Generated from common.c with ROBODoc v3.2.3 on Mon Feb 18 01:16:12 2002

## libAfterImage/tutorials/common.h

SYNOPSIS

     Generic Xlib related functionality, common for all the tutorials.

SEE ALSO

     libAfterImage,
     ASView, ASScale, ASTile, ASMerge, ASGrad, ASFlip, ASText

## libAfterImage/tutorials/_XA_WM_DELETE_WINDOW

SYNOPSIS

     _XA_WM_DELETE_WINDOW - stores value of X Atom "WM_DELETE_WINDOW".

DESCRIPTION

     In X all client's top level windows are managed by window manager.
     That includes moving, resizing, decorating, focusing and closing of
     windows. Interactions between window manager and client window are
     governed by ICCCM specification.
     All the parts of this specification are completely optional, but it
     is recommended that the following minimum set of hints be supplied
     for any client window:
     Window's title(WM_NAME), iconified window title(WM_ICON_NAME), class
     hint (WM_CLASS) and supported protocols (WM_PROTOCOLS). It is
     recommended also that WM_DELETE_WINDOW protocol be supported, as
     otherwise there are no way to safely close client window, but to
     kill it.
     All of the above mentioned hints are identified by atoms that have
     standard preset values, except for WM_DELETE_WINDOW. As the result we
     need to obtain WM_DELETE_WINDOW atoms ID explicitly. We use
     _XA_WM_DELETE_WINDOW to store the ID of that atom, so it is accessible
     anywhere from our application.

SOURCE

        Atom _XA_WM_DELETE_WINDOW = None;

## libAfterImage/tutorials/create_top_level_window()

SYNOPSIS

     Window create_top_level_window( ASVisual *asv, Window root,
                                     int x, int y,
                                     unsigned int width,
                                     unsigned int height,
                                     unsigned int border_width,
                                     unsigned long attr_mask,
                                     XSetWindowAttributes *attr,
                                     char *app_class );

INPUTS

     asv           - pointer to valid preinitialized ASVisual structure.
     root          - root window of the screen on which to create window.
     x, y          - desired position of the window
     width, height - desired window size.
     border_width  - desired initial border width of the window (may not
                     have any effect due to Window Manager intervention.
     attr_mask     - mask of the attributes that has to be set on the
                     window
     attr          - values of the attributes to be set.
     app_class     - title of the application to be used as its window
                     Title and resources class.

RETURN VALUE

     ID of the created window.

DESCRIPTION

     create_top_level_window() is autyomating process of creating top
     level application window. It creates window for specified ASVisual,
     and then sets up basic ICCCM hints for that window, such as WM_NAME,
     WM_ICON_NAME, WM_CLASS and WM_PROTOCOLS.

SOURCE

        Window
        create_top_level_window( ASVisual *asv, Window root, int x, int y,
                                 unsigned int width, unsigned int height,
                                 unsigned int border_width, unsigned long attr_mask,
                                 XSetWindowAttributes *attr, char *app_class )
        {
            Window w = None;
        #ifndef X_DISPLAY_MISSING
            char *tmp ;
            XTextProperty name;
            XClassHint class1;

            w = create_visual_window(asv, root, x, y, width, height, border_width, InputOutput, attr_mask, attr );

            tmp = (char*)get_application_name();
            XStringListToTextProperty (&tmp, 1, &name);

            class1.res_name = tmp;  /* for future use */
            class1.res_class = app_class;
            XSetWMProtocols (dpy, w, &_XA_WM_DELETE_WINDOW, 1);
            XSetWMProperties (dpy, w, &name, &name, NULL, 0, NULL, NULL, &class1);
            /* final cleanup */
            XFree ((char *) name.value);

        #endif /* X_DISPLAY_MISSING */
            return w;
        }

## libAfterImage/tutorials/set_window_background_and_free()

SYNOPSIS

     Pixmap set_window_background_and_free( Window w, Pixmap p );

INPUTS

     w - ID of the window background of which we need to set.
     p - Pixmap to set background to.

RETURN VALUE

     None on success. Pixmap ID of original Pixmap on failure.

DESCRIPTION

     set_window_background_and_free() will set window's background to
     specified Pixmap, Then refresh window contents so that background
     is drawn by the server, flush all the requests to force it to be sent
     to server to be processed as fast as possible.

NOTES

     After Window's background has been set to Pixmap - X server makes
     hidden copy of this Pixmap for later window refreshing. As the result
     original Pixmap is no longer needed and can be freed to conserve
     resources.

SOURCE

        Pixmap
        set_window_background_and_free( Window w, Pixmap p )
        {
        #ifndef X_DISPLAY_MISSING
            if( p != None && w != None )
            {
                XSetWindowBackgroundPixmap( dpy, w, p );
                XClearWindow( dpy, w );
                XFlush( dpy );
                XFreePixmap( dpy, p );
                p = None ;
            }
        #endif /* X_DISPLAY_MISSING */
            return p ;
        }

## libAfterImage/tutorials/wait_closedown()

SYNOPSIS

     void wait_closedown( Window w );

INPUTS

     w - ID of the window from which to wait for events.

DESCRIPTION

     User action requesting window to be closed is generally received
     first by Window Manager. Window Manager is then handles it down to
     the window by sending it ClientMessage event with first 32 bit word
     of data set to the value of WM_DELETE_WINDOW Atom.
     Accordingly, all client has to do is wait for such event from X server
     and, when received, it should destroy its window and generally exit.

NOTES

     It is recommended that XFlush() is issued right after XDestroyWindow()
     as Window Manager itself may attempt to do something with the window
     until it receives DestroyNotify event.

SEE ALSO

     ICCCM, Window

SOURCE

        void
        wait_closedown( Window w )
        {
        #ifndef X_DISPLAY_MISSING
            if( dpy == NULL || w == None )
                return ;

            XSelectInput (dpy, w, (StructureNotifyMask | ButtonPressMask|ButtonReleaseMask));

            while(w != None)
            {
                XEvent event ;
                XNextEvent (dpy, &event);
                switch(event.type)
                {
                    case ClientMessage:
                        if ((event.xclient.format != 32) ||
                            (event.xclient.data.l[0] != _XA_WM_DELETE_WINDOW))
                            break ;
                    case ButtonPress:
                        XDestroyWindow( dpy, w );
                        XFlush( dpy );
                        w = None ;
                        break ;
                }
            }
            XCloseDisplay (dpy);
            dpy = NULL ;
        #endif
        }