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SoPolyLineScreenDrawer Class

Interactively draw a polyline in normalized screen space.

Inheritance Hierarchy

Namespace: OIV.Inventor.Drawers
Assembly: OIV.Inventor (in OIV.Inventor.dll) Version: 2024.2.2.0 (10.16.2.0)
Syntax
public class SoPolyLineScreenDrawer : SoScreenDrawer

The SoPolyLineScreenDrawer type exposes the following members.

Constructors
  NameDescription
Public methodSoPolyLineScreenDrawer

Constructor.

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Methods
  NameDescription
Public methodAffectsState

Returns true if a node has an effect on the state during traversal.

(Inherited from SoNode.)
Public methodCallback
(Inherited from SoScreenDrawer.)
Public methodClear

Convenience method to clear the points in the line.

Public methodCopy
Calls Copy(false).
(Inherited from SoNode.)
Public methodCopy(Boolean)

Creates and returns an exact copy of the node.

(Inherited from SoNode.)
Public methodCopyFieldValues(SoFieldContainer)
Calls CopyFieldValues(fc, false).
(Inherited from SoFieldContainer.)
Public methodCopyFieldValues(SoFieldContainer, Boolean)

Copies the contents of fc's fields into this object's fields.

(Inherited from SoFieldContainer.)
Public methodDispose
Releases all resources used by SoDisposable.
(Inherited from SoDisposable.)
Public methodDistribute
(Inherited from SoNode.)
Public methodDoAction
(Inherited from SoScreenDrawer.)
Public methodEnableNotify

Notification at this Field Container is enabled (if flag == true) or disabled (if flag == false).

(Inherited from SoFieldContainer.)
Public methodEquals
Determines whether the specified Object is equal to the current Object.
(Inherited from Object.)
Public methodFieldsAreEqual

Returns true if this object's fields are exactly equal to fc's fields.

(Inherited from SoFieldContainer.)
Public methodGet

Returns the values of the fields of this object in the Open Inventor ASCII file format in the given string.

(Inherited from SoFieldContainer.)
Public methodGetAllFields

Returns a list of fields, including the eventIn's and eventOut's.

(Inherited from SoFieldContainer.)
Public methodGetAlternateRep

This method is called by actions to allow the node to provide an "alternate representation" when appropriate (typically depending on the action type).

(Inherited from SoNode.)
Public methodGetBoundingBox
(Inherited from SoScreenDrawer.)
Public methodGetEventIn

Returns a the eventIn with the given name.

(Inherited from SoFieldContainer.)
Public methodGetEventOut

Returns the eventOut with the given name.

(Inherited from SoFieldContainer.)
Public methodGetField

Returns a the field of this object whose name is fieldName.

(Inherited from SoFieldContainer.)
Public methodGetFieldName

Returns the name of the given field in the fieldName argument.

(Inherited from SoFieldContainer.)
Public methodGetFields

Appends references to all of this object's fields to resultList, and returns the number of fields appended.

(Inherited from SoFieldContainer.)
Public methodGetHashCode
Overrides GetHashCode().
(Inherited from SoNetBase.)
Public methodGetMatrix
(Inherited from SoNode.)
Public methodGetName

Returns the name of an instance.

(Inherited from SoBase.)
Public methodGetPrimitiveCount
(Inherited from SoScreenDrawer.)
Public methodGetRenderEngineMode

Returns the supported Render engine mode.

(Inherited from SoNode.)
Public methodGetRenderUnitID
(Inherited from SoNode.)
Public methodGetStringName (Inherited from SoBase.)
Public methodGetType
Gets the Type of the current instance.
(Inherited from Object.)
Public methodGLRender
(Inherited from SoScreenDrawer.)
Public methodGLRenderBelowPath
(Inherited from SoNode.)
Public methodGLRenderInPath
(Inherited from SoNode.)
Public methodGLRenderOffPath
(Inherited from SoNode.)
Public methodGrabEventsCleanup
(Inherited from SoNode.)
Public methodGrabEventsSetup
(Inherited from SoNode.)
Public methodHandleEvent

Traversal routine for OIV.Inventor.Actions.SoHandleEventAction - this will call action->setHandled() if the event is handled.

(Inherited from SoScreenDrawer.)
Public methodHasDefaultValues

Returns true if all of the object's fields have their default values.

(Inherited from SoFieldContainer.)
Public methodIsBoundingBoxIgnoring

This method is used by getBoundingBox action traversal to know if the current node must be traversed or not, ie the bounding should be ignored.

(Inherited from SoNode.)
Public methodIsNotifyEnabled

Notification is the process of telling interested objects that this object has changed.

(Inherited from SoFieldContainer.)
Public methodIsOverride

Returns the state of the override flag.

(Inherited from SoNode.)
Public methodIsSynchronizable

Gets the ScaleViz synchronizable state of this object.

(Inherited from SoBase.)
Public methodNormalizePoint

Returns position normalized in range -1..1 relative to specified viewport.

(Inherited from SoScreenDrawer.)
Public methodPick
(Inherited from SoNode.)
Public methodRayPick
(Inherited from SoScreenDrawer.)
Public methodReset

Clears the points in the line and resets internal state to initial values.

(Overrides SoScreenDrawerReset.)
Public methodSearch
(Inherited from SoNode.)
Public methodSet

Sets one or more fields in this object to the values specified in the given string, which should be a string in the Open Inventor file format.

(Inherited from SoFieldContainer.)
Public methodSetName (Inherited from SoBase.)
Public methodSetOverride

Turns the override flag on or off.

(Inherited from SoNode.)
Public methodSetSynchronizable

Sets this to be a ScaleViz synchronizable object.

(Inherited from SoBase.)
Public methodSetToDefaults

Sets all fields in this object to their default values.

(Inherited from SoFieldContainer.)
Public methodToString
Converts this SoBase structure to a human readable string.
(Inherited from SoBase.)
Public methodTouch

Marks an instance as modified, simulating a change to it.

(Inherited from SoNode.)
Public methodWrite
(Inherited from SoNode.)
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Properties
  NameDescription
Public propertycolor

Color of line.

Public propertydoCCW

Make the line counter-clockwise when it is finalized.

Public propertyisClosed

Close the line during display (connect last point to first point).

Public propertyIsDisposable
ISafeDisposable interface implementation.
(Inherited from SoDisposable.)
Public propertylinePattern

Stipple pattern.

Public propertylinePatternScaleFactor

Stipple pattern scale factor.

Public propertylineWidth

Width of lines.

Public propertypoint

Points of line.

Public propertysceneGraph

Scene graph to render.

(Inherited from SoScreenDrawer.)
Public propertysimplificationThreshold

Threshold (in pixels) used to simplify line when it is finished.

Public propertyUserData
Gets or sets the user data to be contained by the field container.
(Inherited from SoFieldContainer.)
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Events
  NameDescription
Public eventOnFinish

Event raised when the line is finished.

Public eventOnMove

Event raised during polyline drawing.

Public eventOnStart

Event raised when starting to draw a polyline.

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Remarks

This class is a base class used to allow the user to dynamically draw line-based shapes (lasso, circle, rectangle, ...) on screen. The geometry is defined in normalized screen space ([-1, 1]x[-1, 1]).

Applications will typically use one of the derived classes, for example, OIV.Inventor.Drawers.SoEllipseScreenDrawer, OIV.Inventor.Drawers.SoRectangleScreenDrawer, OIV.Inventor.Drawers.SoPolygonScreenDrawer or OIV.Inventor.Drawers.SoLassoScreenDrawer.

The line color is specified by the OIV.Inventor.Drawers.SoPolyLineScreenDrawer.color field (default is red).

OIV.Inventor.Drawers.SoPolyLineScreenDrawer classes can automatically reduce the number of points in the shape drawn by the user. This is especially useful with OIV.Inventor.Drawers.SoLassoScreenDrawer. See the OIV.Inventor.Drawers.SoPolyLineScreenDrawer.simplificationThreshold field.

Sub-classes can implement the onMouseDown, onMouseMove, etc... methods, to add and edit points.

Notes:

  • Viewer:

    • Screen drawers, like draggers, depend on OIV.Inventor.Actions.SoHandleEventAction to get events. Therefore when using one of the Open Inventor viewer classes, screen drawers will only work when the viewer is in "selection" mode (arrow cursor). (In "viewing" mode, mouse events are handled by the viewer to control the camera.)

    • The escape key (ESC) can be used to cancel creation of the polyline. However, currently it also changes the viewer mode (this is a known problem).

  • Event handling: The drawer will automatically begin a new polyline when it sees a mouse button 1 down event. However the drawer does not call setHandled(), so other nodes in the scene graph, e.g. OIV.Inventor.Nodes.SoEventCallback or a dragger, may also handle this event.

  • Finish notification:

    • An event is raised to notify the application when the line is finished. (see OnFinish). This event is called at the end of line finalization (after simplification etc). See SbEventHandler for methods to set a callback to be notified when this event is raised.

    • In this callback the application can retrieve coordinates from the OIV.Inventor.Drawers.SoPolyLineScreenDrawer.point field. These points are in Open Inventor normalized device coordinates (-1 to 1), not pixel coordinates.

    • The drawer does not call the OIV.Inventor.Actions.SoHandleEventAction's setHandled() method for the event that finished the polyline. The application can call setHandled() in this callback.

    • With some drawers it is possible to get a call with zero points if the user pressed ESC to cancel the interaction. Applications should check for this case.

    • With some drawers it is also possible to get a call with a non-zero number of points, but all points are the same coordinate. E.g. OIV.Inventor.Drawers.SoRectangleScreenDrawer stores four points even if the mouse down/up events are at the same location.

    • Typically the application will want to remove the polyline from the screen in this callback. See the next note.

  • Part of the scene graph:

    • Note that the polyline remains on the screen (because it is part of the scene graph) until Clear()is called or the user starts a new interaction.

    • Changing the color field or the isClosed field will immediately change the appearance of a polyline currently on the screen.

  • Simplification: Simplification is done (if > 0) when the user releases the mouse button and also if the simplificationThreshold is changed. But note that the old points are thrown away, so you can't re-simplify with a different value.

  • isClosed field: If true (default), the polyline will be closed while being drawn (not just when the user releases the mouse button). The default in this class is false, but most sub-classes set it to true.

  • Coordinates: This node and its subclasses use screen coordinates ranging from -1 to 1. (Because this is the default view volume for an OIV.Inventor.Nodes.SoOrthographicCamera node.) Be careful because other classes in Open Inventor use normalized screen coordinates ranging from 0 to 1. In particular the OIV.Inventor.SbViewportRegion normalize() methods and the OIV.Inventor.SbViewVolume methods that project from 3D to 2D and vice-versa.

  • There should only be one OIV.Inventor.Drawers.SoScreenDrawer derived node in the sceneGraph (to avoid conflicts in mouse events).

EXAMPLE

Create a screen drawer, set the callback and add it to the scene graph:

SoRectangleScreenDrawer drawer = new SoRectangleScreenDrawer();
 drawer.OnFinish += LineDrawerCallback;
 root.AddChild(drawer);
A finish callback that gets the number of points created by the screen drawer:
public void LineDrawerCallback( object sender, SoPolygonScreenDrawer.EventArg eventArg )
{
   SoPolyLineScreenDrawer drawer = eventArg.Source;
   SoHandleEventAction action = eventArg.Action;

   int numPoints = drawer.point.Count;
   if (numPoints > 0)
   {   // Use points
       SbVec2f point0 = drawer.point[0];
   }
   drawer.Clear();  // Remove polyline from screen
   action.SetHandled();
}

See Also