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

 * File:        quspline.h  (Formerly qspline.h)

 * Description: Code for the QSPLINE class.

 * Author:      Ray Smith

 * Created:     Tue Oct 08 17:16:12 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 QUSPLINE_H

#define QUSPLINE_H

#include "scrollview.h" // for ScrollView, ScrollView::Color

#include <cstdint> // for int32_t

struct Pix;

namespace tesseract {

class ICOORD;

class QUAD_COEFFS;

class ROW;

class TBOX;

class TESS_API QSPLINE {

  friend void make_first_baseline(TBOX *, int, int *, int *, QSPLINE *, QSPLINE *, float);

  friend void make_holed_baseline(TBOX *, int, QSPLINE *, QSPLINE *, float);

  friend void tweak_row_baseline(ROW *, double, double);

public:

  QSPLINE() { // empty constructor

    segments = 0;

    xcoords = nullptr; // everything empty

    quadratics = nullptr;

  }

  QSPLINE( // copy constructor

      const QSPLINE &src);

  QSPLINE(                          // constructor

      int32_t count,                // number of segments

      int32_t *xstarts,             // segment starts

      double *coeffs);              // coefficients

  ~QSPLINE();                       // destructor

  QSPLINE(                          // least squares fit

      int xstarts[],                // spline boundaries

      int segcount,                 // no of segments

      int xcoords[],                // points to fit

      int ycoords[], int blobcount, // no of coords

      int degree);                  // function

  double step(   // step change

      double x1, // between coords

      double x2);

  double y(            // evaluate

      double x) const; // at x

  void move(            // reposition spline

      ICOORD vec);      // by vector

  bool overlap(         // test overlap

      QSPLINE *spline2, // 2 cannot be smaller

      double fraction); // by more than this

  void extrapolate(     // linear extrapolation

      double gradient,  // gradient to use

      int left,         // new left edge

      int right);       // new right edge

#ifndef GRAPHICS_DISABLED

  void plot(                           // draw it

      ScrollView *window,              // in window

      ScrollView::Color colour) const; // in colour

#endif

  // Paint the baseline over pix. If pix has depth of 32, then the line will

  // be painted in red. Otherwise it will be painted in black.

  void plot(Image pix) const;

  QSPLINE &operator=(const QSPLINE &source); // from this

private:

  int32_t spline_index(    // binary search

      double x) const;     // for x

  int32_t segments;        // no of segments

  int32_t *xcoords;        // no of coords

  QUAD_COEFFS *quadratics; // spline pieces

};

} // namespace tesseract

#endif