Prima::Widget - window management Prima::Widget is a descendant of Prima::Component, a class, especially crafted to reflect and govern properties of a system-dependent window, such as its position, hierarchy, outlook etc. Prima::Widget is mapped into the screen space as a rectangular area, with distinct boundaries, pointer and sometimes cursor, and a user-selectable input focus. Prima::Widget class and its descendants are used widely throughout the toolkit, and, indeed provide almost all its user interaction and input-output. The notification system, explained in the Prima::Object manpage, is employed in Prima::Widget heavily, providing the programmer with unified access to the system-generated events, that occur when the user moves windows, clicks the mouse, types the keyboard, etc. Descendants of Prima::Widget use the internal, the direct method of overriding the notifications, whereas end programs tend to use the toolkit widgets equipped with anonymous subroutines ( see the Prima::Object manpage for the details). The class functionality is much more extensive comparing to the other built-in classes, and therefore the explanations are grouped in several topics. The widget creation syntax is the same as for the other Prima objects: Prima::Widget-> create( name => 'Widget', size => [ 20, 10], onMouseClick => sub { print "click\n"; }, owner => $owner, ); In the real life, a widget must be almost always explicitly told about its owner. The owner object is either a Prima::Widget descendant, in which case the widget is drawn inside its inferior, or the application object, and in the latter case a widget becomes top-level. This is the reason why the insert syntax is much more often used, as it is more illustrative and is more convenient for creating several widgets in one call ( see the Prima::Object manpage ). $owner-> insert( 'Prima::Widget', name => 'Widget', size => [ 20, 10], onMouseClick => sub { print "click\n"; }, ); These two examples produce identical results. As a descendant of Prima::Component, Prima::Widget sends Create notification when created ( more precisely, after its init stage is finished. See the Prima::Object manpage for details). This notification is called and processed within create() call. In addition, another notification Setup is sent after the widget is created. This message is posted, so it is called within create() but processed in the application event loop. This means that the execution time of Setup is uncertain, as it is with all posted messages; its delivery time is system-dependent, so its use must be considered with care. After a widget is created, it is usually asked to render its content, provided that the widget is visible. This request is delivered by means of Paint notification. When the life time of a widget is over, its method destroy() is called, often implicitly. If a widget gets destroyed because its owner also does, it is guaranteed that the children widgets will be destroyed first, and the owner afterwards. In such situation, widget can operate with a limited functionality both on itself and its owners ( see the Prima::Object manpage, Creation section ). A widget can use two different ways for representing its graphic content to the user. The first method is event-driven, when the Paint notification arrives, notifying the widget that it must re-paint itself. The second is the 'direct' method, when the widget generates graphic output unconditionally.

Event-driven rendering
A notification responsible for widget repainting is Paint. It provides a single ( besides the widget itself ) parameter, an object, where the drawing is performed. In an event-driven call, it is always equals to the widget. However, if a custom mechanism should be used that directly calls, for example, $widget-> notify('Paint', $some_other_widget); for whatever purpose, it is recommended ( not required, though ), to use this parameter, not the widget itself for painting and drawing calls. The example of Paint callback is quite simple: Prima::Widget-> create( ... onPaint => sub { my ( $self, $canvas) = @_; $canvas-> clear; $canvas-> text_out("Clicked $self->{clicked} times", 10, 10); }, onMouseClick => sub { $_[0]-> {clicked}++; $_[0]-> repaint; }, ); The example uses several important features of the event-driven mechanism. First, no begin_paint()/end_paint() brackets are used within the callback. These are called implicitly. Second, when the custom refresh of the widget's graphic content is needed, no code like notify(q(Paint)) is used - repaint() method is used instead. It must be noted, that the actual execution of Paint callbacks might or might not occur inside the repaint() call. This behavior is governed by the ::syncPaint property. repaint() marks the whole widget's area to be refreshed, or invalidates the area. For the finer gradation of the area that should be repainted, invalidate_rect() and validate_rect() pair of functions is used. Thus, $x-> repaint() code is a mere alias to $x-> invalidate_rect( 0, 0, $x-> size); call. It must be realized, that the area, passed to invalidate_rect() only in its ideal ( but a quite often ) execution case will be pertained as a clipping rectangle when a widget executes its Paint notification. The user and system interactions can result in exposition of other parts of a widget ( like, moving windows over a widget ), and the resulting clipping rectangle can be different from the one that was passed to invalidate_rect(). Moreover, the clipping rectangle can become empty as the result of these influences, and the notification will not be called at all. Invalid rectangle is presented differently inside and outside the drawing mode. The first, returned by ::clipRect, employs inclusive-inclusive coordinates, whereas invalidate_rect(), validate_rect() and get_invalid_rect() - inclusive-exclusive coordinates. The ideal case exemplifies the above said: $x-> onPaint( sub { my @c = $_[0]-> clipRect; print "clip rect:@c\n"; }); $x-> invalidate_rect( 10, 10, 20, 20); ... clip rect: 10 10 19 19 As noted above, ::clipRect property is set to the clipping rectangle of the widget area that is needed to be refreshed, and an event handler code can take advantage of this information, increasing the efficiency of the painting procedure. Further assignments of ::clipRect property do not make possible over-painting on the screen area that lies outside the original clipping region. This is also valid for all paint operations, however since the original clipping rectangle is the full area of a canvas, this rule is implicit and unnecessary, because whatever large the clipping rectangle is, drawing and painting cannot be performed outside the physical boundaries of the canvas.

Direct rendering
The direct rendering, contrary to the event-driven, is initiated by the program, not by the system. If a programmer wishes to paint over a widget immediately, then begin_paint() is called, and, if successful, the part of the screen occupied by the widget is accessible to the drawing and painting routines. This method is useful, for example, for graphic demonstration programs, that draw continuously without any input. Another field is the screen drawing, which is performed with Prima::Application class, that does not have Paint notification. Application's graphic canvas represents the whole screen, allowing over-drawing the graphic content of other programs. The event-driven rendering method adds implicit begin_paint()/end_paint() brackets ( plus some system-dependent actions ) and is a convenience version of the direct rendering. Sometimes, however, the changes needed to be made to a widget's graphic context are so insignificant, so the direct rendering method is preferable, because of the cleaner and terser code. As an example might serve a simple progress bar, that draws a simple colored bar. The event-driven code would be ( in short, omitting many details ) as such: $bar = Widget-> create( width => 100, onPaint => sub { my ( $self, $canvas) = @_; $canvas-> color( cl::Blue); $canvas-> bar( 0, 0, $self-> {progress}, $self-> height); $canvas-> color( cl::Back); $canvas-> bar( $self-> {progress}, 0, $self-> size); }, ); ... $bar-> {progress} += 10; $bar-> repaint; # or, more efficiently, ( but clumsier ) # $bar-> invalidate_rect( $bar->{progress}-10, 0, # $bar->{progress}, $bar-> height); And the direct driven: $bar = Widget-> create( width => 100 ); ... $bar-> begin_paint; $bar-> color( cl::Blue); $bar-> bar( $progress, 0, $progress + 10, $bar-> height); $bar-> end_paint; $progress += 10; The pros and contras are obvious: the event-driven rendered widget correctly represents the status after an eventual repaint, for example when the user sweeps a window over the progress bar widget. The direct method cannot be that smart, but if the status bar is an insignificant part of the program, the trade-off of the functionality in favor to the code simplicity might be preferred. Both methods can be effectively disabled using the paint locking mechanism. The lock() and unlock() methods can be called several times, stacking the requests. This feature is useful because many properties implicitly call repaint(), and if several of these properties activate in a row, the unnecessary redrawing of the widget can be avoided. The drawback is that the last unlock() call triggers repaint() unconditionally.

Basic properties
A widget always has its position and size determined, even if it is not visible on the screen. Prima::Widget provides several properties with overlapping functionality, that govern the geometry of a widget. The base properties are ::origin and ::size, and the derived are ::left, ::bottom, ::right, ::top, ::width, ::height and ::rect. ::origin and ::size operate with two integers, ::rect with four, others with one integer value. As the Prima toolkit coordinate space begins in the lower bottom corner, the combination of ::left and ::bottom is same as ::origin, and combination of ::left, ::bottom, ::right and ::top - same as ::rect. When a widget is moved or resized, correspondingly two notifications occur: Move and Size. The parameters to both are old and new position and size. The notifications occur irrespectable to whether the geometry change was issued by the program itself or by the user.

Implicit size regulations
Concerning the size of a widget, two additional two-integer properties exist, ::sizeMin and ::sizeMax, that constrain the extension of a widget in their boundaries. The direct call that assigns values to the size properties that lie outside ::sizeMin and ::sizeMax boundaries, will fail - the widget extension will be adjusted to the boundary values, not to the specified ones. Change to widget's position and size can occur not only by an explicit call to one of the geometry properties. The toolkit contains implicit rules, that can move and resize a widget corresponding to the flags, given to the ::growMode property. The exact meaning of the gm::XXX flags is not given here ( see description to ::growMode in API section ), but in short, it is possible with simple means to maintain widget's size and position regarding its owner, when the latter is resized. By default, and the default behavior corresponds to ::growMode 0, widget does not change neither its size nor position when its owner is resized. It stays always in 'the left bottom corner'. When, for example, a widget is expected to stay in 'the right bottom corner', or 'the left top corner', the gm::GrowLoX and gm::GrowLoY values must be used, correspondingly. When a widget is expected to cover, for example, its owner's lower part and change its width in accord with the owner's, ( a horizontal scroll bar in an editor window is the example), the gm::GrowHiX value must be used. When this implicit size change does occur, the ::sizeMin and ::sizeMax do take their part as well - they still do not allow the widget's size excess their boundaries. However, this algorithm derives a problem, that is illustrated by the following setup. Imagine a widget with size-dependent ::growMode ( with gm::GrowHiX or gm::GrowHiY bits set ) that must maintain certain relation between the owner's size and its own. If the implicit size change would be dependent on the actual widget size, derived as a result from the previous implicit size action, then its size (and probably position) will be incorrect after an attempt is made to change the widget's size to values outside the size boundaries. Example: child widget has width 100, growMode set to gm::GrowHiX and sizeMin set to (95, 95). Its owner has width 200. If the owner widget changes gradually its width from 200 to 190 and then back, the following width table emerges: Owner Child Initial state 200 100 Shrink 195 -5 95 Shrink 190 -5 95 - as it can not be less than 95. Grow 195 +5 100 Grow 200 +5 105 That effect would exist if the differential-size algorithm would be implemented, - the owner changes width by 5, and the child does the same. The situation is fixed by introducing the virtual size term. The ::size property is derived from virtual size, and as ::size cannot exceed the size boundaries, virtual size can. It can even accept the negative values. With this intermediate stage added, the correct picture occurs: Owner Child's Child's virtual width width Initial state 200 100 100 Shrink 195 -5 95 95 Shrink 190 -5 90 95 Grow 195 +5 95 95 Grow 200 +5 100 100 Strictly speaking, the virtual size must be declared a read-only property, but currently it is implemented as a get_virtual_size() function, and it is planned to fix this discrepancy between the document and the implementation in favor of the property syntax.

Geometry managers
The concept of geometry managers is imported from Tk, which in turn is a port of Tcl-Tk. The idea behind it is that a widget size and position is governed by one of the managers, which operate depending on the specific options given to the widget. The selection is operated by ::geometry property, and is one of gt::XXX constants. The native ( and the default ) geometry manager is the described above grow-mode algorithm ( gt::GrowMode ). The currently implemented Tk managers are packer ( gt::Pack ) and placer ( gt::Place). Each has its own set of options and methods, and their manuals are provided separately in the Prima::Widget::pack manpage and the Prima::Widget::place manpage ( the manpages are also imported from Tk ). Another concept that comes along with geometry managers is the 'geometry request size'. It is realized as a two-integer property ::geomSize, which reflects the size selected by some intrinsic widget knowledge, and the idea is that ::geomSize it is merely a request to a geometry manager, whereas the latter changes ::size accordingly. For example, a button might set its 'intrinsic' width in accord with the width of text string displayed in it. If the default width for such a button is not overridden, it is assigned with such a width. By default, under gt::GrowMode geometry manager, setting ::geomSize ( and its two semi-alias properties ::geomWidth and ::geomHeight ) also changes the actual widget size.Moreover, when the size is passed to the Widget initialization code, ::size properties are used to initialize ::geomSize. Such design minimizes the confusion between the two properties, and also minimizes the direct usage of ::geomSize, limiting it for selecting advisory size in widget internal code. The geometry request size is useless under gt::GrowMode geometry manager, but Tk managers use it extensively.

Relative coordinates
Another geometry issue, or rather a programming technique must be mentioned - the relative coordinates. It is the well-known problem, when a dialog window, developed with one font looks garbled on another system with another font. The relative coordinates solve the problem; the solution provides the ::designScale two-integer property, the width and height of the font, that was used when the dialog window was designed. With this property supplied, the position and size supplied when a widget is actually created, are transformed in proportion between the designed and the actual font metrics. The relative coordinates can be used only when passing the geometry properties values, and only before the creation stage, before a widget is created, because the scaling calculations perform in Prima::Widget::profile_check_in() method. In order to employ the relative coordinates scheme, the owner ( or the dialog ) widget must set its ::designScale to the font metrics and ::scaleChildren property to 1. Widgets, created with owner that meets these requirements, participate in the relative coordinates scheme. If a widget must be excluded from the relative geometry applications, either the owner's property ::scaleChildren must be set to 0, or the widget's ::designScale must be set to undef. As the default ::designScale value is undef, no default implicit relative geometry schemes are applied. The ::designScale property is auto-inherited; its value is copied to the children widgets, unless the explicit ::designScale was given during the widget's creation. This is used when such a child widget serves as an owner for some other grand-children widgets; the inheritance scheme allows the grand- ( grand- etc ) children to participate in the relative geometry scheme. Note: it is advised to test such applications with the Prima::Stress module, which assigns a random font as the default, so the testing phase does not involve tweaking of the system settings. In case when two widgets overlap, one of these is drawn in full, whereas the another only partly. Prima::Widget provides management of the Z-axis ordering, but since Z-ordering paradigm can hardly be fit into the properties scheme, the toolkit uses methods instead. A widget can use four query methods: first(), last(), next(), and prev(). These return, correspondingly, the first and the last widgets in Z-order stack, and the direct neighbors of a widget ( $widget-> next-> prev always equals to the $widget itself, given that $widget-> next exists ). The last widget is the topmost one, the one that is drawn fully. The first is the most obscured one, given that all the widgets overlap. Z-order can also be changed at runtime ( but not during widget's creation). There are three methods: bring_to_front(), that sets the widget last in the order, making it topmost, send_to_back(), that does the reverse, and insert_behind(), that sets a widget behind the another widget, passed as an argument. Changes to Z-order trigger ZOrderChanged notification. By default, if a widget is a child to a widget or window, it maintains two features: it is clipped by its owner's boundaries and is moved together as the owner widget moves. It is said also that a child is inferior to its parent. However, a widget without a parent still does have a valid owner. Instead of implementing parent property, the ::clipOwner property was devised. It is 1 by default, and if it is 1, then owner of a widget is its parent, at the same time. However, when it is 0, many things change. The widget is neither clipped nor moved together with its parent. The widget become parentless, or, more strictly speaking, the screen becomes its parent. Moreover, the widget's origin offset is calculated then not from the owner's coordinates but from the screen, and mouse events in the widget do not transgress implicitly to the owner's top-level window eventual decorations. The same results are produced if a widget is inserted in the application object, which does not have screen visualization. A widget that belongs to the application object, can not reset its ::clipOwner value to 1. The ::clipOwner property opens a possibility for the toolkit widgets to live inside other programs' windows. If the ::parentHandle is changed from its default undef value to a valid system window handle, the widget becomes child to this window, which can belong to any application residing on the same display. This option is dangerous, however: normally widgets never get destroyed by no reason. A top-level window is never destroyed before its Close notification grants the destruction. The case with ::parentHandle is special, because a widget, inserted into an alien application, must be prepared to be destroyed at any moment. It is recommended to use prior knowledge about such the application, and, even better, use one or another inter-process communication scheme to interact with it. A widget does not need to undertake anything special to become an 'owner'. Any widget, that was set in ::owner property on any other widget, becomes owner automatically. Its get_widgets() method returns non-empty widget list. get_widgets() serves same purpose as Prima::Component::get_components(), but returns only Prima::Widget descendants. A widget can change its owner at any moment. The ::owner property is both readable and writable, and if a widget is visible during the owner change, it is immediately appeared under different coordinates and different clipping condition after the property change, given that its ::clipOwner is set to 1. A widget is visible by default. Visible means that it is shown on the screen if it is not shadowed by other widgets or windows. The visibility is governed by the ::visible property, and its two convenience aliases, show() and hide(). When a widget is invisible, its geometry is not discarded; the widget pertains its position and size, and is subject to all previously discussed implicit sizing issues. When change to ::visible property is made, the screen is not updated immediately, but in the next event loop invocation, because uncovering of the underlying area of a hidden widget, and repainting of a new-shown widget both depend onto the event-driven rendering functionality. If the graphic content must be updated, update_view() must be called, but there's a problem. It is obvious that if a widget is shown, the only content to be updated is its own. When a widget becomes hidden, it may uncover more than one widget, depending on the geometry, so it is unclear what widgets must be updated. For the practical reasons, it is enough to get one event loop passed, by calling yield() method of the $::application object. The other notifications may pass here as well, however. There are other kinds of visibility. A widget might be visible, but one of its owners might not. Or, a widget and its owners might be visible, but they might be over-shadowed by the other windows. These conditions are returned by showing() and exposed() functions. These return boolean values corresponding to the condition described. So, if a widget is 'exposed', it is 'showing' and 'visible'; exposed() returns always 0 if a widget is either not 'showing' or not 'visible'. If a widget is 'showing', then it is always 'visible'. showing() returns always 0 if a widget is invisible. Visibility changes trigger Hide and Show notifications. One of the key points of any GUI is that only one window at a time can possess a focus. The widget is focused, if the user's keyboard input is directed to it. The toolkit adds another layer in the focusing scheme, as often window managers do, highlighting the decorations of a top-level window over a window with the input focus. Prima::Widget property ::focused governs the focused state of a widget. It is sometimes too powerful to be used. Its more often substitutes, ::selected and ::current properties provide more respect to widget hierarchy. ::selected property sets focus to a widget if it is allowed to be focused, by the usage of the ::selectable property. With this granted, the focus is passed to the widget or to the one of its ( grand-) children. So to say, when 'selecting' a window with a text field by clicking on a window, one does not expect the window to be focused, but the text field. To achieve this goal and reduce unnecessary coding, the ::current property is introduced. With all equal conditions, a widget that is 'current' gets precedence in getting selected over widgets that are not 'current'. De-selecting, in its turn, leaves the system in such a state when no window has input focus. There are two convenience shortcuts select() and deselect() defined, aliased to selected(1) and selected(0), correspondingly. As within the GUI space, there can be only one 'focused' widget, so within the single widget space, there can be only one 'current' widget. A widget can be marked as a current by calling ::current ( or, identically, ::currentWidget on the owner widget ). The reassignments are performed automatically when a widget is focused. The reverse is also true: if a widget is explicitly marked as 'current', and belongs to the widget tree with the focus in one of its widgets, then the focus passed to the 'current' widget, or down to hierarchy if it is not selectable. These relations between current widget pointer and focus allow the toolkit easily implement the focusing hierarchy. The focused widget is always on the top of the chain of its owner widgets, each of whose is a 'current' widget. If, for example, a window that contains a widget that contains a focused button, become un-focused, and then user selects the window again, then the button will become focused automatically. Changes to focus produce Enter and Leave notifications. Below discussed mouse- and keyboard- driven focusing schemes. Note that all of these work via ::selected, and do not focus the widgets with ::selectable property set to 0.

Mouse-aided focusing
Typically, when the user clicks the left mouse button on a widget, the latter becomes focused. One can note that not all widgets become focused after the mouse click - scroll bars are the examples. Another kind of behavior is the described above window with the text field - clicking mouse on a window focuses a text field. Prima::Widget has the ::selectingButtons property, a combination of mb::XXX ( mouse buttons ) flags. If the bits corresponding to the buttons are set, then click of this button will automatically call ::selected(1) ( not ::focused(1) ). Another boolean property, ::firstClick determines the behavior when the mouse button action is up to focus a widget, but the widget's top-level window is not active. The default value of ::firstClick is 1, but if set otherwise, the user must click twice to a widget to get it focused. The property does not influence anything if the top-level window was already active when the click event occured. Due to some vendor-specific GUI designs, it is hardly possibly to force selection of one top-level window when the click was on the another. The window manager or the OS can interfere, although this does not always happen, and produce different results on different platforms. Since the primary goal of the toolkit is portability, such functionality must be considered with care. Moreover, when the user selects a window by clicking not on the toolkit-created widgets, but on the top-level window decorations, it is not possible to discern the case from any other kind of focusing.

Keyboard focusing
The native way to navigate between the toolkit widgets are tab- and arrow- navigation. The tab ( and its reverse, shift-tab ) key combinations circulate the focus between the widgets in same top-level group ( but not inside the same owner widget group ). The arrow keys, if the focused widget is not interested in these keystrokes, move the focus in the specified direction, if it is possible. The methods that provide the navigations are available and called next_tab() and next_positional(), correspondingly ( see API for the details). When next_positional() operates with the geometry of the widgets, next_tab() uses the ::tabStop and ::tabOrder properties. ::tabStop, the boolean property, set to 1 by default, tells if a widget is willing to participate in tab-aided focus circulation. If it doesn't, next_tab() never uses it in its iterations. ::tabOrder value is an integer, unique within the sibling widgets ( sharing same owner ) list, and is used as simple tag when the next tab-focus candidate is picked up. The default ::tabOrder value is -1, which changes automatically after widget creation to a unique value. The toolkit responds to the two basic means of the user input - the keyboard and the mouse. Below described three aspects of the input handling - the event-driven, the polling and the simulated input issues. The event-driven input is the more or less natural way of communicating with the user, so when the user presses the key or moves the mouse, a system event occurs and triggers the notification in one or more widgets. Polling methods provide the immediate state of the input devices; the polling is rarely employed, primarily because of its limited usability, and because the information it provides is passed to the notification callbacks anyway. The simulated input is little more than notify() call with specifically crafted parameters. It interacts with the system, so the emulation can gain the higher level of similarity to the user actions. The simulated input functions allow the notifications to be called right away, or post it, delaying the notification until the next event loop invocation.

Keyboard
Keyboard input generates several notifications, where the most important are KeyDown and KeyUp. Both have almost the same list of parameters ( see API ), that contain the key code, its modifiers ( if any ) that were pressed and an eventual character code. The algorithms that extract the meaning of the key, for example, discretion between character and functional keys etc are not described here. The reader is advised to look at Prima::KeySelector module, which provides convenience functions for keyboard input values transformations, and to the Prima::Edit and Prima::InputLine modules, the classes that use extensively the keyboard input. But in short, the key code is one of the kb::XXX ( like, kb::F10, kb::Esc ) constants, and the modifier value is a combination of the km::XXX ( km::Ctrl, km::Shift) constants. The notable exception is kb::None value, which hints that the character code is of value. Some other kb::XXX-marked keys have the character code as well, and it is up to a programmer how to treat these combinations. It is advised, however, to look at the key code first, and then to the character code. KeyDown event has also the repeat integer parameter, that shows the repetitive count how many times the key was pressed. Usually it is 1, but if a widget was not able to get its portion of events between the key presses, its value can be higher. If a code doesn't check for this parameter, some keyboard input may be lost. If the code will be too much complicated by introducing the repeat-value, one may consider setting the ::briefKeys property to 0. ::briefKeys, the boolean property, is 1 by default. If set to 0, it guarantees that the repeat value will always be 1, but with the price of certain under-optimization. If the core KeyDown processing code sees repeat value greater than 1, it simply calls the notification again. Along with these two notifications, the TranslateAccel event is generated after KeyDown, if the focused widget is not interested in the key event. Its usage covers the needs of the other widgets that are willing to read the user input, even being out of focus. A notable example can be a button with a hot key, that reacts on the key press when the focus is elsewhere within its top-level window. TranslateAccel has same parameters as KeyDown, except the REPEAT parameter. Such out-of-focus input is also used with built-in menu keys translations. If a descendant of Prima::AbstractMenu is in the reach of the widget tree hierarchy, then it is checked whether it contains some hot keys that match the user input. See the Prima::Menu manpage for the details. In particular, Prima::Widget has ::accelTable property, a mere slot for an object that contains a table of hot keys mappings to custom subroutines. The polling function for the keyboard is limited to the modifier keys only. get_shift_state() method returns the press state of the modifier keys, a combination of km::XXX constants. There are two methods, corresponding to the major notifications - key_up() and key_down(), that accept the same parameters as the KeyUp and KeyDown notifications do, plus the POST boolean flag. See the section on API for details. These methods are convenience wrappers for key_event() method, which is never used directly.

Mouse
Mouse notifications are send in response when the user moves the mouse, or presses and releases mouse buttons. The notifications are logically grouped in two sets, the first contains MouseDown, MouseUp, MouseClick, and MouseWheel, and the second - MouseMove, MouseEnter, end MouseLeave. The first set deals with button actions. Pressing, de-pressing, clicking ( and double-clicking ), the turn of mouse wheel correspond to the four notifications. The notifications are sent together with the mouse pointer coordinates, the button that was touched, and the eventual modifier keys that were pressed. In addition, MouseClick provides the boolean flag if the click was single or double, and MouseWheel - the Z-range of the wheel turn. These notifications occur when the mouse event occurs within the geometrical bounds of a widget, with one notable exception, when a widget is in capture mode. If the ::capture is set to 1, then these events are sent to the widget even if the mouse pointer is outside, and not sent to the widgets and windows that reside under the pointer. The second set deals with the pointer movements. When the pointer passes over a widget, it receives first MouseEnter, then series of MouseMove, and finally MouseLeave. MouseMove and MouseEnter notifications provide X,Y-coordinates and modificator keys; MouseLeave passes no parameters. The mouse input polling procedures are get_mouse_state() method, that returns combination of mb::XXX constants, and the ::pointerPos two-integer property that reports the current position of the mouse pointer. There are five methods, corresponding to the mouse events - mouse_up(), mouse_down(), mouse_click(), mouse_wheel() and mouse_move(), that accept the same parameters as their event counterparts do, plus the POST boolean flag. See the section on API for details. These methods are convenience wrappers for mouse_event() method, which is never used directly. Prima::Drawable deals only with such color values, that can be unambiguously decomposed to their red, green and blue components. Prima::Widget extends the range of the values acceptable by its color properties, introducing the color schemes. The color can be set indirectly, without prior knowledge of what is its RGB value. There are several constants defined in cl:: name space, that correspond to the default values of different color properties of a widget. Prima::Widget revises the usage of ::color and ::backColor, the properties inherited from Prima::Drawable. Their values are widget's 'foreground' and 'background' colors, in addition to their function as template values. Moreover, their dynamic change induces the repainting of a widget, and they can be inherited from the owner. The inheritance is governed by properties ::ownerColor and ::ownerBackColor. While these are true, changes to owner ::color or ::backColor copied automatically to a widget. Once the widget's ::color or ::backColor are explicitly set, the owner link breaks automatically by setting ::ownerColor or ::ownerBackColor to 0. In addition to these two color properties, Prima::Widget introduces six others. These are ::disabledColor, ::disabledBackColor, ::hiliteColor, ::hiliteBackColor, ::light3DColor, and ::dark3DColor. The 'disabled' color pair contains the values that are expected to be used as foreground and background when a widget is in the disabled state ( see API, ::enabled property ). The 'hilite' values serve as the colors for representation of selection inside a widget. Selection may be of any kind, and some widgets do not provide any. But for those that do, the 'hilite' color values provide distinct alternative colors. Examples are selections in the text widgets, or in the list boxes. The last pair, ::light3DColor and ::dark3DColor is used for drawing 3D-looking outlines of a widget. The purpose of all these properties is the adequate usage of the color settings, selected by the user using system-specific tools, so the program written with the toolkit would look not such different, and more or less conformant to the user's color preferences. The additional cl:: constants, mentioned above, represent these eight color properties. These named correspondingly, cl::NormalText, cl::Normal, cl::HiliteText, cl::Hilite, cl::DisabledText, cl::Disabled, cl::Light3DColor and cl::Dark3DColor. cl::NormalText is alias to cl::Fore, and cl::Normal - to cl::Back. Another constant set, ci:: can be used with the ::colorIndex property, a multiplexer for all eight color properties. ci:: constants mimic their non-RGB cl:: counterparts, so the call hiliteBackColor(cl::Red) is equal to colorIndex(ci::Hilite, cl::Red). Mapping from these constants to the RGB color representation is used with map_color() method. These cl:: constants alone are sufficient for acquiring the default values, but the toolkit provides wider functionality than this. The cl:: constants can be combined with the wc:: constants, that represent standard widget class. The widget class is implicitly used when single cl:: constant is used; its value is read from the ::widgetClass property, unless one of wc:: constants is combined with the non-RGB cl:: value. wc:: constants are described in the section on API; their usage can make call of, for example, backColor( cl::Back) on a button and on an input line result in different colors, because the cl::Back is translated in the first case into cl::Back|wc::Button, and in another - cl::Back|wc::InputLine. Dynamic change of the color properties result in the ColorChanged notification. Prima::Widget does not change the handling of fonts - the font selection inside and outside begin_paint()/end_paint() is not different at all. A matter of difference is how does Prima::Widget select the default font. First, if the ::ownerFont property is set to 1, then font of the owner is copied to the widget, and is maintained all the time while the property is true. If it is not, the default font values read from the system. The default font metrics for a widget returned by get_default_font() method, that often deals with system-dependent and user-selected preferences ( see the section on Additional resources ). Because a widget can host an eventual Prima::Popup object, it contains get_default_popup_font() method, that returns the default font for the popup objects. The dynamic popup font settings governed, naturally, by the ::popupFont property. Prima::Window extends the functionality to get_default_menu_font() and the ::menuFont property. Dynamic change of the font property results in the FontChanged notification. The resources, operated via Prima::Widget class but not that strictly bound to the widget concept, are gathered in this section. The section includes overview of pointer, cursor, hint, menu objects and user-specified resources.

Pointer
The mouse pointer is the shared resource, that can change its visual representation when it hovers over different kinds of widgets. It is usually a good practice for a text field, for example, set the pointer icon to a jagged vertical line, or indicate a moving window with a cross-arrowed pointer. A widget can select either one of the predefined system pointers, mapped by the cr::XXX constant set, or supply its own pointer icon of an arbitrary size and color depth. NB: Not all systems allow the colored pointer icons. System value under sv::ColorPointer index containing a boolean value, whether the colored icons are allowed or not. In general, the ::pointer property is enough for these actions. It discerns whether it has an icon or a constant passed, and sets the appropriate properties. These properties are also accessible separately, although their usage is not encouraged, primarily because of the tangled relationship between them. These properties are: ::pointerType, ::pointerIcon, and ::pointerHotSpot. See their details in the the section on API sections. Another property, which is present only in Prima::Application name space is called ::pointerVisible, and governs the visibility of the pointer - but for all widget instances at once.

Cursor
The cursor is a blinking rectangular area, indicating the availability of the input focus in a widget. There can be only one active cursor per a GUI space, or none at all. Prima::Widget provides several cursor properties: ::cursorVisible, ::cursorPos, and ::cursorSize. There are also two methods, show_cursor() and hide_cursor(), which are not the convenience shortcuts but the functions accounting the cursor hide count. If hide_cursor() was called three times, then show_cursor() must be called three times as well for the cursor to become visible.

Hint
::hint is a text string, that usually describes the widget's purpose to the user in a brief manner. If the mouse pointer is hovered over the widget longer than some timeout ( see Prima::Application::hintPause ), then a label appears with the hint text, until the pointer is drawn away. The hint behavior is governed by Prima::Application, but a widget can do two additional things about hint: it can enable and disable it by calling ::showHint property, and it can inherit the owner's ::hint and ::showHint properties using ::ownerHint and ::ownerShowHint properties. If, for example, ::ownerHint is set to 1, then ::hint value is automatically copied from the widget's owner, when it changes. If, however, the widget's ::hint or ::showHint are explicitly set, the owner link breaks automatically by setting ::ownerHint or ::ownerShowHint to 0. The widget can also operate the ::hintVisible property, that shows or hides the hint label immediately, if the mouse pointer is inside the widget's boundaries.

Menu objects
The default functionality of Prima::Widget coexists with two kinds of the Prima::AbstractMenu descendants - Prima::AccelTable and Prima::Popup ( Prima::Window is also equipped with Prima::Menu reference). The ::items property of these objects are accessible through ::accelItems and ::popupItems, whereas the objects themselves - through ::accelTable and ::popup, correspondingly. As mentioned in the section on User input, these objects hook the user keyboard input and call the programmer-defined callback subroutine if the key stroke equals to one of their table values. As for ::accelTable, its function ends here. ::popup provides access to a context pop-up menu, which can be invoked by either right-clicking or pressing a system-dependent key combination. As a little customization, the ::popupColorIndex and ::popupFont properties are introduced. ( ::popupColorIndex is multiplexed to ::popupColor, ::popupHiliteColor, ::popupHiliteBackColor, etc etc properties exactly like the ::colorIndex property ). The font and color of a menu object might not always be writable. The underlying system capabilities in this area range from total inability for a program to manage the menu fonts and colors in Win32, to a sport in interactive changing menu fonts and colors in OS/2. The Prima::Window class provides equivalent methods for the menu bar, introducing ::menu, ::menuItems, ::menuColorIndex ( with multiplexing ) and ::menuFont properties.

User-specified resources
It is considered a good idea to incorporate the user preferences into the toolkit look-and-feel. Prima::Widget relies to the system-specific code that tries to map these preferences as close as possible to the toolkit paradigm. Unix version employs XRDB ( X resource database ), which is the natural way for the user to tell the preferences with fine granularity. Win32 and OS/2 read the setting that the user has to set interactively, using system tools. Nevertheless, the toolkit can not emulate all user settings that are available on the supported platforms; it rather takes a 'least common denominator', which is colors and fonts. fetch_resource() method is capable of returning any of such settings, provided it's format is font, color or a string. The method is rarely called directly. The appealing idea of making every widget property adjustable via the user-specified resources is not implemented in full. It can be accomplished up to a certain degree using fetch_resource() existing functionality, but it is believed that calling up the method for the every property for the every widget created is prohibitively expensive.

Properties
Manages items of a Prima::AccelTable object associated with a widget. The ITEM_LIST format is same as Prima::AbstractMenu::items and is described in the Prima::Menu manpage. See also: accelTable Manages a Prima::AccelTable object associated with a widget. The sole purpose of the accelTable object is to provide convenience mapping of key combinations to anonymous subroutines. Instead of writing an interface specifically for Prima::Widget, the existing interface of Prima::AbstractMenu was taken. The accelTable object can be destroyed safely; its cancellation can be done either via accelTable(undef) or destroy() call. Default value: undef See also: accelItems If TRUE, all immediate children widgets maintain the same enabled state as the widget. This property is useful for the group-like widgets ( ComboBox, SpinEdit etc ), that employ their children for visual representation. Default value: 0 In widget paint state, reflects background color in the graphic context. In widget normal state, manages the basic background color. If changed, initiates ColorChanged notification and repaints the widget. See also: color, colorIndex, ColorChanged Maintains the lower boundary of a widget. If changed, does not affect the widget height; but does so, if called in set() together with ::top. See also: left, right, top, origin, rect, growMode, Move If 1, contracts the repetitive key press events into one notification, increasing REPEAT parameter of KeyDown callbacks. If 0, REPEAT parameter is always 1. Default value: 1 See also: KeyDown If 1, a widget Paint callback draws not on the screen, but on the off-screen memory instead. The memory content is copied to the screen then. Used when complex drawing methods are used, or if output smoothness is desired. This behavior can not be always granted, however. If there is not enough memory, then widget draws in the usual manner. Default value: 0 See also: Paint Manipulates capturing of the mouse events. If 1, the mouse events are not passed to the widget the mouse pointer is over, but are redirected to the caller widget. The call for capture might not be always granted due the race conditions between programs. If CLIP_OBJECT widget is defined in set-mode call, the pointer movements are confined to CLIP_OBJECT inferior. See also: MouseDown, MouseUp, MouseMove, MouseWheel, MouseClick. A write-only property. Once set, widget is centered by X and Y axis relative to its owner. See also: x_centered, y_centered, growMode, origin, Move. If 1, a widget is clipped by its owner boundaries. It is the default and expected behavior. If clipOwner is 0, a widget behaves differently: it does not clipped by the owner, it is not moved together with the parent, the origin offset is calculated not from the owner's coordinates but from the screen, and mouse events in a widget do not transgress to the top-level window decorations. In short, it itself becomes a top-level window, that, contrary to the one created from Prima::Window class, does not have any interference with system-dependent window stacking and positioning ( and any other ) policy, and is not ornamented by the window manager decorations. Default value: 1 See the section on Parent-children relationship See also: Prima::Object owner section, parentHandle In widget paint state, reflects foreground color in the graphic context. In widget normal state, manages the basic foreground color. If changed, initiates ColorChanged notification and repaints the widget. See also: backColor, colorIndex, ColorChanged Manages the basic color properties indirectly, by accessing via ci::XXX constant. Is a complete alias for ::color, ::backColor, ::hiliteColor, ::hiliteBackColor, ::disabledColor, ::disabledBackColor, ::light3DColor, and ::dark3DColor properties. The ci::XXX constants are: ci::NormalText or ci::Fore ci::Normal or ci::Back ci::HiliteText ci::Hilite ci::DisabledText ci::Disabled ci::Light3DColor ci::Dark3DColor The non-RGB cl:: constants, specific to the Prima::Widget color usage are identical to their ci:: counterparts: cl::NormalText or cl::Fore cl::Normal or cl::Back cl::HiliteText cl::Hilite cl::DisabledText cl::Disabled cl::Light3DColor cl::Dark3DColor See also: color, backColor, ColorChanged If 1, a widget (or one of its children) is marked as the one to be focused ( or selected) when the owner widget receives select() call. Within children widgets, only one or none at all can be marked as a current. See also: currentWidget, selectable, selected, selectedWidget, focused Points to a children widget, that is to be focused ( or selected) when the owner widget receives select() call. See also: current, selectable, selected, selectedWidget, focused Specifies the lower left corner of the cursor See also: cursorSize, cursorVisible Specifies width and height of the cursor See also: cursorPos, cursorVisible Specifies cursor visibility flag. Default value is 0. See also: cursorSize, cursorPos The color used to draw dark shades. See also: light3DColor, colorIndex, ColorChanged The width and height of a font, that was used when a widget ( usually a dialog or a grouping widget ) was designed. See also: scaleChildren, width, height, size, font The color used to substitute ::backColor when a widget is in its disabled state. See also: disabledColor, colorIndex, ColorChanged The color used to substitute ::color when a widget is in its disabled state. See also: disabledBackColor, colorIndex, ColorChanged Specifies if a widget can accept focus, keyboard and mouse events. Default value is 1, however, being 'enabled' does not automatically allow the widget become focused. Only the reverse is true - if enabled is 0, focusing can never happen. See also: responsive, visible, Enable, Disable Manages font context. Same syntax as in Prima::Drawable. If changed, initiates FontChanged notification and repaints the widget. See also: designScale, FontChanged, ColorChanged Selects one of the available geometry managers. The corresponding integer constants are: gt::GrowMode, gt::Default - the default grow-mode algorithm gt::Pack - Tk packer gt::Place - Tk placer See growMode, the Prima::Widget::pack manpage, the Prima::Widget::place manpage. Specifies widget behavior, when its owner is resized or moved. MODE can be 0 ( default ) or a combination of the following constants: gm::GrowLoX widget's left side is kept in constant distance from owner's right side gm::GrowLoY widget's bottom side is kept in constant distance from owner's top side gm::GrowHiX widget's right side is kept in constant distance from owner's right side gm::GrowHiY widget's top side is kept in constant distance from owner's top side gm::XCenter widget is kept in center on its owner's horizontal axis gm::YCenter widget is kept in center on its owner's vertical axis gm::DontCare widgets origin is maintained constant relative to the screen gm::GrowAll gm::GrowLoX|gm::GrowLoY|gm::GrowHiX|gm::GrowHiY gm::Center gm::XCenter|gm::YCenter gm::Client gm::GrowHiX|gm::GrowHiY gm::Right gm::GrowLoX|gm::GrowHiY gm::Left gm::GrowHiY gm::Floor gm::GrowHiX See also: Move, origin If 0, a widget bypasses first mouse click on it, if the top-level window it belongs to was not activated, so selecting such a widget it takes two mouse clicks. Default value is 1 See also: MouseDown, selectable, selected, focused, selectingButtons Specifies whether a widget possesses the input focus or not. Disregards ::selectable property on set-call. See also: selectable, selected, selectedWidget, KeyDown Three properties that select geometry request size. Writing and reading to ::geomWidth and ::geomHeight is equivalent to ::geomSize. The properies are run-time only, and behave differently under different circumstances: As the properties are run-time only, they can not be set in the profile, and their initial value is fetched from ::size property. Thus, setting the explicit size is aditionally sets the advised size in case the widget is to be used with the Tk geometry managers. Setting the properties under the gt::GrowMode geometry manager also sets the corresponding ::width, ::height, or ::size. When the properties are read, though, the real size properties are not read; the values are kept separately. Setting the properties under Tk geometry managers cause widgets size and position changed according to the geometry manager policy. Maintains the height of a widget. See also: width, growMode, Move, Size, get_virtual_size, sizeMax, sizeMin A string that binds a widget, a logical part it plays with the application and an interactive help topic. STRING format is defined as POD link ( see the perlpod manpage ) - "manpage/section", where 'manpage' is the file with POD content and 'section' is the topic inside the manpage. See also: help The color used to draw alternate background areas with high contrast. See also: hiliteColor, colorIndex, ColorChanged The color used to draw alternate foreground areas with high contrast. See also: hiliteBackColor, colorIndex, ColorChanged A text, shown under mouse pointer if it is hovered over a widget longer than Prima::Application::hintPause timeout. The text shows only if the ::showHint is 1. See also: hintVisible, showHint, ownerHint, ownerShowHint If called in get-form, returns whether the hint label is shown or not. If in set-form, immediately turns on or off the hint label, disregarding the timeouts. It does regard the mouse pointer location, however, and does not turn on the hint label if the pointer is away. See also: hint, showHint, ownerHint, ownerShowHint Maintains the left boundary of a widget. If changed, does not affect the widget width; but does so, if called in set() together with ::right. See also: bottom, right, top, origin, rect, growMode, Move The color used to draw light shades. See also: dark3DColor, colorIndex, ColorChanged If 1, the background color is synchronized with the owner's. Automatically set to 0 if ::backColor property is explicitly set. See also: ownerColor, backColor, colorIndex If 1, the foreground color is synchronized with the owner's. Automatically set to 0 if ::color property is explicitly set. See also: ownerBackColor, color, colorIndex If 1, the font is synchronized with the owner's. Automatically set to 0 if ::font property is explicitly set. See also: font, FontChanged If 1, the hint is synchronized with the owner's. Automatically set to 0 if ::hint property is explicitly set. See also: hint, showHint, hintVisible, ownerShowHint If 1, the show hint flag is synchronized with the owner's. Automatically set to 0 if ::showHint property is explicitly set. See also: hint, showHint, hintVisible, ownerHint If 1, the palette array is synchronized with the owner's. Automatically set to 0 if ::palette property is explicitly set. See also: palette Maintains the left and bottom boundaries of a widget relative to its owner ( or to the screen if ::clipOwner is set to 0 ). See also: bottom, right, top, left, rect, growMode, Move See the Prima::Widget::pack manpage Specifies array of colors, that are desired to be present into the system palette, as close to the PALETTE as possible. This property works only if the graphic device allows palette operations. See the section on palette in the Prima::Drawable manpage. See also: ownerPalette If SYSTEM_WINDOW is a valid system-dependent window handle, then a widget becomes the child of the window specified, given the widget's ::clipOwner is 0. The parent window can belong to another application. Default value is undef. See also: clipOwner See the Prima::Widget::place manpage Specifies the pointer icon; discerns between cr::XXX constants and an icon. If an icon contains a hash variable __pointerHotSpot with an array of two integers, these integers will be treated as the pointer hot spot. In get-mode call, this variable is automatically assigned to an icon, if the result is an icon object. See also: pointerHotSpot, pointerIcon, pointerType Specifies the hot spot coordinates of a pointer icon, associated with a widget. See also: pointer, pointerIcon, pointerType Specifies the pointer icon, associated with a widget. See also: pointerHotSpot, pointer, pointerType Specifies the mouse pointer coordinates relative to widget's coordinates. See also: get_mouse_state, screen_to_client, client_to_screen Specifies the type of the pointer, associated with the widget. TYPE can accept one constant of cr::XXX set: cr::Default same pointer type as owner's cr::Arrow arrow pointer cr::Text text entry cursor-like pointer cr::Wait hourglass cr::Size general size action pointer cr::Move general move action pointer cr::SizeWest, cr::SizeW right-move action pointer cr::SizeEast, cr::SizeE left-move action pointer cr::SizeWE general horizontal-move action pointer cr::SizeNorth, cr::SizeN up-move action pointer cr::SizeSouth, cr::SizeS down-move action pointer cr::SizeNS general vertical-move action pointer cr::SizeNW up-right move action pointer cr::SizeSE down-left move action pointer cr::SizeNE up-left move action pointer cr::SizeSW down-right move action pointer cr::Invalid invalid action pointer cr::User user-defined icon All constants except cr::User and cr::Default present a system-defined pointers, their icons and hot spot offsets. cr::User is a sign that an icon object was specified explicitly via ::pointerIcon property. cr::Default is a way to tell that a widget inherits its owner pointer type, no matter is it a system-defined pointer or a custom icon. See also: pointerHotSpot, pointerIcon, pointer Manages a Prima::Popup object associated with a widget. The purpose of the popup object is to show a context menu when the user right-clicks or selects the corresponding keyboard combination. Prima::Widget can host many children objects, Prima::Popup as well. But only the one that is set in ::popup property will be activated automatically. The popup object can be destroyed safely; its cancellation can be done either via popup(undef) or destroy() call. See also: Prima::Menu, Popup, Menu, popupItems, popupColorIndex, popupFont Maintains eight color properties of a pop-up context menu, associated with a widget. INDEX must be one of ci::XXX constants ( see ::colorIndex property ). See also: popupItems, popupFont, popup Basic foreground in a popup context menu color. See also: popupItems, popupColorIndex, popupFont, popup Basic background in a popup context menu color. See also: popupItems, popupColorIndex, popupFont, popup Color for drawing dark shadings in a popup context menu. See also: popupItems, popupColorIndex, popupFont, popup Foreground color for disabled items in a popup context menu. See also: popupItems, popupColorIndex, popupFont, popup Background color for disabled items in a popup context menu. See also: popupItems, popupColorIndex, popupFont, popup Maintains the font of a pop-up context menu, associated with a widget. See also: popupItems, popupColorIndex, popup Foreground color for selected items in a popup context menu. See also: popupItems, popupColorIndex, popupFont, popup Background color for selected items in a popup context menu. See also: popupItems, popupColorIndex, popupFont, popup Manages items of a Prima::Popup object associated with a widget. The ITEM_LIST format is same as Prima::AbstractMenu::items and is described in the Prima::Menu manpage. See also: popup, popupColorIndex, popupFont Color for drawing light shadings in a popup context menu. See also: popupItems, popupColorIndex, popupFont, popup Maintains the rectangular boundaries of a widget relative to its owner ( or to the screen if ::clipOwner is set to 0 ). See also: bottom, right, top, left, origin, width, height, size growMode, Move, Size, get_virtual_size, sizeMax, sizeMin Maintains the right boundary of a widget. If changed, does not affect the widget width; but does so, if called in set() together with ::left. See also: left, bottom, top, origin, rect, growMode, Move If a widget has ::scaleChildren set to 1, then the newly-created children widgets inserted in it will be scaled corresponding to the owner's ::designScale, given that widget's ::designScale is not undef and the owner's is not [0,0]. Default is 1. See also: designScale If 1, a widget can be granted focus implicitly, or by means of the user actions. select() regards this property, and does not focus a widget that has ::selectable set to 0. Default value is 0 See also: current, currentWidget, selected, selectedWidget, focused If called in get-mode, returns whether a widget or one of its (grand-) children is focused. If in set-mode, either simply turns the system with no-focus state ( if 0 ), or sends input focus to itself or one of the widgets tracked down by ::currentWidget chain. See also: current, currentWidget, selectable, selectedWidget, focused Points to a child widget, that has property ::selected set to 1. See also: current, currentWidget, selectable, selected, focused FLAGS is a combination of mb::XXX ( mouse button ) flags. If a widget receives a click with a mouse button, that has the corresponding bit set in ::selectingButtons, then select() is called. See also: MouseDown, firstClick, selectable, selected, focused Maintains the non-rectangular shape of a widget. IMAGE is monochrome Prima::Image, with 0 bits treated as transparent pixels, and 1 bits as opaque pixels. Successive only if sv::ShapeExtension value is true. If 1, the toolkit is allowed to show the hint label over a widget. If 0, the display of the hint is forbidden. The ::hint property must contain non-empty string as well, if the hint label must be shown. Default value is 1. See also: hint, ownerShowHint, hintVisible, ownerHint Maintains the width and height of a widget. See also: width, height growMode, Move, Size, get_virtual_size, sizeMax, sizeMin Specifies the maximal size for a widget that it is allowed to accept. See also: width, height, size growMode, Move, Size, get_virtual_size, sizeMin Specifies the minimal size for a widget that it is allowed to accept. See also: width, height, size growMode, Move, Size, get_virtual_size, sizeMax If 0, the Paint request notifications are stacked until the event loop is called. If 1, every time the widget surface gets invalidated, the Paint notification is called. Default value is 0. See also: invalidate_rect, repaint, validate_rect, Paint Maintains the order in which tab- and shift-tab- key navigation algorithms select the sibling widgets. INTEGER is unique among the sibling widgets. In set mode, if INTEGER value is already taken, the occupier is assigned another unique value, but without destruction of a queue - widgets with ::tabOrder greater than of the widget, receive their new values too. Special value -1 is accepted as 'the end of list' indicator; the negative value is never returned. See also: tabStop, next_tab, selectable, selected, focused Specifies whether a widget is interested in tab- and shift-tab- key navigation or not. Default value is 1. See also: tabOrder, next_tab, selectable, selected, focused A text string for generic purpose. Many Prima::Widget descendants use this property heavily - buttons, labels, input lines etc, but Prima::Widget itself does not. Maintains the upper boundary of a widget. If changed, does not affect the widget height; but does so, if called in set() together with ::bottom. See also: left, right, bottom, origin, rect, growMode, Move Specifies whether the background of a widget before it starts painting is of any importance. If 1, a widget can gain certain transparency look if it does not clear the background during Paint event. Default value is 0 See also: Paint, buffered. Specifies whether a widget is visible or not. See the section on Visibility. See also: Show, Hide, showing, exposed Maintains the integer value, designating the color class that is defined by the system and is associated with Prima::Widget eight basic color properties. CLASS can be one of wc::XXX constants: wc::Undef wc::Button wc::CheckBox wc::Combo wc::Dialog wc::Edit wc::InputLine wc::Label wc::ListBox wc::Menu wc::Popup wc::Radio wc::ScrollBar wc::Slider wc::Widget or wc::Custom wc::Window wc::Application These constants are not associated with the toolkit classes; any class can use any of these constants in ::widgetClass. See also: map_color, colorIndex Maintains the width of a widget. See also: height growMode, Move, Size, get_virtual_size, sizeMax, sizeMin A write-only property. Once set, widget is centered by the horizontal axis relative to its owner. See also: centered, y_centered, growMode, origin, Move. A write-only property. Once set, widget is centered by the vertical axis relative to its owner. See also: x_centered, centered, growMode, origin, Move.

Methods
Sends a widget on top of all other siblings widgets See also: insert_behind, send_to_back, ZOrderChanged ,first, next, prev, last Sends Close message, and returns its boolean exit state. See also: Close, close Maps array of X and Y integer offsets from widget to screen coordinates. Returns the mapped OFFSETS. See also: screen_to_client, clipOwner Calls can_close(), and if successful, destroys a widget. Returns the can_close() result. See also: can_close, Close Alias for focused(0) call See also: focus, focused, Enter, Leave Alias for selected(0) call See also: select, selected, Enter, Leave Returns a boolean value, indicating whether a widget is at least partly visible on the screen. Never returns 1 if a widget has ::visible set to 0. See also: visible, showing, Show, Hide Returns a system-defined scalar of resource, defined by the widget hierarchy, its class, name and owner. RESOURCE_TYPE can be one of type qualificators: fr::Color - color resource fr::Font - font resource fs::String - text string resource Such a number of the parameters is used because the method can be called before a widget is created. CLASS_NAME is widget class string, NAME is widget name. CLASS_RESOURCE is class of resource, and RESOURCE is the resource name. For example, resources 'color' and 'disabledColor' belong to the resource class 'Foreground'. Returns the first ( from bottom ) sibling widget in Z-order. See also: last, next, prev Alias for focused(1) call See also: defocus, focused, Enter, Leave Sets widget ::visible to 0. See also: hide, visible, Show, Hide, showing, exposed Hides the cursor. As many times hide_cursor() was called, as many time its counterpart show_cursor() must be called to reach the cursor's initial state. See also: show_cursor, cursorVisible Starts an interactive help viewer opened on ::helpContext string value. The string value is combined from the widget's owner ::helpContext strings if the latter is empty or begins with a slash. A special meaning is assigned to an empty string " " - the help() call fails when such value is found to be the section component. This feature can be useful when a window or a dialog presents a standalone functionality in a separate module, and the documentation is related more to the module than to an embedding program. In such case, the grouping widget holds ::helpContext as a pod manpage name with a trailing slash, and its children widgets are assigned ::helpContext to the topics without the manpage but the leading slash instead. If the grouping widget has an empty string " " as ::helpContext then the help is forced to be unavailable for all the children widgets. See also: helpContext Creates one or more widgets with owner property set to the caller widget, and returns the list of references to the newly created widgets. Has two calling formats: $parent-> insert( 'Child::Class', name => 'child', .... ); $parent-> insert( [ 'Child::Class1', name => 'child1', .... ], [ 'Child::Class2', name => 'child2', .... ], ); Sends a widget behind the OBJECT on Z-axis, given that the OBJECT is a sibling to the widget. See also: bring_to_front, send_to_back, ZOrderChanged ,first, next, prev, last Marks the rectangular area of a widget as 'invalid', so re-painting of the area happens. See the section on Graphic content. See also: validate_rect, get_invalid_rect, repaint, Paint, syncPaint, update_view The method sends or posts ( POST flag ) simulated KeyDown event to the system. CODE, KEY, MOD and REPEAT are the parameters to be passed to the notification callbacks. See also: key_up, key_event, KeyDown The method sends or posts ( POST flag ) simulated keyboard event to the system. CODE, KEY, MOD and REPEAT are the parameters to be passed to an eventual KeyDown or KeyUp notifications. COMMAND is allowed to be either cm::KeyDown or cm::KeyUp. See also: key_down, key_up, KeyDown, KeyUp The method sends or posts ( POST flag ) simulated KeyUp event to the system. CODE, KEY and MOD are the parameters to be passed to the notification callbacks. See also: key_down, key_event, KeyUp Returns the last ( the topmost ) sibling widget in Z-order. See also: first, next, prev Turns off the ability of a widget to re-paint itself. As many times lock() was called, as may times its counterpart, unlock() must be called to enable re-painting again. Returns a boolean success flag. See also: unlock, repaint, Paint, get_locked Transforms cl::XXX and ci::XXX combinations into RGB color representation and returns the result. If COLOR is already in RGB format, no changes are made. See also: colorIndex The method sends or posts ( POST flag ) simulated MouseClick event to the system. BUTTON, MOD, X, Y, and DBL_CLICK are the parameters to be passed to the notification callbacks. See also: MouseDown, MouseUp, MouseWheel, MouseMove, MouseEnter, MouseLeave The method sends or posts ( POST flag ) simulated MouseDown event to the system. BUTTON, MOD, X, and Y are the parameters to be passed to the notification callbacks. See also: MouseUp, MouseWheel, MouseClick, MouseMove, MouseEnter, MouseLeave The method sends or posts ( POST flag ) simulated MouseEnter event to the system. MOD, X, and Y are the parameters to be passed to the notification callbacks. See also: MouseDown, MouseUp, MouseWheel, MouseClick, MouseMove, MouseLeave The method sends or posts ( POST flag ) simulated mouse event to the system. BUTTON, MOD, X, Y and DBL_CLICK are the parameters to be passed to an eventual mouse notifications. COMMAND is allowed to be one of cm::MouseDown, cm::MouseUp, cm::MouseWheel, cm::MouseClick, cm::MouseMove, cm::MouseEnter, cm::MouseLeave constants. See also: mouse_down, mouse_up, mouse_wheel, mouse_click, mouse_move, mouse_enter, mouse_leave, MouseDown, MouseUp, MouseWheel, MouseClick, MouseMove, MouseEnter, MouseLeave The method sends or posts ( POST flag ) simulated MouseLeave event to the system. See also: MouseDown, MouseUp, MouseWheel, MouseClick, MouseMove, MouseEnter, MouseLeave The method sends or posts ( POST flag ) simulated MouseMove event to the system. MOD, X, and Y are the parameters to be passed to the notification callbacks. See also: MouseDown, MouseUp, MouseWheel, MouseClick, MouseEnter, MouseLeave The method sends or posts ( POST flag ) simulated MouseUp event to the system. BUTTON, MOD, X, and Y are the parameters to be passed to the notification callbacks. See also: MouseDown, MouseWheel, MouseClick, MouseMove, MouseEnter, MouseLeave The method sends or posts ( POST flag ) simulated MouseUp event to the system. MOD, X, Y and Z are the parameters to be passed to the notification callbacks. See also: MouseDown, MouseUp, MouseClick, MouseMove, MouseEnter, MouseLeave Returns the neighbor sibling widget, next ( above ) in Z-order. If none found, undef is returned. See also: first, last, prev Returns the next widget in the sorted by ::tabOrder list of sibling widgets. FORWARD is a boolean lookup direction flag. If none found, the first ( or the last, depending on FORWARD flag ) widget is returned. Only widgets with ::tabStop set to 1 participate. Also used by the internal keyboard navigation code. See also: next_positional, tabOrder, tabStop, selectable Returns a sibling, (grand-)child of a sibling or (grand-)child widget, that matched best the direction specified by DELTA_X and DELTA_Y. At one time, only one of these parameters can be zero; another parameter must be either 1 or -1. Also used by the internal keyboard navigation code. See also: next_tab, origin See the Prima::Widget::pack manpage See the Prima::Widget::place manpage Returns the neighbor sibling widget, previous ( below ) in Z-order. If none found, undef is returned. See also: first, last, next Marks the whole widget area as 'invalid', so re-painting of the area happens. See the section on Graphic content. See also: validate_rect, get_invalid_rect, invalidate_rect, Paint, update_view, syncPaint Returns a boolean flag, indicating whether a widget and its owners have all ::enabled 1 or not. Useful for fast check if a widget should respond to the user actions. See also: enabled Maps array of X and Y integer offsets from screen to widget coordinates. Returns the mapped OFFSETS. See also: client_to_screen Scrolls the graphic context area by DELTA_X and DELTA_Y pixels. OPTIONS is hash, that contains optional parameters to the scrolling procedure: The clipping area is confined by X1, Y1, X2, Y2 rectangular area. If not specified, the clipping area covers the whole widget. Only the bits, covered by clipRect are affected. Bits scrolled from the outside of the rectangle to the inside are painted; bits scrolled from the inside of the rectangle to the outside are not painted. The scrolling area is confined by X1, Y1, X2, Y2 rectangular area. If not specified, the scrolling area covers the whole widget. If 1, the scrolling performs with the eventual children widgets change their positions to DELTA_X and DELTA_Y as well. Cannot be used inside paint state. See also: Paint, get_invalid_rect Alias for selected(1) call See also: deselect, selected, Enter, Leave Sends a widget at bottom of all other siblings widgets See also: insert_behind, bring_to_front, ZOrderChanged ,first, next, prev, last Sets widget ::visible to 1. See also: hide, visible, Show, Hide, showing, exposed Shows the cursor. As many times hide_cursor() was called, as many time its counterpart show_cursor() must be called to reach the cursor's initial state. See also: hide_cursor, cursorVisible Returns a boolean value, indicating whether the widget and its owners have all ::visible 1 or not. Turns on the ability of a widget to re-paint itself. As many times lock() was called, as may times its counterpart, unlock() must be called to enable re-painting again. When last unlock() is called, an implicit repaint() call is made. Returns a boolean success flag. See also: lock, repaint, Paint, get_locked If any parts of a widget were marked as 'invalid' by either invalidate_rect() or repaint() calls or the exposure caused by window movements ( or any other), then Paint notification is immediately called. If no parts are invalid, no action is performed. If a widget has ::syncPaint set to 1, update_view() is always a no-operation call. See also: invalidate_rect, get_invalid_rect, repaint, Paint, syncPaint, update_view Reverses the effect of invalidate_rect(), restoring the original, 'valid' state of widget area covered by the rectangular area passed. If a widget with previously invalid areas was wholly validated by this method, no Paint notifications occur. See also: invalidate_rect, get_invalid_rect, repaint, Paint, syncPaint, update_view

Get-methods
Returns the default font for a Prima::Widget class. See also: font Returns the default font for a Prima::Popup class. See also: font Returns the result of successive calls invalidate_rect(), validate_rect() and repaint(), as a rectangular area ( four integers ) that cover all invalid regions in a widget. If none found, (0,0,0,0) is returned. See also: validate_rect, invalidate_rect, repaint, Paint, syncPaint, update_view Returns a system handle for a widget See also: get_parent_handle Returns 1 if a widget is in lock() - initiated repaint-blocked state. See also: lock, unlock Returns a combination of mb::XXX constants, reflecting the currently pressed mouse buttons. See also: pointerPos, get_shift_state Returns the owner widget that clips the widget boundaries, or application object if a widget is top-level. See also: clipOwner Returns a system handle for a parent of a widget, a window that belongs to another program. Returns 0 if the widget's owner and parent are in the same application and process space. See also: get_handle, clipOwner Returns two integers, width and height of a icon, that the system accepts as valid for a pointer. If the icon is supplied that is more or less than these values, it is truncated or padded with transparency bits, but is not stretched. Can be called with class syntax. Returns a combination of km::XXX constants, reflecting the currently pressed keyboard modificator buttons. See also: get_shift_state Returns virtual width and height of a widget. See the section on Geometry, Implicit size regulations. See also: width, height, size growMode, Move, Size, sizeMax, sizeMin Returns list of children widgets.

Events
Generic notification, used for Prima::Widget descendants; Prima::Widget itself neither calls not uses the event. Designed to be called when an arbitrary major state of a widget is changed. Generic notification, used for Prima::Widget descendants; Prima::Widget itself neither calls not uses the event. Designed to be called when an arbitrary major action for a widget is called. Triggered by can_close() and close() functions. If the event flag is cleared during execution, these functions fail. See also: close, can_close Called when one of widget's color properties is changed, either by direct property change or by the system. INDEX is one of ci::XXX constants. See also: colorIndex Triggered by a successive enabled(0) call See also: Enable, enabled, responsive Design in progress. Supposed to be triggered when a drag-and-drop session started by the widget. X and Y are mouse pointer coordinates on the session start. See also: DragOver, EndDrag Design in progress. Supposed to be called when a mouse pointer is passed over a widget during a drag-and-drop session. X and Y are mouse pointer coordinates, identical to MouseMove X Y parameters. STATE value is undefined. See also: DragDrop, EndDrag Triggered by a successive enabled(1) call See also: Disable, enabled, responsive Design in progress. Supposed to be called when a drag-and-drop session is finished successfully over a widget. X and Y are mouse pointer coordinates on the session end. See also: DragDrop, DragOver Called when a widget receives the input focus. See also: Leave, focused, selected Called when a widget font is changed either by direct property change or by the system. See also: font, ColorChanged Triggered by a successive visible(0) call See also: Show, visible, showing, exposed Called when the hint label is about to show or hide, depending on SHOW_FLAG. The hint show or hide action fails, if the event flag is cleared during execution. See also: showHint, ownerShowHint, hintVisible, ownerHint Sent to the focused widget when the user presses a key. CODE contains an eventual character code, KEY is one of kb::XXX constants, MOD is a combination of the modificator keys pressed when the event occurred ( km::XXX ). REPEAT is how many times the key was pressed; usually it is 1. ( see ::briefKeys ). The valid km:: constants are: km::Shift km::Ctrl km::Alt km::KeyPad km::DeadKey The valid kb:: constants are grouped in several sets. Some codes are aliased, like, kb::PgDn and kb::PageDown. kb::ShiftL kb::ShiftR kb::CtrlL kb::CtrlR kb::AltL kb::AltR kb::MetaL kb::MetaR kb::SuperL kb::SuperR kb::HyperL kb::HyperR kb::CapsLock kb::NumLock kb::ScrollLock kb::ShiftLock kb::Backspace kb::Tab kb::Linefeed kb::Enter kb::Return kb::Escape kb::Esc kb::Space kb::F1 .. kb::F30 kb::L1 .. kb::L10 kb::R1 .. kb::R10 kb::Clear kb::Pause kb::SysRq kb::SysReq kb::Delete kb::Home kb::Left kb::Up kb::Right kb::Down kb::PgUp kb::Prior kb::PageUp kb::PgDn kb::Next kb::PageDown kb::End kb::Begin kb::Select kb::Print kb::PrintScr kb::Execute kb::Insert kb::Undo kb::Redo kb::Menu kb::Find kb::Cancel kb::Help kb::Break kb::BackTab See also: KeyUp, briefKeys, key_down, help, popup, tabOrder, tabStop, accelTable Sent to the focused widget when the user releases a key. CODE contains an eventual character code, KEY is one of kb::XXX constants, MOD is a combination of the modificator keys pressed when the event occurred ( km::XXX ). See also: KeyDown, key_up Called when the input focus is removed from a widget See also: Enter, focused, selected Called before the user-navigated menu ( pop-up or pull-down ) is about to show another level of submenu on the screen. MENU is Prima::AbstractMenu descendant, that children to a widget, and VAR_NAME is the name of the menu item that is about to be shown. Used for making changes in the menu structures dynamically. See also: popupItems Called when a mouse click ( button is pressed, and then released within system-defined interval of time ) is happened in the widget area. BUTTON is one of mb::XXX constants, MOD is a combination of km::XXX constants, reflecting pressed modificator keys during the event, X and Y are the mouse pointer coordinates. DOUBLE_CLICK is a boolean flag, set to 1 if it was a double click, 0 if a single. mb::XXX constants are: mb::b1 or mb::Left mb::b2 or mb::Middle mb::b3 or mb::Right mb::b4 mb::b5 mb::b6 mb::b7 mb::b8 See also: MouseDown, MouseUp, MouseWheel, MouseMove, MouseEnter, MouseLeave Occurs when the user presses mouse button on a widget. BUTTON is one of mb::XXX constants, MOD is a combination of km::XXX constants, reflecting the pressed modificator keys during the event, X and Y are the mouse pointer coordinates. See also: MouseUp, MouseClick, MouseWheel, MouseMove, MouseEnter, MouseLeave Occurs when the mouse pointer is entered the area occupied by a widget ( without mouse button pressed ). MOD is a combination of km::XXX constants, reflecting the pressed modificator keys during the event, X and Y are the mouse pointer coordinates. See also: MouseDown, MouseUp, MouseClick, MouseWheel, MouseMove, MouseLeave Occurs when the mouse pointer is driven off the area occupied by a widget ( without mouse button pressed ). See also: MouseDown, MouseUp, MouseClick, MouseWheel, MouseMove, MouseEnter Occurs when the mouse pointer is transported over a widget. MOD is a combination of km::XXX constants, reflecting the pressed modificator keys during the event, X and Y are the mouse pointer coordinates. See also: MouseDown, MouseUp, MouseClick, MouseWheel, MouseEnter, MouseLeave Occurs when the user depresses mouse button on a widget. BUTTON is one of mb::XXX constants, MOD is a combination of km::XXX constants, reflecting the pressed modificator keys during the event, X and Y are the mouse pointer coordinates. See also: MouseDown, MouseClick, MouseWheel, MouseMove, MouseEnter, MouseLeave Occurs when the user rotates mouse wheel on a widget. MOD is a combination of km::XXX constants, reflecting the pressed modificator keys during the event, X and Y are the mouse pointer coordinates. Z is the virtual coordinate of a wheel. Typical ( 2001 A.D. ) mouse produces Z 120-fold values. See also: MouseDown, MouseUp, MouseClick, MouseMove, MouseEnter, MouseLeave Triggered when widget changes its position relative to its parent, either by Prima::Widget methods or by the user. OLD_X and OLD_Y are the old coordinates of a widget, NEW_X and NEW_Y are the new ones. See also: Size, origin, growMode, centered, clipOwner Caused when the system calls for the refresh of a graphic context, associated with a widget. CANVAS is the widget itself, however its usage instead of widget is recommended ( see the section on Graphic content ). See also: repaint, syncPaint, get_invalid_rect, scroll, colorIndex, font Called by the system when the user presses a key or mouse combination defined for a context pop-up menu execution. By default executes the associated Prima::Popup object, if it is present. If the event flag is cleared during the execution of callbacks, the pop-up menu is not shown. See also: popup This message is posted right after Create notification, and comes first from the event loop. Prima::Widget does not use it. Triggered by a successive visible(1) call See also: Show, visible, showing, exposed Triggered when widget changes its size, either by Prima::Widget methods or by the user. OLD_WIDTH and OLD_HEIGHT are the old extensions of a widget, NEW_WIDTH and NEW_HEIGHT are the new ones. See also: Move, origin, size, growMode, sizeMax, sizeMin, rect, clipOwner A distributed KeyDown event. Traverses all the object tree that the widget which received original KeyDown event belongs to. Once the event flag is cleared, the iteration stops. Used for tracking keyboard events by out-of-focus widgets. See also: KeyDown Triggered when a widget changes its stacking order, or Z-order among its siblings, either by Prima::Widget methods or by the user. See also: bring_to_front, insert_behind, send_to_back Dmitry Karasik, <dmitry@karasik.eu.org>. the Prima manpage, the Prima::Object manpage, the Prima::Drawable manpage.