NAME¶
Prima::VB::Classes - Visual Builder widgets and types
DESCRIPTION¶
Visual Builder is designed without a prior knowledge of the widget classes that
would be contained in its widget palette. Instead, it provides a registration
interface for new widgets and their specific properties.
This document describes API, provided by the builder, and the widget interface.
Through the document,
widget or
widget class mean not the
original widget or class, but their representatives.
USAGE¶
The widget must provide specific methods to cooperate with the builder. It is
not required, however, to contain these methods in its base module or package;
it can delegate its representation to another, usually very light class, which
is used by the builder.
Such a class must be derived from "Prima::VB::Object", which provides
base functionality. One of basic features here is overloading of property
change method. Since the user can change any property interactively, the class
can catch the properties of interest by declaring "prf_XXX" method,
where XXX is the property name. "Prima::VB::Widget" declares set of
these methods, assuming that a widget would repaint when, for example, its
"color" or "font" properties change.
The hierarchy of VB classes mimics the one of the core toolkit classes, but this
is a mere resemblance, no other dependencies except the names are present. The
hierarchy is as follows:
Prima::VB::Object Prima::Widget
Prima::VB::Component
Prima::VB::Drawable
Prima::VB::Widget
Prima::VB::Control
Prima::VB::Window
NB: "Prima::VB::CoreClasses" extends the hierarchy to the full set of
default widget palette in the builder. This module is not provided with
documentation though since its function is obvious and its code is trivial.
Since the real widgets are used in the interaction with the builder, their
properties are not touched when changed by the object inspector or otherwise.
The widgets keep the set of properties in a separated hash. The properties are
accessible by "prf" and "prf_set" methods.
A type object is a class used to represent a particular type of property in
object inspector window in the builder. The type objects, like the widget
classes, also are not hard-coded. The builder presents a basic set of the type
objects, which can be easily expanded. The hierarchy ( incomplete ) of the
type objects classes is as follows:
Prima::VB::Types::generic
Prima::VB::Types::bool
Prima::VB::Types::color
Prima::VB::Types::point
Prima::VB::Types::icon
Prima::VB::Types::Handle
Prima::VB::Types::textee
Prima::VB::Types::text
Prima::VB::Types::string
Prima::VB::Types::char
Prima::VB::Types::name
Prima::VB::Types::iv
Prima::VB::Types::uiv
The document does not describe the types, since their function can be observed
at runtime in the object inspector. Only "Prima::VB::Types::generic"
API is documented.
Prima::VB::Object¶
Properties¶
- class STRING
- Selects the original widget class. Create-only
property.
- creationOrder INTEGER
- Selects the creation order of the widget.
- module STRING
- Selects the module that contains the original widget class.
Create-only property.
- profile HASH
- Selects the original widget profile. Create-only property.
Changes to profile at run-time performed by "prf_set"
method.
Methods¶
- act_profile
- Returns hash of callbacks to be stored in the form file and
executed by "Prima::VB::VBLoader" when the form file is loaded.
The hash keys are names of VBLoader events and values - strings with code
to be eval'ed. See "Events" in Prima::VB::VBLoader for
description and format of the callbacks.
Called when the builder writes a form file.
- add_hooks @PROPERTIES
- Registers the object as a watcher to set of PROPERTIES.
When any object changes a property listed in the hook record,
"on_hook" callback is triggered.
Special name 'DESTROY' can be used to set a hook on object destruction
event.
- ext_profile
- Returns a class-specific hash, written in a form file. Its
use is to serve as a set of extra parameters, passed from the builder to
"act_profile" events.
- prf_set %PROIFLE
- A main method for setting a property of an object. PROFILE
keys are property names, and value are property values.
- prf_adjust_default PROFILE, DEFAULT_PROFILE
- DEFAULT_PROFILE is a result of "profile_default"
call of the real object class. However, not all properties usually are
exported to the object inspector. "prf_adjust_default" deletes
the unneeded property keys from PROFILE hash.
- prf_delete @PROPERTIES
- Removes PROPERTIES from internal properties hash. This
action results in that the PROPERTIES in the object inspector are set back
to their default values.
- prf_events
- Returns hash of a class-specific events. These appear in
the object inspector on "Events" page. The hash keys are event
names; the hash values are default code pieces, that describe format of
the event parameters. Example:
sub prf_events { return (
$_[0]-> SUPER::prf_events,
onSelectItem => 'my ( $self, $index, $selectState) = @_;',
)}
- prf @PROPERTIES
- Maps array of PROPERTIES names to their values. If called
in scalar context, returns the first value only; if in array context,
returns array of property values.
- prf_types
- Returns an anonymous hash, where keys are names of the type
class without "Prima::VB::Types::" prefix, and values are arrays
of property names.
This callback returns an inverse mapping of properties by the types.
- prf_types_add PROFILE1, PROFILE2
- Adds PROFILE2 content to PROFILE1. PROFILE1 and PROFILE2
are hashes in format of result of "prf_types" method.
- prf_types_delete PROFILE, @NAMES
- Removes @NAMES from PROFILE. Need to be called if property
type if redefined through the inheritance.
- remove_hooks @PROPERTIES
- Cancels watch for set of PROPERTIES.
Events¶
- on_hook NAME, PROPERTY, OLD_VALUE, NEW_VALUE
- Called for all objects, registered as watchers by
"add_hooks" when PROPERTY on object NAME is changed from
OLD_VALUE to NEW_VALUE. Special PROPERTY 'DESTROY' hook is called when
object NAME is destroyed.
Prima::VB::Component¶
Properties¶
- marked MARKED , EXCLUSIVE
- Selects marked state of a widget. If MARKED flag is 1, the
widget is selected as marked. If 0, it is selected as unmarked. If
EXCLUSIVE flag is set to 1, then all marked widgets are unmarked before
the object mark flag is set.
- sizeable BOOLEAN
- If 1, the widget can be resized by the user. If 0, in can
only be moved.
- mainEvent STRING
- Selects the event name, that will be opened in the object
inspector when the user double clicks on the widget.
Methods¶
- common_paint CANVAS
- Draws selection and resize marks on the widget if it is in
the selected state. To be called from all "on_paint"
callbacks.
- get_o_delta
- Returns offset to the owner widget. Since the builder does
not insert widgets in widgets to reflect the user-designed object
hierarchy, this method is to be used to calculate children widgets
relative positions.
- xy2part X, Y
- Maps X, Y point into part of widget. If result is not equal
to 'client' string, the event in X, Y point must be ignored.
- iterate_children SUB, @ARGS
- Traverses all children widget in the hierarchy, calling SUB
routine with widget, self, and @ARGS parameters on each.
- altpopup
- Invokes an alternative, class-specific popup menu, if
present. The popup object must be named 'AltPopup'.
Events¶
- Load
- Called when the widget is loaded from a file or the
clipboard.
Prima::VB::Types::generic¶
Root of all type classes.
A type class can be used with and without object instance. The instantiated
class contains reference to ID string, which is a property name that the
object presents in the object inspector, and WIDGET, which is the property
applied to. When the object inspector switches widgets, the type object is
commanded to update the references.
A class must also be usable without object instance, in particular, in
"write" method. It is called to export the property value in a
storable format as a string, better as a perl-evaluable expression.
Methods¶
- new CONTAINER, ID, WIDGET
- Constructor method. CONTAINER is a panel widget in the
object inspector, where the type object can insert property value selector
widgets.
- renew ID, WIDGET
- Resets property name and the widget.
- quotable STRING
- Returns quotable STRING.
- printable STRING
- Returns a string that can be stored in a file.
Callbacks¶
- change
- Called when the widget property value is changed.
- change_id
- Called when the property name ( ID ) is changed. The type
object may consider update its look or eventual internal variables on this
event.
- get
- Returns property value, based on the selector widgets
value.
- open
- Called when the type object is to be visualized first time.
The object must create property value selector widgets in the
"{container}" panel widget.
- preload_modules
- Returns array of strings of modules, needed to be
pre-loaded before a form file with type class-specific information can be
loaded. Usually it is used when "write" method exports constant
values, which are defined in another module.
- set DATA
- Called when a new value is set to the widget property by
means other than the selector widgets, so these can be updated. DATA is
the property new value.
- valid
- Checks internal state of data and returns a boolean flag,
if the type object data can be exported and set to widget profile.
- write CLASS, ID, DATA
- Called when DATA is to be written in form.
"write" must return such a string that can be loaded by
"Prima::VB::VBLoader" later.
AUTHOR¶
Dmitry Karasik, <dmitry@karasik.eu.org>.
SEE ALSO¶
VB, Prima::VB::VBLoader, Prima::VB::CfgMaint.