class TColor: public TNamed

• The hue value runs from 0 to 360.
• The saturation is the degree of strength or purity and is from 0 to 1. Purity is how much white is added to the color, so S=1 makes the purest color (no white).
• Brightness value also ranges from 0 to 1, where 0 is the black.

• The input values:
  • r,g,b triplet is between [0,1].
• The returned values:
  • The hue value runs from 0 to 360.
  • The saturation is the degree of strength or purity and is from 0 to 1. Purity is how much white is added to the color, so S=1 makes the purest color (no white).
  • Brightness value also ranges from 0 to 1, where 0 is the black.

• Number: The number of end point colors that will form the gradients. Must be at least 2.
• Stops: Where in the whole table the end point colors should lie. Each entry must be on [0, 1], each entry must be greater than the previous entry.
• Red, Green, Blue: The end point color values. Each entry must be on [0, 1]
• NColors: Total number of colors in the table. Must be at least 1.

The table is constructed by tracing lines between the given points in RGB space. Each color value may have a value between 0 and 1. The difference between consecutive "Stops" values gives the fraction of space in the whole table that should be used for the interval between the corresponding color values.

Normally the first element of Stops should be 0 and the last should be 1. If this is not true, fewer than NColors will be used in proportion with the total interval between the first and last elements of Stops.

This definition is similar to the povray-definition of gradient color tables.

For instance:

   UInt_t Number = 3;
   Double_t Red[3]   = { 0.0, 1.0, 1.0 };
   Double_t Green[3] = { 0.0, 0.0, 1.0 };
   Double_t Blue[3]  = { 1.0, 0.0, 1.0 };
   Double_t Stops[3] = { 0.0, 0.4, 1.0 };
   

If you define a very short interval such that less than one color fits in it, no colors at all will be allocated. If this occurs for all intervals, ROOT will revert to the default palette.

Original code by Andreas Zoglauer (zog@mpe.mpg.de)

if ncolors <= 0 a default palette (see below) of 50 colors is defined. The colors defined in this palette are OK for coloring pads, labels.

   index 0->9   : grey colors from light to dark grey
   index 10->19 : "brown" colors
   index 20->29 : "blueish" colors
   index 30->39 : "redish" colors
   index 40->49 : basic colors
   

if ncolors == 1 && colors == 0, a Rainbow Color map is created with 50 colors. It is kept for backward compatibility. Better palettes like kBird are recommended.

High quality predefined palettes with 255 colors are available when colors == 0. The following value of ncolors give access to:

   if ncolors = 51 and colors=0, a Deep Sea palette is used.
   if ncolors = 52 and colors=0, a Grey Scale palette is used.
   if ncolors = 53 and colors=0, a Dark Body Radiator palette is used.
   if ncolors = 54 and colors=0, a Two-Color Hue palette is used.(dark blue through neutral gray to bright yellow)
   if ncolors = 55 and colors=0, a Rain Bow palette is used.
   if ncolors = 56 and colors=0, an Inverted Dark Body Radiator palette is used.
   if ncolors = 57 and colors=0, a monotonically increasing L value palette is used.
   if ncolors = 58 and colors=0, a Cubehelix palette is used
                                   (Cf. Dave Green's "cubehelix" colour scheme at http://www.mrao.cam.ac.uk/~dag/CUBEHELIX/)
   if ncolors = 59 and colors=0, a Green Red Violet palette is used.
   if ncolors = 60 and colors=0, a Blue Red Yellow palette is used.
   if ncolors = 61 and colors=0, an Ocean palette is used.
   if ncolors = 62 and colors=0, a Color Printable On Grey palette is used.
   if ncolors = 63 and colors=0, an Alpine palette is used.
   if ncolors = 64 and colors=0, an Aquamarine palette is used.
   if ncolors = 65 and colors=0, an Army palette is used.
   if ncolors = 66 and colors=0, an Atlantic palette is used.
   if ncolors = 67 and colors=0, an Aurora palette is used.
   if ncolors = 68 and colors=0, an Avocado palette is used.
   if ncolors = 69 and colors=0, a Beach palette is used.
   if ncolors = 70 and colors=0, a Black Body palette is used.
   if ncolors = 71 and colors=0, a Blue Green Yellow palette is used.
   if ncolors = 72 and colors=0, a Brown Cyan palette is used.
   if ncolors = 73 and colors=0, a CMYK palette is used.
   if ncolors = 74 and colors=0, a Candy palette is used.
   if ncolors = 75 and colors=0, a Cherry palette is used.
   if ncolors = 76 and colors=0, a Coffee palette is used.
   if ncolors = 77 and colors=0, a Dark Rain Bow palette is used.
   if ncolors = 78 and colors=0, a Dark Terrain palette is used.
   if ncolors = 79 and colors=0, a Fall palette is used.
   if ncolors = 80 and colors=0, a Fruit Punch palette is used.
   if ncolors = 81 and colors=0, a Fuchsia palette is used.
   if ncolors = 82 and colors=0, a Grey Yellow palette is used.
   if ncolors = 83 and colors=0, a Green Brown Terrain palette is used.
   if ncolors = 84 and colors=0, a Green Pink palette is used.
   if ncolors = 85 and colors=0, an Island palette is used.
   if ncolors = 86 and colors=0, a Lake palette is used.
   if ncolors = 87 and colors=0, a Light Temperature palette is used.
   if ncolors = 88 and colors=0, a Light Terrain palette is used.
   if ncolors = 89 and colors=0, a Mint palette is used.
   if ncolors = 90 and colors=0, a Neon palette is used.
   if ncolors = 91 and colors=0, a Pastel palette is used.
   if ncolors = 92 and colors=0, a Pearl palette is used.
   if ncolors = 93 and colors=0, a Pigeon palette is used.
   if ncolors = 94 and colors=0, a Plum palette is used.
   if ncolors = 95 and colors=0, a Red Blue palette is used.
   if ncolors = 96 and colors=0, a Rose palette is used.
   if ncolors = 97 and colors=0, a Rust palette is used.
   if ncolors = 98 and colors=0, a Sandy Terrain palette is used.
   if ncolors = 99 and colors=0, a Sienna palette is used.
   if ncolors = 100 and colors=0, a Solar palette is used.
   if ncolors = 101 and colors=0, a South West palette is used.
   if ncolors = 102 and colors=0, a Starry Night palette is used.
   if ncolors = 103 and colors=0, a Sunset palette is used.
   if ncolors = 104 and colors=0, a Temperature Map palette is used.
   if ncolors = 105 and colors=0, a Thermometer palette is used.
   if ncolors = 106 and colors=0, a Valentine palette is used.
   if ncolors = 107 and colors=0, a Visible Spectrum palette is used.
   if ncolors = 108 and colors=0, a Water Melon palette is used.
   if ncolors = 109 and colors=0, a Cool palette is used.
   if ncolors = 110 and colors=0, a Copper palette is used.
   if ncolors = 111 and colors=0, a Gist Earth palette is used.
   

   kDeepSea=51,          kGreyScale=52,    kDarkBodyRadiator=53,
   kBlueYellow= 54,      kRainBow=55,      kInvertedDarkBodyRadiator=56,
   kBird=57,             kCubehelix=58,    kGreenRedViolet=59,
   kBlueRedYellow=60,    kOcean=61,        kColorPrintableOnGrey=62,
   kAlpine=63,           kAquamarine=64,   kArmy=65,
   kAtlantic=66,         kAurora=67,       kAvocado=68,
   kBeach=69,            kBlackBody=70,    kBlueGreenYellow=71,
   kBrownCyan=72,        kCMYK=73,         kCandy=74,
   kCherry=75,           kCoffee=76,       kDarkRainBow=77,
   kDarkTerrain=78,      kFall=79,         kFruitPunch=80,
   kFuchsia=81,          kGreyYellow=82,   kGreenBrownTerrain=83,
   kGreenPink=84,        kIsland=85,       kLake=86,
   kLightTemperature=87, kLightTerrain=88, kMint=89,
   kNeon=90,             kPastel=91,       kPearl=92,
   kPigeon=93,           kPlum=94,         kRedBlue=95,
   kRose=96,             kRust=97,         kSandyTerrain=98,
   kSienna=99,           kSolar=100,       kSouthWest=101,
   kStarryNight=102,     kSunset=103,      kTemperatureMap=104,
   kThermometer=105,     kValentine=106,   kVisibleSpectrum=107,
   kWaterMelon=108,      kCool=109,        kCopper=110,
   kGistEarth=111
   

   gStyle->SetPalette->(kBird);
   

The color numbers specified in the palette can be viewed by selecting the item "colors" in the "VIEW" menu of the canvas toolbar. The color parameters can be changed via TColor::SetRGB.

Note that when drawing a 2D histogram h2 with the option "COL" or "COLZ" or with any "CONT" options using the color map, the number of colors used is defined by the number of contours n specified with: h2->SetContour(n)