>  Docs Center  >  Libraries  >  Motley  >  MGHGRGRAPH__DEFINE

MGHGRGRAPH__DEFINE

MGHGRGRAPH__DEFINE

Class Name


  MGHgrGraph

Purpose


  An MGHgrGraph is an IDLgrView with extra facilities that make it
  useful as a container for general-purpose scientific graphs. These
  include:
    - Containers to hold resources (fonts, symbols, palettes)
      required by graphics atoms.
    - Methods to create axes and fit them to the view dimensions.
    - Methods to create or add graphics atoms and scale them to the
      axes.
    - By default, there is a fixed relationship between the
      viewplane dimensions in normalised and physical
      coordinates. (This means that you can assume that a graphics
      atom that is "square" in normalised coordinates will be square
      on the destination device.)
  An MGHgrGraph does not assume anything in particular about the
  layout of the graph. The default axis location and length (centred
  in the viewplane with length 1 in normalised coordinates) makes
  sure that the axes will be seen but will need to be modified for
  actual graphs. Thus this class be useful mainly for "free-form"
  graphs; for most purposes it be used via a subclass such as
  MGHgrGraph2D or MGHgrGraph3D.

Category


  Object graphics.

Superclasses


  IDLgrView.

Properties


  The following properties (ie keywords to the Init, GetProperty &
  SetProperty methods) are supported in addition to those inherited
  from IDLgrView:
    ALL (Get)
      This property wraps the object's other properties in a structure.
    DELTAZ (Get)
      This is a real number specifying the minimum spacing, in
      normalised coordinates, needed in the Z direction to ensure
      that graphic atoms overlap cleanly. The value is calculated
      from the ZCLIP property (inherited from IDLgrView).
    DIMENSIONS (Init, Get, Set)
      As IDLgrView, but by default an MGHgrGraph object is created
      with explicit dimensions calculated from the VIEWPLANE_RECT
      and SCALE properties. Thereafter, if the VIEWPLANE_RECT is
      altered then DIMENSIONS are also altered so as to preserve
      SCALE.
    FONTSIZE (Init, Get, Set)
      The default size in points for font objects created by the
      NewFont method. The default value is determined by
      MGH_GRAPH_DEFAULT.
    N_MODELS (Init, Get)
      The number of IDLgrModel objects directly attached to the
      graph.
    SCALE (Init, Get, Set)
      This is a 2-element vector specifying the size in physical
      dimensions of a unit square on the viewplane. The GetProperty
      method always returns a 2-element vector for SCALE, but in
      calls to Init and SetProperty it should normally be specified
      as a scalar, indicating that the scale is the same in X & Y
      dimensions. The default value of SCALE depends on the UNITS
      property: for UNITS = 2 it is 7.5 cm. A SCALE of 0 or [0,0]
      indicates that the graph's dimensions are not specified
      explicitly (i.e. UNITS = 3 or DIMENSIONS = [0,0]).
    SYMSIZE (Init, Get, Set)
      The default size in normalised coordinates for symbols created
      by the NewSymbol method. Default value is 0.02D0.
    TICKLEN (Init, Get, Set)
      The default tickmark length in normalised coordinates for axes
      created by the NewAxis method. Default value is 0.03.
    UNITS (Init, Get, Set)
      As IDLgrView, but default is 2 (dimensions specified in cm).

Methods


  Most of the methods that create new objects can be called as
  functions (returning the object reference(s)) or procedures
  (references discarded).
    NewFont
      Create a new font object and add it to a container attached to
      the view. Fonts can be retrieved with the GetFont method and
      are destroyed with the view. Several of the methods below use
      the first font in the container when creating text objects.
    AddFont
      Like NewFont, but use an existing font. Obsolete.
    GetFont
      Retrieve object references from the fonts container. Similar
      syntax to IDL_Container::Get.
    NewSymbol
      Create a new symbol object and add it to a container attached
      to the view. Symbols can be retrieved with the GetSymbol
      method and are destroyed with the view. The default symbol
      size, taken from the SYMSIZE property, can be overriden via
      the SIZE keyword.
    GetSymbol
      Retrieve object references from the symbols container. Similar
      syntax to IDL_Container::Get.
    Dispose
      Add an object (eg a palette) to a container for disposal with
      the graph.
    NewAtom
      Create a graphics atom (or atom-like object) and add it to the
      graph. NewAtom is either invoked directly or via a wrapper
      method (below); it takes care of associating the new object
      with the right model & axes. The object type is specified via
      the first parameter & NewAtom can accept up to 3 further
      positional parameters, which are passed to the object's Init
      method.
    AddAtom
      Take an existing graphics atom, add it to the graph and
      associate it with the right model & axes. This is not used as
      often as NewAtom, but is appropriate, for example, when the
      size of a graphics atom will not be known until after it is
      created.
###########################################################################
  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


  Mark Hadfield, 2000-08:
    - Replaced existing classes MGHgrView, MGHgrGraph,
      MGHgrFixedGraph & MGHgrGraph3D with MGHgrGraph (similar to the
      old MGHgrView), MGHgrGraph2D (merges the old MGHgrGraph &
      MGHgrFixedGraph) and MGHgrGraph3D (similar to the old class of
      the same name but much of the logic has been moved to the
      superclass MGHgrGraph).
    - Added a facility for graphs to use master-slave axes, enabled
      by the property USE_MSAXIS, which defaults to 0. In sorting
      this out I introduced a significant backward-incompatible
      change: the GetScaling method picks up its scaling from the
      first suitable axis it finds, not the last. The new convention
      makes the implementation of master-slave graphs much simpler
      and more logical, but the preparation of multi-scaled graphs
      becomes less convenient.
  Mark Hadfield, 2001-01:
    - NewText method now sets the text object's RECOMPUTE_DIMENSIONS
      property to 2 by default.
  Mark Hadfield, 2001-05:
    - Models created by the view are now instances of
      MGHgrModel. Each MGHgrModel keeps track of the axes that have
      been added to it, which this allows the MGHgrGraph code to be
      simpler.
  Mark Hadfield, 2002-06:
    - Default value for USE_MSAXIS changed from 0 to 1.
  Mark Hadfield, 2004-05:
    - Revised GetScaling code, removing calls to MGH_GET_PROPERTY.
  Mark Hadfield, 2004-07:
    - The NewAtom method now sets the REGISTER_PROPERTY keyword by
      default for all atoms.
    - Modified to accommodate the changes in the axis classes.
      Property USE_MSAXIS is no longer supported; master-slave
      behaviour can be suppressed in various methods by setting
      SLAVE to 0.
  Mark Hadfield, 2005-09:
    - Default scale (in cm) increased from 6 to 9.
  Mark Hadfield, 2006-08:
    - Default scale (in cm) decreased from 9 to 8 to suit my new
      monitor better.
  Mark Hadfield, 2007-08:
    - Generalised NormPosition method so it accepts [2,n] or [3,n]
      arrays as input. DataPosition method should also be (but hasn't
      been) generalised in this way.
  Mark Hadfield, 2008-08:
    - Added a NewColorBar method (function and procedure). The
      method of the same name in the MGHgrGraph2D class, now calls
      this one.
  Mark Hadfield, 2009-04:
    A couple of changes have been made to accommodate the change in
    IDLgrWindow resolution in IDL version 7.1. (The value was queried
    from the OS but is now set to a fixed 72 dpi). Code to set the default
    SCALE property is now version-dependent and a FONTSIZE property has
    been added, with a version-dependent default value.
  Mark Hadfield, 2010-11:
    The change in IDLgrWindow resolution (see previous entry) has been
    reversed in IDL 8.0.1; the default values of the SCALE and FONTSIZE
    (which are set by routine MGH_GRAPH_DEFAULT) have been altered
    accordingly.



© 2019 Harris Geospatial Solutions, Inc. |  Legal
My Account    |    Store    |    Contact Us