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