tesseract/ccstruct/quadratc.h
2007-03-07 20:03:40 +00:00

64 lines
2.0 KiB
C++

/**********************************************************************
* 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"
class QUAD_COEFFS
{
public:
QUAD_COEFFS() {
} //empty constructor
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 (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 p = vec.x ();
INT16 q = vec.y ();
c = (float) (c - b * p + a * p * p + q);
b = (float) (b - 2 * a * p);
}
double a; //x squared
float b; //x
float c; //constant
private:
};
#endif