NAME
Prima::Window - top-level window management
SYNOPSIS
use Prima;
use Prima::Application;
# this window, when closed, terminated the application
my $main = Prima::MainWindow-> new( text => 'Hello world' );
# this is a modal window
my $dialog = Prima::Dialog->create( size => [ 100, 100 ]);
my $result = $dialog-> execute;
$dialog-> destroy;
run Prima;
DESCRIPTION
Prima::Window is a descendant of Prima::Widget class. It deals with
top-level windows, the windows that are specially treated by the
system. Its major difference from Prima::Widget is that instances of
Prima::Window can only be inferior by the screen, not the other
windows, and that the system or window manager add decorations to these
- usually menus, buttons and title bars. Prima::Window provides methods
that communicate with the system and hint these decorations.
USAGE
A typical program communicates with the user with aid of widgets,
collected upon one or more top-level windows. Prima::Widget already
has all functionality required for these child-parent operations, so
Prima::Window is not special in respect of widget grouping and
relationship. Its usage therefore is straightforward:
my $w = Prima::Window-> create(
size => [300,300],
text => 'Startup window',
);
There are more about Prima::Window in areas, that it is specifically
designed to - the system window management and the dialog execution.
System window management
As noted before, top-level windows are special for the system, not only
in their ’look’, but also in ’feel’: the system adds specific functions
to the windows, aiding the user to navigate through the desktop. The
system ofter dictates the size and position for windows, and some times
these rules are hard or even impossible to circumvent. This document
will be long if it would venture to describe the features of different
window management systems, and the task would be never accomplished -
brand new window managers emerge every month, and the old change their
behavior in an unpredictable way. The only golden rule is to never rely
on the behavior of one window manager, and test programs with at least
two.
The Prima toolkit provides simple access to buttons, title bar and
borders of a window. Buttons and title bar are managed by the
"::borderIcons" property, and borders by the "::borderStyle" property.
These operate with set of predefined constants, "bi::XXX" and
"bs::XXX", correspondingly. The button constants can be combined with
each other, but not all combinations may be granted by the system. The
same is valid also for the border constant, except that they can not be
combined - the value of "::borderStyle" is one of the integer
constants.
There are other hints that the toolkit can set for a window manager.
The system can be supplied with an icon that a window is bound to; the
icon dimensions are much different, and although can be requested via
"sv::XIcon" and "sv::YIcon" system values, the "::icon" property scales
the image automatically to the closest system-recognizable dimension.
The window icon is not shown by the toolkit, it is usually resides in
the window decorations and sometimes on a task bar, along with the
window’s name. The system can be hinted to not reflect the window on
the task bar, by setting the "::taskListed" property to 0.
Another issue is the window positioning. Usually, if no explicit
position was given, the window is positioned automatically by the
system. The same is valid for the size. But some window managers bend
it to the extreme - for example, default CDE setup force the user to
set newly created windows’ positions explicitly. However, there is at
least one point of certainty. Typically, when the initial size and/or
position of a top-level window are expected to be set by the system,
the "::originDontCare" and "::sizeDontCare" properties can be set to 1
during window creation. If these set, the system is asked to
size/position a window regarding its own windowing policy. The reverse
is not always true, unfortunately. Either if these properties set to
0, or explicit size or positions are given, the system is hinted to use
these values instead, but this does not always happen. Actually, this
behavior is expected by the user and often does not get even noticed as
something special. Therefore it is a good practice to test a top-level
windowing code with several window managers.
There are different policies about window positioning and sizing; some
window managers behave best when the position is given to the window
with the system-dependent decorations. It is hardly can be called a
good policy, since it is not possible to calculate the derived window
coordinates with certainty. This problem results in that it is
impossible to be sure about window position and size before these are
set explicitly. The only, not much efficient help the toolkit can
provide is the property pair "::frameOrigin" and "::frameSize", which
along with "::origin" and "::size" reflect the position and size of a
window, but taking into account the system-dependent decorations.
Dialog execution
Method of Prima::Window, "execute()" brings a window in a modal state
on top of other toolkit windows, and returns after the window is
dismissed in one or another way. This method is special as it is an
implicit event loop, similar to
run Prima;
code. The event flow is not disrupted, but the windows and widgets that
do not belong to the currently executed, the ’modal’ window group can
not be activated. There can be many modal windows on top of each other,
but only one is accessible. As an example a message box can be
depicted, a window that prevents the user to work with the application
windows until dismissed. There can be other message boxes on top of
each other, preventing the windows below from operation as well. This
scheme is called the ’exclusive’ modality.
The toolkit also provides the shared modality scheme, where there can
be several stacks of modal windows, not interfering with each other.
Each window stack is distinct and contains its own windows. An example
analogy is when several independent applications run with modal message
boxes being activated. This scheme, however, can not be achieved with
single execute()-like call without creating interlocking conditions.
The shared model call, "execute_shared()", inserts the window into the
shared modal stack, activates the window and returns immediately.
The both kinds of modal windows can coexist, but the exclusive windows
prevents the shared from operation; while there are exclusive windows,
the shared have same rights as the usual windows.
The stacking order for these two models is slightly different. A
window after execute() call is set on top of the last exclusive modal
window, or, in other words, is added to the exclusive window stack.
There can be only one exclusive window stack, but many shared window
stacks; a window after execute_shared() call is added to a shared
window stack, to the one the window’s owner belongs to. The shared
window stacks are rooted in so-called modal horizons, windows with
boolean property "::modalHorizon" set to "true". The default horizon is
"::application".
A window in modal state can return to the normal (non-modal) state by
calling "end_modal()" method. The window is then hidden and disabled,
and the windows below are accessible to the user. If the window was in
the exclusive modal state, the execute() call is finished and returns
the exit code, the value of "::modalResult" property. There two
shortuct methods that end modal state, setting "::modalResult" to the
basic ’ok’ and ’not ok’ code, correspondingly "ok()" and "cancel()"
methods. Behavior of "cancel()" is identical to when the user closes
the modal window by clicking the system close button, pressing Escape
key, or otherwise cancelling the dialog execution. "ok()" sets
"::modalResult" to "mb::OK", "cancel()" to "mb::Cancel",
correspondingly. There are more "mb::XXX" constants, but these have no
special meaning, any integer value can be passed. For example,
"Prima::MsgBox::message" method uses these constants so the message
window can return up to four different "mb" codes.
Menu
A top-level window can be equipped with a menu bar. Its outlook is
system-dependent, but can be controlled by the toolkit up to a certain
level. The "::menuItems" property, that manages the menu items of a
"::menu" object of Prima::Menu class, arrange the layout of the menu.
The syntax of the items-derived properties is described in Prima::Menu,
but it must be reiterated that menu items contain only hints, not
requests for their exact representation. The same is valid for the
color and font properties, "::menuColorIndex" and "::menuFont".
Only one menu at a time can be displayed in a top-level window,
although a window can be an owner for many menu objects. The key
property is "Prima::Menu::selected" - if a menu object is selected on a
widget or a window object, it refers to the default menu actions,
which, in case of Prima::Window is being displayed as menu bar.
NB: A window can be an owner for several menu objects and still do not
have a menu bar displayed, if no menu objects are marked as selected.
Prima::Dialog
Prima::Dialog, a descendant from Prima::Window, introduces no new
functionality. It has its default values adjusted so the colors use
more appropriate system colors, and hints the system that the outlook
of a window is to be different, to resemble the system dialogs on
systems where such are provided.
Prima::MainWindow
The class is a simple descendant of Prima::Window, which overloads
"on_destroy" notification and calls "$application->close" inside it.
The purpose of declaration of a separate class for such a trifle
difference is that many programs are designed under a paradigm where
these is a main window, which is most ’important’ to the user. As such
consruct is used more often than any other, it is considered an
optimization to write
Prima::MainWindow-> create( ... )
rather than
Prima::Window-> create( ..., onDestroy => sub { $::application-> close })
, although these lines are equivalent.
Also, the $::main_window is pointed to a newly created main window.
API
Properties
borderIcons INTEGER
Hints the system about window’s decorations, by selecting the
combination of "bi::XXX" constants. The constants are:
bi::SystemMenu - system menu button and/or close button
( usually with icon ) is shown
bi::Minimize - minimize button
bi::Maximize - maximize ( and eventual restore )
bi::TitleBar - window title
bi::All - all of the above
Not all systems respect these hints, and many systems provide more
navigating decoration controls than these.
borderStyle STYLE
Hints the system about window’s border style, by selecting one of
"bs::XXX" constants. The constants are:
bs::None - no border
bs::Single - thin border
bs::Dialog - thick border
bs::Sizeable - thick border with interactive resize capabilities
"bs::Sizeable" is an unique window mode. If selected, the user can
resize the window, not only by dragging the window borders with the
mouse but by other system-dependent means. The other border styles
disallow interactive resizing.
Not all systems recognize all these hints, although many recognize
interactive resizing flag.
frameHeight HEIGHT
Maintains the height of a window, including the window decorations.
frameOrigin X_OFFSET, Y_OFFSET
Maintains the left X and bottom Y boundaries of a window’s
decorations relative to the screen.
frameSize WIDTH, HEIGHT
Maintains the width and height of a window, including the window
decorations.
frameWidth WIDTH
Maintains the width of a window, including the window decorations.
icon OBJECT
Hints the system about an icon, associated with a window. If
OBJECT is "undef", the system-default icon is assumed.
See also: "ownerIcon"
menu OBJECT
Manages a Prima::Menu object associated with a window.
Prima::Window can host many Prima::Menu objects, but only the one
that is set in "::menu" property will be seen as a menu bar.
See also: "Prima::Menu", "menuItems"
menuColorIndex INDEX, COLOR
Maintains eight color properties of a menu, associated with a
window. INDEX must be one of "ci::XXX" constants ( see
Prima::Widget, colorIndex section ).
See also: "menuItems", "menuFont", "menu"
menuColor COLOR
Basic foreground menu color.
See also: "menuItems", "menuColorIndex", "menuFont", "menu"
menuBackColor COLOR
Basic background menu color.
See also: "menuItems", "menuColorIndex", "menuFont", "menu"
menuDark3DColor COLOR
Color for drawing dark shadings in menus.
See also: "menuItems", "menuColorIndex", "menuFont", "menu"
menuDisabledColor COLOR
Foreground color for disabled items in menus.
See also: "menuItems", "menuColorIndex", "menuFont", "menu"
menuDisabledBackColor COLOR
Background color for disabled items in menus.
See also: "menuItems", "menuColorIndex", "menuFont", "menu"
menuFont %FONT
Maintains the font of a menu, associated with a window.
See also: "menuItems", "menuColorIndex", "menu"
menuHiliteColor COLOR
Foreground color for selected items in menus.
See also: "menuItems", "menuColorIndex", "menuFont", "menu"
menuHiliteBackColor COLOR
Background color for selected items in menus.
See also: "menuItems", "menuColorIndex", "menuFont", "menu"
menuItems [ ITEM_LIST ]
Manages items of a Prima::Menu object associated with a window.
The ITEM_LIST format is same as "Prima::AbstractMenu::items" and is
described in Prima::Menu.
See also: "menu", "menuColorIndex", "menuFont"
menuLight3DColor COLOR
Color for drawing light shadings in menus.
See also: "menuItems", "menuColorIndex", "menuFont", "menu"
modalHorizon BOOLEAN
Reflects if a window serves as root to the shared modal window
stack. A window with "::modalHorizon" set to 1 in shared modal
state groups its children windows in a window stack, separate from
other shared modal stacks. The "::modalHorizon" is therefore useful
only when several shared modal window stacks are needed.
The property also serves as an additional grouping factor for
widgets and windows. For example, default keyboard navigation by
tab and arrow keys is limited to the windows and widgets of a
single window stack.
modalResult INTEGER
Maintains a custom integer value, returned by "execute()".
Historically it is one of "mb::XXX" constants, but any integer
value can be used. The most useful "mb::" constants are:
mb::OK, mb::Ok
mb::Cancel
mb::Yes
mb::No
mb::Abort
mb::Retry
mb::Ignore
mb::Help
NB: These constants are defined so they can be bitwise-or’ed, and
Prima::MsgBox package uses this feature, where one of its functions
parameters is a combination of "mb::" constants.
onTop BOOLEAN
If set, the window is hinted to stay on top of all other windows.
Default value: 0
ownerIcon BOOLEAN
If 1, the icon is synchronized with the owner’s. Automatically set
to 0 if "::icon" property is explicitly set. Default value is 1,
so assigning an icon to $::application spawns the icon to all
windows.
taskListed BOOLEAN
If set to 0, hints the system against reflecting existence of a
window into a system task bar, or a top-level window list, or
otherwise lower the window’s value before the other windows. If 1,
does not hint anything.
Default value: 1
windowState STATE
A three-state property, that governs the state of a window. STATE
can be one of three "ws::XXX" constants:
ws::Normal
ws::Minimized
ws::Maximized
There can be more or less, or other window states provided by the
system, but these three were chosen as a ’least common
denominator’. The property can be changed either by explicit set-
mode call or by the user. In either case, a "WindowState"
notification is triggered.
The property has three convenience wrappers: "maximize()",
"minimize()" and "restore()".
See also: "WindowState"
Methods
cancel
A standard method to dismiss a modal window with "mb::Cancel"
result. The effect of calling this method is equal to when the user
selects a ’close window’ action with system-provided menu, button
or other tool.
See also: "ok", "modalResult", "execute", "execute_shared"
end_modal
If a window is in modal state, the "EndModal" notification is
activated. Then the window is returned from the modal state, gets
hidden and disabled. If the window was on top in the exclusive
modal state, the last called "execute()" function finishes. If the
window was not on top in the exclusive modal state, the
corresponding "execute()" function finishes after all subsequent
execute() calls are finished.
execute INSERT_BEFORE = undef
A window is turned to the exclusive modal state and is put on top
of non-modal and shared-modal windows. By default, if
INSERT_BEFORE object is undef, the window is also put on top of
other exclusive-modal windows; if INSERT_BEFORE is one of the
exclusive-modal windows the window is placed in queue before the
INSERT_BEFORE window. The window is showed and enabled, if
necessary, and "Execute" notification is triggered.
The function is returned when a window is dismissed, or if the
system-dependent ’exit’-event is triggered by the user ( the latter
case falls through all execute() calls and terminates "run Prima;"
call, exiting gracefully).
execute_shared INSERT_BEFORE = undef
A window is turned to the shared modal state and is put on top of
non-modal windows in the stack of its "::modalHorizon". A window
with "::modalHorizon" set to 1 starts its own stack, independent of
all other window stacks.
By default, if INSERT_BEFORE object is undef, the window is also
put on top of other shared-modal windows in its stack. If
INSERT_BEFORE is one of the shared-modal windows in its stack, the
window is placed in queue before the INSERT_BEFORE window.
The window is showed and enabled, if necessary, and "Execute"
notification is triggered.
The function is returned immediately.
get_default_menu_font
Returns the default font for a Prima::Menu class.
get_modal
Returns one of three constants, reflecting the modal state of a
window:
mt::None
mt::Shared
mt::Exclusive
Value of "mt::None" is 0, so result of get_modal() can be also
treated as a boolean value, if only the fact of modality is needed
to check.
get_modal_window MODALITY_TYPE = mt::Exclusive, NEXT = 1
Returns a modal window, that is next to the given window in the
modality chain. MODALITY_TYPE selects the chain, and can be either
"mt::Exclusive" or "mt::Shared". NEXT is a boolean flag, selecting
the lookup direction; if it is 1, the ’upper’ window is returned,
if 0, the ’lower’ one ( in a simple case when window A is made
modal (executed) after modal window B, the A window is the ’upper’
one ).
If a window has no immediate modal relations, "undef" is returned.
maximize
Maximizes window. A shortcut for "windowState(ws::Maximized)".
minimize
Minimizes window. A shortcut for "windowState(ws::Minimized)".
ok A standard method to dismiss a modal window with "mb::OK" result.
Typically the effect of calling this method is equal to when the
user presses the enter key of a modal window, signaling that the
default action is to be taken.
See also: "cancel", "modalResult", "execute", "execute_shared"
restore
Restores window to normal state from minimized or maximized state.
A shortcut for "windowState(ws::Normal)".
Events
Activate
Triggered when a window is activated by the user. Activation mark
is usually resides on a window that contains keyboard focus, and is
usually reflected by highlighted system decorations.
The toolkit does not provide standalone activation functions;
"select()" call is used instead.
Deactivate
Triggered when a window is deactivated by the user. Window is
usually marked inactive, when it contains no keyboard focus.
The toolkit does not provide standalone de-activation functions;
"deselect()" call is used instead.
EndModal
Called before a window leaves modal state.
Execute
Called after a window enters modal state.
WindowState STATE
Triggered when window state is changed, either by an explicit
"windowState()" call, or by the user. STATE is the new window
state, one of three "ws::XXX" constants.
AUTHOR
Dmitry Karasik, <dmitry@karasik.eu.org>.
SEE ALSO
Prima, Prima::Object, Prima::Drawable, Prima::Widget.