Upsilon/apps/graph/cartesian_function.cpp

#include "cartesian_function.h"

namespace Graph {

CartesianFunction::CartesianFunction(const char * text, KDColor color) :
  Shared::Function(text, color),
  m_displayDerivative(false)
{
}

bool CartesianFunction::displayDerivative() {
  return m_displayDerivative;
}

void CartesianFunction::setDisplayDerivative(bool display) {
  m_displayDerivative = display;
}

double CartesianFunction::approximateDerivative(double x, Poincare::Context * context) const {
  Poincare::Complex<double> abscissa = Poincare::Complex<double>::Float(x);
  Poincare::Expression * args[2] = {expression(context), &abscissa};
  Poincare::Derivative derivative(args, true);
  /* TODO: when we will simplify derivative, we might want to simplify the
   * derivative here. However, we might want to do it once for all x (to avoid
   * lagging in the derivative table. */
  return derivative.approximateToScalar<double>(*context);
}

char CartesianFunction::symbol() const {
  return 'x';
}

}