Name

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      CAT_ELLIPSE__DEFINE

Purpose

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      The purpose of this routine is to provide a circle or ellipse that can be displayed
      in a direct graphics draw widget. The coordinate system of the Cat_Ellipse
      object is either passed to it (a CatCoord object) or is a normalized
      coordinate system by default.

Authors

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        FANNING SOFTWARE CONSULTING BURRIDGE COMPUTING
        1645 Sheely Drive 18 The Green South
        Fort Collins Warborough, Oxon
        CO 80526 USA OX10 7DN, ENGLAND
        Phone: 970-221-0438 Phone: +44 (0)1865 858279
        E-mail: davidf@dfanning.com E-mail: davidb@burridgecomputing.co.uk

Category

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      Objects.

Syntax

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      ellipseObject = Obj_New("CAT_ELLIPSE", X1=0.5, Y1=0.5, X2=0.75, Y2=0.75)
      drawObject -> Add, ellipseObject

Superclasses

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      SELECTABLEOBJECT
      CATDATAATOM
      CATATOM
      CATCONTAINER IDLITCOMPONENT
      IDL_CONTAINER

Class Structure

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  class = { CAT_ELLIPSE, $
            clip_to_data: 0B, $ ; Flag that if set will allow clipping to data range in DRAW method.
            insertedObject: Obj_New(), $; The new object created in the CreateNewObject method. (Ignored in CLEANUP.)
            linestyle: 0L, $ ; The line style of the ellipse.
            layerObject: Obj_New(), $ ; A CATLAYER object for holding the annotation.
            modemap: Obj_New(), $ ; A pixmap for calculating "mode".
            moveend: 0L, $ ; Indicates which end of ellipse you are moving.
            npoints: 0L, $ ; The number of points used to draw the ellipse. 120 by default.
            rotation: 0.0, $ ; The rotation of the x axis of the ellipse.
            sx: 0L, $ ; The static X location.
            sy: 0L, $ ; The static Y location.
            thickness: 0.0, $ ; The thickness of the ellipse.
            xcenter: 0.0, $ ; The midpoint of the ellipse in X.
            ycenter: 0.0, $ ; The midpoint of the ellipse in Y.
            xradius: 0.0, $ ; The radius of the X axis.
            yradius: 0.0, $ ; The radius of the Y axis.
            INHERITS SelectableObject $
          }

Messages

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  CAT_ELLIPSE_CHANGED: This message is sent whenever SetProperty method is called and the NOMESSAGE
                      keyword is NOT set.

Event Structure

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      This object will add the following fields to the event structure created by an interaction.
      The fields are defined as:
      BOUNDARY_BOX: A 2x5 element array in normalized coordinates giving the boundary box of
                        the object.
      XPTS: An array of X points in data coordinates descriping an ellipse.
      YPTS: An array of Y points in data coordinates descriping an ellipse.

Modification History

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      Written by: David W. Fanning, 25 Jan 2004.