Setting Color Palette for TH2D

[Derek_Brehm]

I am having trouble setting the color palette for a TH2D. I am only mildly familiar with making my own ColorGradientTable and I am having trouble creating one for the specifications I want. I want to create one that shows bin values less than 1 blue, shaded appropriately, and then values greater than 1 red, also shaded appropriately. I also would like to set the color of bins equal to 1 as white. I think I just don’t understand how to set the Length and RGB arrays appropriately to achieve this.

I.E. I am not sure how to set the following code to achieve this result:
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);

I want it to look like the following:

Any help would be appreciated!

Derek

[couet]

{
   TH2F *h1 = new TH2F("h1","h1",100,-4,4,100,-4,4);
   h1->SetStats(0);

   Double_t a,b;
   for (Int_t i=0;i<50000;i++) {
      gRandom->Rannor(a,b);
      h1->Fill(a,b,0.16);
   }

   Double_t max = h1->GetMaximum();
   Double_t min = h1->GetMinimum();
   Double_t vw  = 5.;
   Double_t pw  = (vw-min)/(max-min);
   Double_t e   = 0.005;
   Double_t l   = 0.9;

   const Int_t Number = 6;
   Double_t Red[Number]   = { 0.0, l  , 1., 1., 1.0, 1.0};
   Double_t Green[Number] = { 0.0, l  , 1., 1., l  , 0.0};
   Double_t Blue[Number]  = { 1.0, 1.0, 1., 1., l  , 0.0};
   Double_t Stops[Number] = { 0., pw-e, pw-e, pw+e, pw+e, 1. };

   Int_t nb= 256;
   h1->SetContour(nb);

   TColor::CreateGradientColorTable(Number,Stops,Red,Green,Blue,nb);
   h1->Draw("colz");
}

[Derek_Brehm]

Thanks for the response. Do you know if there is a way for me to set the bins that equal one to be white always?

Derek

[couet]

In the macro I sent you change the value of vw to 1.