Thanks Olivier. But how do I create a grayscale using
CreateGradientColorTable instead of the DeepSea palette. What do I set
for Red, Green, Blue, and Stops?
Seng
On Mar 2, 2004, at 12:24 AM, Olivier Couet wrote:
>
>
> You can define more than 50 color. See the help of SetPalette in
> TStyle:
>
> void TStyle::SetPalette(Int_t ncolors, Int_t *colors)
> {
> // 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
> //
> // if ncolors == 1 && colors == 0, then
> // a Pretty Palette with a Spectrum Violet->Red is created.
> // It is recommended to use this Pretty palette when drawing legos,
> // surfaces or contours.
> //
> // 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
> //
> // 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.
>
> This function is accessed via:
>
> gStyle->SetPalette();
>
> Cheers, O.Couet
>
> On Mon, 1 Mar 2004, Woon-Seng Choong wrote:
>
>> I have question concerning the color palette and the number of
>> colors
>> that one can defined in ROOT. I am interested in using ROOT to view a
>> 2D image in grayscale (black and white) using the 2D histogram. I
>> need
>> a grayscale of at least 8 bits. As far as I can understand it, ROOT
>> has a maximum of 50 colors. Is there a way to get more colors, in
>> particular in grayscale? If not, is this a feature that would be added
>> in the future?
>>
>> Seng
>>
>>
>
> --
> Org: CERN - European Laboratory for Particle Physics.
> Mail: 1211 Geneve 23 - Switzerland Mailbox:
> J25910
> E-Mail: Olivier.Couet@cern.ch Phone: +41
> 22 7676522
> WWW: http://cern.ch/Olivier.Couet/ Fax: +41
> 22 7677155
>
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