Class Name

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  MGHgrColorBar

Purpose

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  This class implements an object graphics colour bar, ie a rectangular bar
  showing a mapping between numeric values and colours.

Superclasses

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  This class inherits from IDLgrModel.

Properties

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  The following properties are supported:
  AXIS (Get)
    This keyword returns a reference to the axis object. It can be
    used to modify the axis properties.
  BYTE_RANGE (Init,Get,Set)
    The range of byte values to which the data range is to be mapped.
  COLORSCALE (Init)
    A reference to an object from which default colour mapping
    information (BYTE_RANGE, DATA_RANGE and PALETTE) can be
    retrieved.
  DATA_RANGE (Init,Get,Set)
    The range of data values to be mapped onto the indexed color
    range. Data values outside the range are mapped to the nearest
    end of the range.
  DIMENSIONS (Init,Get,Set)
    X & Y dimensions of the rectangle in data units.
  LOCATION (Init,Get,Set)
    Location of the lower left corner of the rectangle in data units.
  PALETTE (Init,Get,Set)
    A reference to the palette defining the byte-color mapping.
  SHOW_AXIS (Init,Get,Set)
    This property determines whether & where the axis should be
    drawn.
      0 - Do not display axis (the default)
      1 - Display axis on left side or below the color ramp
          (default).
      2 - Display axis on right side or above the color ramp I am
          not 100% sure this works correctly in all cases.
  TICKIN (Init,Get,Set)
    Controls whether tick marks are directed inwards (1) or outwards
    (0). The default is 0.
  TITLE (Init,Get,Set)
    A reference to a text object representing the axis title. If
    this is specified as a string, then a text object is created
    automatically using the current setting of the FONT property.
  VERTICAL (Init,Get,Set)
    Set this property to 1 for a colour bar with its axis in the Y
    direction and 0 for a colour bar with its axis in the X
    direction. Default is 0.
  XCOORD_CONV (Init,Get,Set)
  YCOORD_CONV (Init,Get,Set)
  ZCOORD_CONV (Init,Get,Set)
    Coordinate transformations specifying the relationship between
    normalised & data units.
  XRANGE (Get)
  YRANGE (Get)
  ZRANGE (Get)
    Position of the extremes of the object in data units.

Methods

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  The usual.
###########################################################################
  This software is provided subject to the following conditions:
  1. NIWA makes no representations or warranties regarding the
    accuracy of the software, the use to which the software may
    be put or the results to be obtained from the use of the
    software. Accordingly NIWA accepts no liability for any loss
    or damage (whether direct of indirect) incurred by any person
    through the use of or reliance on the software.
  2. NIWA is to be acknowledged as the original author of the
    software where the software is used or presented in any form.
###########################################################################

Modification History

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  Mark Hadfield, Aug 1998:
    Written.
  Mark Hadfield, Aug 1999:
    Changed the colour ramp from an IDLgrSurface to an
    MGHgrColorPlane for better vector output under IDL 5.3.
  Mark Hadfield, Jul 2001:
      Updated for IDL 5.5. With the new DEPTH_OFFSET keyword I was
      able to omit some awkward & fragile vertical-positioning code
      in the Draw method.