doc/v618/greyscale_8C.html

void greyscale()

{

   TCanvas *c = new TCanvas("grey", "Grey Scale", 500, 500);

   c->SetBorderMode(0);


   Int_t   n = 200;   // tunable parameter

   Float_t n1 = 1./n;

   for (int i = 0; i < n; i++) {

      for (int j = 0; j < n; j++) {

         TBox *b = new TBox(n1*j, n1*(n-1-i), n1*(j+1), n1*(n-i));

         Float_t grey = Float_t(i*n+j)/(n*n);

         b->SetFillColor(TColor::GetColor(grey, grey, grey));

         b->Draw();

      }

   }

   TPad *p = new TPad("p","p",0.3, 0.3, 0.7,0.7);

   const char *guibackground = gEnv->GetValue("Gui.BackgroundColor", "");

   p->SetFillColor(TColor::GetColor(guibackground));

   p->Draw();

   p->cd();

   TText *t = new TText(0.5, 0.5, "GUI Background Color");

   t->SetTextAlign(22);

   t->SetTextSize(.09);

   t->Draw();


   c->SetEditable(kFALSE);

}

b
#define b(i)
Definition: RSha256.hxx:100

c
#define c(i)
Definition: RSha256.hxx:101

Int_t
int Int_t
Definition: RtypesCore.h:41

kFALSE
const Bool_t kFALSE
Definition: RtypesCore.h:88

Float_t
float Float_t
Definition: RtypesCore.h:53

gEnv
R__EXTERN TEnv * gEnv
Definition: TEnv.h:171

TAttFill::SetFillColor
virtual void SetFillColor(Color_t fcolor)
Set the fill area color.
Definition: TAttFill.h:37

TAttText::SetTextAlign
virtual void SetTextAlign(Short_t align=11)
Set the text alignment.
Definition: TAttText.h:41

TAttText::SetTextSize
virtual void SetTextSize(Float_t tsize=1)
Set the text size.
Definition: TAttText.h:46

TBox
Create a Box.
Definition: TBox.h:24

TCanvas
The Canvas class.
Definition: TCanvas.h:31

TColor::GetColor
static Int_t GetColor(const char *hexcolor)
Static method returning color number for color specified by hex color string of form: "#rrggbb",...
Definition: TColor.cxx:1764

TEnv::GetValue
virtual Int_t GetValue(const char *name, Int_t dflt) const
Returns the integer value for a resource.
Definition: TEnv.cxx:491

TObject::Draw
virtual void Draw(Option_t *option="")
Default Draw method for all objects.
Definition: TObject.cxx:195

TPad
The most important graphics class in the ROOT system.
Definition: TPad.h:29

TPad::Draw
virtual void Draw(Option_t *option="")
Draw Pad in Current pad (re-parent pad if necessary).
Definition: TPad.cxx:1285

TPad::cd
TVirtualPad * cd(Int_t subpadnumber=0)
Set Current pad.
Definition: TPad.cxx:594

TText
Base class for several text objects.
Definition: TText.h:23

n
const Int_t n
Definition: legend1.C:16