oracular (3) wxLayoutAlgorithm.3erl.gz
NAME
wxLayoutAlgorithm - Functions for wxLayoutAlgorithm class
DESCRIPTION
wxLayoutAlgorithm implements layout of subwindows in MDI or SDI frames. It sends a wxCalculateLayoutEvent
(not implemented in wx) 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 (not implemented in wx) 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 wxLayoutAlgorithm::OnCalculateLayout events which subtract the
window size and return the remaining rectangle for the next window to process. It is assumed (by
wxSashLayoutWindow::OnCalculateLayout (not implemented in wx)) 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 wxLayoutAlgorithm::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 wxLayoutAlgorithm::OnCalculateLayout chooses
to interpret a window's size and alignment. Therefore you could implement a different window class with a
new wxLayoutAlgorithm::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).
Note: wxLayoutAlgorithm has nothing to do with wxLayoutConstraints (not implemented in wx). It is an
alternative way of specifying layouts for which the normal constraint system is unsuitable.
See: wxSashEvent, wxSashLayoutWindow, Overview events
wxWidgets docs: wxLayoutAlgorithm
DATA TYPES
wxLayoutAlgorithm() = wx:wx_object()
EXPORTS
new() -> wxLayoutAlgorithm()
Default constructor.
destroy(This :: wxLayoutAlgorithm()) -> ok
Destructor.
layoutFrame(This, Frame) -> boolean()
Types:
This = wxLayoutAlgorithm()
Frame = wxFrame:wxFrame()
layoutFrame(This, Frame, Options :: [Option]) -> boolean()
Types:
This = wxLayoutAlgorithm()
Frame = wxFrame:wxFrame()
Option = {mainWindow, wxWindow:wxWindow()}
Lays out the children of a normal frame.
mainWindow is set to occupy the remaining space. This function simply calls layoutWindow/3.
layoutMDIFrame(This, Frame) -> boolean()
Types:
This = wxLayoutAlgorithm()
Frame = wxMDIParentFrame:wxMDIParentFrame()
layoutMDIFrame(This, Frame, Options :: [Option]) -> boolean()
Types:
This = wxLayoutAlgorithm()
Frame = wxMDIParentFrame:wxMDIParentFrame()
Option =
{rect,
{X :: integer(),
Y :: integer(),
W :: integer(),
H :: integer()}}
Lays out the children of an MDI parent frame.
If 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.
layoutWindow(This, Parent) -> boolean()
Types:
This = wxLayoutAlgorithm()
Parent = wxWindow:wxWindow()
layoutWindow(This, Parent, Options :: [Option]) -> boolean()
Types:
This = wxLayoutAlgorithm()
Parent = wxWindow:wxWindow()
Option = {mainWindow, wxWindow:wxWindow()}
Lays out the children of a normal frame or other window.
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).