Class SoLassoScreenDrawer

  • All Implemented Interfaces:

    public class SoLassoScreenDrawer
    extends SoPolyLineScreenDrawer
    Interactively draw a lasso in normalized screen space. This class can be used to interactively draw a lasso (freeform shape) on screen.

    When the lasso is finished, an event is raised to notify the application (see SoPolyLineScreenDrawer.onFinish ). Points are returned as normalized coordinates in the range -1..1, which is conveniently the default view volume for an SoOrthographicCamera node.

    The line color and simplification threshold are specified by fields in the parent class SoPolyLineScreenDrawer.

    Please see SoPolyLineScreenDrawer for general notes and code example.

    Lasso specific notes:

    • The simplificationThreshold field does apply to this node.
    • If user finishes a lasso, then the next click will automatically clear the polyline (begin a new lasso).
    • SbEventHandlers:
      • OnStart : Triggered on LeftMouseDown input event.
      • OnMove : Triggered on MouseMove input events (after Start).
      • OnFinish : Triggered on LeftMouseUp input event.


    • Press left mouse and drag to draw the lasso.
    • Release to finish the lasso.
    • Press Escape to cancel construction of the lasso.

    File format/default:

    LassoScreenDrawer {

      point []
      color 1 0 0
      simplificationThreshold 5
      isClosed true

    See Also:
    SoEllipseScreenDrawer, SoPolyLineScreenDrawer, SoPolygonScreenDrawer, SoRectangleScreenDrawer
    • Constructor Detail

      • SoLassoScreenDrawer

        public SoLassoScreenDrawer()