1Prima::Application(3) User Contributed Perl DocumentationPrima::Application(3)
2
6 Prima::Application - root of widget objects hierarchy
7
9 Prima::Application class serves as a hierarchy root for all objects
10 with child-owner relationship. All toolkit objects, existing with non-
11 null owner property, belong by their top-level parental relationship to
12 Prima::Application object. There can be only one instance of
13 Prima::Application class at a time.
14
16 use Prima;
17 use Prima::Application;
18 or
20 use Prima qw(Application);
22 Prima::MainWindow-> create();
24 run Prima;
26
28 Prima::Application class, and its only instance are treated specially
29 throughout the toolkit. The object instance is contained in
30 $::application
32 scalar, defined in Prima.pm module. The application instance must be
34 created whenever widget and window, or event loop functionality is
35 desired. Usually
36 use Prima::Application;
38 code is enough, but $::application can also be assigned explicitly. The
40 'use' syntax has advantage as more resistant to eventual changes in the
41 toolkit design. It can also be used in conjunction with custom
42 parameters hash, alike the general create() syntax:
43 use Prima::Application name => 'Test application', icon => $icon;
45 In addition to this functionality Prima::Application is also a wrapper
47 to a set of system functions, not directly related to object classes.
48 This functionality is generally explained in "API".
49 Inherited functionality
51 Prima::Application is a descendant of Prima::Widget, but it is designed
52 so because their functional outliers are closest to each other.
53 Prima::Application does not strictly conform ( in OO sense ) to any of
54 the built-in classes. It has methods copied from both Prima::Widget and
55 Prima::Window at one time, and the inherited Prima::Widget methods and
56 properties function differently. For example, "::origin", a property
57 from Prima::Widget, is also implemented in Prima::Application, but
58 returns always (0,0), an expected but not much usable result.
59 "::size", on the contrary, returns the extent of the screen in pixels.
60 There are few properties, inherited from Prima::Widget, which return
61 actual, but uninformative results, - "::origin" is one of those, but
62 same are "::buffered", "::clipOwner", "::enabled", "::growMode",
63 "::owner" and owner-inheritance properties, "::selectable", "::shape",
64 "::syncPaint", "::tabOrder", "::tabStop", "::transparent", "::visible".
65 To this group also belongs "::modalHorizon", Prima::Window class
66 property, but defined for consistency and returning always 1. Other
67 methods and properties, like "::size", that provide different
68 functionality are described in "API".
69 Global functionality
71 Prima::Application is a wrapper to functionality, that is not related
72 to one or another class clearly. A notable example, paint mode, which
73 is derived from Prima::Drawable class, allows painting on the screen,
74 overwriting the graphic information created by the other programs.
75 Although being subject to begin_paint()/end_paint() brackets, this
76 functionality can not be attached to a class-shared API, an therefore
77 is considered global. All such functionality is gathered in the
78 Prima::Application class.
79 These topics enumerated below, related to the global scope, but
81 occupying more than one method or property - such functions described
82 in "API".
83 Painting
85 As stated above, Prima::Application provides interface to the on-
86 screen painting. This mode is triggered by
87 begin_paint()/end_paint() methods pair, and the other pair,
88 begin_paint_info()/end_paint_info() triggers the information mode.
89 This three-state paint functionality is more thoroughly described
90 in Prima::Drawable.
91 The painting on the screen surfaces under certain environments
93 (XQuartz, XWayland) is either silently ignored or results in an
94 error. There, "begin_paint" will return a false value
95 ("begin_paint_info" though returns true).
96 Hint
98 $::application hosts a special Prima::HintWidget class object,
99 accessible via "get_hint_widget()", but with color and font
100 functions aliased ( "::hintColor", "::hintBackColor", "::hintFont"
101 ).
102 This widget serves as a hint label, floating over widgets if the
104 mouse pointer hovers longer than "::hintPause" milliseconds.
105 Prima::Application internally manages all hint functionality. The
107 hint widget itself, however, can be replaced before application
108 object is created, using "::hintClass" create-only property.
109 Printer
111 Result of get_printer method points to an automatically created
112 printer object, responsible for the system-driven printing.
113 Depending on the operating system, it is either Prima::Printer, if
114 the system provides GUI printing capabilities, or generic
115 Prima::PS::Printer, the PostScript document interface.
116 See Prima::Printer for details.
118 Clipboard
120 $::application hosts set of Prima::Clipboard objects, created
121 automatically to reflect the system-provided clipboard IPC
122 functionality. Their number depends on the system, - under X11
123 environment there is three clipboard objects, and only one under
124 Win32.
125 These are no methods to access these clipboard objects, except
127 fetch() ( or, the indirect name calling ) - the clipboard objects
128 are named after the system clipboard names, which are returned by
129 Prima::Clipboard::get_standard_clipboards.
130 The default clipboard is named Clipboard, and is accessible via
132 my $clipboard = $::application-> Clipboard;
134 code.
136 See Prima::Clipboard for details.
138 Help subsystem
140 The toolkit has a built-in help viewer, that understands perl's
141 native POD ( plain old documentation ) format. Whereas the viewer
142 functionality itself is part of the toolkit, and resides in
143 "Prima::HelpViewer" module, any custom help viewing module can be
144 assigned. Create-only "Prima::Application" properties "::helpClass"
145 and "::helpModule" can be used to set these options.
146 "Prima::Application" provides two methods for communicating with
148 the help viewer window: "open_help()" opens a selected topic in the
149 help window, and "close_help()" closes the window.
150 System-dependent information
152 A complex program will need eventually more information than the
153 toolkit provides. Or, knowing the toolkit boundaries in some
154 platforms, the program changes its behavior accordingly. Both these
155 topics are facilitated by extra system information, returned by
156 Prima::Application methods. "get_system_value" returns a system
157 value for one of "sv::XXX" constants, so the program can read the
158 system-specific information. As well as "get_system_info" method,
159 that returns the short description of the system, it is the
160 portable call. To the contrary, "sys_action" method is a wrapper
161 to system-dependent functionality, called in non-portable way. This
162 method is never used within the toolkit, and its usage is
163 discouraged, primarily because its options do not serve the toolkit
164 design, are subject to changes and cannot be relied upon.
165
167 Properties
168 autoClose BOOLEAN
169 If set to 1, issues "close()" after the last top-level window is
170 destroyed. Does not influence anything if set to 0.
171 This feature is designed to help with general 'one main window'
173 application layouts.
174 Default value: 0
176 icon OBJECT
178 Holds the icon object, associated with the application. If
179 "undef", a system-provided default icon is assumed. Prima::Window
180 object instances inherit the application icon by default.
181 insertMode BOOLEAN
183 A system boolean flag, showing whether text widgets through the
184 system should insert ( 1 ) or overwrite ( 0 ) text on user input.
185 Not all systems provide the global state of the flag.
186 helpClass STRING
188 Specifies a class of object, used as a help viewing package. The
189 default value is Prima::HelpViewer.
190 Run-time changes to the property do not affect the help subsystem
192 until "close_help" call is made.
193 helpModule STRING
195 Specifies a perl module, loaded indirectly when a help viewing call
196 is made via "open_help". Used when "::helpClass" property is
197 overridden and the new class is contained in a third-party module.
198 Run-time changes to the property do not affect the help subsystem
200 until "close_help" call is made.
201 hintClass STRING
203 Create-only property.
204 Specifies a class of widget, used as the hint label.
206 Default value: Prima::HintWidget
208 hintColor COLOR
210 An alias to foreground color property for the hint label widget.
211 hintBackColor COLOR
213 An alias to background color property for the hint label widget.
214 hintFont %FONT
216 An alias to font property for the hint label widget.
217 hintPause TIMEOUT
219 Selects the timeout in milliseconds before the hint label is shown
220 when the mouse pointer hovers over a widget.
221 language STRING
223 By default contains user interface language, deduced either from
224 $ENV{LANG} or GUI default. When changed, updates "textDirection"
225 propertly.
226 See also: "get_system_info".
228 modalHorizon BOOLEAN
230 A read-only property. Used as a landmark for the lowest-level modal
231 horizon. Always returns 1.
232 palette [ @PALETTE ]
234 Used only within paint and information modes. Selects solid colors
235 in a system palette, as many as possible. PALETTE is an array of
236 integer triplets, where each is red, green, and blue component,
237 with intensity range from 0 to 255.
238 printerClass STRING
240 Create-only property.
241 Specifies a class of object, used as a printer. The default value
243 is system-dependent, but is either "Prima::Printer" or
244 "Prima::PS::Printer".
245 printerModule STRING
247 Create-only property.
248 Specifies a perl module, loaded indirectly before a printer object
250 of "::printerClass" class is created. Used when "::printerClass"
251 property is overridden and the new class is contained in a third-
252 party module.
253 pointerVisible BOOLEAN
255 Governs the system pointer visibility. If 0, hides the pointer so
256 it is not visible in all system windows. Therefore this property
257 usage must be considered with care.
258 size WIDTH, HEIGHT
260 A read-only property.
261 Returns two integers, width and height of the screen.
263 showHint BOOLEAN
265 If 1, the toolkit is allowed to show the hint label over a widget.
266 If 0, the display of the hint is forbidden. In addition to
267 functionality of "::showHint" property in Prima::Widget,
268 Prima::Application::showHint is another layer of hint visibility
269 control - if it is 0, all hint actions are disabled, disregarding
270 "::showHint" value in widgets.
271 textDirection BOOLEAN
273 Contains preferred text direction, initially calculated from the
274 preferred interface language. If 0 ( default ), the preferred text
275 direction is left-to-right (LTR), otherwise right-to-left (RTL),
276 f.ex. for arabic and hebrew languages.
277 The value is used as a default when shaping text and setting widget
279 input direction.
280 uiScaling FLOAT
282 The property contains an advisory multiplier factor, useful for UI
283 elements that have a fixed pixel value, but that would like to be
284 represented in a useful manner when the display resolution is too
285 high (on modern High-DPI displays) or too low (on ancient
286 monitors).
287 By default, it acquires the system display resolution, and sets the
289 scaling factor so that when the DPI is 96 it is 1.0, 192 it is 2.0,
290 etc. The increase step is 0.25, so that bitmaps may look not that
291 distorted. However, when the value is manually set, there is no
292 such step, any value can be set.
293 See also: "Stress" in Prima.
295 wantUnicodeInput BOOLEAN
297 Selects if the system is allowed to generate key codes in unicode.
298 Returns the effective state of the unicode input flag, which cannot
299 be changed if perl or operating system do not support UTF8.
300 If 1, "Prima::Clipboard::text" property may return UTF8 text from
302 system clipboards is available.
303 Default value: 1
305 Events
307 Clipboard $CLIPBOARD, $ACTION, $TARGET
308 With (the only implemented) $ACTION copy, is called whenever
309 another application requests clipboard data in format $TARGET. This
310 notification is handled internally to optimize image pasting
311 through the cliboard. Since the clipboard pasting semantics in
312 Prima is such that data must be supplied to the clipboard in
313 advance, before another application can request it, there is a
314 problem which format to use. In order to not encode an image or
315 other complex data in all possible formats but do that on demand
316 and in the format the other application wants, this notification
317 can be used.
318 Only implemented for X11.
320 CopyImage $CLIPBOARD, $IMAGE
322 The notification stores $IMAGE in clipboard.
323 CopyText $CLIPBOARD, $TEXT
325 The notification stores $TEXT in clipboard.
326 Idle
328 Called when the event loop handled all pending events, and is about
329 to sleep waiting for more.
330 PasteImage $CLIPBOARD, $$IMAGE_REF
332 The notification queries $CLIPBOARD for image content and stores in
333 $$IMAGE_REF. Default action is that 'Image' format is queried. On
334 unix, encoded formats 'image/bmp', 'image/png' etc are queried if
335 the default 'Image' is not found.
336 The "PasteImage" mechanism is devised to read images from clipboard
338 in GTK environment.
339 PasteText $CLIPBOARD, $$TEXT_REF
341 The notification queries $CLIPBOARD for text content and stores in
342 $$TEXT_REF. Default action is that 'Text' format is queried if
343 "wantUnicodeInput" is unset. Otherwise, 'UTF8' format is queried
344 beforehand.
345 The "PasteText" mechanism is devised to ease defining text
347 unicode/ascii conversion between clipboard and standard widgets, in
348 a standard way.
349 Methods
351 add_startup_notification @CALLBACK
352 CALLBACK is an array of anonymous subs, which is executed when
353 Prima::Application object is created. If the application object is
354 already created during the call, CALLBACKs called immediately.
355 Useful for add-on packages initialization.
357 begin_paint
359 Enters the enabled ( active paint ) state, returns success flag.
360 Once the object is in enabled state, painting and drawing methods
361 can perform write operations on the whole screen.
362 begin_paint_info
364 Enters the information state, returns success flag. The object
365 information state is same as enabled state ( see "begin_paint()"),
366 except that painting and drawing methods are not permitted to
367 change the screen.
368 close
370 Issues a system termination call, resulting in calling "close" for
371 all top-level windows. The call can be interrupted by these, and
372 thus canceled. If not canceled, stops the application event loop.
373 close_help
375 Closes the help viewer window.
376 end_paint
378 Quits the enabled state and returns application object to the
379 normal state.
380 end_paint_info
382 Quits the information state and returns application object to the
383 normal state.
384 font_encodings
386 Returns array of encodings, represented by strings, that are
387 recognized by the system and available for at least one font. Each
388 system provides different sets of encoding strings; the font
389 encodings are not portable.
390 fonts NAME = '', ENCODING = ''
392 Returns hash of font hashes ( see "Fonts" in Prima::Drawable )
393 describing fonts of NAME font family and of ENCODING. If NAME is ''
394 or "undef", returns one fonts hash for each of the font families
395 that match the ENCODING string. If ENCODING is '' or "undef", no
396 encoding match is performed. If ENCODING is not valid ( not
397 present in "font_encodings" result), it is treated as if it was ''
398 or "undef".
399 In the special case, when both NAME and ENCODING are '' or "undef",
401 each font metric hash contains element "encodings", that points to
402 array of the font encodings, available for the fonts of NAME font
403 family.
404 get_active_window
406 Returns object reference to a currently active window, if any, that
407 belongs to the program. If no such window exists, "undef" is
408 returned.
409 The exact definition of 'active window' is system-dependent, but it
411 is generally believed that an active window is the one that has
412 keyboard focus on one of its children widgets.
413 get_caption_font
415 Returns a title font, that the system uses to draw top-level window
416 captions. The method can be called with a class string instead of
417 an object instance.
418 get_default_cursor_width
420 Returns width of the system cursor in pixels. The method can be
421 called with a class string instead of an object instance.
422 get_default_font
424 Returns the default system font. The method can be called with a
425 class string instead of an object instance.
426 get_default_scrollbar_metrics
428 Returns dimensions of the system scrollbars - width of the standard
429 vertical scrollbar and height of the standard horizon scrollbar.
430 The method can be called with a class string instead of an object
431 instance.
432 get_dnd_clipboard
434 Returns the predefined special clipboard used as a proxy for drag
435 and drop interactions.
436 See also: "Widget/Drag and drop", "Clipboard/is_dnd".
438 get_default_window_borders BORDER_STYLE = bs::Sizeable
440 Returns width and height of standard system window border
441 decorations for one of "bs::XXX" constants. The method can be
442 called with a class string instead of an object instance.
443 get_focused_widget
445 Returns object reference to a currently focused widget, if any,
446 that belongs to the program. If no such widget exists, "undef" is
447 returned.
448 get_fullscreen_image
450 Syntax sugar for grabbing whole screen as in
451 $::application->get_image( 0, 0, $::application->size)
453 (MacOSX/XQuartz: get_image() does not grab all screen bits, but
455 "get_fullscreen_image" does (given Prima is compiled with Cocoa
456 library)).
457 get_hint_widget
459 Returns the hint label widget, attached automatically to
460 Prima::Application object during startup. The widget is of
461 "::hintClass" class, Prima::HintWidget by default.
462 get_image X_OFFSET, Y_OFFSET, WIDTH, HEIGHT
464 Returns Prima::Image object with WIDTH and HEIGHT dimensions filled
465 with graphic content of the screen, copied from X_OFFSET and
466 Y_OFFSET coordinates. If WIDTH and HEIGHT extend beyond the screen
467 dimensions, they are adjusted. If the offsets are outside screen
468 boundaries, or WIDTH and HEIGHT are zero or negative, "undef" is
469 returned.
470 Note: When running on MacOSX under XQuartz, the latter does not
472 give access to the whole screen, so the function will not be able
473 to grab top-level menu bar. This problem is addressed in
474 "get_fullscreen_image".
475 get_indents
477 Returns 4 integers that corresponds to extensions of eventual
478 desktop decorations that the windowing system may present on the
479 left, bottom, right, and top edges of the screen. For example, for
480 win32 this reports the size of the part of the scraan that windows
481 taskbar may occupies, if any.
482 get_printer
484 Returns the printer object, attached automatically to
485 Prima::Application object. The object is of "::printerClass" class.
486 get_message_font
488 Returns the font the system uses to draw the message text. The
489 method can be called with a class string instead of an object
490 instance.
491 get_modal_window MODALITY_TYPE = mt::Exclusive, TOPMOST = 1
493 Returns the modal window, that resides on an end of a modality
494 chain. MODALITY_TYPE selects the chain, and can be either
495 "mt::Exclusive" or "mt::Shared". TOPMOST is a boolean flag,
496 selecting the lookup direction; if it is 1, the 'topmost' window is
497 returned, if 0, the 'lowest' one ( in a simple case when window A
498 is made modal (executed) after modal window B, the A window is the
499 'topmost' one ).
500 If a chain is empty "undef" is returned. In case when a chain
502 consists of just one window, TOPMOST value is apparently
503 irrelevant.
504 get_monitor_rects
506 Returns set of rects in format [X,Y,WIDTH,HEIGHT] identifying
507 monitor configurations. Currently works under X11 only.
508 get_scroll_rate
510 Returns two integer values of two system-specific scrolling
511 timeouts. The first is the initial timeout, that is applied when
512 the user drags the mouse from a scrollable widget ( a text field,
513 for example ), and the widget is about to scroll, but the actual
514 scroll is performed after the timeout is expired. The second is the
515 repetitive timeout, - if the dragging condition did not change, the
516 scrolling performs automatically after this timeout. The timeout
517 values are in milliseconds.
518 get_system_info
520 Returns a hash with information about the system. The hash result
521 contains the following keys:
522 apc One of "apc::XXX" constants, reflecting the platform.
524 Currently, the list of the supported platforms is:
525 apc::Win32
527 apc::Unix
528 gui One of "gui::XXX" constants, reflecting the graphic user
530 interface used in the system:
531 gui::Default
533 gui::PM
534 gui::Windows
535 gui::XLib
536 gui::GTK
537 guiDescription
539 Description of graphic user interface, returned as an arbitrary
540 string.
541 guiLanguage
543 Preferred language of the interface, returned as an ISO 639
544 code.
545 system
547 An arbitrary string, representing the operating system
548 software.
549 release
551 An arbitrary string, reflecting the OS version information.
552 vendor
554 The OS vendor string
555 architecture
557 The machine architecture string
558 The method can be called with a class string instead of an object
560 instance.
561 get_system_value
563 Returns the system integer value, associated with one of "sv::XXX"
564 constants. The constants are:
565 sv::YMenu - height of menu bar in top-level windows
567 sv::YTitleBar - height of title bar in top-level windows
568 sv::XIcon - width and height of main icon dimensions,
569 sv::YIcon acceptable by the system
570 sv::XSmallIcon - width and height of alternate icon dimensions,
571 sv::YSmallIcon acceptable by the system
572 sv::XPointer - width and height of mouse pointer icon
573 sv::YPointer acceptable by the system
574 sv::XScrollbar - width of the default vertical scrollbar
575 sv::YScrollbar - height of the default horizontal scrollbar
576 ( see get_default_scrollbar_metrics() )
577 sv::XCursor - width of the system cursor
578 ( see get_default_cursor_width() )
579 sv::AutoScrollFirst - the initial and the repetitive
580 sv::AutoScrollNext scroll timeouts
581 ( see get_scroll_rate() )
582 sv::InsertMode - the system insert mode
583 ( see insertMode )
584 sv::XbsNone - widths and heights of the top-level window
585 sv::YbsNone decorations, correspondingly, with borderStyle
586 sv::XbsSizeable bs::None, bs::Sizeable, bs::Single, and
587 sv::YbsSizeable bs::Dialog.
588 sv::XbsSingle ( see get_default_window_borders() )
589 sv::YbsSingle
590 sv::XbsDialog
591 sv::YbsDialog
592 sv::MousePresent - 1 if the mouse is present, 0 otherwise
593 sv::MouseButtons - number of the mouse buttons
594 sv::WheelPresent - 1 if the mouse wheel is present, 0 otherwise
595 sv::SubmenuDelay - timeout ( in ms ) before a sub-menu shows on
596 an implicit selection
597 sv::FullDrag - 1 if the top-level windows are dragged dynamically,
598 0 - with marquee mode
599 sv::DblClickDelay - mouse double-click timeout in milliseconds
600 sv::ShapeExtension - 1 if Prima::Widget::shape functionality is supported,
601 0 otherwise
602 sv::ColorPointer - 1 if system accepts color pointer icons.
603 sv::CanUTF8_Input - 1 if system can generate key codes in unicode
604 sv::CanUTF8_Output - 1 if system can output utf8 text
605 sv::CompositeDisplay - 1 if system uses double-buffering and alpha composition for the desktop,
606 0 if it doesn't, -1 if unknown
607 sv::LayeredWidgets - 1 if system supports layering
608 sv::FixedPointerSize - 0 if system doesn't support arbitrary sized pointers and will resize custom icons to the system size
609 sv::MenuCheckSize - width and height of default menu check icon
610 sv::FriBidi - 1 if Prima is compiled with libfribidi and full bidi unicode support is available
611 sv::Antialias - 1 if system supports antialiasing and alpha layer for primitives
612 sv::LibThai - 1 if Prima is compiled with libthai
613 The method can be called with a class string instead of an object
615 instance.
616 get_widget_from_handle HANDLE
618 HANDLE is an integer value of a toolkit widget. It is usually
619 passed to the program by other IPC means, so it returns the
620 associated widget. If no widget is associated with HANDLE, "undef"
621 is returned.
622 get_widget_from_point X_OFFSET, Y_OFFSET
624 Returns the widget that occupies screen area under
625 (X_OFFSET,Y_OFFSET) coordinates. If no toolkit widget are found,
626 "undef" is returned.
627 go The main event loop. Called by
629 run Prima;
631 standard code. Returns when the program is about to terminate, if
633 "stop" was called, or if the exception was signaled. In the latter
634 two cases, the loop can be safely re-started.
635 lock
637 Effectively blocks the graphic output for all widgets. The output
638 can be restored with "unlock()".
639 load_font FONTNAME
641 Registers font resource in system-specific format. The resource is
642 freed after prgram ends.
643 Notes for win32: To add a font whose information comes from several
645 resource files, point FONTNAME to a string with the file names
646 separated by a "|" - for example, " abcxxxxx.pfm | abcxxxxx.pfb ".
647 Notes for unix: available only when Prima is compiled with
649 fontconfig and Xft .
650 Returns number of font resources added.
652 open_help TOPIC
654 Opens the help viewer window with TOPIC string in link POD format (
655 see perlpod ) - the string is treated as "manpage/section", where
656 'manpage' is the file with POD content and 'section' is the topic
657 inside the manpage.
658 stop
660 Breaks the event loop. The loop can be started again by "go"
661 thereafter.
662 sync
664 Synchronizes all pending requests where there are any. Is an
665 effective "XSync(false)" on X11, and is a no-op otherwise.
666 sys_action CALL
668 CALL is an arbitrary string of the system service name and the
669 parameters to it. This functionality is non-portable, and its
670 usage should be avoided. The system services provided are not
671 documented and subject to change. The actual services can be looked
672 in the toolkit source code under apc_system_action tag.
673 unlock
675 Unblocks the graphic output for all widgets, previously locked with
676 "lock()".
677 yield $wait_for_event=0
679 An event dispatcher, called from within the event loop. If the
680 event loop can be schematized, then in
681 while ( application not closed ) {
683 yield
684 }
685 draft yield() is the only function, called repeatedly within the
687 event loop. yield(0) call shouldn't be used to organize event
688 loops, but it can be employed to process stacked system events
689 explicitly, to increase responsiveness of a program, for example,
690 inside a long calculation cycle.
691 yield(1) though is adapted exactly for external implementation of
693 event loops; it does exactly the same as yeild(0), but if there are
694 no events, it sleeps until there comes at least one, processes it,
695 and then returns. The return value is 0 if the application doesn't
696 need more event processins, because of shutting down. The
697 corresponding code will be
698 while ( yield(1)) {
700 ...
701 }
702 but in turn, this call cannot be used for UI responsiveness inside
704 tight cycles.
705 The method can be called with a class string instead of an object
707 instance; however, the $::application object must be initialized.
708
710 Dmitry Karasik, <dmitry@karasik.eu.org>.
711
713 Prima, Prima::Object, Prima::Widget, Prima::Window
714perl v5.34.1 2022-04-20 Prima::Application(3)