Provided by: libprima-perl_1.28-1.4_amd64 
NAME
Prima::VB::VBLoader - Visual Builder file loader
DESCRIPTION
The module provides functionality for loading resource files, created by Visual Builder. After the
successful load, the newly created window with all children is returned.
SYNOPSIS
The simple way to use the loader is as that:
use Prima qw(Application);
use Prima::VB::VBLoader;
Prima::VBLoad( './your_resource.fm',
Form1 => { centered => 1 },
)-> execute;
A more complicated but more proof code can be met in the toolkit:
use Prima qw(Application);
eval "use Prima::VB::VBLoader"; die "$@\n" if $@;
$form = Prima::VBLoad( $fi,
'Form1' => { visible => 0, centered => 1},
);
die "$@\n" unless $form;
All form widgets can be supplied with custom parameters, all together combined in a hash of hashes and
passed as the second parameter to "VBLoad()" function. The example above supplies values for "::visible"
and "::centered" to "Form1" widget, which is default name of a form window created by Visual Builder. All
other widgets are accessible by their names in a similar fashion; after the creation, the widget
hierarchy can be accessed in the standard way:
$form = Prima::VBLoad( $fi,
....
'StartButton' => {
onMouseOver => sub { die "No start buttons here\n" },
}
);
...
$form-> StartButton-> hide;
In case a form is to be included not from a fm file but from other data source, AUTOFORM_REALIZE call can
be used to transform perl array into set of widgets:
$form = AUTOFORM_REALIZE( [ Form1 => {
class => 'Prima::Window',
parent => 1,
profile => {
name => 'Form1',
size => [ 330, 421],
}], {});
Real-life examples are met across the toolkit; for instance, Prima/PS/setup.fm dialog is used by
"Prima::PS::Setup".
API
Methods
check_version HEADER
Scans HEADER, - the first line of a .fm file for version info. Returns two scalars - the first is a
boolean flag, which is set to 1 if the file can be used and loaded, 0 otherwise. The second scalar is
a version string.
GO_SUB SUB [ @EXTRA_DATA ]
Depending on value of boolean flag "Prima::VB::VBLoader::builderActive" performs the following: if it
is 1, the SUB text is returned as is. If it is 0, evaluates it in "sub{}" context and returns the
code reference. If evaluation fails, EXTRA_DATA is stored in "Prima::VB::VBLoader::eventContext"
array and the exception is re-thrown. "Prima::VB::VBLoader::builderActive" is an internal flag that
helps the Visual Builder use the module interface without actual SUB evaluation.
AUTOFORM_REALIZE WIDGETS, PARAMETERS
WIDGETS is an array reference that contains evaluated data of the read content of .fm file ( its data
format is preserved). PARAMETERS is a hash reference with custom parameters passed to widgets during
creation. The widgets are distinguished by the names. Visual Builder ensures that no widgets have
equal names.
"AUTOFORM_REALIZE" creates the tree of widgets and returns the root window, which is usually named
"Form1". It automatically resolves parent-child relations, so the order of WIDGETS does not matter.
Moreover, if a parent widget is passed as a parameter to a children widget, the parameter is deferred
and passed after the creation using "::set" call.
During the parsing and creation process internal notifications can be invoked. These notifications
(events) are stored in .fm file and usually provide class-specific loading instructions. See Events
for details.
AUTOFORM_CREATE FILENAME, %PARAMETERS
Reads FILENAME in .fm file format, checks its version, loads, and creates widget tree. Upon
successful load the root widget is returned. The parsing and creation is performed by calling
"AUTOFORM_REALIZE". If loading fails, "die()" is called.
Prima::VBLoad FILENAME, %PARAMETERS
A wrapper around "AUTOFORM_CREATE", exported in "Prima" namespace. FILENAME can be specified either
as a file system path name, or as a relative module name. In a way,
Prima::VBLoad( 'Module::form.fm' )
and
Prima::VBLoad(
Prima::Utils::find_image( 'Module' 'form.fm'))
are identical. If the procedure finds that FILENAME is a relative module name, it calls
"Prima::Utils::find_image" automatically. To tell explicitly that FILENAME is a file system path
name, FILENAME must be prefixed with "<" symbol ( the syntax is influenced by "CORE::open" ).
%PARAMETERS is a hash with custom parameters passed to widgets during creation. The widgets are
distinguished by the names. Visual Builder ensures that no widgets have equal names.
If the form file loaded successfully, returns the form object reference. Otherwise, "undef" is
returned and the error string is stored in $@ variable.
Events
The events, stored in .fm file are called during the loading process. The module provides no
functionality for supplying the events during the load. This interface is useful only for developers of
Visual Builder - ready classes.
The events section is located in "actions" section of widget entry. There can be more than one event of
each type, registered to different widgets. NAME parameter is a string with name of the widget; INSTANCE
is a hash, created during load for every widget provided to keep internal event-specific or class-
specific data there. "extras" section of widget entry is present there as an only predefined key.
Begin NAME, INSTANCE
Called upon beginning of widget tree creation.
FormCreate NAME, INSTANCE, ROOT_WIDGET
Called after the creation of a form, which reference is contained in ROOT_WIDGET.
Create NAME, INSTANCE, WIDGET.
Called after the creation of the widget. The newly created widget is passed in WIDGET
Child NAME, INSTANCE, WIDGET, CHILD_NAME
Called before child of WIDGET is created with CHILD_NAME as name.
ChildCreate NAME, INSTANCE, WIDGET, CHILD_WIDGET.
Called after child of WIDGET is created; the newly created widget is passed in CHILD_WIDGET.
End NAME, INSTANCE, WIDGET
Called after the creation of all widgets is finished.
FILE FORMAT
The idea of format of .fm file is that is should be evaluated by perl "eval()" call without special
manipulations, and kept as plain text. The file begins with a header, which is a #-prefixed string, and
contains a signature, version of file format, and version of the creator of the file:
# VBForm version file=1 builder=0.1
The header can also contain additional headers, also prefixed with #. These can be used to tell the
loader that another perl module is needed to be loaded before the parsing; this is useful, for example,
if a constant is declared in the module.
# [preload] Prima::ComboBox
The main part of a file is enclosed in "sub{}" statement. After evaluation, this sub returns array of
paired scalars, where each first item is a widget name and second item is hash of its parameters and
other associated data:
sub
{
return (
'Form1' => {
class => 'Prima::Window',
module => 'Prima::Classes',
parent => 1,
code => GO_SUB('init()'),
profile => {
width => 144,
name => 'Form1',
origin => [ 490, 412],
size => [ 144, 100],
}},
);
}
The hash has several predefined keys:
actions HASH
Contains hash of events. The events are evaluated via "GO_SUB" mechanism and executed during creation
of the widget tree. See Events for details.
code STRING
Contains a code, executed before the form is created. This key is present only on the root widget
record.
class STRING
Contains name of a class to be instantiated.
extras HASH
Contains a class-specific parameters, used by events.
module STRING
Contains name of perl module that contains the class. The module will be "use"'d by the loader.
parent BOOLEAN
A boolean flag; set to 1 for the root widget only.
profile HASH
Contains profile hash, passed as parameters to the widget during its creation. If custom parameters
were passed to "AUTOFORM_CREATE", these are coupled with "profile" ( the custom parameters take
precedence ) before passing to the "create()" call.
AUTHOR
Dmitry Karasik, <dmitry@karasik.eu.org>.
SEE ALSO
Prima, VB
perl v5.22.1 2009-02-24 Prima::VB::VBLoader(3)