| /********************************************************************** |
| * 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 |