Name

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      FREEHAND_ROI__DEFINE

Purpose

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      The purpose of this routine is to create a freehand ROI drawing
      interaction. When the interaction is in place, the user can
      draw a freehand polygon ROI in the display window.

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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      theObject = Obj_New("FREEHAND_ROI")

Superclasses

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      INTERACTION
      CATATOM
      CATCONTAINER IDLITCOMPONENT
      IDL_CONTAINER

Class Structure

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  class = { FREEHAND_ROI, $
            xpts: Ptr_New(), $ ; The X points in the ROI.
            ypts: Ptr_New(), $ ; The X points in the ROI.
            count: 0L, $ ; The number of points in the ROI.
            bufferID: Obj_New(), $ ; A pixmap buffer for smooth graphics display.
            thick: 0.0, $ ; The thickness of the line used to draw ROI.
            linestyle: 0L, $ ; The line style of the line used to draw ROI.
            INHERITS INTERACTION $
          }

Messages

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  None.

Event Structure

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      event = { ID:theObject, TOP:topObject, HANDLER:Obj_New(), EVENT_NAME='FREEHAND_ROI_EVENT', $
                  NAME: self._name, XPTS:FLTARR(), YPTS:FLATARR(), COUNT:0L }
      In which the XPTS and YPTS fields contain the X and Y locations of the polygon in a form
      suitable for drawing the ROI on the display with PLOTS. The COUNT field contains the number
      of points in the XPTS and YPTS vectors. The XPTS and YPTS are converted to the coordinate
      system of the draw widget associated with the interaction before being placed in the event structure.

Modification History

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      Written by: David W. Fanning, February 6, 2004.