"
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58 VALIGN="bottom"
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59 ><A
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60 HREF="guidevideo.html"
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61 >Next</A
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62 ></TD
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63 ></TR
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64 ></TABLE
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65 ><HR
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66 ALIGN="LEFT"
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67 WIDTH="100%"></DIV
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68 ><DIV
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69 CLASS="SECT1"
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70 ><H1
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71 CLASS="SECT1"
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72 ><A
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73 NAME="GUIDEBASICSINIT"
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74 >Initializing SDL</A
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75 ></H1
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76 ><P
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77 >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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78 HREF="sdlinit.html"
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79 ><TT
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80 CLASS="FUNCTION"
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81 >SDL_Init</TT
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82 ></A
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83 > (or <A
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84 HREF="sdlinitsubsystem.html"
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85 ><TT
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86 CLASS="FUNCTION"
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87 >SDL_InitSubSystem</TT
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88 ></A
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89 >. <TT
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90 CLASS="FUNCTION"
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91 >SDL_Init</TT
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92 > 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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93 <PRE
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94 CLASS="PROGRAMLISTING"
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95 > SDL_Init ( SDL_INIT_VIDEO );</PRE
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96 >
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97 To initialize the default subsystems, the Video subsystem and the Timers subsystem you would call:
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98 <PRE
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99 CLASS="PROGRAMLISTING"
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100 > SDL_Init ( SDL_INIT_VIDEO | SDL_INIT_TIMER );</PRE
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101 ></P
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102 ><P
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103 ><TT
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104 CLASS="FUNCTION"
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105 >SDL_Init</TT
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106 > is complemented by <A
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107 HREF="sdlquit.html"
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108 ><TT
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109 CLASS="FUNCTION"
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110 >SDL_Quit</TT
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111 ></A
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112 > (and <A
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113 HREF="sdlquitsubsystem.html"
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114 ><TT
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115 CLASS="FUNCTION"
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116 >SDL_QuitSubSystem</TT
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117 ></A
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118 >). <TT
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119 CLASS="FUNCTION"
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120 >SDL_Quit</TT
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121 > shuts down all subsystems, including the default ones. It should always be called before a SDL application exits.</P
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122 ><P
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123 >With <TT
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124 CLASS="FUNCTION"
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125 >SDL_Init</TT
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126 > and <TT
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127 CLASS="FUNCTION"
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128 >SDL_Quit</TT
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129 > 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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130 CLASS="FUNCTION"
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131 >SDL_Init</TT
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132 >, 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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133 CLASS="FUNCTION"
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134 >SDL_GetError</TT
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135 >. Use this often, you can never know too much about an error.</P
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136 ><P
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137 ><PRE
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138 CLASS="PROGRAMLISTING"
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139 >#include "SDL.h" /* All SDL App's need this */
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140 #include <stdio.h>
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141
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142 int main() {
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143
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144 printf("Initializing SDL.\n");
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145
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146 /* Initialize defaults, Video and Audio */
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147 if((SDL_Init(SDL_INIT_VIDEO|SDL_INIT_AUDIO)==-1)) {
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148 printf("Could not initialize SDL: %s.\n", SDL_GetError());
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149 exit(-1);
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150 }
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151
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152 printf("SDL initialized.\n");
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153
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154 printf("Quiting SDL.\n");
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155
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156 /* Shutdown all subsystems */
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157 SDL_Quit();
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158
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159 printf("Quiting....\n");
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160
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161 exit(0);
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162 } </PRE
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163 ></P
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164 ></DIV
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165 ><DIV
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166 CLASS="NAVFOOTER"
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167 ><HR
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168 ALIGN="LEFT"
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169 WIDTH="100%"><TABLE
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170 WIDTH="100%"
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171 BORDER="0"
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172 CELLPADDING="0"
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173 CELLSPACING="0"
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174 ><TR
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175 ><TD
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176 WIDTH="33%"
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177 ALIGN="left"
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178 VALIGN="top"
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179 ><A
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180 HREF="guidethebasics.html"
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181 >Prev</A
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182 ></TD
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183 ><TD
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184 WIDTH="34%"
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185 ALIGN="center"
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186 VALIGN="top"
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187 ><A
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188 HREF="index.html"
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189 >Home</A
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190 ></TD
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191 ><TD
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192 WIDTH="33%"
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193 ALIGN="right"
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194 VALIGN="top"
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195 ><A
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196 HREF="guidevideo.html"
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197 >Next</A
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198 ></TD
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199 ></TR
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200 ><TR
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201 ><TD
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202 WIDTH="33%"
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203 ALIGN="left"
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204 VALIGN="top"
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205 >The Basics</TD
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206 ><TD
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207 WIDTH="34%"
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208 ALIGN="center"
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209 VALIGN="top"
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210 ><A
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211 HREF="guidethebasics.html"
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212 >Up</A
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213 ></TD
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214 ><TD
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215 WIDTH="33%"
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216 ALIGN="right"
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217 VALIGN="top"
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218 >Graphics and Video</TD
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219 ></TR
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220 ></TABLE
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221 ></DIV
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222 ></BODY
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223 ></HTML
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224 > |
