man Prima::Printer (3): system printing services

SYNOPSIS

my $printer = $::application-> get_printer;
print "printing to ", $printer->printer, "...\n";
$p-> options( Orientation => 'Landscape', PaperSize => 'A4');
if ( $p-> begin_doc) {
$p-> bar( 0, 0, 100, 100);
print "another page...\n";
$p-> new_page or die "new_page:$@";
$p-> ellipse( 100, 100, 200, 200);
(time % 1) ? # depending on the moon phase, print it or cancel out
$p-> end_doc :
$p-> abort_doc;
} else {
print "failed:$@\n";
}

DESCRIPTION

Prima::Printer is a descendant of Prima::Drawable class. It provides access to the system printing services, where available. If the system provides no graphics printing, the default PostScript (tm) interface module Prima::PS::Printer is used instead.

Usage

Prima::Printer objects are never created directly. During the life of a program, there exists only one instance of a printer object, created automatically by Prima::Application. Prima::Printer object is created only when the system provides graphic printing capabilities - drawing and painting procedures on a graphic device. If there are no such API, Prima::Application creates an instance of Prima::PS::Printer instead, which emulates a graphic device, producing PostScript output. The discretion between Prima::Printer and Prima::PS::Printer is transparent for both the user and the programmer, unless printer device specific adjustments desired.

A printing session is started by "begin_doc()", which switches the object into the painting state. If finished by "end_doc()", the document is delivered to a printer device. Alternative finishing method, "abort_doc()", terminates the printing session with no information printed, unless the document is multi-paged and pages were sent to the printer via "new_page()".

A printer object ( that means, both Prima::Printer and Prima::PS::Printer ) provides selection of the printer mechanism. "printers()" method returns array of hashes, each describing a printer device; "get_default_printer()" returns a default printer string identifier. A printer device can be selected via the "::printer" property.

The capabilities of the selected printer can be adjusted via "setup_dialog()" method, that invokes a system-provided ( or, in case of Prima::PS::Printer, toolkit-provided ) printer setup dialog, so the user can adjust settings of a printer device. It depends on the system, whether the setup changes only the instance settings, or the default behavior of a printer driver is affected for all programs.

Some printer capabilities can be queried by the "::size()" property, that reports the dimension of the page, the "::resolution()" property, that reports the DPI resolution selected by a printer driver and font list ( by "fonts()" method ), available for usage.

Typical code that prints the document looks like

   my $p = $::application-> get_printer;
   if ( $p-> begin_doc) {
      ... draw ...
      $p-> end_doc;
   } else {
      print "failed:$@\n";
   }

In addition, a standard package Prima::PrintDialog can be recommended so the user can select a printer device and adjust its setup interactively.

API

Properties

printer STRING: Selects a printer device, specified by its STRING identifier. Can not select a device if a printing session is started.
resolution X, Y: A read-only property; returns a DPI horizontal and vertical resolution, currently selected for a printer device. The user can change this, if the printer device supports several resolutions, inside "setup_dialog()".
size WIDTH, HEIGHT: A read-only property; returns dimensions of a printer device page. The user can change this, if the printer device supports several resolutions or page formats, inside "setup_dialog()".

Methods

abort_doc

Stops the printing session, returns the object to the disabled painting state. Since the document can be passed to the system spooler, parts of it could have been sent to a printing device when "abort_doc()" is called, so some information could still been printed.

begin_doc DOCUMENT_NAME = ""

Initiates the printing session, and triggers the object into the enabled painting state. The document is assigned DOCUMENT_NAME string identifier.

Returns success flag; if failed, $@ contains the error.

begin_paint

Identical to "begin_doc("")" call.

begin_paint_info

Triggers the object into the information painting state. In this state, all graphic functions can be accessed, but no data is printed. Neither "new_page()" and "abort_doc()" methods work. The information mode is exited via "end_paint_info()" method.

end_doc

Quits the printing session and delivers the document to a printer device. Does not report eventual errors, occurred during the spooling process - the system is expected to take care about such situations.

end_paint

Identical to "abort_doc()".

end_paint_info

Quits the information painting mode, initiated by "begin_paint_info()" and returns the object into the disabled painting state.

font_encodings

Returns array of encodings, represented by strings, that are recognized by the system and available in at least one font. Each system provides different sets of encoding strings; the font encodings are not portable.

fonts NAME = '', ENCODING = ''

Returns hash of font hashes ( see Prima::Drawable, Fonts section ) describing fonts of NAME font family and of ENCODING. If NAME is '' or "undef", returns one fonts hash for each of the font families that match the ENCODING string. If ENCODING is '' or "undef", no encoding match is performed. If ENCODING is not valid ( not present in "font_encodings" result), it is treated as if it was '' or "undef".

In the special case, when both NAME and ENCODING are '' or "undef", each font metric hash contains element "encodings", that points to array of the font encodings, available for the fonts of NAME font family.

new_page

Finalizes the current page and starts a new blank page.

Returns success flag; if failed, $@ contains the error.

options [ OPTION, [ VALUE, [ ... ]]]

Queries and sets printer-specific setup options, such as orientation, paper size, etc. If called without parameters, returns list of options the printer supports. If called with one parameter, treats is as the option name and return the corresponsing value. Otherwise, treats parameters as a list of key-value pairs, and sets the printer options. Returns number of options that were successfully set.

The compatibility between options and values used by different OSes is low here. The only fully compatible options are

- "Orientation"["Portrait | Landscape"]
- "Color"["Color | Monochrome"]
- "Copies"["integer"]
- "PaperSize"["Ainteger | Binteger | Executive | Folio | Ledger | Legal | Letter | Tabloid"].

: The other options are OS-dependant. For win32, consult Microsoft manual on DEVMODEstructure <http://msdn.microsoft.com/library/en-us/gdi/prntspol_8nle.asp>; for Prima's own PostScript printer, consult Prima::PS::Printer.

printers

Returns array of hashes, where each entry describes a printer device. The hash consists of the following entries:

name: A printer device name
device: A physical device name, that the printer is connected to
defaultPrinter: A boolean flag, 1 if the printer is default, 0 otherwise.

setup_dialog

Invokes the system-provided printer device setup dialog. In this setup, the user can adjust the capabilities of the printer, such as page setup, resolution, color, etc etc.

get_default_printer

Returns a string, identifying a default printer device.

get_handle

Returns a system handle for a printer object.

AUTHOR

Dmitry Karasik, <[email protected]>.