class TImagePalette: public TObject

TAttImage

Image attributes are:
Image Quality (see EImageQuality for the list of qualities)
Compression defines the compression rate of the color data in the
internal image structure. Speed and memory depends
on this rate, but not the image display itself
0: no compression;  100: max compression
Radio Flag: kTRUE  the x/y radio of the displayed image is always
identical to the original image
                kFALSE the x and y size of the displayed image depends
on the size of the pad
Palette:    Defines the conversion from a pixel value to the
screen color

This class is used (in general by secondary inheritance)
by some other classes (image display).


TImagePalette

A class to define a conversion from pixel values to pixel color.
A Palette is defined by some anchor points. Each anchor point has
a value between 0 and 1 and a color. An image has to be normalized
and the values between the anchor points are interpolated.
All member variables are public and can be directly manipulated.
In most cases the default operator will be used to create a
TImagePalette. In this case the member arrays have to be allocated
by an application and will be deleted in the destructor of this
class.

We provide few predifined palettes:

o gHistImagePalette - palette used in TH2::Draw("col")

o gWebImagePalette
The web palette is a set of 216 colors that will not dither or
shift on PCs or Macs. Browsers use this built-in palette when
they need to render colors on monitors with only 256 colors
(also called 8-bit color monitors).
The 6x6x6 web palette provides very quick color index lookup
and can be used for good quality convertion of images into
2-D histograms.

o  TImagePalette(Int_t ncolors, Int_t *colors)
if ncolors <= 0 a default palette (see below) of 50 colors
is defined.

if ncolors == 1 && colors == 0, then
a Pretty Palette with a Spectrum Violet->Red is created.

if ncolors > 50 and colors=0, the DeepSea palette is used.
(see TStyle::CreateGradientColorTable for more details)

if ncolors > 0 and colors = 0, the default palette is used
with a maximum of ncolors.

The default palette defines:
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


TPaletteEditor

This class provides a way to edit the palette via a GUI.