Coyote Library Color Programs

cgCOLOR24

    IDL> Plot, data, Color=Color24([255,255,0])

CINDEX

COLORSAREIDENTICAL

cgCOLOR

To see a list of all the colors available by name, type this:

   IDL> Print, cgColor(/Names), Format='(5(A14, 2x))'
        White            Snow           Ivory    Light Yellow        Cornsilk
         Beige        Seashell           Linen   Antique White          Papaya
        Almond          Bisque        Moccasin           Wheat       Burlywood
           Tan      Light Gray        Lavender     Medium Gray            Gray
    Slate Gray       Dark Gray        Charcoal           Black      Light Cyan
   Powder Blue        Sky Blue      Steel Blue     Dodger Blue      Royal Blue
          Blue            Navy        Honeydew      Pale Green      Aquamarine
  Spring Green            Cyan       Turquoise       Sea Green    Forest Green
  Green Yellow      Chartreuse      Lawn Green           Green      Lime Green
    Olive Drab           Olive      Dark Green  Pale Goldenrod           Khaki
    Dark Khaki          Yellow            Gold       Goldenrod  Dark Goldenrod
  Saddle Brown            Rose            Pink      Rosy Brown     Sandy Brown
          Peru      Indian Red       Chocolate          Sienna     Dark Salmon
        Salmon    Light Salmon          Orange           Coral     Light Coral
     Firebrick           Brown        Hot Pink       Deep Pink         Magenta
        Tomato      Orange Red             Red      Violet Red          Maroon
       Thistle            Plum          Violet          Orchid   Medium Orchid
   Dark Orchid     Blue Violet          Purple

The normal calling sequence for producing device-independent drawing colors, will look similar to this. The first parameter is the name of the color you want, the second parameter is the color table index where you would like to load the specified color.

   axisColor = cgCOLOR("Green", !D.Table_Size-2)
   backColor = cgCOLOR("Dark Gray", !D.Table_Size-3)
   dataColor = cgCOLOR("Yellow", !D.Table_Size-4)
   Plot, Findgen(11), Color=axisColor, Background=backColor, /NoData
   OPlot, Findgen(11), Color=dataColor

If color decomposition is turned off, then the color is loaded at the specified index. If color decomposition is turned on, then no color is loaded into the color table.

If a color index is not specified and color decomposition is turned off, then the specified color is loaded into the !P.Color index.

The output of these commands looks like this:

The value that is returned by cgCOLOR depends upon the keywords used to call it and on the version of IDL you are using. In general, the return value will be either a color index number where the specified color is loaded by the program, or a 24-bit color value that can be decomposed into the specified color on true-color systems.

If you are running IDL 5.2 or higher, the program will determine which return value to use, based on the color decomposition state at the time the program is called. If you are running a version of IDL before IDL 5.2, then the program will return the color index number. This behavior can be overruled in all versions of IDL by setting the DECOMPOSED keyword. If this keyword is 0, the program always returns a color index number. If the keyword is 1, the program always returns a 24-bit color value.

If the TRIPLE keyword is set, the program always returns the color triple, no matter what the current decomposition state or the value of the DECOMPOSED keyword. This is useful, for example, if you want to load a color in the color table yourself.

   IDL> TVLCT, cgColor('dodger blue', /Triple), 10

If the ALLCOLORS keyword is used, then instead of a single value, modified as described above, then all the color values are returned in an array. In other words, the return value will be either an NCOLORS-element vector of color table index numbers, an NCOLORS-element vector of 24-bit color values, or an NCOLORS-by-3 array of color triples.

This program can also read an ASCII file of color names and values, so you don't have to use the 88 colors provided.

And if you prefer to have the user select a color name, you can use the SELECTCOLOR keyword. (This requires cgPickColorName.) For example, suppose you want the RGB color triple of a user-supplied color. You would type this:

   IDL> color = cgCOLOR(/SelectColor, /Triple)
   IDL> Print, color

The output keyword COLORSTRUCTURE is useful if you want to get all of the colors in a structure variable with the color names as fields in the structure.

   IDL> d = cgCOLOR(/AllColors, ColorStructure=c)
   IDL> Plot, Findgen(11), Color=c.green, Background=c.charcoal, /NoData
   IDL> OPlot, Findgen(11), Color=c.dodgerblue

It is also possible to specify a vector of color names. For example, if you are overploting several lines in a plot, and you wish to each to have a different color, you might do this:

   IDL> d = cgColor(/AllColors, ColorStructure=c)
   IDL> Plot, x, y[0,*], Color=c.yellow, Background=c.charcoal, /NoData
   IDL> colors = cgColor( ['dodger blue', 'indian red', 'pale green'] )
   IDL> FOR j=0,2 DO OPlot, x, y[j,*], Color=colors[j]

The plot might look something like this.

Updated 15 May 2008 to use Brewer Colors in addition to the normal colors.

cgCOLORBAR

cgCOLORFILL

cgDCBAR

cgDEFAULTCOLOR

    color = cgDefaultColor(inputColor, Default='Opposite')
    IF Size(color, /TNAME) EQ 'STRING' THEN color = cgColor(color)

cgPICKCOLORNAME

DECOMPOSEDCOLOR

FSC_COLORBAR__DEFINE

PICKCOLOR

SETDECOMPOSEDSTATE

This program set the current color decomposition state of a graphics device in a device-independent and version-independent manner. An output keyword, CurrentState, is availabe to return the current color decomposition state of the device at the time it is set. This avoids a problem with UNIX machines obtaining the state in a different way than Windows machines.

XCOLORS