NAME
Prima::Printer - 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 DEVMODE structure
<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, <dmitry@karasik.eu.org>.
SEE ALSO
Prima, Prima::Drawable, Prima::PS::Printer