-- File:	Viewer_View.cdl
-- Created:	Thu Mar  7 14:06:17 1996
-- Author:	Jean-Louis Frenkel
--		<rmi@pernox>
---Copyright:	 Matra Datavision 1996

deferred class View from Viewer inherits TShared from MMgt
    	---Purpose: This class defines a view.        
uses
    Length from Quantity,Factor from Quantity
raises
    BadValue from Viewer
is 
    Initialize;

    Update(me)
    	---Purpose: Clears the window and redraws all primitives.
    is deferred;

  
    SetImmediateUpdate(me: mutable; onoff: Boolean from Standard)
    	---Purpose: sets the immediate update mode and returns the previous one.
    returns Boolean from Standard;
    
    ImmediateUpdate(me)
    	---Purpose: 
    is static protected;
    
    WindowFit(me: mutable ; Xmin, Ymin, Xmax, Ymax : Integer)
    	---Purpose: Centres the defined pixel window defined by the
    	-- minimum and maximum pixels Xmin, Ymin, Xmax,
    	-- Ymax so that it occupies the largest possible space
    	-- while maintaining the initial height/width ratio.
    	-- Exceptions
    	-- Viewer_BadValue if the size of the defined
    	-- projection window is equal to 0.
    raises BadValue from Viewer
    is deferred;

    Place (me:mutable; x,y: Integer from Standard;
                      aZoomFactor: Factor from Quantity = 1)
    	---Purpose: Sets the center of the object space defined by x, y
    	-- and the zoom factor aZoomFactor. The view is updated.
    is deferred;

fields

    myImmediateUpdate: Boolean from Standard is protected;


end View from Viewer;