Inherited functionality¶

Prima::Application is a descendant of Prima::Widget but does not conform strictly ( in the OO sense ) to any of the built-in classes. It has methods from both Prima::Widget and Prima::Window, also, the methods inherited from the Prima::Widget class may work quite differently. For example, the "::origin" property from Prima::Widget is also implemented in Prima::Application, but always returns (0,0), an expected but not much usable result. The "::size" property, on the contrary, returns the extent of the screen in pixels. There are a few properties inherited from Prima::Widget, which return actual but uninformative results, - "::origin" is one of those, but there are several others. The methods and properties, that are like "::size" providing different functionality, are described separately in "API".

Global functionality¶

Prima::Application is a wrapper to a set of unrelated functions that do not belong to other classes. A notable example, the painting functionality that is inherited from the Prima::Drawable class, allows drawing on the screen, possibly overwriting the graphic information created by the other programs. Although it is still a subject to the begin_paint()/end_paint() brackets, this functionality does not belong to a single object and is considered global.

Painting

As stated above, the Prima::Application class provides an interface to the on-screen painting. This mode is triggered by the begin_paint()/end_paint() methods, while 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.

The painting on the screen surfaces under certain environments (XQuartz, XWayland) is either silently ignored or results in an error. There, "begin_paint" may return a false value ("begin_paint_info" though always true).

Hints

$::application hosts a special "Prima::HintWidget" class object, accessible via get_hint_widget(), but with its color and font functions aliased ( see "::hintColor", "::hintBackColor", "::hintFont" ).

This widget serves as a hint label, floating over other widgets if the mouse pointer hovers longer than "::hintPause" milliseconds.

Prima::Application internally manages all of the hint functionality. The hint widget itself, however, can be replaced before the application object is created, using the "::hintClass" create-only property.

Printer

The result of the get_printer method points to an automatically created printer object, responsible for the system 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/PDF document interface.

See Prima::Printer for details.

Clipboard

$::application hosts a set of Prima::Clipboard objects created automatically to reflect the system-provided clipboard IPC functionality. Their number depends on the system, - under the X11 environment, there are three clipboard objects, and one under Win32.

There are no specific methods to access these clipboard objects, except bring() ( or the indirect name call ); the clipboard objects are named after the system clipboard names, which are returned by the Prima::Clipboard::get_standard_clipboards method.

The default clipboard is named Clipboard, and is accessible via the

        my $clipboard = $::application-> Clipboard;
    

call.

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 a part of the toolkit that resides in the "Prima::HelpViewer" module, any custom help viewing module can be assigned. The 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. Knowing the toolkit boundaries in some platforms, the program may change its behavior accordingly. Both these topics are facilitated by extra system information returned by Prima::Application methods. The "get_system_value" method returns a system-defined value for each of the "sv::XXX" constants, so the program can read the system-specific information. Another method "get_system_info" returns the short description of the system that augments perl's $^O variable.

The "sys_action" method is a wrapper to system-dependent functionality that is called in a non-portable way. This method is rarely used in the toolkit, its usage is discouraged, primarily because its options do not serve the toolkit design, its syntax is subject to changes, and cannot be relied upon.

Exceptions and signals

By default Prima doesn't track exceptions caused by "die", "warn", and signals. Currently, it is possible to enable a GUI dialog tracking the "die" exceptions, by either operating the boolean "guiException" property or using the

   use Prima qw(sys::GUIException)
    

syntax.

If you need to track signals or warnings you may do so by using standard perl practices. It is though not advisable to call Prima interactive methods directly inside signal handlers but use a minimal code instead. F.ex. code that would ask whether the user wants to quit would look like this:

   use Prima qw(Utils MsgBox);
   $SIG{INT} = sub {
      Prima::Utils::post( sub {
          exit if message_box("Got Ctrl+C", "Do you really want to quit?", mb::YesNo) == mb::Yes;
      });
   };
    

and if you want to treat all warnings as potentially fatal, like this:

   use Prima qw(Utils MsgBox);
   $SIG{__WARN__} = sub {
      my ($warn, $stack) = ($_[0], Carp::longmess);
      Prima::Utils::post( sub {
          exit if $::application && Prima::MsgBox::signal_dialog("Warning", $warn, $stack) == mb::Abort;
      });
   };
    

See also: Die, "signal_dialog" in Prima::MsgBox

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 generic 'one main window' application layouts.

Default value: 0

guiException BOOLEAN

If set to 1, when a "die" exception is thrown, displays a system message dialog. allowing the user to choose the course of action -- to stop, to continue, etc.

Is 0 by default.

Note that the exception is only handled inside the "Prima::run" and "Prima::Dialog::execute" calls; if there is a call to f ex "Prima::Window::execute" or a manual event loop run with "yield", the signal dialog will not be shown. One needs to explicitly call "$::application->notify(Die => $@)" and check the notification result to decide whether to propagate the exception or not.

The alternative syntax for setting "guiException" to 1 is the

   use Prima::sys::GUIException;
    

or

   use Prima qw(sys::GUIException);
    

statement.

If for some reason an exception is thrown during dialog execution, it will not be handled by Prima but by the current $SIG{__DIE__} handler.

See also "signal_dialog" in Prima::MsgBox .

icon OBJECT

Holds the icon object associated with the application. If "undef", the system-provided default icon is assumed. Prima::Window objects inherit this application icon by default.

insertMode BOOLEAN

The system boolean flag signaling 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 the class of the object used as the help viewing package. The default value is Prima::HelpViewer. Run-time changes to the property do not affect the help subsystem until a call to "close_help" is made.

helpModule STRING

Specifies the perl module loaded indirectly when a help viewing call is made via the "open_help" method. Used when the "::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 a call to "close_help" is made.

hintClass STRING

Create-only property.

Specifies the class of the widget used as the hint label.

Default value: Prima::HintWidget

hintColor COLOR

The alias to the foreground color property of the hint label widget.

hintBackColor COLOR

The alias to the background color property of the hint label widget.

hintFont %FONT

The alias to the font property of the hint label widget.

hintPause TIMEOUT

Sets the timeout in milliseconds before the hint label is shown when the mouse pointer hovers over a widget.

language STRING

By default contains the user interface language deduced either from the $ENV{LANG} environment variable (unix) or a system default setting (win32). When changed, updates the "textDirection" property.

See also: "get_system_info".

modalHorizon BOOLEAN

A read-only property. Used as the lowest-level modal horizon. Always returns 1.

palette [ @PALETTE ]

Used only within the paint and information modes. Selects solid colors in the system palette, as many as possible. PALETTE is an array of 8-bit integer triplets, where each is a red, green, and blue component.

printerClass STRING

Create-only property.

Specifies the class of the object used as the printer. The default value is system-dependent, but is either "Prima::Printer" or "Prima::PS::Printer".

printerModule STRING

Create-only property.

Specifies the perl module loaded indirectly before the printer object of the "::printerClass" class is created. Used when the "::printerClass" property is overridden and the new class is contained in a third-party module.

pointerVisible BOOLEAN

Manages 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, the 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 the functionality of the "::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 the widgets.

skin SCALAR

The same as "skin" in Prima::Widget, but is mentioned here because it is possible to change the whole application skin by changing this property, f ex like this:

   use Prima::Application skin => 'flat';
    

textDirection BOOLEAN

Contains the preferred text direction initially deduced from the preferred interface language. If 0 ( default ), the preferred text direction is left-to-right (LTR), otherwise right-to-left (RTL), f.ex. for Arabic and Hebrew languages.

The value is used as a default when shaping text and setting widget input direction.

uiScaling FLOAT

The property contains an advisory multiplier factor, useful for UI elements that have a fixed pixel value, but that would like to be represented in a useful manner when the display resolution is too high (on modern High-DPI displays) or too low (on ancient monitors).

By default, it acquires the system display resolution and sets the scaling factor so that when the DPI is 96 it is 1.0, 192 it is 2.0, etc. The increase step is 0.25, so that bitmaps may look not that distorted when scaled. However, when the value is manually set the step is not enforced and any value can be accepted.

See also: "Stress" in Prima.

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 the operating system does not support UTF8.

If 1, the "Prima::Clipboard::text" property may return UTF8 text from system clipboards is available.

Default value: 1

Events¶

Clipboard $CLIPBOARD, $ACTION, $TARGET

With (the only implemented) $ACTION copy, is called whenever another application requests clipboard data in the format $TARGET. This notification is handled internally to optimize image pasting through the clipboard. Since the clipboard pasting semantics in Prima is such that data must be supplied to the clipboard in advance, before another application can request it, there is a problem with which format to use. To avoid encoding an image or other complex data in all possible formats but do that on demand and in the format the other application wants, this notification can be used.

Only implemented for X11.

CopyImage $CLIPBOARD, $IMAGE

The notification stores $IMAGE in the clipboard.

CopyText $CLIPBOARD, $TEXT

The notification stores $TEXT in the clipboard.

Die $@, $STACK

Called when an exception occurs inside the event loop "Prima::run". By default, consults the "guiException" property, and if it is set, displays the system message dialog allowing the user to decide what to do next.

Idle

Called when the event loop handled all pending events, and is about to sleep waiting for more.

PasteImage $CLIPBOARD, $$IMAGE_REF

The notification queries $CLIPBOARD for image content and stores in $$IMAGE_REF. The default action is that the 'Image' format is queried. On unix, encoded formats 'image/bmp', 'image/png' etc are queried if the default 'Image' is not found.

The "PasteImage" mechanism can read images from the clipboard in the GTK environment.

PasteText $CLIPBOARD, $$TEXT_REF

The notification queries $CLIPBOARD for text content and stores it in the $$TEXT_REF scalar. Its default action is that only the 'Text' format is queried if "wantUnicodeInput" is unset. Otherwise, the 'UTF8' format is queried first.

The "PasteText" mechanism is devised to ease defining text unicode/ascii conversion between clipboard and standard widgets, in a unified way.

Methods¶

add_startup_notification @CALLBACK

CALLBACK is an array of anonymous subs, which are all executed when the Prima::Application object is created. If the application object is already created during the call, CALLBACKs are called immediately.

Useful for initialization of add-on packages.

begin_paint

Enters the enabled ( active paint ) state, and returns the success flag. Once the object is in the enabled state, painting and drawing methods can perform drawing operations on the whole screen.

begin_paint_info

Enters the information state, and returns the success flag. The object information state is the same as the 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 the "close" method for all top-level windows. The call can be interrupted by the latter, and effectively canceled. If not canceled stops the application event loop.

close_help

Closes the help viewer window.

end_paint

Quits the enabled state and returns the application object to the normal state.

end_paint_info

Quits the information state and returns the application object to the normal state.

font_encodings

Returns an 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 a hash of font hashes ( see "Fonts" in Prima::Drawable ) describing fonts of NAME font family and of ENCODING text encoding. If NAME is '' or "undef", returns one font 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 the "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 the element "encodings", which points to an array of the font encodings, available for the fonts of the NAME font family.

get_active_window

Returns the object reference to the 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 a keyboard focus on one of its children widgets.

get_caption_font

Returns the 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 the 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_dnd_clipboard

Returns the predefined special clipboard used as a proxy for drag-and-drop interactions.

See also: "Widget/Drag and drop", "Clipboard/is_dnd".

get_default_window_borders BORDER_STYLE = bs::Sizeable

Returns width and height of standard system window border decorations for one of the "bs::XXX" constants. The method can be called with a class string instead of an object instance.

get_focused_widget

Returns object reference to the currently focused widget, if any, that belongs to the program. If no such widget exists, "undef" is returned.

get_fullscreen_image

Syntax sugar for grabbing the whole screen as in

   $::application->get_image( 0, 0, $::application->size)
    

(MacOSX/XQuartz note: get_image() does not grab all screen bits, but "get_fullscreen_image" does if Prima is compiled with the Cocoa library).

get_hint_widget

Returns the hint label widget, attached automatically to the Prima::Application object during startup. The widget is of the "::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 the screen boundaries, or WIDTH and HEIGHT are zero or negative, "undef" is returned.

Note: When running on MacOSX under XQuartz, the latter does not give access to the whole screen, so the function will not be able to grab the top-level menu bar. This problem is addressed in the "get_fullscreen_image" method.

get_indents

Returns 4 integers that correspond 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 screen that the windows taskbar may occupy, if any.

get_printer

Returns the printer object attached automatically to the Prima::Application object. The object is an instance of the "::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 the 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 'lower-most' one ( in a simple case when window A is made modal (executed) after modal window B, the A window is the 'topmost' one ).

If the chain is empty "undef" is returned. In case the chain consists of just one window, the TOPMOST value is irrelevant.

get_monitor_rects

Returns set of rectangles in the format of (X,Y,WIDTH,HEIGHT) identifying monitor layouts.

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 has expired. The second value 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 the following keys containing information about the system:

get_system_value

Returns the system integer value, associated with one of the "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 the system accepts color pointer icons.
        sv::CanUTF8_Input    - 1 if the system can generate key codes in unicode
        sv::CanUTF8_Output   - 1 if the system can output utf8 text
        sv::CompositeDisplay - 1 if the system uses double-buffering and alpha composition for the desktop,
                               0 if it doesn't, -1 if unknown
        sv::LayeredWidgets   - 1 if the system supports layering
        sv::FixedPointerSize - 0 if the system doesn't support arbitrarily sized pointers and will resize custom icons to the system size
        sv::MenuCheckSize    - width and height of default menu check icon
        sv::FriBidi          - 1 if Prima is compiled with libfribidi and full bidi unicode support is available
        sv::Antialias        - 1 if the system supports antialiasing and alpha layer for primitives
        sv::LibThai          - 1 if Prima is compiled with libthai
    

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 handle as used in the underlying GUI level, for example, it is a HWND value on win32. It is usually passed to the program by other IPC means, so that the method can return 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 the screen area under (X_OFFSET,Y_OFFSET) coordinates. If no toolkit widgets are found, "undef" is returned.

go

The main event loop. Called by the

   run Prima;
    

standard code. Returns when the program is about to terminate, if "stop" was called, or if the exception was signaled. In the latter two cases, the loop can be safely restarted.

lock

Effectively blocks the graphic output for all widgets. The output can be restored with unlock().

load_font FONTNAME

Registers a font resource in the system-specific format. The resource is freed after the program ends.

Notes for win32: To add a font whose information comes from several resource files, point FONTNAME to a string with the file names separated by a "|" - for example, " abcxxxxx.pfm | abcxxxxx.pfb ".

Notes for unix: available only when Prima is compiled with fontconfig and Xft .

Returns the number of the font resources added.

open_help TOPIC

Opens the help viewer window with TOPIC string in the 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.

Alternatively can handle the syntax in the form of " file://path|section " where "path" is the file with the pod content and "section" is an optional pod section within the file.

stop

Stops the event loop. The loop can be started again.

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 are subject to change. The actual services can be looked at in the toolkit source code under the apc_system_action tag.

unlock

Unlocks the graphic output for all widgets, previously locked with lock().

yield $wait_for_event=0

An event dispatcher, called from within the event loop. If the event loop can be schematized, then in this code

        while ( application not closed ) {
                yield
        }
    

yield() is the only function called repeatedly inside the loop. The yield(0) call shouldn't be used to organize event loops, but it can be employed to process stacked system events explicitly, to increase the responsiveness of a program, for example, inside a long calculation cycle.

yield(1) though is adapted exactly for external implementation of event loops; it does the same as yield(0), but if there are no events it sleeps until there comes at least one, processes it, and then returns. The return value is 0 if the application doesn't need more event processing, because of shutting down. The corresponding code will be

        while ( yield(1)) {
            ...
        }
    

but in turn, this call cannot be used for increasing UI responsiveness inside tight calculation loops.

The method can be called with a class string instead of an object instance; however, the $::application object must be initialized.