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
#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 ;
    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: \"%s\" #%8.8lX",
                      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 \"%s\" to "
            "%dx%d%+d%+d tinting with #%8.8lX\n",
            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 ; }
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

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 a lot 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().