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1 /**********************************************************************
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.
9  ** you may not use this file except in compliance with the License.
10  ** You may obtain a copy of the License at
12  ** Unless required by applicable law or agreed to in writing, software
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
22
23 #include "points.h"
24
26 {
27  public:
29  } //empty constructor
31  double xsq, //coefficients
32  float x,
33  float constant) {
34  a = xsq;
35  b = x;
36  c = constant;
37  }
38
39  float y( //evaluate
40  float x) const { //at x
41  return (float) ((a * x + b) * x + c);
42  }
43
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
double a
float c
inT16 y() const
access_function
Definition: points.h:56
QUAD_COEFFS(double xsq, float x, float constant)
integer coordinate
Definition: points.h:30
float y(float x) const