# coyote: CGLEGEND

- coyote/Graphics
- [Source code]

Description

      The purpose of this program is to a create simple legend that can be drawn in a
      graphics window. Users needing more complex legends may prefer to use AL_Legend from
      the NASA Astronomy IDL Library. This program has a more limited set of functionality,
      especially in regard to placement options. This program is a wrapper for the
      cgLegendItem object.

Categories

      Graphics

Examples

      A plot with a simple legend::
          cgDisplay, 800, 450
          cgPlot, cgDemoData(17), PSym=-6, SymColor='red7', Position=[0.15, 0.15, 0.7, 0.9]
          cgOPlot, cgDemoData(17), PSym=-15, SymColor='blu7'
          cgLegend, SymColors=['red7', 'blu7'], PSyms=[6,15], Symsize=1.5, Location=[0.725, 0.9], $
             Titles=['May 27', 'June 27'], Length=0.075, /Box, VSpace=2.75, /Background, BG_Color='rose'
      Same as the previous example, but in a resizeable graphics window::
          cgWindow, WXSize=800, WYSize=450
          cgPlot, cgDemoData(17), PSym=-6, SymColor='red7', Position=[0.15, 0.15, 0.7, 0.9], /AddCmd
          cgOPlot, cgDemoData(17), PSym=-15, SymColor='blu7', /AddCmd
          cgLegend, SymColors=['red7', 'blu7'], PSyms=[6,15], Symsize=1.5, Location=[0.725, 0.9], $
             Titles=['May 27', 'June 27'], Length=0.075, /Box, VSpace=2.75, /Background, $
             BG_Color='rose', /AddCmd

Keywords

      addcmd: in, optional, type=boolean,default=0
         If this keyword is set, the object is added to the resizeable graphics
         window, cgWindow. The DRAW method of the object is called in cgWindow.
      alignment: in, optional, type=integer, default=0
         This keyword affects the alignment of the legend box with respect to the `Location` point.
         There are nine possible values (0 to 8) that assign the location point to be one of the
         four corners of the legend box, or the middle of one of the four sides of the legend box.
         The values are specified as follows::
            0 - Location specifies the upper left corner of the legend box.
            1 - Location specifies the upper right corner of the legend box.
            2 - Location specifies the lower right corner of the legend box.
            3 - Location specifies the lower left corner of the legend box.
            4 - Location specifies the top side of the legend box (centered horizontally).
            5 - Location specifies the bottom side of the legend box (centered horizontally).
            6 - Location specifies the left side of the legend box (centered vertically).
            7 - Location specifies the right side of the legend box (centered vertically).
            8 - Location specified the very center of the legend box.
      background: out, optional, type=boolean, default=0
         Set this keyword to draw a colored background for the legend.
      bg_color: out, optional, type=string, default="white"
         The name of the background color.
      box: in, optional, type=boolean, default=0
         Set this keyword to draw a box around the legend items.
      bx_color: in, optional, type=varies, default="black"
         The color of the box drawn around the legend items.
      bx_thick: in, optional, type=float
         The thickness of the line used to draw the box around the legend items.
         If not set, use !P.Thick at drawing time.
      center_sym: in, optional, type=boolean
         Set this keyword to place a single symbol in the center of the line. The default
         is to draw a symbol at each endpoint of the line.
      charsize: in, optional, type=float
         The character size for the legend text. Uses cgDefCharsize by default.
         Ignored if using hardware fonts on the display.
      charthick: in, optional, type=float
         The thickness of the legend text. If undefined, use `Thick` value.
      colors: in, optional, type=varies, default="black"
         The name of the data color. This is the color of each data line. May be an array.
      data: in, optional, type=boolean, default=0
         If set the values specified by the `Location` keyword are taken to be in data
         coordinate space.
      hardware: in, optional, type=boolean
         Set this keyword if you want to output the legend text in a hardware font.
      length: in, optional, type=float, default=0.075
         The length of the line connecting symbols in the legend, in normalized
         coordinates (0 to 1 in the graphics window). Set this equal to 0.0 if
         you wish to only plot symbols in the legend.
      linestyles: in, optional, type=integer
         The line style for drawing each line. May be an array.
      location: in, optional, type=fltarr
         A two-element vector giving the X and Y location of upper-left corner of the legend
         (or legend box, if the `Box` keyword is set) in normalized coordinates. If the `Data`
         keyword is set, the locations are taken to be in data coordinate space.
      psyms: in, optional, type=integer
         Any normal IDL PSYM values, plus any value supported by the Coyote Library
         routine cgSYMCAT. An integer between 0 and 46. May be an array.
      symcolors: in, optional, type=varies
         The name of the symbol color. By default, the same as the `COLOR` keyword. May be an array.
      symsize: in, optional, type=float, default=1.0
         The symbol size.
      symthick: in, optional, type=float
         The thickness of the symbol. If not set, use !P.Thick at drawing time.
      tcolors: in, optional, type=varies, default="black"
         The `Title` color. May be an array.
      thick: in, optional, type=float
         The thickness of the line. If not set, use !P.Thick at drawing time.
      titles: in, optional, type=string/strarr, default='Plot Item'
         The "title" or text for each legend item.
      tt_font: in, optional, type=string
         The name of a true-type font to use for the legend text.
      visible: in, optional, type=boolean, default=1
         Set this keyword to determine if the legend should be drawn (visible=1), or
         if the legend should not be drawn (visible=0).
      vspace: in, optional, type=float, default=1.5
          A scale factor for vertical spacing between legend items. This number is multiplied by
          `Charsize` to determine vertical spacing.
      window: in, optional, type=boolean, default=0
          If this keyword is set, the object replaces any commands in a current
          cgWindow or it opens a new cgWindow and adds itself to it.
      x_margin: in, optional, type=float, default=2.25
         A scale factor for the horizontal margin within a box. This number is multiplied by
         `Charsize` to determine horizontal spacing.
      y_margin: in, optional, type=float, default=1.75
         A scale factor for the vertical margin within a box. This number is multiplied by
         `Charsize` to determine vertical spacing.

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

      Copyright (c) 2013, Fanning Software Consulting, Inc.

History

      Change History::
         Written 5 Dec 2013. David W Fanning.
         Added CharThick keyword. 1 Sept 2014. DWF.