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asview

Section: AfterStep X11 window manager (1)
Updated: AfterStep v.2.2.2
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NAME

asview - demonstrates loading and displaying of imageslibAfterImage/tutorials/ASView

NAMEASView

SYNOPSIS

Simple image viewer based on libAfterImage.

DESCRIPTION

All we want to do here is to get image filename from the command line,then load this image, and display it in simple window.After that we would want to wait, until user closes our window.

SOURCE

Source :

#define DO_CLOCKING#include "../afterbase.h"#include "../afterimage.h"#include "common.h"#ifdef DO_CLOCKING#if TIME_WITH_SYS_TIME# include <sys/time.h># include <time.h>#else# if HAVE_SYS_TIME_H#  include <sys/time.h># else#  include <time.h># endif#endif#endifvoid usage(){    printf( "Usage: asview [-h]|[image]);    printf( "Where: image - filename of the image to display.);}int main(int argc, char* argv[]){    char *image_file = "rose512.jpg" ;    ASImage *im ;    ASVisual *asv ;    int screen, depth ;    /* see ASView.1 : */    set_application_name( argv[0] );#if (HAVE_AFTERBASE_FLAG==1)    set_output_threshold(OUTPUT_LEVEL_DEBUG);#ifdef DEBUG_ALLOCS    fprintf( stderr, "have DEBUG_ALLOCS);#endif#ifdef AFTERBASE_DEBUG_ALLOCS    fprintf( stderr, "have AFTERBASE_DEBUG_ALLOCS);#endif#endif    if( argc > 1 )    {        if( strcmp( argv[1], "-h" ) == 0 )        {            usage();            return 0;        }        image_file = argv[1] ;    }else    {        show_warning(   "Image filename was not specified. "                        "Using default:         usage();    }#ifndef X_DISPLAY_MISSING    dpy = XOpenDisplay(NULL);    XSynchronize (dpy, True);    _XA_WM_DELETE_WINDOW = XInternAtom( dpy, "WM_DELETE_WINDOW",                                         False);    screen = DefaultScreen(dpy);    depth = DefaultDepth( dpy, screen );    /* see ASView.3 : */    asv = create_asvisual( dpy, screen, depth, NULL );    /*asv = create_asvisual_for_id( dpy, screen, depth, 0x25, None, NULL ); */#endif      /* see ASView.2 : */    im = file2ASImage( image_file, 0xFFFFFFFF, SCREEN_GAMMA, 0, getenv("IMAGE_PATH"), NULL );    /* The following could be used to dump JPEG version of the image into     * stdout : */    /* ASImage2file( im, NULL, NULL, ASIT_Jpeg, NULL ); */    if( im != NULL )    {#ifndef X_DISPLAY_MISSING        Window w ;#if 0        XRectangle *rects ; unsigned int rects_count =0; int i ;        rects = get_asimage_channel_rects( im, IC_ALPHA, 10,                                             &rects_count );        fprintf( stderr, " %d rectangles generated : , rects_count );        for( i = 0 ; i < rects_count ; ++i )            fprintf( stderr, "	rect[%d]=%dx%d%+d%+d;,                      i, rects[i].width, rects[i].height,                      rects[i].x, rects[i].y );#endif#if 0                /* test example for fill_asimage : */        fill_asimage(asv, im, 0, 0, 50, 50, 0xFFFF0000);        fill_asimage(asv, im, 50, 50, 100, 50, 0xFFFF0000);        fill_asimage(asv, im, 0, 100, 200, 50, 0xFFFF0000);        fill_asimage(asv, im, 150, 0, 50, 50, 0xFFFF0000);#endif#if 0        /* test example for conversion to argb32 :*/        {            ASImage *tmp = tile_asimage( asv, im, 0, 0, im->width, im->height, TINT_NONE, ASA_ARGB32,                                           0, ASIMAGE_QUALITY_DEFAULT );              destroy_asimage( &im );            set_flags( tmp->flags, ASIM_DATA_NOT_USEFUL|ASIM_XIMAGE_NOT_USEFUL );            im = tmp ;        }          #endif                 /* see ASView.4 : */        w = create_top_level_window( asv, DefaultRootWindow(dpy), 32, 32,                                     im->width, im->height, 1, 0, NULL,                                     "ASView", image_file );        if( w != None )        {            Pixmap p ;                        XMapRaised   (dpy, w);            XSync(dpy,False);            /* see ASView.5 : */            show_warning( "asimage2pmap");            p = create_visual_pixmap( asv, DefaultRootWindow(dpy), im->width, im->height, 0 );                {                /*int i ;*/                START_TIME(started);                time_t t = time(NULL);                /* for( i = 0 ; i < 100 ; ++i )  */                    asimage2drawable( asv, p, im, NULL, 0, 0, 0, 0, im->width, im->height, False);                SHOW_TIME("", started);                show_progress( "runtime = %d sec, time(NULL)-t );            }            show_warning( "asimage2pmap Done");            /* print_storage(NULL); */            destroy_asimage( &im );            /* see common.c:set_window_background_and_free(): */            p = set_window_background_and_free( w, p );        }        /* no longer need this - lets clean it up :*/        destroy_asvisual( asv, False );        asv = NULL ;        /* see common.c: wait_closedown() : */        wait_closedown(w);#else        /* writing result into the file */        ASImage2file( im, NULL, "asview.jpg", ASIT_Jpeg, NULL );#endif    }#ifdef DEBUG_ALLOCS    flush_ashash_memory_pool();    asxml_var_cleanup();    custom_color_cleanup();    build_xpm_colormap( NULL );    flush_default_asstorage();    print_unfreed_mem();#endif    return 0 ;}

SYNOPSIS

Step 1. Initialization.

DESCRIPTION

libAfterImage requires only 2 global things to be setup, and both ofthose are inherited from libAfterBase: dpy - pointer to open X display-naturally that is something we cannot live without; application name -used in all the text output, such as error and warning messages andalso debugging messages if such are enabled.The following two line are about all that is required to setup bothof this global variables :

EXAMPLE

    set_application_name( argv[0] );    dpy = XOpenDisplay(NULL);

NOTES

First line is setting up application name from command line'sprogram name. Second opens up X display specified in DISPLAY env.variable. Naturally based on application purpose different parameterscan be passed to these functions, such as some custom display string.

SYNOPSIS

Step 2. Loading image file.

DESCRIPTION

At this point we are ready to load image from file into memory. SincelibAfterImage does not use any X facilities to store image - we don'thave to create any window or anything else yet. Even dpy is optionalhere - it will only be used to try and parse names of colors from

EXAMPLE

    im = file2ASImage( image_file, 0xFFFFFFFF, SCREEN_GAMMA, 0, NULL);

NOTES

We used compression set to 0, as we do not intend to storeimage in memory for any considerable amount of time, and we want toavoid additional processing overhead related to image compression.If image was loaded successfully, which is indicated by returnedpointer being not NULL, we can proceed to creation of the window anddisplaying of the image.

SYNOPSIS

Step 3. Preparation of the visual.

DESCRIPTION

At this point we have to obtain Visual information, as windowcreation is highly dependant on Visual being used. In fact when Xcreates a window it ties it to a particular Visual, and all itsattributes, such as colormap, pixel values, pixmaps, etc. must beassociated with the same Visual. Accordingly we need to acquireASVisual structure, which is our abstraction layer from them naughtyX Visuals. :

EXAMPLE

    asv = create_asvisual( dpy, screen, depth, NULL );

NOTES

If any Window or Pixmap is created based on particular ASVisual, thenthis ASVisual structure must not be destroyed untill all suchWindows and Pixmaps are destroyed.

SYNOPSIS

Step 4. Preparation of the window.

DESCRIPTION

Creation of top level window consists of several steps of its own:a) create the window of desired size and placementb) set ICCCM hints on the windowc) select appropriate events on the windowc) map the window.First two steps has been moved out into create_top_level_window()function.

EXAMPLE

    w = create_top_level_window( asv, DefaultRootWindow(dpy), 32, 32,                                 im->width, im->height, 1, 0, NULL,                                 "ASView" );    if( w != None )    {        XSelectInput (dpy, w, (StructureNotifyMask | ButtonPress));        XMapRaised   (dpy, w);    }

NOTES

Map request should be made only for window that has all its hints setup already, so that Window Manager can read them right away.We want to map window as soon as possible so that User could see thatsomething really is going on, even before image is displayed.

SYNOPSIS

Step 5. Displaying the image.

DESCRIPTION

The simplest way to display image in the window is to convert itinto Pixmap, then set Window's background to this Pixmap, and,at last, clear the window, so that background shows up.

EXAMPLE

 p = asimage2pixmap( asv, DefaultRootWindow(dpy), im, NULL, False ); destroy_asimage( &im );

NOTES

We no longer need ASImage after we transfered it onto the Pixmap, sowe better destroy it to conserve resources.

Index

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NAMEASView
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This document was created byman2html,using the manual pages.

asview

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