/**********************************************************************

 * File:        quadratc.h  (Formerly quadrtic.h)

 * Description: Code for the QUAD_COEFFS class.

 * Author:      Ray Smith

 * Created:     Tue Oct 08 17:24:40 BST 1991

 *

 * (C) Copyright 1991, Hewlett-Packard Ltd.

 ** Licensed under the Apache License, Version 2.0 (the "License");

 ** you may not use this file except in compliance with the License.

 ** You may obtain a copy of the License at

 ** http://www.apache.org/licenses/LICENSE-2.0

 ** Unless required by applicable law or agreed to in writing, software

 ** distributed under the License is distributed on an "AS IS" BASIS,

 ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 ** See the License for the specific language governing permissions and

 ** limitations under the License.

 *

 **********************************************************************/

#ifndef QUADRATC_H

#define QUADRATC_H

#include "points.h"

namespace tesseract {

class QUAD_COEFFS {

public:

  QUAD_COEFFS() = default;

  QUAD_COEFFS(    // constructor

      double xsq, // coefficients

      float x, float constant) {

    a = xsq;

    b = x;

    c = constant;

  }

  float y(             // evaluate

      float x) const { // at x

    return static_cast<float>((a * x + b) * x + c);

  }

  void move(        // reposition word

      ICOORD vec) { // by vector

    /************************************************************

  y - q = a (x - p)^2 + b (x - p) + c

  y - q = ax^2 - 2apx + ap^2 + bx - bp + c

    y = ax^2 + (b - 2ap)x + (c - bp + ap^2 + q)

************************************************************/

    int16_t p = vec.x();

    int16_t q = vec.y();

    c = static_cast<float>(c - b * p + a * p * p + q);

    b = static_cast<float>(b - 2 * a * p);

  }

  double a; // x squared

  float b;  // x

  float c;  // constant

private:

};

} // namespace tesseract

#endif