.\

cgpolygon.pro

top cgPolygon

Graphics

cgPolygon, x, y [, z] [, /ADDCMD] [, /CHECKFORFINITE] [, COLOR=string] [, FCOLOR=string/integer/long] [, /FILL] [, MAP_OBJECT=object] [, /NORMAL] [, /DEVICE] [, POSITION=fltarr(4)] [, /WINDOW] [, _REF_EXTRA=appropriate]

Provides a device-independent and color-model-independent way to draw a filled or unfilled polygon.

The program requires the Coyote Library to be installed on your machine.

Parameters

x in required type=number

A vector argument providing the X coordinates of the points to be connected. The vector must contain at least three elements. If only one argument is specified, X must be an array of either two or three vectors (i.e., (2,*) or (3,*)). In this special case, the vector X[0,*] specifies the X values, X[1,*] specifies Y, and X[2,*] contain the Z values.

y in required type=number

A vector argument providing the Y coordinates of the points to be connected. Y must contain at least three elements.

z in optional type=number

An optional vector argument providing the Z coordinates of the points to be connected. Z must contain at least three elements.

Keywords

ADDCMD in optional type=boolean default=0

Set this keyword to add the command to an cgWindow. Setting this keyword automatically sets the WINDOW keyword, but the command does not erase the graphics window as it would normally.

CHECKFORFINITE in optional type=boolean default=0

If the input data is not finite (i.e., it contains NaNs), then the drawing of the polygons will be affected. This is particularly true if you are drawing polygons on map projections using the Map_Object keyword. The program could check all input for NaNs, but this would be quite slow when a great number of polygons are being drawn. For this reason, the program only checks polygon input when this keyword is set. Only polygons containing all finite values are drawn when this keyword is set.

COLOR in optional type=string default=rose

The name of the polygon color. Color names are those used with cgColor. This value can also be a long integer or an index into the current color table.

FCOLOR in optional type=string/integer/long

The name of the polygon fill color. Color names are those used with cgColor. This value can also be a long integer or an index into the current color table. The default is the same as Color.

FILL in optional type=boolean default=0

Set this keyword to draw a filled polygon, rather than an open polygon.

MAP_OBJECT in optional type=object

If you are drawing on a map projection set up with Map_Proj_Init and using projected meter space, rather than lat/lon space, then you can use this keyword to provide a cgMap object that will allow you to convert the x and y parameters from longitude and latitude, respectively, to projected meter space before drawing. X and Y must both be present.

NORMAL in optional type=boolean default=0

Set to indicate the polygon vertices are in normalized coordinates.

DEVICE in optional type=boolean default=0

Set to indicate the polygon vertices are in device coordinates.

POSITION in optional type=fltarr(4)

Set this keyword to a four-element position array of normalized coordinates to fill a rectangular area on the graphics display. The normal input parameters are ignored if this keyword is set.

WINDOW in optional type=boolean default=0

Set this keyword to add the command to the current cgWindow application.

_REF_EXTRA in optional type=appropriate

Any other keywords to the IDL POLYFILL command may be used.

Examples

Used like the IDL Plots or Polyfill commands:

  IDL> cgPolygon, [0.25, 0.25, 0.75, 0.75, 0.25], [0.25, 0.75, 0.75, 0.25, 0.25], $
            /NORMAL, COLOR='blue'
  IDL> cgPolygon, [0.25, 0.25, 0.75, 0.75, 0.25], [0.25, 0.75, 0.75, 0.25, 0.25], $
            /NORMAL, COLOR='blue', FCOLOR='rose', /FILL

Author information

Author:

FANNING SOFTWARE CONSULTING:

   David W. Fanning
   1645 Sheely Drive
   Fort Collins, CO 80526 USA
   Phone: 970-221-0438
   E-mail: david@idlcoyote.com
   Coyote's Guide to IDL Programming: http://www.idlcoyote.com

Copyright:

History:

Change History:

  Written, 26 March 2012. David Fanning.
  Added Position keyword to allow a fill of a particular portion of the graphics
      window. 20 Apr 2012. DWF.
  Added AddCmd keyword. 25 Oct 2012. DWF.
  Added a MAP_OBJECT keyword to allow polygon filling on maps. 16 Dec 2013. DWF.
  Completely forgot to deconstruct a single parameter into component parts. 11 Jan 2014. DWF.
  Added CheckForFinite keyword to check output for NaN values before display. 22 Jan 2014. DWF.

File attributes

Modification date:	Fri Mar 27 11:07:38 2015
Lines:	320
Docformat:	rst rst

Coyote Graphics Routines

Date: Fri Mar 27 12:14:20 2015