Predefined Colors in ROOT

In ROOT every seperately usable color (namely when you aren't using the palette option) is collected in the TColorWheel. Since the colors are grouped by hue and each segment vary only in their brightness and intensity, I feel that you are supposed to (or at least try) to only use colors with the same modifier in one plot. I therefore rearranged the colors in a way, that you can see all the colors with the same modifier in a palette like way.

Mixed Colors

Base Colors

There are also a number of predefined Palettes in ROOT listed in the TColor class documentation. The THistPainter class documentation explains in detail how to automatically pick colors from a palette. It also lists all the different draw options that can be used for Histograms and functions.

Colors in PlottI

Personalised colors can be defined using the color structure. The Constructor takes 3 Float_t numbers between 0. and 1. corresponding to RGB values. The values are given in relation to the maximum value of 255. E.g a blue value of 51 would correspond to a relative value of 51/255 = 0.2.
The structure color will automatically add the new color to the ROOT colors using TColor::GetColor(r, g, b). The corresponding ROOT color index can then be accessed via the index parameter of the structure.

Predefined Colors

The following colors are already defined in PlottI and can be used individually or in the definition of a color gradient:

Some basic colors.

Colors extracted from the ALICE logo

Colors close to citrus fruit

Colors resembling different oceans

Color Gradients in PlottI

Personalised color gradients can be defined using the ColorGradient class. The constructor takes two mandatory arguments:

One Int_t that specifies the number of colors the color gradient will have and
a vector of RGB colors defined using the color structure.

Optionally you can specify:

A vector containing the spacing of the colors and
the transparency of the colors

The color gradient can be accessed by calling the methods GetPalette() or GetGradient() that will return a vector of type Int_t or Color_t respectively. If you are using the SetPalette() option that PlottI provides you can use the ColorGradient instance directly.