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425d593ebe
git-svn-id: https://tesseract-ocr.googlecode.com/svn/trunk/trunk@2 d0cd1f9f-072b-0410-8dd7-cf729c803f20
383 lines
13 KiB
C++
383 lines
13 KiB
C++
/**********************************************************************
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* File: quspline.cpp (Formerly qspline.c)
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* Description: Code for the QSPLINE class.
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* Author: Ray Smith
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* Created: Tue Oct 08 17:16:12 BST 1991
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*
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* (C) Copyright 1991, Hewlett-Packard Ltd.
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** Licensed under the Apache License, Version 2.0 (the "License");
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** you may not use this file except in compliance with the License.
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** You may obtain a copy of the License at
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** http://www.apache.org/licenses/LICENSE-2.0
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** Unless required by applicable law or agreed to in writing, software
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** distributed under the License is distributed on an "AS IS" BASIS,
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** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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** See the License for the specific language governing permissions and
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** limitations under the License.
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*
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**********************************************************************/
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#include "mfcpch.h"
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#include "memry.h"
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#include "quadlsq.h"
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#include "quspline.h"
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#define QSPLINE_PRECISION 16 //no of steps to draw
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/**********************************************************************
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* QSPLINE::QSPLINE
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*
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* Constructor to build a QSPLINE given the components used in the old code.
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**********************************************************************/
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QSPLINE::QSPLINE( //constructor
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INT32 count, //no of segments
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INT32 *xstarts, //start coords
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double *coeffs //coefficients
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) {
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INT32 index; //segment index
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//get memory
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xcoords = (INT32 *) alloc_mem ((count + 1) * sizeof (INT32));
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quadratics = (QUAD_COEFFS *) alloc_mem (count * sizeof (QUAD_COEFFS));
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segments = count;
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for (index = 0; index < segments; index++) {
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//copy them
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xcoords[index] = xstarts[index];
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quadratics[index] = QUAD_COEFFS (coeffs[index * 3],
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coeffs[index * 3 + 1],
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coeffs[index * 3 + 2]);
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}
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//right edge
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xcoords[index] = xstarts[index];
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}
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/**********************************************************************
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* QSPLINE::QSPLINE
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*
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* Constructor to build a QSPLINE by appproximation of points.
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**********************************************************************/
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QSPLINE::QSPLINE ( //constructor
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int xstarts[], //spline boundaries
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int segcount, //no of segments
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int xpts[], //points to fit
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int ypts[], int pointcount, //no of pts
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int degree //fit required
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) {
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register int pointindex; /*no along text line */
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register int segment; /*segment no */
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INT32 *ptcounts; //no in each segment
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QLSQ qlsq; /*accumulator */
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segments = segcount;
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xcoords = (INT32 *) alloc_mem ((segcount + 1) * sizeof (INT32));
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ptcounts = (INT32 *) alloc_mem ((segcount + 1) * sizeof (INT32));
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quadratics = (QUAD_COEFFS *) alloc_mem (segcount * sizeof (QUAD_COEFFS));
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memmove (xcoords, xstarts, (segcount + 1) * sizeof (INT32));
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ptcounts[0] = 0; /*none in any yet */
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for (segment = 0, pointindex = 0; pointindex < pointcount; pointindex++) {
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while (segment < segcount && xpts[pointindex] >= xstarts[segment]) {
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segment++; /*try next segment */
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/*cumulative counts */
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ptcounts[segment] = ptcounts[segment - 1];
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}
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ptcounts[segment]++; /*no in previous partition */
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}
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while (segment < segcount) {
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segment++;
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/*zero the rest */
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ptcounts[segment] = ptcounts[segment - 1];
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}
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for (segment = 0; segment < segcount; segment++) {
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qlsq.clear ();
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/*first blob */
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pointindex = ptcounts[segment];
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if (pointindex > 0
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&& xpts[pointindex] != xpts[pointindex - 1]
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&& xpts[pointindex] != xstarts[segment])
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qlsq.add (xstarts[segment],
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ypts[pointindex - 1]
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+ (ypts[pointindex] - ypts[pointindex - 1])
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* (xstarts[segment] - xpts[pointindex - 1])
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/ (xpts[pointindex] - xpts[pointindex - 1]));
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for (; pointindex < ptcounts[segment + 1]; pointindex++) {
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qlsq.add (xpts[pointindex], ypts[pointindex]);
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}
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if (pointindex > 0 && pointindex < pointcount
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&& xpts[pointindex] != xstarts[segment + 1])
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qlsq.add (xstarts[segment + 1],
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ypts[pointindex - 1]
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+ (ypts[pointindex] - ypts[pointindex - 1])
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* (xstarts[segment + 1] - xpts[pointindex - 1])
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/ (xpts[pointindex] - xpts[pointindex - 1]));
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qlsq.fit (degree);
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quadratics[segment].a = qlsq.get_a ();
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quadratics[segment].b = qlsq.get_b ();
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quadratics[segment].c = qlsq.get_c ();
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}
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free_mem(ptcounts);
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}
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/**********************************************************************
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* QSPLINE::QSPLINE
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*
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* Constructor to build a QSPLINE from another.
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**********************************************************************/
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QSPLINE::QSPLINE( //constructor
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const QSPLINE &src) {
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segments = 0;
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xcoords = NULL;
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quadratics = NULL;
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*this = src;
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}
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/**********************************************************************
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* QSPLINE::~QSPLINE
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*
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* Destroy a QSPLINE.
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**********************************************************************/
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QSPLINE::~QSPLINE ( //constructor
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) {
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if (xcoords != NULL) {
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free_mem(xcoords);
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xcoords = NULL;
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}
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if (quadratics != NULL) {
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free_mem(quadratics);
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quadratics = NULL;
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}
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}
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/**********************************************************************
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* QSPLINE::operator=
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*
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* Copy a QSPLINE
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**********************************************************************/
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QSPLINE & QSPLINE::operator= ( //assignment
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const QSPLINE & source) {
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if (xcoords != NULL)
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free_mem(xcoords);
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if (quadratics != NULL)
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free_mem(quadratics);
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segments = source.segments;
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xcoords = (INT32 *) alloc_mem ((segments + 1) * sizeof (INT32));
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quadratics = (QUAD_COEFFS *) alloc_mem (segments * sizeof (QUAD_COEFFS));
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memmove (xcoords, source.xcoords, (segments + 1) * sizeof (INT32));
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memmove (quadratics, source.quadratics, segments * sizeof (QUAD_COEFFS));
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return *this;
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}
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/**********************************************************************
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* QSPLINE::step
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*
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* Return the total of the step functions between the given coords.
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**********************************************************************/
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double QSPLINE::step( //find step functions
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double x1, //between coords
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double x2) {
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int index1, index2; //indices of coords
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double total; /*total steps */
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index1 = spline_index (x1);
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index2 = spline_index (x2);
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total = 0;
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while (index1 < index2) {
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total +=
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(double) quadratics[index1 + 1].y ((float) xcoords[index1 + 1]);
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total -= (double) quadratics[index1].y ((float) xcoords[index1 + 1]);
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index1++; /*next segment */
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}
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return total; /*total steps */
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}
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/**********************************************************************
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* QSPLINE::y
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*
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* Return the y value at the given x value.
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**********************************************************************/
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double QSPLINE::y( //evaluate
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double x //coord to evaluate at
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) const {
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INT32 index; //segment index
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index = spline_index (x);
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return quadratics[index].y (x);//in correct segment
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}
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/**********************************************************************
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* QSPLINE::spline_index
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*
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* Return the index to the largest xcoord not greater than x.
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**********************************************************************/
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INT32 QSPLINE::spline_index( //evaluate
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double x //coord to evaluate at
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) const {
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INT32 index; //segment index
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INT32 bottom; //bottom of range
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INT32 top; //top of range
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bottom = 0;
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top = segments;
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while (top - bottom > 1) {
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index = (top + bottom) / 2; //centre of range
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if (x >= xcoords[index])
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bottom = index; //new min
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else
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top = index; //new max
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}
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return bottom;
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}
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/**********************************************************************
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* QSPLINE::move
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*
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* Reposition spline by vector
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**********************************************************************/
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void QSPLINE::move( // reposition spline
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ICOORD vec // by vector
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) {
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INT32 segment; //index of segment
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INT16 x_shift = vec.x ();
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for (segment = 0; segment < segments; segment++) {
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xcoords[segment] += x_shift;
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quadratics[segment].move (vec);
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}
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xcoords[segment] += x_shift;
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}
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/**********************************************************************
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* QSPLINE::overlap
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*
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* Return TRUE if spline2 overlaps this by no more than fraction less
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* than the bounds of this.
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**********************************************************************/
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BOOL8 QSPLINE::overlap( //test overlap
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QSPLINE *spline2, //2 cannot be smaller
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double fraction //by more than this
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) {
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int leftlimit; /*common left limit */
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int rightlimit; /*common right limit */
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leftlimit = xcoords[1];
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rightlimit = xcoords[segments - 1];
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/*or too non-overlap */
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if (spline2->segments < 3 || spline2->xcoords[1] > leftlimit + fraction * (rightlimit - leftlimit)
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|| spline2->xcoords[spline2->segments - 1] < rightlimit
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- fraction * (rightlimit - leftlimit))
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return FALSE;
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else
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return TRUE;
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}
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/**********************************************************************
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* extrapolate_spline
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*
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* Extrapolates the spline linearly using the same gradient as the
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* quadratic has at either end.
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**********************************************************************/
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void QSPLINE::extrapolate( //linear extrapolation
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double gradient, //gradient to use
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int xmin, //new left edge
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int xmax //new right edge
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) {
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register int segment; /*current segment of spline */
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int dest_segment; //dest index
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int *xstarts; //new boundaries
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QUAD_COEFFS *quads; //new ones
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int increment; //in size
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increment = xmin < xcoords[0] ? 1 : 0;
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if (xmax > xcoords[segments])
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increment++;
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if (increment == 0)
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return;
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xstarts = (int *) alloc_mem ((segments + 1 + increment) * sizeof (int));
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quads =
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(QUAD_COEFFS *) alloc_mem ((segments + increment) * sizeof (QUAD_COEFFS));
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if (xmin < xcoords[0]) {
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xstarts[0] = xmin;
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quads[0].a = 0;
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quads[0].b = gradient;
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quads[0].c = y (xcoords[0]) - quads[0].b * xcoords[0];
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dest_segment = 1;
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}
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else
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dest_segment = 0;
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for (segment = 0; segment < segments; segment++) {
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xstarts[dest_segment] = xcoords[segment];
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quads[dest_segment] = quadratics[segment];
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dest_segment++;
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}
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xstarts[dest_segment] = xcoords[segment];
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if (xmax > xcoords[segments]) {
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quads[dest_segment].a = 0;
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quads[dest_segment].b = gradient;
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quads[dest_segment].c = y (xcoords[segments])
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- quads[dest_segment].b * xcoords[segments];
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dest_segment++;
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xstarts[dest_segment] = xmax + 1;
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}
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segments = dest_segment;
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free_mem(xcoords);
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free_mem(quadratics);
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xcoords = (INT32 *) xstarts;
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quadratics = quads;
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}
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/**********************************************************************
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* QSPLINE::plot
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*
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* Draw the QSPLINE in the given colour.
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**********************************************************************/
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#ifndef GRAPHICS_DISABLED
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void QSPLINE::plot( //draw it
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WINDOW window, //window to draw in
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COLOUR colour //colour to draw in
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) const {
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INT32 segment; //index of segment
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INT16 step; //index of poly piece
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double increment; //x increment
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double x; //x coord
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line_color_index(window, colour);
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for (segment = 0; segment < segments; segment++) {
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increment =
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(double) (xcoords[segment + 1] -
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xcoords[segment]) / QSPLINE_PRECISION;
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x = xcoords[segment];
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for (step = 0; step <= QSPLINE_PRECISION; step++) {
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if (segment == 0 && step == 0)
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move2d (window, x, quadratics[segment].y (x));
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else
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draw2d (window, x, quadratics[segment].y (x));
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x += increment;
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}
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}
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}
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#endif
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