XmRedisplayWidget - Man Page

#include <Xm/Xm​.h>
voidXmRedisplayWidget(
Widgetwidget);

This function is a convenience routine that hides the details of the Xt internals to the application programmer by calling the expose method of the given widget with a well formed Expose event and Region corresponding to the total area of the widget​. If the widget doesn​'t have an Expose method, the function does nothing​.

This is primarily used in the context of X Printing if the programming model chosen by the application is synchronous; that is, it doesn​'t rely of X Print events for the driving of page layout but wants to completely control the sequence of rendering requests​.

XmRedisplayWidget doesn​'t clear the widget window prior to calling the expose method, since this is handled by calls to XpStartPage ​.

widget

The widget to redisplay​.

None​.

Not applicable

In the following, a simple application wants to print the content of a multi-page text widget (similar to dtpad)​.

PrintOKCallback(print_dialog​.​.​.)
/*-------------*/
{
    pshell = XmPrintSetup (print_dialog, pbs->print_screen,
                                   "Print", NULL, 0);

    XpStartJob(XtDisplay(pshell), XPSpool);

    /**** here I realize the shell, get its size, create my widget
     hierarchy: a bulletin board, and then a text widget,
     that I stuff with the video text widget buffer */

    /* get the total number of pages to print */
    XtVaGetValues(ptext, XmNrows, &prows,
                         XmNtotalLines, n_lines, NULL);
    n_pages = n_lines / prows;

    /***** now print the pages in a loop */

    for (cur_page=0; cur_page != n_pages; cur_page++) {

               XpStartPage(XtDisplay(pshell), XtWindow(pshell), False);
               XmRedisplayWidget(ptext);  /* do the drawing */
               XpEndPage(XtDisplay(pshell));

        XmTextScroll(ptext, prows);  /* get ready for next page */
    }

    /***** I​'m done */
    XpEndJob(XtDisplay(pshell));

}

Of course, one could change the above code to include it in a fork() branch so that the main program is not blocked while printing is going on​. Another way to achieve a "print-in-the-background" effect is to use an Xt workproc​. Using the same sample application, that gives us:

Boolean
PrintOnePageWP(XtPointer npages) /* workproc */
/*-------------*/
{
    static int cur_page = 0;
    cur_page++;

    XpStartPage(XtDisplay(pshell), XtWindow(pshell), False);
    XmRedisplayWidget(ptext);  /* do the drawing */
    XpEndPage(XtDisplay(pshell));

    XmTextScroll(ptext, prows);  /*  get ready for next page */

    if (cur_page == n_pages) { /***** I​'m done */
        XpEndJob(XtDisplay(pshell));

        XtDestroyWidget(pshell);
        XtCloseDisplay(XtDisplay(pshell));
    }

    return (cur_page == n_pages);
}

PrintOKCallback(​.​.​.)
/*-------------*/
{
    pshell = XmPrintSetup (widget, pbs->print_screen,
                                   "Print", NULL, 0);

    XpStartJob(XtDisplay(pshell), XPSpool);

    /**** here I get the size of the shell, create my widget
          hierarchy: a bulletin board, and then a text widget,
                  that I stuff with the video text widget buffer */

    /* get the total number of pages to print */
    /* ​.​.​. same code as above example */

    /***** print the pages in the background */
    XtAppAddWorkProc(app_context, PrintOnePageWP, n_pages);
}

XmPrintSetup(3), XmPrintShell(3)