NAME
Prima::Application - root of widget objects hierarchy
DESCRIPTION
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 by their top-level parental relationship to
Prima::Application object. There can be only one instance of
Prima::Application class at a time.
SYNOPSIS
use Prima;
use Prima::Application;
or
use Prima qw(Application);
Prima::MainWindow-> create();
run Prima;
USAGE
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".
Inherited functionality
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", Prima::Window class
property, but defined for consistency and returning always 1. Other
methods and properties, like "::size", that provide different
functionality are described in "API".
Global functionality
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 graphic information created by the other programs.
Although being subject to begin_paint()/end_paint() brackets, this
functionality can not be attached to a class-shared API, an therefore
is considered global. All such functionality is gathered in the
Prima::Application class.
These topics enumerated below, related to the global scope, but
occupying more than one method or property - such functions described
in "API".
Painting
As stated above, Prima::Application provides interface to the on-
screen painting. This mode is triggered by
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 Prima::Drawable.
Hint
$::application hosts a special Prima::HintWidget class object,
accessible via "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.
Printer
Result of get_printer method points to an automatically created
printer object, responsible for the system-driven printing.
Depending on the operating system, it is either Prima::Printer, if
the system provides GUI printing capabilities, or generic
Prima::PS::Printer, the PostScript document interface.
See Prima::Printer for details.
Clipboard
$::application hosts set of Prima::Clipboard objects, created
automatically to reflect the system-provided clipboard IPC
functionality. Their number depends on the system, - under X11
environment there is three clipboard objects, and only one under
Win32 and OS/2.
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 by
Prima::Clipboard::get_standard_clipboards.
The default clipboard is named Clipboard, and is accessible via
my $clipboard = $::application-> Clipboard;
code.
See Prima::Clipboard for details.
Help subsystem
The toolkit has a built-in help viewer, that understands perl’s
native POD ( plain old documentation ) format. Whereas the viewer
functionality itself is part of the toolkit, and resides in
"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
help window, and "close_help()" closes the window.
System-dependent information
A complex program will need eventually more information than the
toolkit provides. Or, knowing the toolkit boundaries in some
platforms, the program changes its behavior accordingly. Both these
topics are facilitated by extra system information, returned by
Prima::Application methods. "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. 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, are subject to changes and cannot be relied upon.
API
Properties
autoClose BOOLEAN
If set to 1, issues "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
icon OBJECT
Holds the icon object, associated with the application. If
"undef", a system-provided default icon is assumed. Prima::Window
object instances inherit the application icon by default.
insertMode BOOLEAN
A system boolean flag, showing whether text widgets through the
system should insert ( 1 ) or overwrite ( 0 ) text on user input.
Not all systems provide the global state of the flag.
helpClass STRING
Specifies a class of object, used as a help viewing package. The
default value is Prima::HelpViewer.
Run-time changes to the property do not affect the help subsystem
until "close_help" call is made.
helpModule STRING
Specifies a perl module, loaded indirectly when a help viewing call
is made via "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.
hintClass STRING
Create-only property.
Specifies a class of widget, used as the hint label.
Default value: Prima::HintWidget
hintColor COLOR
An alias to foreground color property for the hint label widget.
hintBackColor COLOR
An alias to background color property for the hint label widget.
hintFont %FONT
An alias to font property for the hint label widget.
hintPause TIMEOUT
Selects the timeout in milliseconds before the hint label is shown
when the mouse pointer hovers over a widget.
modalHorizon BOOLEAN
A read-only property. Used as a landmark for the lowest-level modal
horizon. Always returns 1.
palette [ @PALETTE ]
Used only within paint and information modes. Selects solid colors
in a system palette, as many as possible. PALETTE is an array of
integer triplets, where each is red, green, and blue component,
with intensity range from 0 to 255.
printerClass STRING
Create-only property.
Specifies a class of object, used as a printer. The default value
is system-dependent, but is either "Prima::Printer" or
"Prima::PS::Printer".
printerModule STRING
Create-only property.
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.
pointerVisible BOOLEAN
Governs the system pointer visibility. If 0, hides the pointer so
it is not visible in all system windows. Therefore this property
usage must be considered with care.
size WIDTH, HEIGHT
A read-only property.
Returns two integers, width and height of the screen.
showHint BOOLEAN
If 1, the toolkit is allowed to show the hint label over a widget.
If 0, the display of the hint is forbidden. In addition to
functionality of "::showHint" property in Prima::Widget,
Prima::Application::showHint is another layer of hint visibility
control - if it is 0, all hint actions are disabled, disregarding
"::showHint" value in widgets.
wantUnicodeInput BOOLEAN
Selects if the system is allowed to generate key codes in unicode.
Returns the effective state of the unicode input flag, which cannot
be changed if perl or operating system do not support UTF8.
If 1, "Prima::Clipboard::text" property may return UTF8 text from
system clipboards is available.
Default value: 0
Events
PasteText $CLIPBOARD, $$TEXT_REF
The notification queries $CLIPBOARD for text content and stores in
$$TEXT_REF. Default action is that 'Text' format is queried if
"wantUnicodeInput" is unset. Otherwise, 'UTF8' format is queried
beforehand.
The "PasteText" mechanism is devised to ease defining text
unicode/ascii conversion between clipboard and standard widgets, in
a standard way.
Methods
add_startup_notification @CALLBACK
CALLBACK is an array of anonymous subs, which is executed when
Prima::Application object is created. If the application object is
already created during the call, CALLBACKs called immediately.
Useful for add-on packages initialization.
begin_paint
Enters the enabled ( active paint ) state, returns success flag.
Once the object is in enabled state, painting and drawing methods
can perform write operations on the whole screen.
begin_paint_info
Enters the information state, returns success flag. The object
information state is same as enabled state ( see "begin_paint()"),
except that painting and drawing methods are not permitted to
change the screen.
close
Issues a system termination call, resulting in calling "close" for
all top-level windows. The call can be interrupted by these, and
thus canceled. If not canceled, stops the application event loop.
close_help
Closes the help viewer window.
end_paint
Quits the enabled state and returns application object to the
normal state.
end_paint_info
Quits the information state and returns application object to the
normal state.
font_encodings
Returns array of encodings, represented by strings, that are
recognized by the system and available for 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 "Fonts" in Prima::Drawable )
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.
get_active_window
Returns object reference to a currently active window, if any, that
belongs to the program. If no such window exists, "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.
get_caption_font
Returns a title font, that the system uses to draw top-level window
captions. The method can be called with a class string instead of
an object instance.
get_default_cursor_width
Returns width of the system cursor in pixels. The method can be
called with a class string instead of an object instance.
get_default_font
Returns the default system font. The method can be called with a
class string instead of an object instance.
get_default_scrollbar_metrics
Returns dimensions of the system scrollbars - width of the standard
vertical scrollbar and height of the standard horizon scrollbar.
The method can be called with a class string instead of an object
instance.
get_default_window_borders BORDER_STYLE = bs::Sizeable
Returns width and height of standard system window border
decorations for one of "bs::XXX" constants. The method can be
called with a class string instead of an object instance.
get_focused_widget
Returns object reference to a currently focused widget, if any,
that belongs to the program. If no such widget exists, "undef" is
returned.
get_hint_widget
Returns the hint label widget, attached automatically to
Prima::Application object during startup. The widget is of
"::hintClass" class, Prima::HintWidget by default.
get_image X_OFFSET, Y_OFFSET, WIDTH, HEIGHT
Returns Prima::Image object with WIDTH and HEIGHT dimensions filled
with graphic content of the screen, copied from X_OFFSET and
Y_OFFSET coordinates. If WIDTH and HEIGHT extend beyond the screen
dimensions, they are adjusted. If the offsets are outside screen
boundaries, or WIDTH and HEIGHT are zero or negative, "undef" is
returned.
get_indents
Returns 4 integers that corresponds to extensions of eventual
desktop decorations that the windowing system may present on the
left, bottom, right, and top edges of the screen. For example, for
win32 this reports the size of the part of the scraan that windows
taskbar may occupies, if any.
get_printer
Returns the printer object, attached automatically to
Prima::Application object. The object is of "::printerClass" class.
get_message_font
Returns the font the system uses to draw the message text. The
method can be called with a class string instead of an object
instance.
get_modal_window MODALITY_TYPE = mt::Exclusive, TOPMOST = 1
Returns the modal window, that resides on an end of a modality
chain. MODALITY_TYPE selects the chain, and can be either
"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.
get_scroll_rate
Returns two integer values of two system-specific scrolling
timeouts. The first is the initial timeout, that is applied when
the user drags the mouse from a scrollable widget ( a text field,
for example ), and the widget is about to scroll, but the actual
scroll is performed after the timeout is expired. The second is the
repetitive timeout, - if the dragging condition did not change, the
scrolling performs automatically after this timeout. The timeout
values are in milliseconds.
get_system_info
Returns a hash with information about the system. The hash result
contains the following keys:
apc One of "apc::XXX" constants, reflecting the platform.
Currently, the list of the supported platforms is:
apc::Os2
apc::Win32
apc::Unix
gui One of "gui::XXX" constants, reflecting the graphic user
interface used in the system:
gui::Default
gui::PM
gui::Windows
gui::XLib
gui::GTK2
guiDescription
Description of graphic user interface, returned as an arbitrary
string.
system
An arbitrary string, representing the operating system
software.
release
An arbitrary string, reflecting the OS version information.
vendor
The OS vendor string
architecture
The machine architecture string
The method can be called with a class string instead of an object
instance.
get_system_value
Returns the system integer value, associated with one of "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 get_default_scrollbar_metrics() )
sv::XCursor - width of the system cursor
( see get_default_cursor_width() )
sv::AutoScrollFirst - the initial and the repetitive
sv::AutoScrollNext scroll timeouts
( see get_scroll_rate() )
sv::InsertMode - the system insert mode
( see 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 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.
get_widget_from_handle HANDLE
HANDLE is an integer value of a toolkit widget. It is usually
passed to the program by other IPC means, so it returns the
associated widget. If no widget is associated with HANDLE, "undef"
is returned.
get_widget_from_point X_OFFSET, Y_OFFSET
Returns the widget that occupies screen area under
(X_OFFSET,Y_OFFSET) coordinates. If no toolkit widget are found,
"undef" is returned.
go The main event loop. Called by
run Prima;
standard code. Returns when the program is about to terminate, or
if the exception was signaled. In the latter case, the loop can be
safely re-started.
lock
Effectively blocks the graphic output for all widgets. The output
can be restored with "unlock()".
open_help TOPIC
Opens the help viewer window with TOPIC string in link POD format (
see perlpod ) - the string is treated as "manpage/section", where
’manpage’ is the file with POD content and ’section’ is the topic
inside the manpage.
sync
Synchronizes all pending requests where there are any. Is an
effective "XSync(false)" on X11, and is a no-op otherwise.
sys_action CALL
CALL is an arbitrary string of the system service name and the
parameters to it. This functionality is non-portable, and its
usage should be avoided. The system services provided are not
documented and subject to change. The actual services can be looked
in the toolkit source code under apc_system_action tag.
unlock
Unblocks the graphic output for all widgets, previously locked with
"lock()".
yield
An event dispatcher, called from within the event loop. If the
event loop can be schematized, then in
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 cycle.
The method can be called with a class string instead of an object
instance; however, the $::application object must be initialized.
AUTHOR
Dmitry Karasik, <dmitry@karasik.eu.org>.
SEE ALSO
Prima, Prima::Object, Prima::Widget, Prima::Window