Creates a new window:

A freshly-created window is hidden and locked. After construction, you add BViews to the BWindow through AddChild(), and then show the window (and start its message loop) by calling Show().

You never delete your BWindows; call Quit() instead.

These hook functions are invoked just after the window's frame is moved or resized, whether by the user or programatically. The arguments give the window's new origin (in screen coordinates) or dimensions. The default implementations do nothing.

See also: B_WINDOW_MOVED, B_WINDOW_RESIZED.

The MenusBeginning() hook function is called just before menus belonging to the window are about to be shown to the user. MenusEnded() is called when the menus have been removed from the screen. The default implementations do nothing. You can implement these functions to make sure the menus' states accurately reflect the state of the window.

Important

These hook functions are not invoked because of messages—don't go looking for a "menus beginning" or "menus ended" message.

Implementation detail. See BHandler::MessageReceived().

Hook function that's called when the screen (on which this window is located) changes size or location in the screen coordinate system, or changes color space (depth). frame is the screen's new frame rectangle, and mode is its new color space.

See also: BScreen::Frame()

WindowActivated() is a hook function that's automatically invoked on the BWindow (and each of its BView children) when the window is activated or deactivated. If active is true, the window has just become the active window; if it's false, it's about to give up that status. You can implement WindowActivated() to do whatever you want; the default implementation does nothing.

Implemented by derived classes to respond to a notification that the workspace displayed on the screen has changed. All windows in the newly activated workspace as well as those in the one that was just deactivated get this notification.

The workspace argument is an index to the workspace in question and the active flag conveys its current status. If active is true, the workspace has just become the active workspace. If active is false, it has just stopped being the active workspace.

The default (BWindow) version of this function is empty.

See also: "B_WORKSPACE_ACTIVATED" in the Message Protocols appendix, activate_workspace()

Implemented by derived classes to respond to a notification the the window has just changed the set of workspaces in which it can be displayed from oldWorkspaces to newWorkspaces. This typically happens when the user moves a window from one workspace to another, but it may also happen when a programmatic change is made to the set of permitted workspaces. Each workspace is represented by a corresponding bit in the oldWorkspaces and newWorkspaces masks.

The default (BWindow) version of this function is empty.

See also: B_WORKSPACES_CHANGED in the Message Protocols appendix, SetWorkspaces()

The non-virtual Zoom() (which is called when the user clicks the zoom button, but can also be called programatically) figures out a new size and location for the window (as described below), and then passes these dimensions to the virtual Zoom() hook function. It's hook Zoom()'s responsibility to actually resize and move the window; the default version applies the arguments explicitly by calling MoveTo() and ResizeTo(). You can re-implement hook Zoom() to create a new zooming algorithm that incorporates or ignores the arguments as you see fit.

The dimensions that non-virtual Zoom() passes to hook Zoom() are deduced from the smallest of three rectangles: 1) the screen rectangle, 2) the rectangle defined by SetZoomLimits(), 3) the rectangle defined by SetSizeLimits(). However, if the window's rectangle already matches these "zoom" dimensions (give or take a few pixels), Zoom() passes the window's previous ("non-zoomed") size and location.

You can effectively call Zoom() even if the window is B_NOT_ZOOMABLE.

Zoom() may both move and resize the window, resulting in FrameMoved() and FrameResized() notifications.

Activate() makes the BWindow the active window (if flag is true), or causes it to relinquish that status (if flag is false). The active window is made frontmost, its title tab is highlighted, and it becomes the target of keyboard events. The Show() function automatically activates the window.

Important

You can't activate a hidden window.

Note

You rarely call Activate() yourself. Deciding which window to make active is the user's choice.

IsActive() returns true if the window is currently the active window, and false if it's not.

See also: BView::WindowActivated()

AddChild() places aView (and its child views) in the window, adds it to the window's view list, and adds it to the window's list of handlers:

• Graphically, the view is placed in the window's coordinate system at the location defined by the view's frame rectangle.

• In the window's view list, aView is inserted before sibling. if sibling is NULL, aView is added at the end of the list. Note, however, that window list order is of little significance; for example, it doesn't affect the order in which sibling views are drawn.

• aView and its children are added to the window's handler list; aView's next handler is set to this BWindow.

Each BView in aView's hierarchy is sent an AttachedToWindow() call. When they've all had a chance to respond, they're each sent an AllAttached() call.

If aView has already been added to a view hierarchy, or if sibling isn't in the window's view list, AddChild() fails.

RemoveChild() removes aView (and its children) from the window's display, view list, and handler list, and sets aView's next handler to NULL.

DetachedFromWindow() and AllDetached() are invoked on aView and each of its children. If aView isn't in the window's view list, the function fails and returns false; it returns true upon success.

ChildAt() returns the index'th view in the window's view list, or NULL if index is out of bounds (you've reached the end of the list). The view list doesn't recurse; to build a full map of a window's view hierarchy, you call BView::ChildAt() iteratively on each of the window's views (and each of their children, etc.).

See also: BView::Parent()

AddShortcut() creates a keyboard shortcut: When the user types Command+modifiers+key, message is sent to handler. If a shortcut already exists for modifiers+key, it's removed before the new shortcut is added.

RemoveShortcut() removes the shortcut for modifiers+key.

Warning

Don't use these functions to create and remove menu shortcuts; use BMenuItem objects instead.

Notes on the arguments:

• key is a case-insensitive character value. If you want to map to an uppercase character, you have to include B_SHIFT_KEY in the modifiers mask.

• modifiers is an OR'd list of modifier key numbers. B_COMMAND_KEY, which is always assumed, needn't be added to the mask. See modifiers() for a list of modifier keys.

• message is a model of the BMessage you want sent when the user types the shortcut. The BWindow takes ownership of the message object and adds a when field to it:

  Field name	Type code	Description
  when	B_INT64_TYPE	The time of the key-down, in microseconds since 01/01/70.

• handler must be in the window's handler list (or the message won't be sent). If you exclude the argument, this BWindow handles the message. If handler is (literally) NULL, the message is sent to the BWindow's focus view (or to the BWindow if no view is in focus).

As with all Command events, a B_KEY_DOWN message isn't sent when the user invokes a keyboard shortcut, but the subsequent B_KEY_UP is.

Every BWindow has five built-in shortcuts:

In addition, BWindows respond to Command+q by posting B_QUIT_REQUESTED to be_app.

Adds windows to and removes them from this window's subset. This affects modal and floating windows with a subset feel only (i.e. B_MODAL_SUBSET_WINDOW_FEEL or B_FLOATING_SUBSET_WINDOW_FEEL). A subset feel window blocks or floats above only those windows in its subset. To set the window's feel, use SetFeel().

Archives the BWindow by recording its frame rectangle, title, type, and flags in the BMessage archive. If the deep flag is true, this function also archives all the views in the window's view hierarchy. If the flag is false, only the BWindow is archived.

See also: BArchivable::Archive(), Instantiate() static function

These functions return the rectangle that encloses the window's content area. The bounds rectangle (Bounds()) is expressed in the window's coordinate system; the frame rectangle (Frame()) is expressed in the screen's coordinate system.

The rectangles are cached by the BWindow itself—calling these functions doesn't incur a trip to the App Server.

Converts the argument from window coordinates to screen coordinates or vice versa. The point or rect needn't fall within this BWindow's bounds.

If the argument is passed by value, the function returns the converted value; if it's by pointer, the conversion is done in-place.

The BWindow must be locked.

returns the current focus view for the BWindow, or NULL if no view is currently in focus. The focus view is the BView that's responsible for showing the current selection and is the target for keyboard messages directed at this BWindow. The focus view is set through BView::MakeFocus().

The BWindow sets its preferred handler to be the focus view, so the inherited PreferredHandler() function will return this same object (but as a BHandler).

These functions disable automatic updating within the window, and re-enable it again. Any drawing that's done while updates are disabled is suppressed until updates are re-enabled. If you're doing a lot of drawing within the window, and you want the results of the drawing to appear all at once, you should disable updates, draw, and then re-enable updates.

See also: BView::Invalidate(), UpdateIfNeeded()

Implementation detail; see BLooper::DispatchMessage().

Warning

You shouldn't override this function in a BWindow subclass; if you want to augment the window's message-dispatching mechanism, override MessageReceived().

Returns the view located at point within the window, or the view tagged with name. The functions returns NULL if no view is found.

Both of these functions cause this window's App Server-bound messages to be sent immediately. Flush() sends the messages and returns immediately; Sync() send the messages and waits for the App Server to respond. In other words, when Sync() returns you're guaranteed that all of the flushed messages have been processed.

See also: BView::Flush()

Adds the name "suite/vnd.Be-window" to the message.

See also: BHandler::GetSupportedSuites()

These functions return true if the window is frontmost on screen, if it has a floating window feel, and if it has a modal window feel, respectively.

Note

A floating window can never be the frontmost window.

Returns a pointer to the view in this window that most recently received a B_MOUSE_MOVED message.

These functions move the window without resizing it. MoveBy() adds horizontal coordinate units to the left and right components of the window's frame rectangle and vertical units to the frame's top and bottom. if horizontal and vertical are negative, the window moves upward and to the left. if they're positive, it moves downward and to the right. MoveTo() moves the left top corner of the window's content area to point—or (x, y) – in the screen coordinate system; it adjusts all coordinates in the frame rectangle accordingly.

None of the values passed to these functions should specify fractional coordinates; a window must be aligned on screen pixels. Fractional values will be rounded to the closest whole number.

Neither function alters the BWindow's coordinate system or bounds rectangle.

When these functions move a window, a window-moved event is reported to the window. This results in the BWindow's FrameMoved() function being called.

Returns true if any of the views within the window need to be updated, and false if they're all up-to-date.

These two functions bracket a series of "batched" drawing instructions. After you call OpenViewTransaction(), everything you draw in the window is bundled up and then sent to the app server (and rendered) when you call CommitViewTransaction(). You can only perform one transaction (per window) at a time. The BWindow must be locked when you call OpenViewTransaction(), and must remain locked until after you call CommitViewTransaction(). Invocations of Flush() are ignored while a transaction is open (and locked).

Quit() removes the window from the screen, deletes all the BViews in its view hierarchy, destroys the window thread, removes the window's connection to the Application Server, and deletes the BWindow object.

Use this function, rather than the delete operator, to destroy a window.

BWindow's Quit() works much like the BLooper function it overrides. When called from the BWindow's thread, it doesn't return. When called from another thread, it returns after all previously posted messages have been processed and the BWindow and its thread have been destroyed.

Note

The window must be locked when you call Quit().

See also: BLooper::QuitRequested(), BLooper::Quit(), BApplication::QuitRequested()

These functions resize the window, while keeping its left top corner constant. ResizeBy() adds horizontal pixels to the width of the window's frame and vertical pixels to its height. ResizeTo() sets the frame absolutely to [width, height] pixels. Fractional components are rounded to the nearest whole number.

The FrameResized() hook function is called after the frame has been resized.

Resolves specifiers for the "Frame", "Title", and "View" properties. See "Scripting Support" in the class overview for more information.

See also: BHandler::ResolveSpecifier()

Relayers the windows on the screen so this window is behind window.

Set and return the window's default button. This is the button that's mapped to the Enter key. The user can activate the default button at any time—even if another BView is the focus view (the focus view will not receive a B_KEY_DOWN message). To remove the current default (without promoting another button) call SetDefaultButton(NULL). There can only be one default button at a time; SetDefaultButton() demotes the previous default.

When you promote or demote a default button, it's automatically redisplayed and receives a BButton::MakeDefault() call.

SetFeel() changes the window's feel to the specified value.

Feel() returns the current feel of the window.

See the BWindow constructor for a list of window_feel constants.

SetFlags() set the window's flags (or "user attributes") to the specified combination. Flags() returns the current flags.

See "Window Flags". for a list of the flag values.

SetKeyMenuBar() makes the specified BMenuBar object the "key" menu bar for the window—the object that's at the root of the menu hierarchy that users can navigate using the keyboard. KeyMenuBar() returns the object with key status, or NULL if the window doesn't have a BMenuBar object in its view hierarchy.

If a window contains only one BMenuBar view, it's automatically designated the key menu bar. If there's more than one BMenuBar in the window, the last one added to the window's view hierarchy is considered to be the key one.

If there's a "true" menu bar displayed along the top of the window, its menu hierarchy is the one that users should be able to navigate with the keyboard. SetKeyMenuBar() can be called to make sure that the BMenuBar object at the root of that hierarchy is the "key" menu bar.

SetLook() changes the window's look to the specified value.

Look() returns the current look of the window.

See the BWindow constructor for a list of window_look constants.

These functions set and return how often BView::Pulse() is called for the BWindow's views (how often B_PULSE messages are posted to the window). All BViews attached to the same window share the same pulse rate.

By turning on the B_PULSE_NEEDED flag, a BView can request periodic BView::Pulse() notifications. By default, B_PULSE messages are posted every 500,000 microseconds, as long as no other messages are pending. Each message causes BView::Pulse() to be called once for every BView that requested the notification. There are no pulses if no BViews request them.

SetPulseRate() permits you to set a different interval. The interval set should not be less than 100,000 microseconds; differences less than 50,000 microseconds may not be noticeable. A finer granularity can't be guaranteed.

Setting the pulse rate to 0 disables pulsing for all views in the window.

See also: The BView constructor

These functions set and report limits on the size of the window. The user won't be able to resize the window beyond the limits set by SetSizeLimits()–to make it have a width less than minWidth or greater than maxWidth, nor a height less than minHeight or greater than maxHeight. By default, the minimums are sufficiently small and the maximums sufficiently large to accommodate any window within reason.

SetSizeLimits() constrains the user, not the programmer. It's legal for an application to set a window size that falls outside the permitted range. The limits are imposed only when the user attempts to resize the window; at that time, the window will jump to a size that's within range.

GetSizeLimits() writes the current limits to the variables provided.

SetZoomLimits() sets the maximum size that the window will zoom to (when the Zoom() function is called). The maximums set by SetSizeLimits() also apply to zooming; the window will zoom to the screen size or to the smaller of the maximums set by these two functions.

Since the sides of a window must line up on screen pixels, the values passed to both SetSizeLimits() and SetZoomLimits() should be whole numbers.

These functions set and return the window's title. SetTitle() replaces the current title with newTitle. It also renames the window thread in the following format:

"w>newTitle"

where as many characters of the newTitle are included in the thread name as will fit.

Title() returns a pointer to the current title. The returned string is null-terminated. It belongs to the BWindow object, which may alter the string or free the memory where it resides without notice. Applications should ask for the title each time it's needed and make a copy for their own purposes.

A window's title and thread name are originally set by an argument passed to the BWindow constructor.

SetType() changes the type of the window to the specified value. Type() returns the type. You normally set the window's type when it's constructed.

The type is set at construction (or by SetType()) as one of the following constants (full descriptions can be found in the discussion of the BWindow constructor):

• B_UNTYPED_WINDOW

• B_MODAL_WINDOW

• B_BORDERED_WINDOW

• B_TITLED_WINDOW

• B_DOCUMENT_WINDOW

• B_FLOATING_WINDOW

SetWindowAlignment() sets the current alignment of the window content on the screen. mode is either B_PIXEL_ALIGNMENT or B_BYTE_ALIGNMENT.

If mode is B_PIXEL_ALIGNMENT, SetWindowAlignment() aligns the window in pixel coordinates. h and hOffset together determine the horizontal alignment: h gives the horizontal origin step while hOffset is the horizontal offset. hOffset must be between 1 and h (as a convenience, 0 is taken to mean 1). For example, if h is 4 and hOffset is 1, valid horizontal origins would be …, -7, -3, 1, 5, 9, … Similarly, width/widthOffset, v/vOffset, height/heightOffset give you control over the other window parameters.

If mode is B_BYTE_ALIGNMENT, then the alignment is given in terms of frame buffer offsets. However, the setting only affects the horizontal origin and width. You can't align the right and bottom edges in B_BYTE_ALIGNMENT mode.

GetWindowAlignment() returns the current window alignment.

Both methods return B_NO_ERROR on success and B_ERROR otherwise.

These functions set and return the set of workspaces where the window can be displayed. The workspaces argument passed to SetWorkspaces() and the value returned by Workspaces() is a bitfield with one bit set for each workspace in which the window can appear. Usually a window appears in just one workspace.

SetWorkspaces() can associate a window with workspaces that don't exist yet. The window will appear in those workspaces if and when the user creates them.

You can pass B_CURRENT_WORKSPACE as the workspaces argument to place the window in the workspace that's currently displayed (the active workspace) and remove it from all others, or B_ALL_WORKSPACES to make sure the window shows up in all workspaces, including any new ones that the user might create. Workspaces() may return B_ALL_WORKSPACES, but will identify the current workspace rather than return B_CURRENT_WORKSPACE.

Changing a BWindow's set of workspaces causes it to be notified with a WorkspacesChanged() function call.

See also: the BWindow constructor

These functions hide and show the window.

Show() places the window frontmost on the screen (but behind any applicable floating or modal windows), places it on Deskbar's window list, and makes it the active window. If this is the BWindow's first Show(), the object's message loop is started, and the object is unlocked.

Hide() removes the window from the screen, removes it from Deskbar's window list, and passes active status to some other window (if this is the active window). If Hide() is called more than once, you'll need to call Show() an equal number of times for the window to become visible again.

Minimize() hides and shows the window (and passes active status), as minimize is true or false. The difference between this function and Hide()/Show() is that Minimize() dims (and undims) the window's entry in Deskbar's window list, but doesn't remove the entry altogether. Also, a single Minimize(false) "undoes" any number of Minimize(true) calls.

Minimize() also acts as a hook that's invoked when the user double-clicks the window's title tab or selects the window from DeskBar's window list. If minimize is true, the window is about to be hidden; if false, it's about to be shown. The Minimize() function itself does the hiding and showing–if you override Minimize() and you want to inherit the BWindow behaviour, you must call BWindow::Minimize() in your implementation.

IsHidden() returns true if the window is currently hidden (i.e. through Hide()). IsMinimized() returns true if the window is minimized. Hiding takes precendence over minimization. For example, in both of these sequences…

window->Hide();
window->Minimize(true);
/* or */
window->Minimize(true);
window->Hide();

…the window is hidden but not minimized.

See also: B_MINIMIZE

Immediately and synchronously invokes Draw() on each child view that needs updating. This function is ignored if its called from any thread other than the BWindow's message loop. You call it as part of the implementation of a user interface hook function ( MouseMoved(), KeyDown()(), et. al.) to force invalid views to be immediately redrawn without having to wait for the hook function to finish. See "Forcing an Update while Responding to an Event" for details and an example.

See BArchivable::Instantiate()

The window_look constants define the appearance of the window–the look of its title tab, border, and the type of "resize control" (in the bottom right corner of the window). The look is set in the constructor or in the SetLook() function. The table below lists and briefly describes the window_look values.

The window_feel constants govern a window's behavior in relation to other windows. The feel is set in the BWindow constructor or in SetFeel(). The table below briefly describes the window feels.

• To set a window's subset, use AddToSubset().

• Modal windows are drawn in front of floating windows.

The window_type constants are pre-defined combinations of looks and feels. You set the type through the BWindow constructor or SetType().

The window flags (or "user attributes") define miscellaneous aspects of the window's interface, such as whether it can be moved or closed by the user. You combine the flags that you want and pass them to the BWindow constructor or SetFlags().

The default behavior is the inverse of all these flags–i.e. a window is normally movable, closable, resizable, and so on. However, some window looks and feels cause imply some of these flags. For example, a modal feel window can't be minimized (hidden)

You tell a window which workspaces to appear through the constructor, or through the SetWorkspaces() function. In practice, the only two realistic settings are represented by these constants.