Data Attributes of Objects

Wpy adds a number of data attributes to the objects it uses.  All these
attributes start with "wpy" to prevent name collisions with user-defined
data attributes.  You may need to write to these attributes to control
wpy.  Some of the data is more or less standard, while certain objects
have special data attributes.

These are the standard data attributes for most visible objects.

wpyText		Text to appear as window titles or control text.
wpyParent	The parent of the object.
wpyChildList	The list of children of the object, or an empty list.
wpySizeX, Y	The requested width and height of the object (see Geometry).
wpyLocX, Y	The requested location of the object within its parent (see Geometry).
wpyAnchor	The point of the object which should placed at wpyLocX/Y.  A
		compass string n, ne, e, se, s, sw, w, nw, or center.
wpyVisible	For controls, 0/1 if the object is invisible/visible.
wpyEnabled	For controls, 0/1 if the object is disabled/enabled.
wpyCharSizeX, Y		The size of the system font in pixels.  See Geometry.
wpyScreenSizeX, Y	The screen size in pixels.
wpyOneMeter	The number of pixels in one meter on the screen.
wpyCreated	Is 0/1 if the object is not created/created by the underlying GUI.
wpyHandler	For controls, the name of the message handler.
wpyMenu		The menu for the object, or None.
wpyApp		The single application object.

To find out about more specialized attributes, you must read the wpy.py source,
or the documentation for each class.

Parent and Child Relationships

It is often necessary to access an object from another object, for example,
to find the document given the view.  To support this, objects have an attribute
"wpyParent" which gives the parent of the object, and a "wpyChildList" listing
the descendants of the object.  Here are the parents and child lists for
common objects:

Object		wpyParent	wpyChildList

CWinApp		None		Document templates
template	CWinApp		documents
documents	template	frames
frame		document	views
view		frame		controls if any
menu		None		menu items

These objects have special parent/child attributes:

Object		Attribute	Description

document	wpyViewList	A list of views for this document
CWinApp		wpyMainFrame	The main window for the application, a frame
main frame	wpyWindowList	A list of windows for the main frame (MDI)
view		wpyDocument	The document shown by this view.

Most objects in WPY are derived from CObject.  Since there is only one
CWinApp object in any WPY application, the app object is a data attribute
of CObject.  The application object is available from (almost)
any WPY object as self.wpyApp.

There is a concept of the active frame, document and view.  Use the
methods CFrameWnd::GetActiveDocument(), CFrameWnd::GetActiveView(),
CWinApp::GetActiveFrame() and CWinApp::GetActiveFrameDV().