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 class QUAD_COEFFS 26 { 27 public: QUAD_COEFFS()28 QUAD_COEFFS() { 29 } //empty constructor QUAD_COEFFS(double xsq,float x,float constant)30 QUAD_COEFFS( //constructor 31 double xsq, //coefficients 32 float x, 33 float constant) { 34 a = xsq; 35 b = x; 36 c = constant; 37 } 38 y(float x)39 float y( //evaluate 40 float x) const { //at x 41 return (float) ((a * x + b) * x + c); 42 } 43 move(ICOORD vec)44 void move( // reposition word 45 ICOORD vec) { // by vector 46 /************************************************************ 47 y - q = a (x - p)^2 + b (x - p) + c 48 y - q = ax^2 - 2apx + ap^2 + bx - bp + c 49 y = ax^2 + (b - 2ap)x + (c - bp + ap^2 + q) 50 ************************************************************/ 51 inT16 p = vec.x (); 52 inT16 q = vec.y (); 53 54 c = (float) (c - b * p + a * p * p + q); 55 b = (float) (b - 2 * a * p); 56 } 57 58 double a; //x squared 59 float b; //x 60 float c; //constant 61 private: 62 }; 63 #endif 64