The color creation and management class.

Introduction

Colors are defined by their red, green and blue components, simply called the RGB components. The colors are also known by the hue, light and saturation components also known as the HLS components. When a new color is created the components of both color systems are computed.

At initialization time, a table of colors is generated. An existing color can be retrieved by its index:

TColor *color = gROOT->GetColor(10);

Then it can be manipulated. For example its RGB components can be modified:

color->SetRGB(0.1, 0.2, 0.3);

A new color can be created the following way:

Int_t ci = 1756; // color index

TColor *color = new TColor(ci, 0.1, 0.2, 0.3);

Two sets of colors are initialized;

The basic colors: colors with index from 0 to 50.
The color wheel: colors with indices from 300 to 1000.

Basic colors

The following image displays the 50 basic colors.

{
   TCanvas *c = new TCanvas("c","Fill Area colors",0,0,500,200);
   c->DrawColorTable();
   return c;
}

The color wheel

The wheel contains the recommended 216 colors to be used in web applications.

The colors in the color wheel are created by TColor::CreateColorWheel.

Using this color set for your text, background or graphics will give your application a consistent appearance across different platforms and browsers.

Colors are grouped by hue, the aspect most important in human perception. Touching color chips have the same hue, but with different brightness and vividness.

Colors of slightly different hues clash. If you intend to display colors of the same hue together, you should pick them from the same group.

Each color chip is identified by a mnemonic (e.g. kYellow) and a number. The keywords, kRed, kBlue, kYellow, kPink, etc are defined in the header file Rtypes.h that is included in all ROOT other header files. It is better to use these keywords in user code instead of hardcoded color numbers, e.g.:

myObject.SetFillColor(kRed);
myObject.SetFillColor(kYellow-10);
myLine.SetLineColor(kMagenta+2);

{
   TColorWheel *w = new TColorWheel();
   w->Draw();
   return w->GetCanvas();
}

Bright and dark colors

The dark and bright color are used to give 3-D effects when drawing various boxes (see TWbox, TPave, TPaveText, TPaveLabel, etc).

The dark colors have an index = color_index+100
The bright colors have an index = color_index+150
Two static functions return the bright and dark color number corresponding to a color index. If the bright or dark color does not exist, they are created:
Int_t dark = TColor::GetColorDark(color_index);

Int_t bright = TColor::GetColorBright(color_index);

Grayscale view of of canvas with colors

One can toggle between a grayscale preview and the regular colored mode using TCanvas::SetGrayscale(). Note that in grayscale mode, access via RGB will return grayscale values according to ITU standards (and close to b&w printer gray-scales), while access via HLS returns de-saturated gray-scales. The image below shows the ROOT color wheel in grayscale mode.

{
   TColorWheel *w = new TColorWheel();
   w->Draw();
   w->GetCanvas()->SetGrayscale();
   w->GetCanvas()->Modified();
   w->GetCanvas()->Update();
   return w->GetCanvas();
}

Color palettes

It is often very useful to represent a variable with a color map. The concept of "color palette" allows to do that. One color palette is active at any time. This "current palette" is set using:

gStyle->SetPalette(...);

This function has two parameters: the number of colors in the palette and an array of containing the indices of colors in the palette. The following small example demonstrates how to define and use the color palette:

{
   TCanvas *c1  = new TCanvas("c1","c1",0,0,600,400);
   TF2 *f1 = new TF2("f1","0.1+(1-(x-2)*(x-2))*(1-(y-2)*(y-2))",1,3,1,3);
   Int_t palette[5];
   palette[0] = 15;
   palette[1] = 20;
   palette[2] = 23;
   palette[3] = 30;
   palette[4] = 32;
   gStyle->SetPalette(5,palette);
   f1->Draw("colz");
   return c1;
}

To define more a complex palette with a continuous gradient of color, one should use the static function TColor::CreateGradientColorTable(). The following example demonstrates how to proceed:

{
   TCanvas *c2  = new TCanvas("c2","c2",0,0,600,400);
   TF2 *f2 = new TF2("f2","0.1+(1-(x-2)*(x-2))*(1-(y-2)*(y-2))",1,3,1,3);
   const Int_t Number = 3;
   Double_t Red[Number]    = { 1.00, 0.00, 0.00};
   Double_t Green[Number]  = { 0.00, 1.00, 0.00};
   Double_t Blue[Number]   = { 1.00, 0.00, 1.00};
   Double_t Length[Number] = { 0.00, 0.50, 1.00 };
   Int_t nb=50;
   TColor::CreateGradientColorTable(Number,Length,Red,Green,Blue,nb);
   f2->SetContour(nb);
   f2->SetLineWidth(1);
   f2->SetLineColor(kBlack);
   f2->Draw("surf1z");
   return c2;
}

The function TColor::CreateGradientColorTable() automatically calls gStyle->SetPalette(), so there is not need to add one.

After a call to TColor::CreateGradientColorTable() it is sometimes useful to store the newly create palette for further use. In particular, it is recommended to do if one wants to switch between several user define palettes. To store a palette in an array it is enough to do:

Int_t MyPalette[100];
Double_t r[]    = {0., 0.0, 1.0, 1.0, 1.0};
Double_t g[]    = {0., 0.0, 0.0, 1.0, 1.0};
Double_t b[]    = {0., 1.0, 0.0, 0.0, 1.0};
Double_t stop[] = {0., .25, .50, .75, 1.0};
Int_t FI = TColor::CreateGradientColorTable(5, stop, r, g, b, 100);
for (int i=0;i<100;i++) MyPalette[i] = FI+i;

Later on to reuse the palette MyPalette it will be enough to do

gStyle->SetPalette(100, MyPalette);

As only one palette is active, one need to use TExec to be able to display plots using different palettes on the same pad. The following macro illustrate this feature.

#include "TStyle.h"
#include "TColor.h"
#include "TF2.h"
#include "TExec.h"
#include "TCanvas.h"
void Pal1()
{
   static Int_t  colors[50];
   static Bool_t initialized = kFALSE;
   Double_t Red[3]    = { 1.00, 0.00, 0.00};
   Double_t Green[3]  = { 0.00, 1.00, 0.00};
   Double_t Blue[3]   = { 1.00, 0.00, 1.00};
   Double_t Length[3] = { 0.00, 0.50, 1.00 };
   if(!initialized){
      Int_t FI = TColor::CreateGradientColorTable(3,Length,Red,Green,Blue,50);
      for (int i=0; i<50; i++) colors[i] = FI+i;
      initialized = kTRUE;
      return;
   }
   gStyle->SetPalette(50,colors);
}
void Pal2()
{
   static Int_t  colors[50];
   static Bool_t initialized = kFALSE;
   Double_t Red[3]    = { 1.00, 0.50, 0.00};
   Double_t Green[3]  = { 0.50, 0.00, 1.00};
   Double_t Blue[3]   = { 1.00, 0.00, 0.50};
   Double_t Length[3] = { 0.00, 0.50, 1.00 };
   if(!initialized){
      Int_t FI = TColor::CreateGradientColorTable(3,Length,Red,Green,Blue,50);
      for (int i=0; i<50; i++) colors[i] = FI+i;
      initialized = kTRUE;
      return;
   }
   gStyle->SetPalette(50,colors);
}
TCanvas* multipalette() {
   TCanvas *c3  = new TCanvas("c3","C3",0,0,600,400);
   c3->Divide(2,1);
   TF2 *f3 = new TF2("f3","0.1+(1-(x-2)*(x-2))*(1-(y-2)*(y-2))",1,3,1,3);
   f3->SetLineWidth(1);
   f3->SetLineColor(kBlack);
   c3->cd(1);
   f3->Draw("surf1");
   TExec *ex1 = new TExec("ex1","Pal1();");
   ex1->Draw();
   f3->Draw("surf1 same");
   c3->cd(2);
   f3->Draw("surf1");
   TExec *ex2 = new TExec("ex2","Pal2();");
   ex2->Draw();
   f3->Draw("surf1 same");
   return c3;
}

Color transparency

To make a graphics object transparent it is enough to set its color to a transparent one. The color transparency is defined via its alpha component. The alpha value varies from 0. (fully transparent) to 1. (fully opaque). To set the alpha value of an existing color it is enough to do:

TColor *col26 = gROOT->GetColor(26);

col26->SetAlpha(0.01);

A new color can be created transparent the following way:

Int_t ci = 1756;

TColor *color = new TColor(ci, 0.1, 0.2, 0.3, "", 0.5); // alpha = 0.5

An example of transparency usage with parallel coordinates can be found in $ROOTSYS/tutorials/tree/parallelcoordtrans.C.

To ease the creation of a transparent color the static method GetColorTransparent(Int_t color, Float_t a) is provided. In the following example the trans_red color index point to a red color 30% transparent. The alpha value of the color index kRed is not modified.

Int_t trans_red = GetColorTransparent(kRed, 0.3);

This function is also used in the methods SetFillColorAlpha(), SetLineColorAlpha(), SetMarkerColorAlpha() and SetTextColorAlpha(). In the following example the fill color of the histogram histo is set to blue with a transparency of 35%. The color kBlue itself remains fully opaque.

histo->SetFillColorAlpha(kBlue, 0.35);

The transparency is available on all platforms when the flagOpenGL.CanvasPreferGL is set to 1 in $ROOTSYS/etc/system.rootrc, or on Mac with the Cocoa backend. On the file output it is visible with PDF, PNG, Gif, JPEG, SVG ... but not PostScript.

Definition at line 47 of file TColor.h.

Public Member Functions
	TColor ()
	Default constructor. More...

	TColor (Int_t color, Float_t r, Float_t g, Float_t b, const char *name="", Float_t a=1)
	Normal color constructor. More...

	TColor (const TColor &color)
	Color copy constructor. More...

virtual	~TColor ()
	Color destructor. More...

const char *	AsHexString () const
	Return color as hexadecimal string. More...

void	Copy (TObject &color) const
	Copy this color to obj. More...

virtual void	GetRGB (Float_t &r, Float_t &g, Float_t &b) const

virtual void	GetHLS (Float_t &h, Float_t &l, Float_t &s) const

Int_t	GetNumber () const

ULong_t	GetPixel () const
	Return pixel value corresponding to this color. More...

Float_t	GetRed () const

Float_t	GetGreen () const

Float_t	GetBlue () const

Float_t	GetHue () const

Float_t	GetLight () const

Float_t	GetSaturation () const

Float_t	GetAlpha () const

virtual Float_t	GetGrayscale () const

virtual void	ls (Option_t *option="") const
	List this color with its attributes. More...

virtual void	Print (Option_t *option="") const
	Dump this color with its attributes. More...

virtual void	SetAlpha (Float_t a)

virtual void	SetRGB (Float_t r, Float_t g, Float_t b)
	Initialize this color and its associated colors. More...

Public Member Functions inherited from TNamed
	TNamed ()

	TNamed (const char name, const char title)

	TNamed (const TString &name, const TString &title)

	TNamed (const TNamed &named)

TNamed &	operator= (const TNamed &rhs)
	TNamed assignment operator. More...

virtual	~TNamed ()

virtual void	Clear (Option_t *option="")
	Set name and title to empty strings (""). More...

virtual TObject *	Clone (const char *newname="") const
	Make a clone of an object using the Streamer facility. More...

virtual Int_t	Compare (const TObject *obj) const
	Compare two TNamed objects. More...

virtual void	FillBuffer (char *&buffer)
	Encode TNamed into output buffer. More...

virtual const char *	GetName () const
	Returns name of object. More...

virtual const char *	GetTitle () const
	Returns title of object. More...

virtual ULong_t	Hash () const
	Return hash value for this object. More...

virtual Bool_t	IsSortable () const

virtual void	SetName (const char *name)
	Change (i.e. More...

virtual void	SetNameTitle (const char name, const char title)
	Change (i.e. set) all the TNamed parameters (name and title). More...

virtual void	SetTitle (const char *title="")
	Change (i.e. set) the title of the TNamed. More...

virtual Int_t	Sizeof () const
	Return size of the TNamed part of the TObject. More...

Public Member Functions inherited from TObject
	TObject ()

	TObject (const TObject &object)
	TObject copy ctor. More...

TObject &	operator= (const TObject &rhs)
	TObject assignment operator. More...

virtual	~TObject ()
	TObject destructor. More...

virtual void	AppendPad (Option_t *option="")
	Append graphics object to current pad. More...

virtual void	Browse (TBrowser *b)
	Browse object. May be overridden for another default action. More...

virtual const char *	ClassName () const
	Returns name of class to which the object belongs. More...

virtual void	Delete (Option_t *option="")
	Delete this object. More...

virtual Int_t	DistancetoPrimitive (Int_t px, Int_t py)
	Computes distance from point (px,py) to the object. More...

virtual void	Draw (Option_t *option="")
	Default Draw method for all objects. More...

virtual void	DrawClass () const
	Draw class inheritance tree of the class to which this object belongs. More...

virtual TObject *	DrawClone (Option_t *option="") const
	Draw a clone of this object in the current pad. More...

virtual void	Dump () const
	Dump contents of object on stdout. More...

virtual void	Execute (const char method, const char params, Int_t *error=0)
	Execute method on this object with the given parameter string, e.g. More...

virtual void	Execute (TMethod method, TObjArray params, Int_t *error=0)
	Execute method on this object with parameters stored in the TObjArray. More...

virtual void	ExecuteEvent (Int_t event, Int_t px, Int_t py)
	Execute action corresponding to an event at (px,py). More...

virtual TObject *	FindObject (const char *name) const
	Must be redefined in derived classes. More...

virtual TObject *	FindObject (const TObject *obj) const
	Must be redefined in derived classes. More...

virtual Option_t *	GetDrawOption () const
	Get option used by the graphics system to draw this object. More...

virtual UInt_t	GetUniqueID () const
	Return the unique object id. More...

virtual const char *	GetIconName () const
	Returns mime type name of object. More...

virtual Option_t *	GetOption () const

virtual char *	GetObjectInfo (Int_t px, Int_t py) const
	Returns string containing info about the object at position (px,py). More...

virtual Bool_t	HandleTimer (TTimer *timer)
	Execute action in response of a timer timing out. More...

virtual Bool_t	InheritsFrom (const char *classname) const
	Returns kTRUE if object inherits from class "classname". More...

virtual Bool_t	InheritsFrom (const TClass *cl) const
	Returns kTRUE if object inherits from TClass cl. More...

virtual void	Inspect () const
	Dump contents of this object in a graphics canvas. More...

virtual Bool_t	IsFolder () const
	Returns kTRUE in case object contains browsable objects (like containers or lists of other objects). More...

virtual Bool_t	IsEqual (const TObject *obj) const
	Default equal comparison (objects are equal if they have the same address in memory). More...

Bool_t	IsOnHeap () const

Bool_t	IsZombie () const

virtual Bool_t	Notify ()
	This method must be overridden to handle object notification. More...

virtual void	Paint (Option_t *option="")
	This method must be overridden if a class wants to paint itself. More...

virtual void	Pop ()
	Pop on object drawn in a pad to the top of the display list. More...

virtual Int_t	Read (const char *name)
	Read contents of object with specified name from the current directory. More...

virtual void	RecursiveRemove (TObject *obj)
	Recursively remove this object from a list. More...

virtual void	SaveAs (const char filename="", Option_t option="") const
	Save this object in the file specified by filename. More...

virtual void	SavePrimitive (std::ostream &out, Option_t *option="")
	Save a primitive as a C++ statement(s) on output stream "out". More...

virtual void	SetDrawOption (Option_t *option="")
	Set drawing option for object. More...

virtual void	SetUniqueID (UInt_t uid)
	Set the unique object id. More...

virtual void	UseCurrentStyle ()
	Set current style settings in this object This function is called when either TCanvas::UseCurrentStyle or TROOT::ForceStyle have been invoked. More...

virtual Int_t	Write (const char *name=0, Int_t option=0, Int_t bufsize=0)
	Write this object to the current directory. More...

virtual Int_t	Write (const char *name=0, Int_t option=0, Int_t bufsize=0) const
	Write this object to the current directory. More...

void *	operator new (size_t sz)

void *	operator new[] (size_t sz)

void *	operator new (size_t sz, void *vp)

void *	operator new[] (size_t sz, void *vp)

void	operator delete (void *ptr)
	Operator delete. More...

void	operator delete[] (void *ptr)
	Operator delete []. More...

void	SetBit (UInt_t f, Bool_t set)
	Set or unset the user status bits as specified in f. More...

void	SetBit (UInt_t f)

void	ResetBit (UInt_t f)

Bool_t	TestBit (UInt_t f) const

Int_t	TestBits (UInt_t f) const

void	InvertBit (UInt_t f)

virtual void	Info (const char method, const char msgfmt,...) const
	Issue info message. More...

virtual void	Warning (const char method, const char msgfmt,...) const
	Issue warning message. More...

virtual void	Error (const char method, const char msgfmt,...) const
	Issue error message. More...

virtual void	SysError (const char method, const char msgfmt,...) const
	Issue system error message. More...

virtual void	Fatal (const char method, const char msgfmt,...) const
	Issue fatal error message. More...

void	AbstractMethod (const char *method) const
	Use this method to implement an "abstract" method that you don't want to leave purely abstract. More...

void	MayNotUse (const char *method) const
	Use this method to signal that a method (defined in a base class) may not be called in a derived class (in principle against good design since a child class should not provide less functionality than its parent, however, sometimes it is necessary). More...

void	Obsolete (const char method, const char asOfVers, const char *removedFromVers) const
	Use this method to declare a method obsolete. More...

Static Public Member Functions
static void	CreateColorWheel ()
	Static function steering the creation of all colors in the color wheel. More...

static void	CreateColorsGray ()
	Create the Gray scale colors in the Color Wheel. More...

static void	CreateColorsCircle (Int_t offset, const char name, UChar_t rgb)
	Create the "circle" colors in the color wheel. More...

static void	CreateColorsRectangle (Int_t offset, const char name, UChar_t rgb)
	Create the "rectangular" colors in the color wheel. More...

static Int_t	CreateGradientColorTable (UInt_t Number, Double_t Stops, Double_t Red, Double_t Green, Double_t Blue, UInt_t NColors, Float_t alpha=1.)
	Static function creating a color table with several connected linear gradients. More...

static Int_t	GetColorPalette (Int_t i)
	Static function returning the color number i in current palette. More...

static Int_t	GetNumberOfColors ()
	Static function returning number of colors in the color palette. More...

static void	InitializeColors ()
	Initialize colors used by the TCanvas based graphics (via TColor objects). More...

static void	HLS2RGB (Float_t h, Float_t l, Float_t s, Float_t &r, Float_t &g, Float_t &b)
	Static method to compute RGB from HLS. More...

static void	HLS2RGB (Int_t h, Int_t l, Int_t s, Int_t &r, Int_t &g, Int_t &b)
	Static method to compute RGB from HLS. More...

static void	HLStoRGB (Float_t h, Float_t l, Float_t s, Float_t &r, Float_t &g, Float_t &b)

static void	HSV2RGB (Float_t h, Float_t s, Float_t v, Float_t &r, Float_t &g, Float_t &b)
	Static method to compute RGB from HSV: More...

static void	RGB2HLS (Float_t r, Float_t g, Float_t b, Float_t &h, Float_t &l, Float_t &s)
	Static method to compute HLS from RGB. More...

static void	RGB2HLS (Int_t r, Int_t g, Int_t b, Int_t &h, Int_t &l, Int_t &s)
	Static method to compute HLS from RGB. More...

static void	RGBtoHLS (Float_t r, Float_t g, Float_t b, Float_t &h, Float_t &l, Float_t &s)

static void	RGB2HSV (Float_t r, Float_t g, Float_t b, Float_t &h, Float_t &s, Float_t &v)
	Static method to compute HSV from RGB. More...

static Int_t	GetColor (const char *hexcolor)
	Static method returning color number for color specified by hex color string of form: "#rrggbb", where rr, gg and bb are in hex between [0,FF], e.g. More...

static Int_t	GetColor (Float_t r, Float_t g, Float_t b)
	Static method returning color number for color specified by r, g and b. More...

static Int_t	GetColor (Int_t r, Int_t g, Int_t b)
	Static method returning color number for color specified by r, g and b. More...

static Int_t	GetColor (ULong_t pixel)
	Static method returning color number for color specified by system dependent pixel value. More...

static Int_t	GetColorBright (Int_t color)
	Static function: Returns the bright color number corresponding to n If the TColor object does not exist, it is created. More...

static Int_t	GetColorDark (Int_t color)
	Static function: Returns the dark color number corresponding to n If the TColor object does not exist, it is created. More...

static Int_t	GetColorTransparent (Int_t color, Float_t a)
	Static function: Returns the transparent color number corresponding to n. More...

static ULong_t	Number2Pixel (Int_t ci)
	Static method that given a color index number, returns the corresponding pixel value. More...

static ULong_t	RGB2Pixel (Int_t r, Int_t g, Int_t b)
	Convert r,g,b to graphics system dependent pixel value. More...

static ULong_t	RGB2Pixel (Float_t r, Float_t g, Float_t b)
	Convert r,g,b to graphics system dependent pixel value. More...

static void	Pixel2RGB (ULong_t pixel, Int_t &r, Int_t &g, Int_t &b)
	Convert machine dependent pixel value (obtained via RGB2Pixel or via Number2Pixel() or via TColor::GetPixel()) to r,g,b triplet. More...

static void	Pixel2RGB (ULong_t pixel, Float_t &r, Float_t &g, Float_t &b)
	Convert machine dependent pixel value (obtained via RGB2Pixel or via Number2Pixel() or via TColor::GetPixel()) to r,g,b triplet. More...

static const char *	PixelAsHexString (ULong_t pixel)
	Convert machine dependent pixel value (obtained via RGB2Pixel or via Number2Pixel() or via TColor::GetPixel()) to a hexadecimal string. More...

static void	SaveColor (std::ostream &out, Int_t ci)
	Save a color with index > 228 as a C++ statement(s) on output stream out. More...

static Bool_t	IsGrayscale ()
	Return whether all colors return grayscale values. More...

static void	SetGrayscale (Bool_t set=kTRUE)
	Set whether all colors should return grayscale values. More...

static void	SetPalette (Int_t ncolors, Int_t *colors, Float_t alpha=1.)
	Static function. More...

Static Public Member Functions inherited from TObject
static Long_t	GetDtorOnly ()
	Return destructor only flag. More...

static void	SetDtorOnly (void *obj)
	Set destructor only flag. More...

static Bool_t	GetObjectStat ()
	Get status of object stat flag. More...

static void	SetObjectStat (Bool_t stat)
	Turn on/off tracking of objects in the TObjectTable. More...

Protected Attributes
Int_t	fNumber

Protected Attributes inherited from TNamed
TString	fName

TString	fTitle

Private Member Functions
void	Allocate ()
	Make this color known to the graphics system. More...

Static Private Member Functions
static Float_t	HLStoRGB1 (Float_t rn1, Float_t rn2, Float_t huei)
	Static method. Auxiliary to HLS2RGB(). More...

Private Attributes
Float_t	fRed

Float_t	fGreen

Float_t	fBlue

Float_t	fHue

Float_t	fLight

Float_t	fSaturation

Float_t	fAlpha

Additional Inherited Members
Public Types inherited from TObject
enum	EStatusBits { kCanDelete = BIT(0), kMustCleanup = BIT(3), kObjInCanvas = BIT(3), kIsReferenced = BIT(4), kHasUUID = BIT(5), kCannotPick = BIT(6), kNoContextMenu = BIT(8), kInvalidObject = BIT(13) }

enum	{ kIsOnHeap = 0x01000000, kNotDeleted = 0x02000000, kZombie = 0x04000000, kBitMask = 0x00ffffff }

enum	{ kSingleKey = BIT(0), kOverwrite = BIT(1), kWriteDelete = BIT(2) }

Protected Member Functions inherited from TObject
void	MakeZombie ()

virtual void	DoError (int level, const char location, const char fmt, va_list va) const
	Interface to ErrorHandler (protected). More...

#include <TColor.h>

Inheritance diagram for TColor:

[legend]

Constructor & Destructor Documentation

TColor::TColor ( )

Default constructor.

Definition at line 295 of file TColor.cxx.

Referenced by CreateColorsCircle(), CreateColorsGray(), CreateColorsRectangle(), CreateGradientColorTable(), GetColor(), GetColorBright(), GetColorDark(), GetColorTransparent(), and InitializeColors().

TColor::TColor	(	Int_t	color,
		Float_t	r,
		Float_t	g,
		Float_t	b,
		const char *	name = `""`,
		Float_t	a = `1`
	)

Normal color constructor.

Initialize a color structure. Compute the RGB and HLS color components.

Definition at line 306 of file TColor.cxx.

TColor::TColor ( const TColor & color )

Color copy constructor.

Definition at line 355 of file TColor.cxx.

TColor::~TColor ( )

virtual

Color destructor.

Definition at line 346 of file TColor.cxx.

Member Function Documentation

void TColor::Allocate ( )

private

Make this color known to the graphics system.

Definition at line 1008 of file TColor.cxx.

Referenced by SetGrayscale(), and SetRGB().

const char * TColor::AsHexString ( ) const

Return color as hexadecimal string.

This string can be directly passed to, for example, TGClient::GetColorByName(). String will be reused so copy immediately if needed.

Definition at line 491 of file TColor.cxx.

Referenced by CreateColorsCircle(), CreateColorsRectangle(), TImageDump::DrawBox(), TImageDump::DrawFrame(), TImageDump::DrawPolyMarker(), TImageDump::DrawPS(), and TASImage::DrawText().

void TColor::Copy ( TObject & color ) const

virtual

Copy this color to obj.

Reimplemented from TNamed.

Definition at line 512 of file TColor.cxx.

Referenced by TEveUtil::SetColorBrightness().

void TColor::CreateColorsCircle	(	Int_t	offset,
		const char *	name,
		UChar_t *	rgb
	)

static

Create the "circle" colors in the color wheel.

Definition at line 544 of file TColor.cxx.

Referenced by CreateColorWheel().

void TColor::CreateColorsGray ( )

static

Create the Gray scale colors in the Color Wheel.

Definition at line 528 of file TColor.cxx.

Referenced by CreateColorWheel().

void TColor::CreateColorsRectangle	(	Int_t	offset,
		const char *	name,
		UChar_t *	rgb
	)

static

Create the "rectangular" colors in the color wheel.

Definition at line 564 of file TColor.cxx.

Referenced by CreateColorWheel().

void TColor::CreateColorWheel ( )

static

Static function steering the creation of all colors in the color wheel.

Definition at line 584 of file TColor.cxx.

Referenced by InitializeColors().

Int_t TColor::CreateGradientColorTable	(	UInt_t	Number,
		Double_t *	Stops,
		Double_t *	Red,
		Double_t *	Green,
		Double_t *	Blue,
		UInt_t	NColors,
		Float_t	alpha = `1.`
	)

static

Static function creating a color table with several connected linear gradients.

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.

Returns a positive value on success and -1 on error.

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 };

This defines a table in which there are three color end points: RGB = {0, 0, 1}, {1, 0, 0}, and {1, 1, 1} = blue, red, white The first 40% of the table is used to go linearly from blue to red. The remaining 60% of the table is used to go linearly from red to white.

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@m.nosp@m.pe.m.nosp@m.pg.de)

Definition at line 1431 of file TColor.cxx.

Referenced by TMVA::StatDialogBDT::DrawTree(), and SetPalette().

Float_t TColor::GetAlpha ( ) const

inline

Definition at line 91 of file TColor.h.

Referenced by TAttFillEditor::DoFillAlphaColor(), TAttLineEditor::DoLineAlphaColor(), TAttMarkerEditor::DoMarkerAlphaColor(), TAttTextEditor::DoTextAlphaColor(), Rgl::Pad::ExtractRGBA(), TColorGradient::ResetColor(), SaveColor(), TSVG::SetColor(), TTeXDump::SetColor(), TPDF::SetColor(), ROOT::Quartz::SetFillColor(), ROOT::Quartz::SetFillPattern(), ROOT::Quartz::SetLineColor(), and TColor().

Float_t TColor::GetBlue ( ) const

inline

Int_t TColor::GetColor ( const char * hexcolor )

static

Static method returning color number for color specified by hex color string of form: "#rrggbb", where rr, gg and bb are in hex between [0,FF], e.g.

"#c0c0c0".

If specified color does not exist it will be created with as name "#rrggbb" with rr, gg and bb in hex between [0,FF].

Definition at line 1023 of file TColor.cxx.

Int_t TColor::GetColor	(	Float_t	r,
		Float_t	g,
		Float_t	b
	)

static

Static method returning color number for color specified by r, g and b.

The r,g,b should be in the range [0,1].

If specified color does not exist it will be created with as name "#rrggbb" with rr, gg and bb in hex between [0,FF].

Definition at line 1042 of file TColor.cxx.

Int_t TColor::GetColor	(	Int_t	r,
		Int_t	g,
		Int_t	b
	)

static

Static method returning color number for color specified by r, g and b.

The r,g,b should be in the range [0,255]. If the specified color does not exist it will be created with as name "#rrggbb" with rr, gg and bb in hex between [0,FF].

Definition at line 1073 of file TColor.cxx.

Int_t TColor::GetColor ( ULong_t pixel )

static

Static method returning color number for color specified by system dependent pixel value.

Pixel values can be obtained, e.g., from the GUI color picker.

Definition at line 1057 of file TColor.cxx.

Int_t TColor::GetColorBright ( Int_t n )

static

Static function: Returns the bright color number corresponding to n If the TColor object does not exist, it is created.

The convention is that the bright color nb = n+150

Definition at line 1133 of file TColor.cxx.

Referenced by TWbox::GetLightColor(), THistPainter::PaintBar(), THistPainter::PaintBarH(), TPad::PaintBorder(), THistPainter::PaintBoxes(), and TWbox::PaintFrame().

Int_t TColor::GetColorDark ( Int_t n )

static

Static function: Returns the dark color number corresponding to n If the TColor object does not exist, it is created.

The convention is that the dark color nd = n+100

Definition at line 1165 of file TColor.cxx.

Referenced by TEveGeoNode::DumpShapeTree(), TWbox::GetDarkColor(), InitializeColors(), TPie::Paint(), THistPainter::PaintBar(), THistPainter::PaintBarH(), TPad::PaintBorder(), THistPainter::PaintBoxes(), TWbox::PaintFrame(), and THistPainter::PaintLego().

Int_t TColor::GetColorPalette ( Int_t i )

static

Static function returning the color number i in current palette.

Definition at line 672 of file TColor.cxx.

Referenced by TStyle::GetColorPalette().

Int_t TColor::GetColorTransparent	(	Int_t	n,
		Float_t	a
	)

static

Static function: Returns the transparent color number corresponding to n.

The transparency level is given by the alpha value a.

Definition at line 1196 of file TColor.cxx.

Referenced by TAttFillEditor::DoLiveAlpha(), TAttLineEditor::DoLiveAlpha(), TAttMarkerEditor::DoLiveAlpha(), TAttTextEditor::DoLiveAlpha(), TAttAxis::SetAxisColor(), TAttFill::SetFillColorAlpha(), TAttAxis::SetLabelColor(), TAttLine::SetLineColorAlpha(), TAttMarker::SetMarkerColorAlpha(), and TAttText::SetTextColorAlpha().

virtual Float_t TColor::GetGrayscale ( ) const

inlinevirtual

Definition at line 92 of file TColor.h.

Referenced by GetBlue(), GetGreen(), and GetRed().

Float_t TColor::GetGreen ( ) const

inline

virtual void TColor::GetHLS	(	Float_t &	h,
		Float_t &	l,
		Float_t &	s
	)		const

inlinevirtual

Definition at line 81 of file TColor.h.

Referenced by TGeoPainter::DefineColors().

Float_t TColor::GetHue ( ) const

inline

Definition at line 88 of file TColor.h.

Referenced by GetColorBright(), GetColorDark(), GetHLS(), and TColor().

Float_t TColor::GetLight ( ) const

inline

Definition at line 89 of file TColor.h.

Referenced by GetColorBright(), GetColorDark(), GetHLS(), TColorWheel::PaintCircle(), TColorWheel::PaintRectangles(), and TColor().

Int_t TColor::GetNumber ( ) const

inline

Definition at line 83 of file TColor.h.

Referenced by CreateGradientColorTable(), TAttFillEditor::DoFillAlphaColor(), TAttLineEditor::DoLineAlphaColor(), TAttMarkerEditor::DoMarkerAlphaColor(), TAttTextEditor::DoTextAlphaColor(), TStructViewerGUI::GetColor(), GetColor(), TROOT::GetColor(), GetColorTransparent(), TASImage::Paint(), and TColor().

Int_t TColor::GetNumberOfColors ( )

static

Static function returning number of colors in the color palette.

Definition at line 684 of file TColor.cxx.

Referenced by TStyle::GetNumberOfColors().

ULong_t TColor::GetPixel ( ) const

Return pixel value corresponding to this color.

This pixel value can be used in the GUI classes. This call does not work in batch mode since it needs to communicate with the graphics system.

Definition at line 694 of file TColor.cxx.

Referenced by TStructNodeProperty::GetPixel(), Number2Pixel(), TGColorPopup::PreviewAlphaColor(), TGColorDialog::SetColorInfo(), TGLabel::SetTextColor(), and TGTextEntry::SetTextColor().

Float_t TColor::GetRed ( ) const

inline

virtual void TColor::GetRGB	(	Float_t &	r,
		Float_t &	g,
		Float_t &	b
	)		const

inlinevirtual

Definition at line 79 of file TColor.h.

Referenced by TGLPlotBox::DrawBack(), Rgl::Pad::ExtractRGBA(), TGeoPainter::GetColor(), TEveManager::GetGeometry(), TPainter3dAlgorithms::ImplicitFunction(), InitializeColors(), TGLAxis::PaintGLAxisBody(), THistPainter::PaintH3Iso(), THistPainter::PaintSurface(), TGLViewer::PreDraw(), TColorGradient::ResetColor(), TGLScene::RGBAFromColorIdx(), SaveColor(), TEveUtil::SetColorBrightness(), ROOT::Quartz::SetFillColor(), and ROOT::Quartz::SetLineColor().

Float_t TColor::GetSaturation ( ) const

inline

Definition at line 90 of file TColor.h.

Referenced by GetColorBright(), GetColorDark(), GetHLS(), and TColor().

void TColor::HLS2RGB	(	Float_t	hue,
		Float_t	light,
		Float_t	satur,
		Float_t &	r,
		Float_t &	g,
		Float_t &	b
	)

static

Static method to compute RGB from HLS.

The l and s are between [0,1] and h is between [0,360]. The returned r,g,b triplet is between [0,1].

Definition at line 711 of file TColor.cxx.

Referenced by ClassImp(), TGColorPick::CreateDitheredImage(), TGeoPainter::DefineColors(), HLStoRGB(), TGColorPick::InitImages(), TGColorDialog::ProcessMessage(), TGColorPick::SetSliderColor(), and TGColorPick::UpdateCurrentColor().

void TColor::HLS2RGB	(	Int_t	h,
		Int_t	l,
		Int_t	s,
		Int_t &	r,
		Int_t &	g,
		Int_t &	b
	)

static

Static method to compute RGB from HLS.

The h,l,s are between [0,255]. The returned r,g,b triplet is between [0,255].

Definition at line 751 of file TColor.cxx.

static void TColor::HLStoRGB	(	Float_t	h,
		Float_t	l,
		Float_t	s,
		Float_t &	r,
		Float_t &	g,
		Float_t &	b
	)

inlinestatic

Definition at line 101 of file TColor.h.

Referenced by GetColorBright(), GetColorDark(), HLS2RGB(), TPainter3dAlgorithms::ImplicitFunction(), InitializeColors(), THistPainter::PaintH3Iso(), THistPainter::PaintSurface(), and SetRGB().

Float_t TColor::HLStoRGB1	(	Float_t	rn1,
		Float_t	rn2,
		Float_t	huei
	)

staticprivate

Static method. Auxiliary to HLS2RGB().

Definition at line 736 of file TColor.cxx.

Referenced by HLS2RGB().

void TColor::HSV2RGB	(	Float_t	hue,
		Float_t	satur,
		Float_t	value,
		Float_t &	r,
		Float_t &	g,
		Float_t &	b
	)

static

Static method to compute RGB from HSV:

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 returned r,g,b triplet is between [0,1].

Definition at line 777 of file TColor.cxx.

void TColor::InitializeColors ( )

static

Initialize colors used by the TCanvas based graphics (via TColor objects).

This method should be called before the ApplicationImp is created (which initializes the GUI colors).

Definition at line 365 of file TColor.cxx.

Referenced by ClassImp(), CreateGradientColorTable(), TGeoPainter::DefineColors(), GetColor(), TROOT::GetColor(), TApplication::InitializeGraphics(), Number2Pixel(), SetGrayscale(), SetPalette(), SetRGB(), TSelectorDraw::TakeAction(), and TColor().

Bool_t TColor::IsGrayscale ( )

static

Return whether all colors return grayscale values.

Definition at line 1362 of file TColor.cxx.

Referenced by GetBlue(), GetGreen(), GetRed(), and GetSaturation().

void TColor::ls ( Option_t * option = "" ) const

virtual

List this color with its attributes.

Reimplemented from TNamed.

Definition at line 833 of file TColor.cxx.

Referenced by Print().

ULong_t TColor::Number2Pixel ( Int_t ci )

static

Static method that given a color index number, returns the corresponding pixel value.

This pixel value can be used in the GUI classes. This call does not work in batch mode since it needs to communicate with the graphics system.

Definition at line 1219 of file TColor.cxx.

void TColor::Pixel2RGB	(	ULong_t	pixel,
		Int_t &	r,
		Int_t &	g,
		Int_t &	b
	)

static

Convert machine dependent pixel value (obtained via RGB2Pixel or via Number2Pixel() or via TColor::GetPixel()) to r,g,b triplet.

The r,g,b triplet will be [0,255].

Definition at line 1295 of file TColor.cxx.

Referenced by ClassImp(), TGColorPick::CreateDitheredImage(), GetColor(), TGCompositeFrame::HandleDragEnter(), PixelAsHexString(), TGLOverlayButton::Render(), TGColorPick::SetColor(), TGColorPick::SetSliderColor(), TGColorDialog::UpdateHLSentries(), and TGColorDialog::UpdateRGBentries().

void TColor::Pixel2RGB	(	ULong_t	pixel,
		Float_t &	r,
		Float_t &	g,
		Float_t &	b
	)

static

Convert machine dependent pixel value (obtained via RGB2Pixel or via Number2Pixel() or via TColor::GetPixel()) to r,g,b triplet.

The r,g,b triplet will be [0,1].

Definition at line 1280 of file TColor.cxx.

const char * TColor::PixelAsHexString ( ULong_t pixel )

static

Convert machine dependent pixel value (obtained via RGB2Pixel or via Number2Pixel() or via TColor::GetPixel()) to a hexadecimal string.

This string can be directly passed to, for example, TGClient::GetColorByName(). String will be reused so copy immediately if needed.

Definition at line 1312 of file TColor.cxx.

Referenced by TGProgressBar::SavePrimitive(), TGGC::SavePrimitive(), TGColorSelect::SavePrimitive(), and TGFrame::SaveUserColor().

void TColor::Print ( Option_t * option = "" ) const

virtual

Dump this color with its attributes.

Reimplemented from TNamed.

Definition at line 842 of file TColor.cxx.

void TColor::RGB2HLS	(	Float_t	rr,
		Float_t	gg,
		Float_t	bb,
		Float_t &	hue,
		Float_t &	light,
		Float_t &	satur
	)

static

Static method to compute HLS from RGB.

The r,g,b triplet is between [0,1], hue is between [0,360], light and satur are [0,1].

Definition at line 851 of file TColor.cxx.

Referenced by ClassImp(), TGColorPick::CreateDitheredImage(), RGBtoHLS(), TGColorPick::SetColor(), TGColorPick::SetSliderColor(), and TGColorDialog::UpdateHLSentries().

void TColor::RGB2HLS	(	Int_t	r,
		Int_t	g,
		Int_t	b,
		Int_t &	h,
		Int_t &	l,
		Int_t &	s
	)

static

Static method to compute HLS from RGB.

The r,g,b triplet is between [0,255], hue, light and satur are between [0,255].

Definition at line 944 of file TColor.cxx.

void TColor::RGB2HSV	(	Float_t	r,
		Float_t	g,
		Float_t	b,
		Float_t &	hue,
		Float_t &	satur,
		Float_t &	value
	)

static

Static method to compute HSV from RGB.

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.

Definition at line 909 of file TColor.cxx.

ULong_t TColor::RGB2Pixel	(	Int_t	r,
		Int_t	g,
		Int_t	b
	)

static

Convert r,g,b to graphics system dependent pixel value.

The r,g,b triplet must be [0,255].

Definition at line 1257 of file TColor.cxx.

Referenced by ClassImp(), TRootGuiBuilder::GetBgnd(), TGColorPalette::GetCurrentColor(), TASImage::GetPixels(), TRootGuiBuilder::GetPopupBgnd(), TRootGuiBuilder::GetPopupHlght(), TGCompositeFrame::HandleDragEnter(), TGColorPick::InitImages(), TGColorDialog::ProcessMessage(), TGTable::SetDefaultColors(), TGColorPick::SetSliderColor(), TGColorDialog::TGColorDialog(), TGColorPalette::TGColorPalette(), and TGColorPick::UpdateCurrentColor().

ULong_t TColor::RGB2Pixel	(	Float_t	r,
		Float_t	g,
		Float_t	b
	)

static

Convert r,g,b to graphics system dependent pixel value.

The r,g,b triplet must be [0,1].

Definition at line 1235 of file TColor.cxx.

static void TColor::RGBtoHLS	(	Float_t	r,
		Float_t	g,
		Float_t	b,
		Float_t &	h,
		Float_t &	l,
		Float_t &	s
	)

inlinestatic

Definition at line 106 of file TColor.h.

Referenced by TPainter3dAlgorithms::ImplicitFunction(), InitializeColors(), THistPainter::PaintH3Iso(), THistPainter::PaintSurface(), RGB2HLS(), and SetRGB().

void TColor::SaveColor	(	std::ostream &	out,
		Int_t	ci
	)

static

Save a color with index > 228 as a C++ statement(s) on output stream out.

Definition at line 1324 of file TColor.cxx.

Referenced by TAttAxis::SaveAttributes(), TAttFill::SaveFillAttributes(), TAttLine::SaveLineAttributes(), TPaveText::SaveLines(), TAttMarker::SaveMarkerAttributes(), TF3::SavePrimitive(), TGaxis::SavePrimitive(), TF2::SavePrimitive(), TPad::SavePrimitive(), TCanvas::SavePrimitive(), TF1::SavePrimitive(), TCanvas::SaveSource(), and TAttText::SaveTextAttributes().

virtual void TColor::SetAlpha ( Float_t a )

inlinevirtual

Definition at line 95 of file TColor.h.

Referenced by CreateGradientColorTable(), TGColorDialog::DoPreview(), THistPainter::ExecuteEvent(), TPad::ExecuteEventAxis(), GetColorTransparent(), and TGColorDialog::ProcessMessage().

void TColor::SetGrayscale ( Bool_t set = kTRUE )

static

Set whether all colors should return grayscale values.

Definition at line 1370 of file TColor.cxx.

Referenced by TPad::Paint(), and TPad::PaintModified().

void TColor::SetPalette	(	Int_t	ncolors,
		Int_t *	colors,
		Float_t	alpha = `1.`
	)

static

Static function.

The color palette is used by the histogram classes (see TH1::Draw options). For example TH1::Draw("col") draws a 2-D histogram with cells represented by a box filled with a color CI function of the cell content. if the cell content is N, the color CI used will be the color number in colors[N],etc. If the maximum cell content is > ncolors, all cell contents are scaled to ncolors.

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.
if ncolors = 112 and colors=0, a Viridis palette is used.

These palettes can also be accessed by names:

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        kViridis=112

For example:

gStyle->SetPalette(kBird);

Set the current palette as "Bird" (number 57).

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)

Definition at line 1642 of file TColor.cxx.

Referenced by CreateGradientColorTable(), InitializeColors(), and TStyle::SetPalette().