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# AFTERImage example 3: Image tiling/croping

demonstrates image tiling/cropping and tinting

libAfterImage/tutorials/ASTile

- NAME

  ASTile

- SYNOPSIS

      Simple program based on libAfterImage to tile and tint image.

- DESCRIPTION

      All we want to do here is to get image filename, tint color and
      desired geometry from the command line. We then load this image, and
      proceed on to tiling it based on parameters. Tiling geometry
      specifies rectangular shape on limitless plane on which original
      image is tiled. While we are at tiling the image we also tint it to
      specified color, or to some random value derived from the current
      time in seconds elapsed since 1971.
      We then display the result in simple window.
      After that we would want to wait, until user closes our window.

      In this tutorial we will only explain new steps, not described in
      previous tutorial. New steps described in this tutorial are :
      ASTile.1. Parsing ARGB32 tinting color.
      ASTile.2. Parsing geometry spec.
      ASTile.3. Tiling and tinting ASImage.

- SEE ALSO

      ASView - explanation of basic steps needed to use libAfterImage and
               some other simple things.

- SOURCE

      #include "../afterbase.h"
      #include "../afterimage.h"
      #include "common.h"

      void usage()
      {
          printf( "Usage: astile [-h]|[[-g geometry][-t tint_color] image]\n");
          printf( "Where: image    - source image filename.\n");
          printf( "       geometry - width and height of the resulting image,\n");
          printf( "                  and x, y of the origin of the tiling on "
                  "source image.\n");
          printf( "       tint_color - color to tint image with.( defaults to "
                  "current time :)\n");
      }

      int main(int argc, char* argv[])
      {
          Window w ;
          ASVisual *asv ;
          int screen = 0, depth = 0;
          char *image_file = "rose512.jpg" ;
          ARGB32 tint_color = time(NULL);
          int tile_x, tile_y, geom_flags = 0;
          unsigned int tile_width, tile_height ;
          ASImage *im ;

          /* see ASView.1 : */
          set_application_name( argv[0] );

      #ifndef X_DISPLAY_MISSING
          /* parse_argb_color can only be used after display is open,
             otherwise we are limited to colors defined as ARGB values : */
          dpy = XOpenDisplay(NULL);
          _XA_WM_DELETE_WINDOW = XInternAtom( dpy, "WM_DELETE_WINDOW", False);
          screen = DefaultScreen(dpy);
          depth = DefaultDepth( dpy, screen );
      #endif

          if( argc > 1 )
          {
              int i ;

              if( strncmp( argv[1], "-h", 2 ) == 0 )
              {
                  usage();
                  return 0;
              }

              for( i = 1 ; i < argc ; i++ )
              {
                  if( argv[i][0] == '-' && i < argc-1 )
                  {
                      switch(argv[i][1])
                      {
                          case 't' :          /* see ASTile.1 : */
                              if( parse_argb_color( argv[i+1], &tint_color ) ==
                                  argv[i+1] )
                                  show_warning( "unable to parse tint color - "
                                                "default used: #%8.8X",
                                                tint_color );
                              break ;
                          case 'g' :          /* see ASTile.2 : */
                              geom_flags = XParseGeometry( argv[i+1],
                                                           &tile_x, &tile_y,
                                                           &tile_width,
                                                           &tile_height );
                              break ;
                      }
                      ++i ;
                  }else
                      image_file = argv[i] ;
              }
          }else
          {
              show_warning( "no image file or tint color specified - "
                            "defaults used: \"%s\" #%8.8lX",
                            image_file, tint_color );
              usage();
          }

          /* see ASView.2 : */
          im = file2ASImage( image_file, 0xFFFFFFFF, SCREEN_GAMMA, 0, getenv("IMAGE_PATH"), NULL );

          /* Making sure tiling geometry is sane : */
          if( !get_flags(geom_flags, XValue ) )
              tile_x = im->width/2 ;
          if( !get_flags(geom_flags, YValue ) )
              tile_y = im->height/2 ;
          if( !get_flags(geom_flags, WidthValue ) )
              tile_width = im->width*2 ;
          if( !get_flags(geom_flags, HeightValue ) )
              tile_height = im->height*2;
          printf( "%s: tiling image \"%s\" to "
                  "%dx%d%+d%+d tinting with #%8.8lX\n",
                  get_application_name(), image_file, tile_width, tile_height,
                  tile_x, tile_y, tint_color );

          if( im != NULL )
          {
              /* see ASView.3 : */
              asv = create_asvisual( dpy, screen, depth, NULL );
              w = None ;
      #ifndef X_DISPLAY_MISSING
              /* see ASView.4 : */
              w = create_top_level_window( asv, DefaultRootWindow(dpy), 32, 32,
                                           tile_width, tile_height, 1, 0, NULL,
                                           "ASTile", image_file );
              if( w != None )
              {
                  Pixmap p ;
                  ASImage *tinted_im ;

                  XMapRaised   (dpy, w);
                  /* see ASTile.3 : */
                  tinted_im = tile_asimage( asv, im, tile_x, tile_y,
                                            tile_width, tile_height,
                                            tint_color, ASA_XImage, 0,
                                            ASIMAGE_QUALITY_TOP );
                  destroy_asimage( &im );
                  /* see ASView.5 : */
                  p = asimage2pixmap( asv, DefaultRootWindow(dpy), tinted_im,
                                      NULL, True );
                  destroy_asimage( &tinted_im );
                  /* see common.c: set_window_background_and_free() : */
                  p = set_window_background_and_free( w, p );
              }
              /* see common.c: wait_closedown() : */
              wait_closedown(w);
      #else
              {
                  ASImage *tinted_im ;
                  /* see ASTile.3 : */
                  tinted_im = tile_asimage( asv, im, tile_x, tile_y,
                                            tile_width, tile_height,
                                            tint_color, ASA_ASImage, 0,
                                            ASIMAGE_QUALITY_TOP );
                  destroy_asimage( &im );
                  /* writing result into the file */
                  ASImage2file( tinted_im, NULL, "astile.jpg", ASIT_Jpeg, NULL );
                  destroy_asimage( &tinted_im );
              }
      #endif
          }
          return 0 ;
      }

libAfterImage/tutorials/ASTile.1 [3.1]

- SYNOPSIS

      Step 1. Color parsing.

- DESCRIPTION

      libAfterImage utilizes function provided by libAfterBase for color
      parsing. In case libAfterBase is unavailable - libAfterImage
      includes its own copy of that function. This function differs from
      standard XParseColor in a way that it allows for parsing of alpha
      channel in addition to red, green and blue. It autodetects if value
      include alpha channel or not, using the following logic:
      If number of hex digits in color spec is divisible by 4 and is not
      equal to 12 then first digits are treated as alpha channel.
      In case named color is specified or now apha channel is specified
      alpha value of 0xFF will be used, marking this color as solid.

- EXAMPLE

          if( parse_argb_color( argv[i+1], &tint_color ) == argv[i+1] )
                 show_warning( "unable to parse tint color - default used: #%8.8X",
                             tint_color );

- NOTES

      On success parse_argb_color returns pointer to the character
      immidiately following color specification in original string.
      Therefore test for returned value to be equal to original string will
      can be used to detect error.

- SEE ALSO

      libAfterBase, parse_argb_color(), ARGB32

libAfterImage/tutorials/ASTile.2 [3.2]

- SYNOPSIS

      Step 2. Parsing the geometry.

- DESCRIPTION

      Geometry can be specified in WIDTHxHEIGHT+X+Y format. Accordingly we
      use standard X function to parse it: XParseGeometry. Returned flags
      tell us what values has been specified. We only have to fill the rest
      with some sensible defaults. Default x is width/2, y is height/2, and
      default size is same as image's width.

- EXAMPLE

          geom_flags = XParseGeometry ( argv[i+1], &tile_x, &tile_y,
                                        &tile_width, &tile_height );

- SEE ALSO

      ASScale.1

libAfterImage/tutorials/ASTile.3 [3.3]

- SYNOPSIS

      Step 3. Actuall tiling of the image.

- DESCRIPTION

      Actuall tiling is quite simple - just call tile_asimage and it will
      generate new ASImage containing tiled and tinted image. For the sake
      of example we set quality to TOP, but normally GOOD quality is quite
      sufficient, and is a default. Again, compression is set to 0 since we
      do not intend to store image for long time. Even better we don't need
      to store it at all - all we need is XImage, so we can transfer it to
      the server easily. That is why to_xim argument is set to ASA_XImage.
      As the result obtained ASImage will not have any data in its buffers,
      but it will have ximage member set to point to valid XImage.
      Subsequently we enjoy that convinience, by setting use_cached to True
      in call to asimage2pixmap(). That ought to save us alot of processing.

      Tinting works in both directions - it can increase intensity of the
      color or decrease it. If any particular channel of the tint_color is
      greater then 127 then intensity is increased, otherwise its decreased.

- EXAMPLE

      tinted_im = tile_asimage( asv, im, tile_x, tile_y,
                              tile_width, tile_height,
                              tint_color,
                              ASA_XImage, 0, ASIMAGE_QUALITY_TOP );
      destroy_asimage( &im );

- NOTES

- SEE ALSO

      tile_asimage().

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