NAME

XmPrintShell — a shell widget class used for printing in Motif

SYNOPSIS

#include <Xm/Print.h>
Boolean XmIsPrintShell(
Widget);

DESCRIPTION

The XmPrintShell provides the Motif application programmer with an Xt widget oriented API to some of the X Print resources and a callback to drive the pagination.

The XmPrintShell provides a simple callback to handle the pagination logic, and a set of resources to get and set common printer attributes.

If not created on an XPrint connection, XmPrintShell behaves as a regular applicationShell.

The XmPrintShell also initializes the Xp extension event handling mechanism, by registering an extension selector that calls XpSelectInput and event dispatcher for print and attributes Xp events, so applications can use XtInsertEventTypeHandler to register their own handler with the Xp events.

Arguments

No XmCreate function is provided, since this is a toplevel shell, most likely created thru some Xt shell creation routine or XmPrintSetup.

Classes

XmPrintShell is a subclass of ApplicationShell; it inherits behavior, resources and traits from all its superclasses. The class pointer is XmPrintShellWidgetClass.

New Resources

XmPrintShell Resource Set
Name	Class	Type	Default	Access
XmNstartJobCallback	XmCCallback	XtCallbackList	NULL	CSG
XmNendJobCallback	XmCCallback	XtCallbackList	NULL	CSG
XmNpageSetupCallback	XmCCallback	XtCallbackList	NULL	CSG
XmNminX	XmCMinX	Dimension	dynamic	G
XmNminY	XmCMinY	Dimension	dynamic	G
XmNmaxX	XmCMaxX	Dimension	dynamic	G
XmNmaxY	XmCMaxY	Dimension	dynamic	G
XmNdefaultPixmapResolution	XmCDefaultPixmapResolution	unsigned short	100	CSG
XmNpdmNotificationCallback	XmCCallback	XtCallbackList	NULL	CSG

XmNstartJobCallback: Specifies the callback driving the beginning of rendering. It is safe for an application to start rendering after this callback has been activated. XpStartJob must be called to trigger this callback.
XmNendJobCallback: Specifies the callback driving the end of rendering. Notify the client that all rendering has been processed (whether on print-to-file or regular spool). XpEndJob is called by the print shell to trigger this callback.
XmNpageSetupCallback: Specifies the callback driving the page layout. It is safe for an app to start rendering from this callback even if the XmNstartJobCallback is not used.
XmNminX, XmNminY, XmNmaxX, XmNmaxY: Specify the imageable area of the page in the current print context. XmPrintShell also maintains a proper size at all times by updating its own widget dimension whenever an attribute, such as resolution or orientation, changes. It is sized in its Initialize routine so that the application can rely on a proper size before the first StartPage call is issued.
XmNdefaultPixmapResolution: Indicates the resolution in dpi (dot per inch) of the image files read and converted by Motif for the widget descendants of this shell. It is used to determine a scaling ratio to be applied to pixmap created thru regular pixmap/icon conversion of the following Widget resources:

•: XmLabel.label*Pixmap, XmIconG.*IconPixmap XmToggleB.selectPixmap, XmPushBG.armPixmap, XmIconG.*IconMask, XmMessageBox.symbolPixmap, XmContainer.*StatePixmap, ...
•: Leaving out the pixmap resources being used for tiling (XmNhighlightPixmap, XmNtopShadowPixmap, XmNbottomShadowPixmap, XmNbackgroundPixmap, ...)

XmNpdmNotificationCallback: A callback notifying the application about the status of the PDM (see XmPrintPopupPDM). A XmPrintShellCallbackStruct is used, with reason:

•: XmCR_PDM_NONE: no PDM available on this display for the named selection (provided in detail)
•: XmCR_PDM_START_VXAUTH : the PDM is not authorized to connect to the video display.
•: XmCR_PDM_START_PXAUTH : the PDM is not authorized to connect to the print display.
•: XmCR_PDM_UP : the PDM is up and running
•: XmCR_PDM_OK : the PDM has exited with OK status
•: XmCR_PDM_CANCEL : the PDM has exited with CANCEL
•: XmCR_PDM_START_ERROR : the PDM cannot start due to some error (usually logged)
•: XmCR_PDM_EXIT_ERROR : the PDM has exited with an error

Callback Information

The XmNstartJobCallback, XmNendJobCallback, XmNpageSetupCallback and XmNpdmNotificationCallback operate on a XmPrintShellCallbackStruct, which is defined as follow:

typedef struct
{
    int     reason;  /* XmCR_START_JOB, XmCR_END_JOB,
                        XmCR_PAGE_SETUP, XmCR_PDM_* */
    XEvent  *event;
    XPContext print_context;
    Boolean last_page; /* in_out */
    XtPointer detail;
} XmPrintShellCallbackStruct;

Additional Behavior

The last_page field is only meaningful when the reason is XmCR_PAGE_SETUP.

The page setup callback is called with last_page False to notify the application that it has to get its internal layout state ready for the next page. Typically, a widget based application will change the content of a Label showing the page number, or scroll the content of the Text widget.

When the application has processed its last page, it should set the last_page field in the callback struct to True. The callback will be called a last time after that with last_page False to notify the application that it can safely clean-up its internal state (e.g., destroy widgets).

No drawing should occur from within the callback function in the application, this is an Exposure event-driven programming model where widgets render themselves from their expose methods.

The print shell calls XpStartPage after the pageSetupCallback returns, and XpEndPage upon reception of StartPageNotify.

ERRORS/WARNINGS

XmPrintShell can generate the following warnings:

•: Not connected to a valid X Print Server: behavior undefined.
•: Attempt to set an invalid resolution on a printer: %s
•: Attempt to set an invalid orientation on a printer: %s

RETURN VALUE

Not applicable

EXAMPLES

PrintOnePageCB(Widget pshell, XtPointer npages,
/*----------*/ XmPrintSetPageCBStruct psp)
{
    static int cur_page = 0;
    cur_page++;
    if (! psp->last_page
        && curPage > 1) /* no need to scroll for the first page */
    {
        XmTextScroll(ptext, prows);  /* get ready for next page */
    } else {    /**** I'm done */
       XtDestroyWidget(pshell);
       XtCloseDisplay(XtDisplay(pshell));
    }
    if (cur_page == (int) n_pages) psp->last_page = True;
}
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 bulleting 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 previous example to get n_pages */
    /****  set up my print callback */
    XtAddCallback(pshell,  XmNpageSetUpCallback,
                           PrintOnePageCB, n_pages);
}

Examples of XmNdefaultPixmapResolution usage:

•: An application reuses the same image sources it uses for the video interface, in XBM, XPM, PNG ot JPEG, to layout on its printed pages. In this case, scaling is seamless.

    ! icon.xpm is 30x30 pixels
    app*dialog.pushb.labelPixmap:icon.xpm
    ! print is 400dpi
    app.print*form.lab.labelPixmap:icon.xpm
    ! 120x120 pixels on the paper (auto scaling)

•: An application provides a new set of image files, for a given printer resolution (say 300). It doesn't want automatic scaling by the toolkit for that resolution, it wants scaling based on these 300dpi images for higher resolution. It creates its print shell inside using the name "printHiRes" and adds the following in its resource file:

    app.printHiRes.defaultPixmapResolution:300
    ! icon300.xpm is 120x120 pixels
    app.printHiRes*form.lab.labelPixmap:icon300.xpm
    ! 120x120 pixels on the paper (no scaling)

This way a printer resolution of 600 will result in a scale of a 300 dpi image by 2 (dpi=600 divided by base=300), while a printer resolution of 150 (using default print shell name "print") will use the 100 dpi icon scaled by 1.5 (dpi=150 divided by default base=100).