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Application - root of widget objects hierarchy |
Application - root of widget objects hierarchy
Prima::Application class serves as a hierarchy root for all objects with child-owner relationship. All toolkit objects, existing with non-null owner property, belong in their top-level parental relationship to Prima::Application object. There can be only one instance of Prima::Application class at one time.
Prima::Application class, and its only instance are treated specially throughout the toolkit. The object instance is contained in
$::application
scalar, defined in Prima.pm module. The application instance must be created whenever widget and window, or event loop functionality is desired. Usually
use Prima::Application;
code is enough, but $::application can also
be assigned explicitly. The 'use' syntax has advantage
as more resistant to eventual changes in the toolkit design.
It can also be used in conjunction with custom parameters hash,
alike the general create() syntax:
use Prima::Application name => 'Test application', icon => $icon;
In addition to this functionality Prima::Application is also a wrapper to a set of system functions, not directly related to object classes. This functionality is generally explained in API.
Prima::Application is a descendant of Prima::Widget, but
it is designed so because their functional outliers are closest
to each other.
Prima::Application does not strictly conform ( in OO sense )
to any of the built-in classes. It has methods copied from both
Prima::Widget and Prima::Window at one time, and the inherited
Prima::Widget methods and properties function differently.
For example, ::origin, a property from Prima::Widget, is
also implemented in Prima::Application, but returns always (0,0),
an expected but not much usable result.
::size, on the contrary, returns the extent of the screen in pixels.
There are few properties, inherited from Prima::Widget, which return
actual, but uninformative results, - ::origin is one of those, but
same are ::buffered, ::clipOwner, ::enabled, ::growMode,
::owner and owner-inheritance properties, ::selectable, ::shape,
::syncPaint, ::tabOrder, ::tabStop, ::transparent, ::visible.
To this group also belongs ::modalHorizon, a Prima::Window property,
but defined for consistency and returning always 1.
Other methods and properties, like ::size, that provide different
functionality are described in API.
Prima::Application is a wrapper to functionality, that
is not related to one or another class clearly.
A notable example, paint mode, which is derived from Prima::Drawable
class, allows painting on the screen, overwriting the information
output by other programs. Although being subject to begin_paint()/end_paint()
brackets, this functionality can not be attached to a class-shared
API, an therefore considered 'global'. All such functionality is gathered
in the Prima::Application class.
These topics enumerated below, related do global function, but occupying more than one method or property - such functions described in API.
begin_paint()/end_paint()
methods pair, and the other pair, begin_paint_info()/end_paint_info()
triggers the information mode. This three-state paint functionality
is more thoroughly described in the Prima::Drawable manpage.
get_hint_widget(), but with color and font functions
aliased ( ::hintColor, ::hintBackColor, ::hintFont ).
This widget serves as a hint label, floating over widgets
if the mouse pointer hovers longer than ::hintPause milliseconds.
Prima::Application internally manages all hint functionality.
The hint widget itself, however, can be replaced before application
object is created, using ::hintClass create-only property.
See the Prima::Printer manpage for details.
These are no methods to access these clipboard objects, except
fetch() ( or, the indirect name calling ) - the clipboard objects
are named after the system clipboard names, which are
returned from Prima::Clipboard::get_standard_clipboards.
The default clipboard is named Clipboard, and is accessible via
my $clipboard = $::application-> Clipboard;
code.
See the Prima::Clipboard manpage for details.
Prima::HelpViewer module, any custom
help viewing module can be assigned. Create-only Prima::Application
properties ::helpClass and ::helpModule can be used to
set these options.
Prima::Application provides two methods for communicating
with the help viewer window: open_help() opens a selected topic
in the window, and close_help() closes that window.
get_system_value returns a system value for one of sv::XXX constants,
so the program can read the system-specific information. As well as
get_system_info method, that returns the short description of the system,
it is the portable call. All systems return such information.
To the contrary, sys_action method is a wrapper to system-dependent
functionality, called in non-portable way. This method is never used
within the toolkit, and its usage is discouraged, primarily because
its options do not serve the toolkit design, so are subject to change
and cannot be relied upon.
close() after the last top-level window
is destroyed. Does not influence anything if set to 0.
This feature is designed to help with general 'one main window' application layouts.
Default value: 0
undef, a system-provided default icon is assumed.
Prima::Window object instances inherit the application
icon by default.
Run-time changes to the property do not affect the help
subsystem until close_help call is made.
open_help.
Used when ::helpClass property is overridden and
the new class is contained in a third-party module.
Run-time changes to the property do not affect the help
subsystem until close_help call is made.
Specifies a class of widget, used as a hint label.
Default value: Prima::HintWidget
Specifies a class of object, used as a printer. The default value is system-dependent, but is either Prima::Printer or Prima::PS::Printer.
Specifies a perl module, loaded indirectly before
a printer object of ::printerClass class is created.
Used when ::printerClass property is overridden and
the new class is contained in a third-party module.
Returns two integers, width and height of the screen.
::showHint property in Prima::Widget, Prima::Application::showHint
is an another layer of hint visibility control - if it is 0,
all hint actions are disabled, disregarding ::showHint value
of widgets.
Useful for add-on packages initialization.
begin_paint()),
except that painting and drawing methods are not permitted to change
the screen.
close for all top-level windows. The call can be interrupted by these,
and thus canceled. If not canceled, stops the application event loop.
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.
undef is returned.
The exact definition of 'active window' is system-dependent, but it is generally believed that an active window is the one that has keyboard focus on one of its children widgets.
bs::XXX constants.
The method can be called with a class string instead of an object instance.
undef is returned.
undef is returned.
::hintClass class, Prima::HintWidget by
default.
::printerClass
class.
mt::Exclusive or mt::Shared. TOPMOST is a boolean flag, selecting
the lookup direction; if it is 1, the 'topmost' window is returned,
if 0, the 'lowest' one ( in a simple case when window A is made modal
(executed) after modal window B, the A window is the 'topmost' one ).
If a chain is empty undef is returned. In case when a chain consists
of just one window, TOPMOST value is apparently irrelevant.
apc::XXX constants, reflecting the platform.
Currently, the list of the supported platforms is:
apc::Os2 apc::Win32 apc::Unix
gui::XXX constants, reflecting the graphic
user interface used in the system:
gui::Default gui::PM gui::Windows gui::XLib gui::OpenLook gui::Motif
The meaning of this field is somewhat vague, and the field might be deprecated in future releases.
The method can be called with a class string instead of an object instance.
sv::XXX constants. The constants are:
sv::YMenu - height of menu bar in top-level windows
sv::YTitleBar - height of title bar in top-level windows
sv::XIcon - width and height of main icon dimensions,
sv::YIcon acceptable by the system
sv::XSmallIcon - width and height of alternate icon dimensions,
sv::YSmallIcon acceptable by the system
sv::XPointer - width and height of mouse pointer icon
sv::YPointer acceptable by the system
sv::XScrollbar - width of the default vertical scrollbar
sv::YScrollbar - height of the default horizontal scrollbar
( see C<get_default_scrollbar_metrics()> )
sv::XCursor - width of the system cursor
( see C<get_default_cursor_width()> )
sv::AutoScrollFirst - the initial and the repetitive
sv::AutoScrollNext scroll timeouts
( see C<get_scroll_rate()>
sv::InsertMode - the system insert mode
( see C<::insertMode>
sv::XbsNone - widths and heights of the top-level window
sv::YbsNone decorations, correspondingly, with borderStyle
sv::XbsSizeable bs::None, bs::Sizeable, bs::Single, and
sv::YbsSizeable bs::Dialog.
sv::XbsSingle ( see C<get_default_window_borders()> )
sv::YbsSingle
sv::XbsDialog
sv::YbsDialog
sv::MousePresent - 1 if the mouse is present, 0 otherwise
sv::MouseButtons - number of the mouse buttons
sv::WheelPresent - 1 if the mouse wheel is present, 0 otherwise
sv::SubmenuDelay - timeout ( in ms ) before a sub-menu shows on an implicit selection
sv::FullDrag - 1 if the top-level windows are dragged dynamically, 0 - with marquee mode
sv::DblClickDelay - mouse double-click timeout in milliseconds
sv::ShapeExtension - 1 if Prima::Widget::shape functionality is supported, 0 otherwise
sv::ColorPointer - 1 if system accepts color pointer icons.
sv::CanUTF8_Input - 1 if system can generate key codes in unicode
sv::CanUTF8_Output - 1 if system can output utf8 text
The method can be called with a class string instead of an object instance.
undef is returned.
undef is returned.
run Prima;
standard code. Returns when the program is about to terminate, or if the exception was signaled. In the latter case, can be safely re-started.
unlock().
lock().
while ( application not closed ) {
yield
}
draft yield() is the only function, called repeatedly
within the event loop. yield() cannot be used to
organize event loops, but it can be employed to
process stacked system events explicitly, to
increase responsiveness of a program, for example,
inside a long calculation loop.
The method can be called with a class string instead of an object instance; however, the $::application object must be initialized.
Dmitry Karasik, <dmitry@karasik.eu.org>.
Prima, the Prima::Object manpage, the Prima::Widget manpage, the Prima::Window manpage
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Application - root of widget objects hierarchy |