ONE_ARROW

       Draws an arrow labeled with a single character on the current device

       ONE_ARROW is called, for example, by ARROWS to create a
       "weathervane" showing the N-E orientation of an image.

       one_arrow, xcen, ycen, angle, label, CHARSIZE = , THICK = , COLOR =
                       ARROWSIZE=, FONT =  ]

    xcen, ycen = starting point of arrow in device coordinates, floating
                       point scalars,
    angle      = angle of arrow in degrees counterclockwise from +X direction
    label      = single-character label (may be blank)
 OUTPUT PARAMETERS:  none

       CHARSIZE   = usual IDL meaning, default = 2.0
       THICK      = usual IDL meaning, default = 2.0
       COLOR      = usual IDL meaning, default = !P.COLOR
       ARROWSIZE  = 3-element vector defining appearance of arrow.
               Default = [30.0, 9.0, 35.0], meaning arrow is 30 pixels
               long; arrowhead lines 9 pixels long and inclined 35
               degrees from arrow shaft.
               If you try to use a non-TV device, you will probably
               want to change this.
       FONT - IDL vector font number to use (1-20).   For example, to write
               the 'N' and 'E' characters in complex script, set font=13

       Draw an triple size arrow emanating from the point (212,224)
       and labeled with the character 'S'
       IDL> one_arrow,212,224,270,'S',charsize=3

       Calls one_ray to vector-draw arrow.

       Written by R. S. Hill, Hughes STX Corp., 20-May-1992.
       Added font keyword, W.B. Landsman Hughes STX Corp. April 1995
       Modified to work correctly for COLOR=0  J.Wm.Parker, HITC   1995 May 25
       Converted to IDL V5.0   W. Landsman   September 1997

[Home Page] [Software, Documentation] [IDL Documentation] [Quick Reference] [Feedback]