wxWidgets/interface/laywin.h

/////////////////////////////////////////////////////////////////////////////
// Name:        laywin.h
// Purpose:     documentation for wxLayoutAlgorithm class
// Author:      wxWidgets team
// RCS-ID:      $Id$
// Licence:     wxWindows license
/////////////////////////////////////////////////////////////////////////////

/**
    @class wxLayoutAlgorithm
    @wxheader{laywin.h}

    wxLayoutAlgorithm implements layout of subwindows in MDI or SDI frames.
    It sends a wxCalculateLayoutEvent event
    to children of the frame, asking them for information about
    their size. For MDI parent frames, the algorithm allocates
    the remaining space to the MDI client window (which contains the MDI child
    frames).
    For SDI (normal) frames, a 'main' window is specified as taking up the
    remaining space.

    Because the event system is used, this technique can be applied to any windows,
    which are not necessarily 'aware' of the layout classes (no virtual functions
    in wxWindow refer to wxLayoutAlgorithm or its events). However, you
    may wish to use wxSashLayoutWindow for your subwindows
    since this class provides handlers for the required events, and accessors
    to specify the desired size of the window. The sash behaviour in the base class
    can be used, optionally, to make the windows user-resizable.

    wxLayoutAlgorithm is typically used in IDE (integrated development environment)
    applications,
    where there are several resizable windows in addition to the MDI client window,
    or
    other primary editing window. Resizable windows might include toolbars, a
    project
    window, and a window for displaying error and warning messages.

    When a window receives an OnCalculateLayout event, it should call SetRect in
    the given event object, to be the old supplied rectangle minus whatever space
    the
    window takes up. It should also set its own size accordingly.
    wxSashLayoutWindow::OnCalculateLayout generates an OnQueryLayoutInfo event
    which it sends to itself to determine the orientation, alignment and size of
    the window,
    which it gets from internal member variables set by the application.

    The algorithm works by starting off with a rectangle equal to the whole frame
    client area.
    It iterates through the frame children, generating OnCalculateLayout events
    which subtract
    the window size and return the remaining rectangle for the next window to
    process. It
    is assumed (by wxSashLayoutWindow::OnCalculateLayout) that a window stretches
    the full dimension
    of the frame client, according to the orientation it specifies. For example, a
    horizontal window
    will stretch the full width of the remaining portion of the frame client area.
    In the other orientation, the window will be fixed to whatever size was
    specified by
    OnQueryLayoutInfo. An alignment setting will make the window 'stick' to the
    left, top, right or
    bottom of the remaining client area. This scheme implies that order of window
    creation is important.
    Say you wish to have an extra toolbar at the top of the frame, a project window
    to the left of
    the MDI client window, and an output window above the status bar. You should
    therefore create
    the windows in this order: toolbar, output window, project window. This ensures
    that the toolbar and
    output window take up space at the top and bottom, and then the remaining
    height in-between is used for
    the project window.

    wxLayoutAlgorithm is quite independent of the way in which
    OnCalculateLayout chooses to interpret a window's size and alignment. Therefore
    you
    could implement a different window class with a new OnCalculateLayout event
    handler,
    that has a more sophisticated way of laying out the windows. It might allow
    specification of whether stretching occurs in the specified orientation, for
    example,
    rather than always assuming stretching. (This could, and probably should, be
    added to the existing
    implementation).

    @e Note: wxLayoutAlgorithm has nothing to do with wxLayoutConstraints. It is an
    alternative
    way of specifying layouts for which the normal constraint system is unsuitable.

    @library{wxadv}
    @category{winlayout}

    @seealso
    wxSashEvent, wxSashLayoutWindow, @ref overview_eventhandlingoverview
*/
class wxLayoutAlgorithm : public wxObject
{
public:
    /**
        Default constructor.
    */
    wxLayoutAlgorithm();

    /**
        Destructor.
    */
    ~wxLayoutAlgorithm();

    /**
        Lays out the children of a normal frame. @a mainWindow is set to occupy the
        remaining space.
        This function simply calls LayoutWindow().
    */
    bool LayoutFrame(wxFrame* frame, wxWindow* mainWindow = NULL) const;

    /**
        Lays out the children of an MDI parent frame. If @a rect is non-@NULL, the
        given rectangle will be used as a starting point instead of the frame's client
        area.
        The MDI client window is set to occupy the remaining space.
    */
    bool LayoutMDIFrame(wxMDIParentFrame* frame, wxRect* rect = NULL) const;

    /**
        Lays out the children of a normal frame or other window.
        @a mainWindow is set to occupy the remaining space. If this is not specified,
        then
        the last window that responds to a calculate layout event in query mode will
        get the remaining space
        (that is, a non-query OnCalculateLayout event will not be sent to this window
        and the window will be set
        to the remaining size).
    */
    bool LayoutWindow(wxWindow* parent, wxWindow* mainWindow = NULL) const;
};


/**
    @class wxSashLayoutWindow
    @wxheader{laywin.h}

    wxSashLayoutWindow responds to OnCalculateLayout events generated
    by wxLayoutAlgorithm. It allows the
    application to use simple accessors to specify how the window should be
    laid out, rather than having to respond to events. The fact that
    the class derives from wxSashWindow allows sashes to be used if required,
    to allow the windows to be user-resizable.

    The documentation for wxLayoutAlgorithm explains
    the purpose of this class in more detail.

    @library{wxadv}
    @category{miscwnd}

    @seealso
    wxLayoutAlgorithm, wxSashWindow, @ref overview_eventhandlingoverview
*/
class wxSashLayoutWindow : public wxSashWindow
{
public:
    //@{
    /**
        Constructs a sash layout window, which can be a child of a frame, dialog or any
        other non-control window.
        
        @param parent
            Pointer to a parent window.
        @param id
            Window identifier. If -1, will automatically create an identifier.
        @param pos
            Window position. wxDefaultPosition is (-1, -1) which indicates that
        wxSashLayoutWindows
            should generate a default position for the window. If using the
        wxSashLayoutWindow class directly, supply
            an actual position.
        @param size
            Window size. wxDefaultSize is (-1, -1) which indicates that
        wxSashLayoutWindows
            should generate a default size for the window.
        @param style
            Window style. For window styles, please see wxSashLayoutWindow.
        @param name
            Window name.
    */
    wxSashLayoutWindow();
    wxSashLayoutWindow(wxSashLayoutWindow* parent, wxWindowID id,
                       const wxPoint& pos = wxDefaultPosition,
                       const wxSize& size = wxDefaultSize,
                       long style = wxCLIP_CHILDREN | wxSW_3D,
                       const wxString& name = "layoutWindow");
    //@}

    /**
        Initializes a sash layout window, which can be a child of a frame, dialog or
        any other non-control window.
        
        @param parent
            Pointer to a parent window.
        @param id
            Window identifier. If -1, will automatically create an identifier.
        @param pos
            Window position. wxDefaultPosition is (-1, -1) which indicates that
        wxSashLayoutWindows
            should generate a default position for the window. If using the
        wxSashLayoutWindow class directly, supply
            an actual position.
        @param size
            Window size. wxDefaultSize is (-1, -1) which indicates that
        wxSashLayoutWindows
            should generate a default size for the window.
        @param style
            Window style. For window styles, please see wxSashLayoutWindow.
        @param name
            Window name.
    */
    bool Create(wxSashLayoutWindow* parent, wxWindowID id,
                const wxPoint& pos = wxDefaultPosition,
                const wxSize& size = wxDefaultSize,
                long style = wxCLIP_CHILDREN | wxSW_3D,
                const wxString& name = "layoutWindow");

    /**
        Returns the alignment of the window: one of wxLAYOUT_TOP, wxLAYOUT_LEFT,
        wxLAYOUT_RIGHT, wxLAYOUT_BOTTOM.
    */
    wxLayoutAlignment GetAlignment() const;

    /**
        Returns the orientation of the window: one of wxLAYOUT_HORIZONTAL,
        wxLAYOUT_VERTICAL.
    */
    wxLayoutOrientation GetOrientation() const;

    /**
        The default handler for the event that is generated by wxLayoutAlgorithm. The
        implementation
        of this function calls wxCalculateLayoutEvent::SetRect to shrink the provided
        size according to
        how much space this window takes up. For further details,
        see wxLayoutAlgorithm and wxCalculateLayoutEvent.
    */
    void OnCalculateLayout(wxCalculateLayoutEvent& event);

    /**
        The default handler for the event that is generated by OnCalculateLayout to get
        size, alignment and orientation information for the window. The implementation
        of this function uses member variables as set by accessors called by the
        application.
        For further details, see wxLayoutAlgorithm and wxQueryLayoutInfoEvent.
    */
    void OnQueryLayoutInfo(wxQueryLayoutInfoEvent& event);

    /**
        Sets the alignment of the window (which edge of the available parent client
        area the window
        is attached to). @a alignment is one of wxLAYOUT_TOP, wxLAYOUT_LEFT,
        wxLAYOUT_RIGHT, wxLAYOUT_BOTTOM.
    */
    void SetAlignment(wxLayoutAlignment alignment);

    /**
        Sets the default dimensions of the window. The dimension other than the
        orientation will be fixed to this
        value, and the orientation dimension will be ignored and the window stretched
        to fit the available space.
    */
    void SetDefaultSize(const wxSize& size);

    /**
        Sets the orientation of the window (the direction the window will stretch in,
        to fill the available
        parent client area). @a orientation is one of wxLAYOUT_HORIZONTAL,
        wxLAYOUT_VERTICAL.
    */
    void SetOrientation(wxLayoutOrientation orientation);
};


/**
    @class wxQueryLayoutInfoEvent
    @wxheader{laywin.h}

    This event is sent when wxLayoutAlgorithm wishes to get
    the size, orientation and alignment of a window. More precisely, the event is
    sent
    by the OnCalculateLayout handler which is itself invoked by wxLayoutAlgorithm.

    @library{wxadv}
    @category{events}

    @seealso
    wxCalculateLayoutEvent, wxSashLayoutWindow, wxLayoutAlgorithm.
*/
class wxQueryLayoutInfoEvent : public wxEvent
{
public:
    /**
        Constructor.
    */
    wxQueryLayoutInfoEvent(wxWindowID id = 0);

    /**
        Specifies the alignment of the window (which side of the remaining parent
        client area
        the window sticks to). One of wxLAYOUT_TOP, wxLAYOUT_LEFT, wxLAYOUT_RIGHT,
        wxLAYOUT_BOTTOM.
    */
    void GetAlignment() const;

    /**
        Returns the flags associated with this event. Not currently used.
    */
    int GetFlags() const;

    /**
        Returns the orientation that the event handler specified to the event object.
        May be one of wxLAYOUT_HORIZONTAL,
        wxLAYOUT_VERTICAL.
    */
    wxLayoutOrientation GetOrientation() const;

    /**
        Returns the requested length of the window in the direction of the window
        orientation. This information
        is not yet used.
    */
    int GetRequestedLength() const;

    /**
        Returns the size that the event handler specified to the event object as being
        the requested size of the window.
    */
    wxSize GetSize() const;

    /**
        Call this to specify the alignment of the window (which side of the remaining
        parent client area
        the window sticks to). May be one of wxLAYOUT_TOP, wxLAYOUT_LEFT,
        wxLAYOUT_RIGHT, wxLAYOUT_BOTTOM.
    */
    void SetAlignment(wxLayoutAlignment alignment);

    /**
        Sets the flags associated with this event. Not currently used.
    */
    void SetFlags(int flags);

    /**
        Call this to specify the orientation of the window. May be one of
        wxLAYOUT_HORIZONTAL,
        wxLAYOUT_VERTICAL.
    */
    void SetOrientation(wxLayoutOrientation orientation);

    /**
        Sets the requested length of the window in the direction of the window
        orientation. This information
        is not yet used.
    */
    void SetRequestedLength(int length);

    /**
        Call this to let the calling code know what the size of the window is.
    */
    void SetSize(const wxSize& size);
};


/**
    @class wxCalculateLayoutEvent
    @wxheader{laywin.h}

    This event is sent by wxLayoutAlgorithm to
    calculate the amount of the remaining client area that the window should
    occupy.

    @library{wxadv}
    @category{events}

    @seealso
    wxQueryLayoutInfoEvent, wxSashLayoutWindow, wxLayoutAlgorithm.
*/
class wxCalculateLayoutEvent : public wxEvent
{
public:
    /**
        Constructor.
    */
    wxCalculateLayoutEvent(wxWindowID id = 0);

    /**
        Returns the flags associated with this event. Not currently used.
    */
    int GetFlags() const;

    /**
        Before the event handler is entered, returns the remaining parent client area
        that the window
        could occupy. When the event handler returns, this should contain the remaining
        parent client rectangle,
        after the event handler has subtracted the area that its window occupies.
    */
    wxRect GetRect() const;

    /**
        Sets the flags associated with this event. Not currently used.
    */
    void SetFlags(int flags);

    /**
        Call this to specify the new remaining parent client area, after the space
        occupied by the
        window has been subtracted.
    */
    void SetRect(const wxRect& rect);
};