473 lines
9.9 KiB
HTML
473 lines
9.9 KiB
HTML
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<HTML
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><HEAD
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><TITLE
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>Video Examples</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="Examples"
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HREF="guideexamples.html"><LINK
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REL="PREVIOUS"
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TITLE="Examples"
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HREF="guideexamples.html"><LINK
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REL="NEXT"
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TITLE="Event Examples"
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HREF="guideeventexamples.html"></HEAD
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><BODY
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CLASS="SECT1"
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BGCOLOR="#FFF8DC"
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TEXT="#000000"
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LINK="#0000ee"
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VLINK="#551a8b"
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ALINK="#ff0000"
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><DIV
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CLASS="NAVHEADER"
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><TABLE
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WIDTH="100%"
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BORDER="0"
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CELLPADDING="0"
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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="guideexamples.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 4. Examples</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="guideeventexamples.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="GUIDEVIDEOEXAMPLES"
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>Video Examples</A
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></H1
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><P
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></P
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><DIV
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CLASS="SECT2"
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><H2
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CLASS="SECT2"
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><A
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NAME="AEN375"
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>Initializing the video display</A
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></H2
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><P
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><PRE
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CLASS="PROGRAMLISTING"
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> SDL_Surface *screen;
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/* Initialize the SDL library */
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if( SDL_Init(SDL_INIT_VIDEO) < 0 ) {
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fprintf(stderr,
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"Couldn't initialize SDL: %s\n", SDL_GetError());
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exit(1);
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}
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/* Clean up on exit */
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atexit(SDL_Quit);
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/* Initialize the display in a 640x480 8-bit palettized mode */
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screen = SDL_SetVideoMode(640, 480, 8, SDL_SWSURFACE);
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if ( screen == NULL ) {
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fprintf(stderr, "Couldn't set 640x480x8 video mode: %s\n",
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SDL_GetError());
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exit(1);
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}</PRE
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></P
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></DIV
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><DIV
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CLASS="SECT2"
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><H2
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CLASS="SECT2"
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><A
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NAME="AEN379"
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>Initializing the best video mode</A
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></H2
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><P
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><PRE
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CLASS="PROGRAMLISTING"
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> /* Have a preference for 8-bit, but accept any depth */
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screen = SDL_SetVideoMode(640, 480, 8, SDL_SWSURFACE|SDL_ANYFORMAT);
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if ( screen == NULL ) {
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fprintf(stderr, "Couldn't set 640x480x8 video mode: %s\n",
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SDL_GetError());
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exit(1);
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}
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printf("Set 640x480 at %d bits-per-pixel mode\n",
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screen->format->BitsPerPixel);</PRE
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></P
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></DIV
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><DIV
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CLASS="SECT2"
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><H2
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CLASS="SECT2"
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><A
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NAME="AEN383"
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>Loading and displaying a BMP file</A
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></H2
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><P
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><PRE
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CLASS="PROGRAMLISTING"
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> SDL_Surface *image;
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SDL_Rect dest;
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int ncolors, i;
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SDL_Color *colors;
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/* Load the BMP file into a surface */
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image = SDL_LoadBMP("sample.bmp");
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if ( image == NULL ) {
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fprintf(stderr, "Couldn't load sample.bmp: %s\n",
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SDL_GetError());
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return;
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}
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/* Set the display colors -- SDL_SetColors() only does something on
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palettized displays, but it doesn't hurt anything on HiColor or
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TrueColor displays.
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If the display colors have already been set, this step can be
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skipped, and the library will automatically map the image to
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the current display colors.
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*/
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if ( image->format->palette ) {
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ncolors = image->format->palette->ncolors;
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colors = (SDL_Color *)malloc(ncolors*sizeof(SDL_Color));
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memcpy(colors, image->format->palette->colors, ncolors);
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}
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else {
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int r, g, b;
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/* Allocate 256 color palette */
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ncolors = 256;
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colors = (SDL_Color *)malloc(ncolors*sizeof(SDL_Color));
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/* Set a 3,3,2 color cube */
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for ( r=0; r<8; ++r ) {
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for ( g=0; g<8; ++g ) {
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for ( b=0; b<4; ++b ) {
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i = ((r<<5)|(g<<2)|b);
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colors[i].r = r<<5;
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colors[i].g = g<<5;
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colors[i].b = b<<6;
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}
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}
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}
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/* Note: A better way of allocating the palette might be
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to calculate the frequency of colors in the image
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and create a palette based on that information.
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*/
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}
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/* Set colormap, try for all the colors, but don't worry about it */
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SDL_SetColors(screen, colors, 0, ncolors);
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free(colors);
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/* Blit onto the screen surface */
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dest.x = 0;
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dest.y = 0;
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dest.w = image->w;
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dest.h = image->h;
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SDL_BlitSurface(image, NULL, screen, &dest);
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SDL_UpdateRects(screen, 1, &dest);
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/* Free the allocated BMP surface */
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SDL_FreeSurface(image);
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return;</PRE
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></P
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></DIV
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><DIV
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CLASS="SECT2"
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><H2
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CLASS="SECT2"
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><A
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NAME="AEN387"
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>Drawing directly to the display</A
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></H2
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><P
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><PRE
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CLASS="PROGRAMLISTING"
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> /* Code to set a yellow pixel at the center of the screen */
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Sint32 X, Y;
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Uint32 pixel;
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Uint8 *bits, bpp;
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/* Map the color yellow to this display (R=0xFF, G=0xFF, B=0x00)
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Note: If the display is palettized, you must set the palette first.
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*/
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pixel = SDL_MapRGB(screen->format, 0xFF, 0xFF, 0x00);
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/* Calculate the framebuffer offset of the center of the screen */
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if ( SDL_MUSTLOCK(screen) ) {
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if ( SDL_LockSurface(screen) < 0 )
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return;
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}
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bpp = screen->format->BytesPerPixel;
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X = screen->w/2;
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Y = screen->h/2;
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bits = ((Uint8 *)screen->pixels)+Y*screen->pitch+X*bpp;
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/* Set the pixel */
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switch(bpp) {
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case 1:
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*((Uint8 *)(bits)) = (Uint8)pixel;
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break;
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case 2:
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*((Uint16 *)(bits)) = (Uint16)pixel;
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break;
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case 3: { /* Format/endian independent */
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Uint8 r, g, b;
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r = (pixel>>screen->format->Rshift)&0xFF;
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g = (pixel>>screen->format->Gshift)&0xFF;
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b = (pixel>>screen->format->Bshift)&0xFF;
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*((bits)+screen->format->Rshift/8) = r;
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*((bits)+screen->format->Gshift/8) = g;
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*((bits)+screen->format->Bshift/8) = b;
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}
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break;
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case 4:
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*((Uint32 *)(bits)) = (Uint32)pixel;
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break;
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}
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/* Update the display */
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if ( SDL_MUSTLOCK(screen) ) {
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SDL_UnlockSurface(screen);
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}
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SDL_UpdateRect(screen, X, Y, 1, 1);
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return;</PRE
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></P
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></DIV
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><DIV
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CLASS="SECT2"
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><H2
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CLASS="SECT2"
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><A
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NAME="AEN391"
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>Fastest possible surface blit</A
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></H2
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><P
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>There are three different ways you can draw an image to the screen:
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<P
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></P
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><TABLE
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BORDER="0"
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><TBODY
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><TR
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><TD
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>1.Create a surface and use <A
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HREF="sdlblitsurface.html"
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><TT
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CLASS="FUNCTION"
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>SDL_BlitSurface</TT
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></A
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> to blit it to the screen</TD
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></TR
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><TR
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><TD
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>2.Create the video surface in system memory and call <A
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HREF="sdlupdaterect.html"
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><TT
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CLASS="FUNCTION"
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>SDL_UpdateRect</TT
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></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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>3.Create the video surface in video memory and call <A
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HREF="sdllocksurface.html"
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><TT
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CLASS="FUNCTION"
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>SDL_LockSurface</TT
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></A
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></TD
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></TR
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></TBODY
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></TABLE
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><P
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></P
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>
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The best way to do this is to combine methods:
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<PRE
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CLASS="PROGRAMLISTING"
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>#include <stdio.h>
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#include <stdlib.h>
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#include "SDL.h"
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#include "SDL_timer.h"
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void ComplainAndExit(void)
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{
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fprintf(stderr, "Problem: %s\n", SDL_GetError());
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exit(1);
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}
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int main(int argc, char *argv[])
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{
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SDL_PixelFormat fmt;
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SDL_Surface *screen, *locked;
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SDL_Surface *imagebmp, *image;
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SDL_Rect dstrect;
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int i;
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Uint8 *buffer;
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/* Initialize SDL */
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if ( SDL_Init(SDL_INIT_VIDEO) < 0 ) {
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ComplainAndExit();
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}
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atexit(SDL_Quit);
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/* Load a BMP image into a surface */
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imagebmp = SDL_LoadBMP("image.bmp");
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if ( imagebmp == NULL ) {
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ComplainAndExit();
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}
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/* Set the video mode (640x480 at native depth) */
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screen = SDL_SetVideoMode(640, 480, 0, SDL_HWSURFACE|SDL_FULLSCREEN);
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if ( screen == NULL ) {
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ComplainAndExit();
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}
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/* Set the video colormap */
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if ( imagebmp->format->palette != NULL ) {
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SDL_SetColors(screen,
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imagebmp->format->palette->colors, 0,
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imagebmp->format->palette->ncolors);
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}
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/* Convert the image to the video format (maps colors) */
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image = SDL_DisplayFormat(imagebmp);
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SDL_FreeSurface(imagebmp);
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if ( image == NULL ) {
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ComplainAndExit();
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}
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/* Draw bands of color on the raw surface */
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if ( SDL_MUSTLOCK(screen) ) {
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if ( SDL_LockSurface(screen) < 0 )
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ComplainAndExit();
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}
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buffer=(Uint8 *)screen->pixels;
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for ( i=0; i<screen->h; ++i ) {
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memset(buffer,(i*255)/screen->h,
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screen->w*screen->format->BytesPerPixel);
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buffer += screen->pitch;
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}
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if ( SDL_MUSTLOCK(screen) ) {
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SDL_UnlockSurface(screen);
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}
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/* Blit the image to the center of the screen */
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dstrect.x = (screen->w-image->w)/2;
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dstrect.y = (screen->h-image->h)/2;
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dstrect.w = image->w;
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dstrect.h = image->h;
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if ( SDL_BlitSurface(image, NULL, screen, &dstrect) < 0 ) {
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SDL_FreeSurface(image);
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ComplainAndExit();
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}
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SDL_FreeSurface(image);
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/* Update the screen */
|
||
|
|
SDL_UpdateRects(screen, 1, &dstrect);
|
||
|
|
|
||
|
|
SDL_Delay(5000); /* Wait 5 seconds */
|
||
|
|
exit(0);
|
||
|
|
}</PRE
|
||
|
|
></P
|
||
|
|
></DIV
|
||
|
|
></DIV
|
||
|
|
><DIV
|
||
|
|
CLASS="NAVFOOTER"
|
||
|
|
><HR
|
||
|
|
ALIGN="LEFT"
|
||
|
|
WIDTH="100%"><TABLE
|
||
|
|
WIDTH="100%"
|
||
|
|
BORDER="0"
|
||
|
|
CELLPADDING="0"
|
||
|
|
CELLSPACING="0"
|
||
|
|
><TR
|
||
|
|
><TD
|
||
|
|
WIDTH="33%"
|
||
|
|
ALIGN="left"
|
||
|
|
VALIGN="top"
|
||
|
|
><A
|
||
|
|
HREF="guideexamples.html"
|
||
|
|
>Prev</A
|
||
|
|
></TD
|
||
|
|
><TD
|
||
|
|
WIDTH="34%"
|
||
|
|
ALIGN="center"
|
||
|
|
VALIGN="top"
|
||
|
|
><A
|
||
|
|
HREF="index.html"
|
||
|
|
>Home</A
|
||
|
|
></TD
|
||
|
|
><TD
|
||
|
|
WIDTH="33%"
|
||
|
|
ALIGN="right"
|
||
|
|
VALIGN="top"
|
||
|
|
><A
|
||
|
|
HREF="guideeventexamples.html"
|
||
|
|
>Next</A
|
||
|
|
></TD
|
||
|
|
></TR
|
||
|
|
><TR
|
||
|
|
><TD
|
||
|
|
WIDTH="33%"
|
||
|
|
ALIGN="left"
|
||
|
|
VALIGN="top"
|
||
|
|
>Examples</TD
|
||
|
|
><TD
|
||
|
|
WIDTH="34%"
|
||
|
|
ALIGN="center"
|
||
|
|
VALIGN="top"
|
||
|
|
><A
|
||
|
|
HREF="guideexamples.html"
|
||
|
|
>Up</A
|
||
|
|
></TD
|
||
|
|
><TD
|
||
|
|
WIDTH="33%"
|
||
|
|
ALIGN="right"
|
||
|
|
VALIGN="top"
|
||
|
|
>Event Examples</TD
|
||
|
|
></TR
|
||
|
|
></TABLE
|
||
|
|
></DIV
|
||
|
|
></BODY
|
||
|
|
></HTML
|
||
|
|
>
|