path: root/src/V3d/V3d_Viewer.cdl

-- File:    Viewer.cdl
-- Created: Fri Jan 17 11:23:08 1992
-- Author:  GG
-- Modified FMN - 02/02/98 -> Specifique UNIX
--          CAL - 16/07/98 -> S3892. Ajout grilles 3d.
--          GG  - 15/12/99 -> GER61351 Add SetDefaultBackgroundColor()
--                                     and DefaultBackgroundColor() methods
--          GG  - 20/01/00 -> IMP200100 Add GridDrawMode() method
--          GG  - 24/01/00 -> IMP240100 Add SetGridEcho() methods
--                                      Add GridEcho() method.
--                                      Add ShowGridEcho() private method
--          SAV - 26/11/02 -> Add new field to store grid echo aspect
--
---Copyright:        Matra Datavision 1992

class Viewer from V3d

        ---Version:

        ---Purpose: Defines services on Viewer type objects.
        --            The methods of this class allow editing and
        --            interrogation of the parameters linked to the viewer
        --            its friend classes (View,light,plane).

        ---Keywords: Viewer,Default Attributes

        ---References:

inherits

        Viewer from Viewer

uses

        GraphicDevice from Aspect,
        TypeOfUpdate from V3d,
        TypeOfVisualization from V3d,
        TypeOfShadingModel from V3d,
        TypeOfSurfaceDetail from V3d,
        TypeOfOrientation from V3d,
        View from V3d,
        Light from V3d,
        Plane from V3d,
        ListOfTransient from V3d,
        ListIteratorOfListOfTransient from TColStd,
        TypeOfView from V3d,
        Vector from Graphic3d,
        ViewManager from Visual3d,
        NameOfColor from Quantity,
        TypeOfColor from Quantity,
        Color from Quantity,
        Length from Quantity,
        PlaneAngle from Quantity,
        Background from Aspect,
        GradientBackground from Aspect,
        Parameter from Quantity,
        OrthographicView from V3d,
        PerspectiveView from V3d,
        AsciiString,ExtendedString from TCollection,
        Ax3 from gp,Structure from Graphic3d,
        Vertex from Graphic3d,
        Group from Graphic3d,
        AspectMarker3d from Graphic3d,
        RectangularGrid from V3d,
        CircularGrid from V3d,
        Grid from Aspect,
        GridType from Aspect,
        GridDrawMode from Aspect,
        GradientFillMethod from Aspect

raises

        BadValue from Viewer

is

        Create ( Device     : GraphicDevice from Aspect;
             aName          : ExtString from Standard;
             aDomain        : CString from Standard = "";
             ViewSize       : Length from Quantity = 1000.0 ;
             ViewProj       : TypeOfOrientation from V3d= V3d_XposYnegZpos ;
             ViewBackground : NameOfColor from Quantity = Quantity_NOC_GRAY30;
             Visualization  : TypeOfVisualization from V3d = V3d_ZBUFFER;
             ShadingModel   : TypeOfShadingModel  from V3d = V3d_GOURAUD ;
             UpdateMode     : TypeOfUpdate from V3d = V3d_WAIT;
             ComputedMode   : Boolean from Standard = Standard_True;
             DefaultComputedMode: Boolean from Standard = Standard_True;
             SurfaceDetail  : TypeOfSurfaceDetail  from V3d = V3d_TEX_NONE)
        returns mutable Viewer from V3d
        ---Purpose: Create a Viewer on the given device with the given parameters  or
        --          with their default values.
        raises BadValue from Viewer ;
        ---Purpose:        If the size of the view is <= 0
        --      if ComputedMode is false, only the degenerate mode will be used.
        --
        --  Warning: Client must creates a graphic-device of type
        --            Graphic3d_GraphicDevice under UNIX
        --         or Graphic3d_WNTGraphicDevice under WindowsNT

        CreateView (me: mutable) returns mutable View from V3d;
        ---Level: Public
        ---Purpose: creates a view in the viewer according to its
        --          default parameters.

        DefaultOrthographicView(me: mutable) returns mutable OrthographicView from V3d;

        DefaultPerspectiveView(me: mutable) returns mutable PerspectiveView from V3d;

        -------------------------------------------------------
        ---Category: Methods to modify the status of the viewer
        -------------------------------------------------------

        SetViewOn (me:mutable );
        ---Level: Public
        ---Purpose: Activates all of the views of a viewer attached
        --            to a window.

        SetViewOn (me:mutable; View : View from V3d )
        ---Level: Public
        ---Purpose: Activates a particular view in the Viewer .
        --            Must be call if the Window attached to the view
        --            has been Deiconified .
                raises BadValue from Viewer;
        --        If the view is not mapped on the window.

        SetViewOff (me:mutable);
        ---Level: Public
        ---Purpose: Deactivates all the views of a Viewer
        --            attached to a window.

        SetViewOff (me:mutable; View : View from V3d)
        ---Level: Public
        ---Purpose: Deactivates a particular view in the Viewer.
        --            Must be call if the Window attached to the view
        --            has been Iconified .
                raises BadValue from Viewer;
        --        If the view is not mapped on the window.

        Update (me:mutable ) is redefined static;
        ---Level: Public
        ---Purpose: Updates the display of all the views of a viewer.
        --            Must be called when the views must be updated
        --            simultaneously while the Update mode is deferred (WAIT).

        UpdateLights (me: mutable);
        ---Level: Public
        ---Purpose: Updates the lights of all the views of a viewer.

        Redraw ( me );
        ---Level: Public
        ---Purpose: Redraws all the views of the Viewer even if no
        --            modification has taken place. Must be called if
        --            all the views of the Viewer are exposed, as for
        --           example in a global DeIconification.

        Remove (me:mutable);
        ---Level: Public
        ---Purpose: Suppresses the Viewer.

        Erase ( me );
        ---Level: Public
        ---Purpose: Erase all Objects in All the views.

        UnHighlight ( me );
        ---Level: Public
        ---Purpose: UnHighlight all Objects in All the views.

        SetDefaultBackgroundColor (me:mutable; Type : TypeOfColor; V1, V2, V3 : Parameter );
        ---Level: Public
        ---Purpose: Defines the default base colour of views attached
        --            to the Viewer by supplying the type of colour
        --            definition and the three component values..

        SetDefaultBackgroundColor (me:mutable; Name : NameOfColor );
        ---Level: Public
        ---Purpose: Defines the default background colour of views
        --            attached to the viewer by supplying the name of the
        --            colour under the form Quantity_NOC_xxxx .

        SetDefaultBackgroundColor (me:mutable; Color : Color from Quantity);
        ---Level: Public
        ---Purpose: Defines the default background colour of views
        --            attached to the viewer by supplying the color object

        SetDefaultBgGradientColors ( me:mutable;
                                     Name1 : NameOfColor;
                                     Name2 : NameOfColor;
                                     FillStyle : GradientFillMethod from Aspect = Aspect_GFM_HOR  );
        ---Level: Public
        ---Purpose: Defines the default gradient background colours of view
        --            attached to the viewer by supplying the name of the
        --            colours under the form Quantity_NOC_xxxx .

        SetDefaultBgGradientColors ( me : mutable ;
                                     Color1 : Color from Quantity;
                                     Color2 : Color from Quantity;
                                     FillStyle : GradientFillMethod from Aspect = Aspect_GFM_HOR );
        ---Level: Public
        ---Purpose: Defines the default gradient background colours of views
        --            attached to the viewer by supplying the colour objects

        SetDefaultViewSize (me:mutable; Size : Length )
        ---Level: Public
        ---Purpose: Gives a default size for the creation of views of
        --            the viewer.
                raises BadValue from Viewer;
        --        If the size of the view is <= 0

        SetDefaultViewProj (me:mutable; Orientation : TypeOfOrientation );
        ---Level: Public
        ---Purpose: Gives the default projection for creating views
        --            in the viewer.

        SetDefaultVisualization(me:mutable; Type : TypeOfVisualization from V3d);
        ---Level: Public
        ---Purpose: Gives the default visualisation mode..


        SetZBufferManagment(me: mutable; Automatic: Boolean from Standard);
        ---Level: Public
        ---Purpose: defines the strategy concerning the ZBuffer activity.
        --          If Automatic is true, ZBuffer will be activated or
        --          deactivated depending on the fact that faces exist or
        --          not in the Viewer. This will optimize the response time
        --          in the case where only wireframe objects are displayed.
        --          If Automatic is False, ZBuffer will be activated or
        --          deactivated depending on the choice of SetVisualization
        --          in each View.
        --          Note that by default, the ZBufferManagment is not automatic.

        ZBufferManagment(me) returns Boolean from Standard;
        ---Level: Public
        ---Purpose: returns the ZBuffer stategy choice.

        SetDefaultShadingModel(me:mutable; Type : TypeOfShadingModel from V3d);
        ---Level: Public
        ---Purpose: Gives the default type of SHADING.

        SetDefaultSurfaceDetail(me:mutable; Type : TypeOfSurfaceDetail from V3d);
        ---Level: Public
        ---Purpose: Gives the default type of texture mapping.

        SetDefaultAngle (me:mutable; Angle : PlaneAngle from Quantity);
        ---Level: Public

        SetUpdateMode ( me: mutable ; Mode : TypeOfUpdate from V3d );
        ---Level: Public
        ---Purpose: Defines the mode of regenerating the views making
        --            up the viewer. This can be immediate <ASAP> or
        --            deferred <WAIT>. In this latter case, the views are
        --            updated when the method Update(me) is called.

        SetDefaultTypeOfView(me:mutable; Type : TypeOfView from V3d);
        ---Level: Public


        SetPrivilegedPlane(me: mutable; aPlane: Ax3 from gp);
        ---Level: Public

        PrivilegedPlane(me) returns Ax3 from gp;
        ---Level: Public

        DisplayPrivilegedPlane(me: mutable; OnOff: Boolean from Standard; aSize: Length from Quantity = 1);
        ---Level: Public

        SetLightOn(me:mutable; MyLight : Light from V3d )
        ---Level: Public
        ---Purpose: Activates MyLight in the viewer.
                raises BadValue from Viewer;
        --        If No More Light can be activated in MyViewer .

        SetLightOn(me:mutable)
        ---Level: Public
        ---Purpose: Activates all the lights defined in this viewer.
                raises BadValue from Viewer;
        --        If No More Light can be activated in MyViewer .

        SetLightOff(me:mutable; MyLight : Light  from V3d );
        ---Level: Public
        ---Purpose: Desactivate MyLight in this viewer.

        SetLightOff(me:mutable);
        ---Level: Public
        ---Purpose: Deactivate all the Lights defined in this viewer.

        DelLight(me:mutable; MyLight : Light from V3d);
        ---Level: Internal
        ---Purpose: Delete Light in Sequence Of Lights.

        SetCurrentSelectedLight (me : mutable; TheLight : Light from V3d);
        ---Level: Advanced
        ---Purpose: Defines the selected light.

            ClearCurrentSelectedLight (me : mutable);
        ---Level: Advanced
        ---Purpose: Defines the selected light at NULL.

        -----------------------------------------
        ---Category: Inquire methods
        -----------------------------------------

        DefaultBackgroundColor ( me ; Type : TypeOfColor ; V1,V2,V3 : out Parameter);
        ---Level:  Public
        ---Purpose: Returns the default background colour depending of the type.
        DefaultBackgroundColor ( me ) returns Color from Quantity;
        ---Level:  Public
        ---Purpose: Returns the default background colour object.

        DefaultBgGradientColors( me;
                                 Color1 : out Color from Quantity;
                                 Color2 : out Color from Quantity) ;
        ---Level: Public
        ---Purpose: Returns the gradient background colour objects of the view.

        DefaultViewSize ( me) returns Length;
        ---Level:  Public
        ---Purpose: Returns the default size of the view.

        DefaultViewProj ( me) returns TypeOfOrientation;
        ---Level:  Public
        ---Purpose: Returns the default Projection.

        DefaultVisualization ( me ) returns TypeOfVisualization from V3d;
        ---Level:  Public
        ---Purpose: Returns the default type of Visualization.

        DefaultShadingModel ( me ) returns TypeOfShadingModel from V3d;
        ---Level:  Public
        ---Purpose: Returns the default type of Shading

        DefaultSurfaceDetail ( me ) returns TypeOfSurfaceDetail from V3d;
        ---Level:  Public
        ---Purpose: Returns the default type of texture mapping

        DefaultAngle ( me ) returns PlaneAngle from Quantity;
        ---Level:  Public

        UpdateMode ( me ) returns TypeOfUpdate from V3d;
        ---Level:  Public
        ---Purpose: Returns the regeneration mode of views in the viewer.

        IfMoreViews( me ) returns Boolean;
        ---Level:   Advanced
        ---Purpose: Returns True if One View more can be
        --          activated in this Viewer.
        --

        ------------------------------
        ---Category: iteration methods
        ------------------------------

        InitActiveViews(me: mutable);
        ---Level:   Advanced
        ---Purpose: initializes an iteration on the active views.

        MoreActiveViews (me) returns Boolean from Standard;
        ---Level:   Advanced
        ---Purpose: returns true if there are more active view(s) to return.

        NextActiveViews (me: mutable);
        ---Level:   Advanced
        ---Purpose : Go to the next active view
        --           (if there is not, ActiveView will raise an exception)

        ActiveView(me) returns mutable View from V3d;
        ---Level:   Advanced

        LastActiveView(me) returns Boolean from Standard;
        ---Level:   Advanced
        ---Purpose: returns true if there is only
        --          one active view.

        InitDefinedViews(me: mutable);
        ---Level:   Advanced
        ---Purpose: initializes an iteration on the Defined views.


        MoreDefinedViews (me) returns Boolean from Standard;
        ---Level:   Advanced
        ---Purpose: returns true if there are more Defined view(s) to return.


        NextDefinedViews (me: mutable);
        ---Level:   Advanced
        ---Purpose : Go to the next Defined view
        --           (if there is not, DefinedView will raise an exception)

        DefinedView(me)        returns View from V3d;
        ---Level:   Advanced

        InitActiveLights(me: mutable);
        ---Level:   Advanced
        ---Purpose: initializes an iteration on the active Lights.

        MoreActiveLights (me) returns Boolean from Standard;
        ---Level:   Advanced
        ---Purpose: returns true if there are more active Light(s) to return.


        NextActiveLights (me: mutable);
        ---Level:   Advanced
        ---Purpose : Go to the next active Light
        --           (if there is not, ActiveLight will raise an exception)


        ActiveLight(me)        returns mutable Light from V3d;
        ---Level:   Advanced

        InitDefinedLights(me: mutable);
        ---Level:   Advanced
        ---Purpose: initializes an iteration on the Defined Lights.

        MoreDefinedLights (me)        returns Boolean from Standard;
        ---Level:   Advanced
        ---Purpose: returns true if there are more Defined Light(s) to return.

        NextDefinedLights (me: mutable);
        ---Level:   Advanced
        ---Purpose : Go to the next Defined Light
        --           (if there is not, DefinedLight will raise an exception)

        DefinedLight(me) returns Light from V3d;
        ---Level:   Advanced

        AddPlane( me: mutable; MyPlane : Plane from V3d);
        ---Purpose: Adds Plane in Sequence Of Planes.

        DelPlane( me: mutable; MyPlane : Plane from V3d);
        ---Purpose: Delete Plane in Sequence Of Planes.

        InitDefinedPlanes(me: mutable);
        ---Level:   Advanced
        ---Purpose: initializes an iteration on the Defined Planes.

        MoreDefinedPlanes (me) returns Boolean from Standard;
        ---Level:   Advanced
        ---Purpose: returns true if there are more Defined Plane(s) to return.

        NextDefinedPlanes (me: mutable);
        ---Level:   Advanced
        ---Purpose : Go to the next Defined Plane
        --           (if there is not, DefinedPlane will raise an exception)

        DefinedPlane(me) returns Plane from V3d;
        ---Level:   Advanced

        Viewer (me) returns mutable ViewManager ;
        ---Level:   Advanced
        ---Purpose: Returns the viewer associated to Visual3d .

        CurrentSelectedLight (me) returns Light from V3d;
        ---Level:   Advanced
        ---Purpose: Returns the Selected Light.

        IsGlobalLight (me; TheLight : Light from V3d) returns Boolean;
        ---Level:   Advanced

        ComputedMode(me) returns Boolean from Standard;
        ---Level:   Public
        ---Purpose: returns true if the computed mode can be used.

        DefaultComputedMode(me) returns Boolean from Standard;
        ---Level:   Public
        ---Purpose: returns true if by default the computed mode must be used.

        -----------------------------------------
        ---Category: grid management
        -----------------------------------------

        ActivateGrid (me                : mutable;
                      aGridType                : GridType from Aspect;
                      aGridDrawMode        : GridDrawMode from Aspect)
        is static;
        ---Purpose: Activates the grid in all views of <me>.
        ---Level : Public
        ---Category: grid management

        DeactivateGrid (me        : mutable)
        is static;
        ---Purpose: Deactivates the grid in all views of <me>.
        ---Level : Public
        ---Category: grid management

        SetGridEcho (me : mutable;
                showGrid: Boolean from Standard = Standard_True) is static;
        ---Purpose: Show/Don't show grid echo to the hit point.
        -- If TRUE,the grid echo will be shown at ConvertToGrid() time.
        ---Level : Public
        ---Category: grid management

        SetGridEcho (me : mutable;
                aMarker: AspectMarker3d from Graphic3d) is static;
        ---Purpose: Show grid echo <aMarker> to the hit point.
        --  Warning: When the grid echo marker is not set,
        --           a default marker is build with the attributes:
        --           marker type : Aspect_TOM_STAR
        --           marker color : Quantity_NOC_GRAY90
        --           marker size : 3.0
        ---Level : Public
        ---Category: grid management

        GridEcho (me) returns Boolean from Standard is static;
        ---Purpose: Returns TRUE when grid echo must be displayed
        --           at hit point.
        ---Level : Public
        ---Category: grid management

        IsActive (me)
                returns Boolean from Standard
        is static;
        ---Purpose: Returns Standard_True if a grid is activated in <me>.
        ---Level : Public
        ---Category: grid management

        Grid (me)
        returns mutable Grid from Aspect
        is static;
        ---Purpose : Returns the defined grid in <me>.
        ---Level : Public
        ---Category: grid management

        GridType (me)
                returns GridType from Aspect
        is static;
        ---Purpose: Returns the current grid type defined in <me>.
        ---Level : Public
        ---Category: grid management

        GridDrawMode (me)
                returns GridDrawMode from Aspect
        is static;
        ---Purpose: Returns the current grid draw mode defined in <me>.
        ---Level : Public
        ---Category: grid management

        RectangularGridValues (me;
                XOrigin, YOrigin        : out Length from Quantity;
                XStep, YStep                : out Length from Quantity;
                RotationAngle                : out PlaneAngle from Quantity)
        is static;
        ---Purpose: Returns the definition of the rectangular grid.
        ---Level : Public
        ---Category: grid management

        SetRectangularGridValues (me        : mutable;
                XOrigin, YOrigin        : Length from Quantity;
                XStep, YStep                : Length from Quantity;
                RotationAngle                : PlaneAngle from Quantity)
        is static;
        ---Purpose: Sets the definition of the rectangular grid.
        ---            <XOrigin>, <YOrigin> defines the origin of the grid.
        ---            <XStep> defines the interval between 2 vertical lines.
        ---            <YStep> defines the interval between 2 horizontal lines.
        ---            <RotationAngle> defines the rotation angle of the grid.
        ---Level : Public
        ---Category: grid management

        CircularGridValues (me;
                XOrigin, YOrigin        : out Length from Quantity;
                RadiusStep                : out Length from Quantity;
                DivisionNumber                : out Integer from Standard;
                RotationAngle                : out PlaneAngle from Quantity)
        is static;
        ---Purpose: Returns the definition of the circular grid.
        ---Level : Public
        ---Category: grid management

        SetCircularGridValues (me        : mutable;
                XOrigin, YOrigin        : Length from Quantity;
                RadiusStep                : Length from Quantity;
                DivisionNumber                : Integer from Standard;
                RotationAngle                : PlaneAngle from Quantity)
        is static;
        ---Purpose: Sets the definition of the circular grid.
        ---            <XOrigin>, <YOrigin> defines the origin of the grid.
        ---            <RadiusStep> defines the interval between 2 circles.
        ---            <DivisionNumber> defines the section number of one half circle.
        ---            <RotationAngle> defines the rotation angle of the grid.
        ---Level : Public
        ---Category: grid management

        CircularGridGraphicValues (me;
                Radius                        : out Length from Quantity;
                OffSet                        : out Length from Quantity)
        is static;
        ---Purpose: Returns the location and the size of the grid.
        ---Level : Public
        ---Category: grid management

        SetCircularGridGraphicValues (me        : mutable;
                Radius                        : Length from Quantity;
                OffSet                        : Length from Quantity)
        is static;
        ---Purpose: Sets the location and the size of the grid.
        ---            <XSize> defines the width of the grid.
        ---            <YSize> defines the height of the grid.
        ---            <OffSet> defines the displacement along the plane normal.
        ---Level : Public
        ---Category: grid management

        RectangularGridGraphicValues (me;
                XSize, YSize                : out Length from Quantity;
                OffSet                        : out Length from Quantity)
        is static;
        ---Purpose: Returns the location and the size of the grid.
        ---Level : Public
        ---Category: grid management

        SetRectangularGridGraphicValues (me        : mutable;
                XSize, YSize                : Length from Quantity;
                OffSet                        : Length from Quantity)
        is static;
        ---Purpose: Sets the location and the size of the grid.
        ---            <XSize> defines the width of the grid.
        ---            <YSize> defines the height of the grid.
        ---            <OffSet> defines the displacement along the plane normal.
        ---Level : Public
        ---Category: grid management

        -----------------------------------------
        ---Category: Private or Protected methods
        -----------------------------------------

        GetBackgroundColor ( me )
                        returns Background from Aspect is private;
        ---Purpose: Returns the default background colour.

        GetGradientBackground ( me ) returns GradientBackground from Aspect;
        ---Level: Public
        ---Purpose: Returns the gradient background of the view.

        AddView( me: mutable; MyView : View from V3d) is private;
        ---Purpose: Adds View in Sequence Of Views.

        DelView( me: mutable; MyView : View from V3d) is private;
        ---Purpose: Delete View in Sequence Of Views.

        AddLight( me: mutable; MyLight : Light from V3d) is private;
        ---Purpose: Adds Light in Sequence Of Lights.

        SetDefaultLights(me: mutable);
        ---Purpose: defines default lights  -
        --          positional-light 0.3 0. 0.
        --          directional-light V3d_XnegYposZpos
        --          directional-light V3d_XnegYneg
        --          ambient-light

        Init(me: mutable);

        IsActive(me; aView: View from V3d)
        returns Boolean from Standard is private;

        ShowGridEcho(me : mutable;
                        aView: View from V3d;
                        aPoint: Vertex from Graphic3d) is private;
        ---Purpose:
        -- Display grid echo at requested point in the view.

fields

        MyViewer:               ViewManager from Visual3d ;
        MyDefinedViews:                ListOfTransient from V3d;
        MyActiveViews:                ListOfTransient from V3d;
        MyDefinedLights:        ListOfTransient from V3d;
        MyActiveLights:          ListOfTransient from V3d;
        MyDefinedPlanes:        ListOfTransient from V3d;
        MyBackground:                Background from Aspect ;
        MyGradientBackground:        GradientBackground from Aspect ;
        MyViewSize:                Real ;
        MyViewProj:                TypeOfOrientation from V3d ;
        MyVisualization:        TypeOfVisualization from V3d ;
        MyShadingModel:         TypeOfShadingModel from V3d ;
        MySurfaceDetail:        TypeOfSurfaceDetail from V3d ;
        MyDefaultAngle:         PlaneAngle from Quantity;
        MyDefaultTypeOfView:    TypeOfView from V3d;
        MyDefaultOrthographicView: OrthographicView from V3d;
        MyDefaultPerspectiveView: PerspectiveView from V3d;
        MyCurrentSelectedLight:   Light from V3d;
        myActiveViewsIterator: ListIteratorOfListOfTransient from TColStd;
        myDefinedViewsIterator: ListIteratorOfListOfTransient from TColStd;
        myActiveLightsIterator: ListIteratorOfListOfTransient from TColStd;
        myDefinedLightsIterator: ListIteratorOfListOfTransient from TColStd;
        myDefinedPlanesIterator: ListIteratorOfListOfTransient from TColStd;
        myComputedMode: Boolean from Standard;
        myDefaultComputedMode: Boolean from Standard;
        myPrivilegedPlane: Ax3 from gp;
        myPlaneStructure: Structure from Graphic3d;
        myDisplayPlane: Boolean from Standard;
        myDisplayPlaneLength: Length from Quantity;

        myRGrid: RectangularGrid from V3d;
        myCGrid: CircularGrid from V3d;
        myGridType: GridType from Aspect;

        myGridEcho: Boolean from Standard;
        myGridEchoStructure: Structure from Graphic3d;
        myGridEchoGroup: Group from Graphic3d;
        myGridEchoAspect : AspectMarker3d from Graphic3d;
friends

        class View from V3d,
        class Light from V3d,
        class Plane from V3d,
        SetPlane  from package V3d (aViewer: Viewer from V3d; x1,y1,z1,x2,y2,z2: Length from Quantity)
end Viewer;