astile(1)                AfterStep X11 window manager                astile(1)



NAME
       astile - demonstrates image tiling/cropping and tinting
       libAfterImage/tutorials/ASTile

NAMEASTile
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
       Source :
       #include "../afterbase.h"
       #include "../afterimage.h"
       #include "common.h"

       void usage()
       {
           printf( "Usage: astile [-h]|[[-g geometry][-t tint_color] image]0);
           printf( "Where: image    - source image filename.0);
           printf( "       geometry - width and height of the resulting image,0);
           printf( "                  and x, y of the origin of the tiling on "
                   "source image.0);
           printf( "       tint_color - color to tint image with.( defaults to "
                   "current time :)0);
       }

       int main(int argc, char* argv[])
       {
           Window w ;
           Display *dpy = NULL;
           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: #%8.8lX",
                                                 (unsigned long)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:
                             image_file, (unsigned long)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
                   "%dx%d%+d%+d tinting with #%8.8lX0,
                   get_application_name(), image_file, tile_width, tile_height,
                   tile_x, tile_y, (unsigned long)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);
               dpy = NULL;
       #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 ;
       }

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

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

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().



3rd Berkeley Distribution      AfterStep v.2.2.9                     astile(1)
