1 /********************************************************************** 2 * File: quadratc.h (Formerly quadrtic.h) 3 * Description: Code for the QUAD_COEFFS class. 4 * Author: Ray Smith 5 * Created: Tue Oct 08 17:24:40 BST 1991 6 * 7 * (C) Copyright 1991, Hewlett-Packard Ltd. 8 ** Licensed under the Apache License, Version 2.0 (the "License"); 9 ** you may not use this file except in compliance with the License. 10 ** You may obtain a copy of the License at 11 ** http://www.apache.org/licenses/LICENSE-2.0 12 ** Unless required by applicable law or agreed to in writing, software 13 ** distributed under the License is distributed on an "AS IS" BASIS, 14 ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 15 ** See the License for the specific language governing permissions and 16 ** limitations under the License. 17 * 18 **********************************************************************/ 19 20 #ifndef QUADRATC_H 21 #define QUADRATC_H 22 23 #include "points.h" 24 25 namespace tesseract { 26 27 class QUAD_COEFFS { 28 public: 29 QUAD_COEFFS() = default; QUAD_COEFFS(double xsq,float x,float constant)30 QUAD_COEFFS( // constructor 31 double xsq, // coefficients 32 float x, float constant) { 33 a = xsq; 34 b = x; 35 c = constant; 36 } 37 y(float x)38 float y( // evaluate 39 float x) const { // at x 40 return static_cast<float>((a * x + b) * x + c); 41 } 42 move(ICOORD vec)43 void move( // reposition word 44 ICOORD vec) { // by vector 45 /************************************************************ 46 y - q = a (x - p)^2 + b (x - p) + c 47 y - q = ax^2 - 2apx + ap^2 + bx - bp + c 48 y = ax^2 + (b - 2ap)x + (c - bp + ap^2 + q) 49 ************************************************************/ 50 int16_t p = vec.x(); 51 int16_t q = vec.y(); 52 53 c = static_cast<float>(c - b * p + a * p * p + q); 54 b = static_cast<float>(b - 2 * a * p); 55 } 56 57 double a; // x squared 58 float b; // x 59 float c; // constant 60 private: 61 }; 62 63 } // namespace tesseract 64 65 #endif 66