TColorGradient.cxx

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// @(#)root/base:$Id$
// Author: Timur Pocheptsov   20/3/2012

/*************************************************************************
 * Copyright (C) 1995-2012, Rene Brun and Fons Rademakers.               *
 * All rights reserved.                                                  *
 *                                                                       *
 * For the licensing terms see $ROOTSYS/LICENSE.                         *
 * For the list of contributors see $ROOTSYS/README/CREDITS.             *
 *************************************************************************/

/** \class TColorGradient
TColorGradient extends basic TColor.
Actually, this is not a simple color, but linear gradient + shadow
for filled area. By inheriting from TColor, gradients can be placed
inside gROOT's list of colors and use it in all TAttXXX descendants
without modifying any existing code.

Shadow, of course, is not a property of any color, and gradient is
not, but this is the best way to add new attributes to filled area
without re-writing all the graphics code.
*/

#include <cassert>

#include "TColorGradient.h"
#include "TObjArray.h"
#include "TString.h"
#include "TError.h"
#include "TROOT.h"

ClassImp(TColorGradient)

////////////////////////////////////////////////////////////////////////////////
/// Constructor.

TColorGradient::TColorGradient()
                   : fCoordinateMode(kObjectBoundingMode)
{
}

////////////////////////////////////////////////////////////////////////////////
/// There is no way to validate parameters here, so it's up to user
/// to pass correct arguments.

TColorGradient::TColorGradient(Color_t colorIndex, UInt_t nPoints, const Double_t *points,
                               const Color_t *indices, ECoordinateMode mode)
                   : fCoordinateMode(mode)
{
   assert(nPoints != 0 && "TColorGradient, number of points is 0");
   assert(points != 0 && "TColorGradient, points parameter is null");
   assert(indices != 0 && "TColorGradient, indices parameter is null");

   ResetColor(nPoints, points, indices);
   RegisterColor(colorIndex);
}

////////////////////////////////////////////////////////////////////////////////
/// There is no way to validate parameters here, so it's up to user
/// to pass correct arguments.

TColorGradient::TColorGradient(Color_t colorIndex, UInt_t nPoints, const Double_t *points,
                               const Double_t *colors, ECoordinateMode mode)
                  : fCoordinateMode(mode)
{
   assert(nPoints != 0 && "TColorGradient, number of points is 0");
   assert(points != 0 && "TColorGradient, points parameter is null");
   assert(colors != 0 && "TColorGradient, colors parameter is null");

   ResetColor(nPoints, points, colors);
   RegisterColor(colorIndex);
}

////////////////////////////////////////////////////////////////////////////////
/// Reset color.

void TColorGradient::ResetColor(UInt_t nPoints, const Double_t *points, const Color_t *colorIndices)
{
   assert(nPoints != 0 && "ResetColor, number of points is 0");
   assert(points != 0 && "ResetColor, points parameter is null");
   assert(colorIndices != 0 && "ResetColor, colorIndices parameter is null");

   fColorPositions.assign(points, points + nPoints);
   fColors.resize(nPoints * 4);//4 == rgba.

   Float_t rgba[4];
   for (UInt_t i = 0, pos = 0; i < nPoints; ++i, pos += 4) {
      const TColor *clearColor = gROOT->GetColor(colorIndices[i]);
      if (!clearColor || dynamic_cast<const TColorGradient *>(clearColor)) {
         //TColorGradient can not be a step in TColorGradient.
         Error("ResetColor", "Bad color for index %d, set to opaque black", colorIndices[i]);
         fColors[pos] = 0.;
         fColors[pos + 1] = 0.;
         fColors[pos + 2] = 0.;
         fColors[pos + 3] = 1.;//Alpha.
      } else {
         clearColor->GetRGB(rgba[0], rgba[1], rgba[2]);
         rgba[3] = clearColor->GetAlpha();
         fColors[pos] = rgba[0];
         fColors[pos + 1] = rgba[1];
         fColors[pos + 2] = rgba[2];
         fColors[pos + 3] = rgba[3];
      }
   }
}

////////////////////////////////////////////////////////////////////////////////
/// Reset color.

void TColorGradient::ResetColor(UInt_t nPoints, const Double_t *points,
                                const Double_t *colors)
{
   assert(nPoints != 0 && "ResetColor, number of points is 0");
   assert(points != 0 && "ResetColor, points parameter is null");
   assert(colors != 0 && "ResetColor, colors parameter is null");

   fColorPositions.assign(points, points + nPoints);
   fColors.assign(colors, colors + nPoints * 4);
}

////////////////////////////////////////////////////////////////////////////////
/// Set coordinate mode.

void TColorGradient::SetCoordinateMode(ECoordinateMode mode)
{
   fCoordinateMode = mode;
}

////////////////////////////////////////////////////////////////////////////////
/// Get coordinate mode.

TColorGradient::ECoordinateMode TColorGradient::GetCoordinateMode()const
{
   return fCoordinateMode;
}

////////////////////////////////////////////////////////////////////////////////
/// Get number of steps.

TColorGradient::SizeType_t TColorGradient::GetNumberOfSteps()const
{
   return fColorPositions.size();
}

////////////////////////////////////////////////////////////////////////////////
/// Get color positions

const Double_t *TColorGradient::GetColorPositions()const
{
   return &fColorPositions[0];
}

////////////////////////////////////////////////////////////////////////////////
/// Get colors.

const Double_t *TColorGradient::GetColors()const
{
   return &fColors[0];
}

////////////////////////////////////////////////////////////////////////////////
/// Register color

void TColorGradient::RegisterColor(Color_t colorIndex)
{
   fNumber = colorIndex;
   SetName(TString::Format("Color%d", colorIndex));

   if (gROOT) {
      if (gROOT->GetColor(colorIndex)) {
         Warning("RegisterColor", "Color with index %d is already defined", colorIndex);
         return;
      }

      if (TObjArray *colors = (TObjArray*)gROOT->GetListOfColors()) {
         colors->AddAtAndExpand(this, colorIndex);
      } else {
         Error("RegisterColor", "List of colors is a null pointer in gROOT, color was not registered");
         return;
      }
   }
}

ClassImp(TLinearGradient)

/** \class TLinearGradient
Define a linear color gradient.
*/

TLinearGradient::TLinearGradient()
{
}

////////////////////////////////////////////////////////////////////////////////
/// Constructor.

TLinearGradient::TLinearGradient(Color_t newColor, UInt_t nPoints, const Double_t *points,
                                 const Color_t *colorIndices, ECoordinateMode mode)
                   : TColorGradient(newColor, nPoints, points, colorIndices, mode)
{
}

////////////////////////////////////////////////////////////////////////////////
/// Constructor.

TLinearGradient::TLinearGradient(Color_t newColor, UInt_t nPoints, const Double_t *points,
                                 const Double_t *colors, ECoordinateMode mode)
                   : TColorGradient(newColor, nPoints, points, colors, mode)
{
}

////////////////////////////////////////////////////////////////////////////////
/// Set end and start.

void TLinearGradient::SetStartEnd(const Point &p1, const Point &p2)
{
   fStart = p1;
   fEnd = p2;
}

////////////////////////////////////////////////////////////////////////////////
/// Get start.

const TColorGradient::Point &TLinearGradient::GetStart()const
{
   return fStart;
}

////////////////////////////////////////////////////////////////////////////////
/// Get end.

const TColorGradient::Point &TLinearGradient::GetEnd()const
{
   return fEnd;
}

ClassImp(TRadialGradient)

/** \class TRadialGradient
Define a radial color gradient
*/

TRadialGradient::TRadialGradient()
{
}

////////////////////////////////////////////////////////////////////////////////
/// Constructor.

TRadialGradient::TRadialGradient(Color_t newColor, UInt_t nPoints, const Double_t *points,
                                 const Color_t *colorIndices, ECoordinateMode mode)
                   : TColorGradient(newColor, nPoints, points, colorIndices, mode)
{
}

////////////////////////////////////////////////////////////////////////////////
/// Constructor.

TRadialGradient::TRadialGradient(Color_t newColor, UInt_t nPoints, const Double_t *points,
                                 const Double_t *colors, ECoordinateMode mode)
                   : TColorGradient(newColor, nPoints, points, colors, mode)
{
}

////////////////////////////////////////////////////////////////////////////////
/// Get gradient type.

TRadialGradient::EGradientType TRadialGradient::GetGradientType()const
{
   return fType;
}

////////////////////////////////////////////////////////////////////////////////
/// Set start and end R1 and R2.

void TRadialGradient::SetStartEndR1R2(const Point &p1, Double_t r1, const Point &p2, Double_t r2)
{
   fStart = p1;
   fR1 = r1;
   fEnd = p2;
   fR2 = r2;

   fType = kExtended;
}

////////////////////////////////////////////////////////////////////////////////
/// Get start.

const TColorGradient::Point &TRadialGradient::GetStart()const
{
   return fStart;
}

////////////////////////////////////////////////////////////////////////////////
// Get R1.

Double_t TRadialGradient::GetR1()const
{
   return fR1;
}

////////////////////////////////////////////////////////////////////////////////
/// Get end.

const TColorGradient::Point &TRadialGradient::GetEnd()const
{
   return fEnd;
}

////////////////////////////////////////////////////////////////////////////////
/// Get R2.

Double_t TRadialGradient::GetR2()const
{
   return fR2;
}

////////////////////////////////////////////////////////////////////////////////
/// Set radial gradient.

void TRadialGradient::SetRadialGradient(const Point &center, Double_t radius)
{
   fStart = center;
   fR1 = radius;

   fType = kSimple;
}

////////////////////////////////////////////////////////////////////////////////
/// Get center.

const TColorGradient::Point &TRadialGradient::GetCenter()const
{
   return fStart;
}

////////////////////////////////////////////////////////////////////////////////
/// Get radius.

Double_t TRadialGradient::GetRadius()const
{
   return fR1;
}