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1 <HTML
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2 ><HEAD
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3 ><TITLE
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4 >Event Examples</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="Examples"
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14 HREF="guideexamples.html"><LINK
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15 REL="PREVIOUS"
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16 TITLE="Video Examples"
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17 HREF="guidevideoexamples.html"><LINK
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18 REL="NEXT"
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19 TITLE="Audio Examples"
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20 HREF="guideaudioexamples.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="guidevideoexamples.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 4. Examples</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="guideaudioexamples.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="GUIDEEVENTEXAMPLES"
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74 >Event Examples</A
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75 ></H1
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76 ><P
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77 ></P
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78 ><DIV
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79 CLASS="SECT2"
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80 ><H2
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81 CLASS="SECT2"
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82 ><A
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83 NAME="AEN336"
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84 >Filtering and Handling Events</A
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85 ></H2
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86 ><P
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87 ><PRE
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88 CLASS="PROGRAMLISTING"
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89 >#include <stdio.h>
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90 #include <stdlib.h>
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91
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92 #include "SDL.h"
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93
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94 /* This function may run in a separate event thread */
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95 int FilterEvents(const SDL_Event *event) {
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96 static int boycott = 1;
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97
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98 /* This quit event signals the closing of the window */
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99 if ( (event->type == SDL_QUIT) && boycott ) {
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100 printf("Quit event filtered out -- try again.\n");
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101 boycott = 0;
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102 return(0);
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103 }
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104 if ( event->type == SDL_MOUSEMOTION ) {
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105 printf("Mouse moved to (%d,%d)\n",
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106 event->motion.x, event->motion.y);
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107 return(0); /* Drop it, we've handled it */
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108 }
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109 return(1);
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110 }
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111
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112 int main(int argc, char *argv[])
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113 {
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114 SDL_Event event;
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115
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116 /* Initialize the SDL library (starts the event loop) */
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117 if ( SDL_Init(SDL_INIT_VIDEO) < 0 ) {
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118 fprintf(stderr,
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119 "Couldn't initialize SDL: %s\n", SDL_GetError());
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120 exit(1);
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121 }
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122
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123 /* Clean up on exit, exit on window close and interrupt */
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124 atexit(SDL_Quit);
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125
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126 /* Ignore key events */
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127 SDL_EventState(SDL_KEYDOWN, SDL_IGNORE);
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128 SDL_EventState(SDL_KEYUP, SDL_IGNORE);
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129
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130 /* Filter quit and mouse motion events */
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131 SDL_SetEventFilter(FilterEvents);
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132
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133 /* The mouse isn't much use unless we have a display for reference */
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134 if ( SDL_SetVideoMode(640, 480, 8, 0) == NULL ) {
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135 fprintf(stderr, "Couldn't set 640x480x8 video mode: %s\n",
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136 SDL_GetError());
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137 exit(1);
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138 }
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139
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140 /* Loop waiting for ESC+Mouse_Button */
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141 while ( SDL_WaitEvent(&event) >= 0 ) {
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142 switch (event.type) {
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143 case SDL_ACTIVEEVENT: {
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144 if ( event.active.state & SDL_APPACTIVE ) {
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145 if ( event.active.gain ) {
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146 printf("App activated\n");
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147 } else {
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148 printf("App iconified\n");
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149 }
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150 }
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151 }
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152 break;
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153
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154 case SDL_MOUSEBUTTONDOWN: {
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155 Uint8 *keys;
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156
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157 keys = SDL_GetKeyState(NULL);
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158 if ( keys[SDLK_ESCAPE] == SDL_PRESSED ) {
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159 printf("Bye bye...\n");
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160 exit(0);
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161 }
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162 printf("Mouse button pressed\n");
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163 }
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164 break;
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165
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166 case SDL_QUIT: {
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167 printf("Quit requested, quitting.\n");
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168 exit(0);
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169 }
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170 break;
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171 }
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172 }
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173 /* This should never happen */
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174 printf("SDL_WaitEvent error: %s\n", SDL_GetError());
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175 exit(1);
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176 }</PRE
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177 ></P
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178 ></DIV
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179 ></DIV
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180 ><DIV
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181 CLASS="NAVFOOTER"
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182 ><HR
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183 ALIGN="LEFT"
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184 WIDTH="100%"><TABLE
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185 WIDTH="100%"
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186 BORDER="0"
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187 CELLPADDING="0"
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188 CELLSPACING="0"
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189 ><TR
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190 ><TD
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191 WIDTH="33%"
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192 ALIGN="left"
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193 VALIGN="top"
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194 ><A
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195 HREF="guidevideoexamples.html"
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196 >Prev</A
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197 ></TD
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198 ><TD
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199 WIDTH="34%"
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200 ALIGN="center"
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201 VALIGN="top"
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202 ><A
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203 HREF="index.html"
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204 >Home</A
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205 ></TD
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206 ><TD
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207 WIDTH="33%"
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208 ALIGN="right"
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209 VALIGN="top"
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210 ><A
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211 HREF="guideaudioexamples.html"
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212 >Next</A
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213 ></TD
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214 ></TR
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215 ><TR
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216 ><TD
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217 WIDTH="33%"
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218 ALIGN="left"
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219 VALIGN="top"
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220 >Video Examples</TD
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221 ><TD
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222 WIDTH="34%"
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223 ALIGN="center"
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224 VALIGN="top"
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225 ><A
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226 HREF="guideexamples.html"
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227 >Up</A
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228 ></TD
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229 ><TD
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230 WIDTH="33%"
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231 ALIGN="right"
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232 VALIGN="top"
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233 >Audio Examples</TD
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234 ></TR
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235 ></TABLE
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236 ></DIV
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237 ></BODY
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238 ></HTML
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239 > |
