/*
* Copyright (c) 2005, Graph Builder
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* * Neither the name of Graph Builder nor the names of its contributors may be
* used to endorse or promote products derived from this software without
* specific prior written permission.
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package com.graphbuilder.curve;
/**
The CatmullRomSpline is equal to the CardinalSpline with the value of alpha fixed at 0.5.
The implementation for the CatmullRomSpline is about 10% faster then the CardinalSpline
implementation.
@see com.graphbuilder.curve.CardinalSpline
*/
public class
CatmullRomSpline extends
ParametricCurve {
private static double[][]
pt = new double[4][];
public
CatmullRomSpline(
ControlPath cp,
GroupIterator gi) {
super(
cp,
gi);
}
protected void
eval(double[]
p) {
double
t =
p[
p.length - 1];
double
t2 =
t *
t;
double
t3 =
t2 *
t;
// Note: The 0.5 does NOT represent alpha. It is a result of the simplification.
for (int
i = 0;
i <
p.length - 1;
i++) {
p[
i] = 0.5 * ((
pt[3][
i] -
pt[0][
i] + 3 * (
pt[1][
i] -
pt[2][
i])) *
t3
+ (2 * (
pt[0][
i] + 2*
pt[2][
i]) - 5*
pt[1][
i] -
pt[3][
i]) *
t2
+ (
pt[2][
i] -
pt[0][
i]) *
t) +
pt[1][
i];
}
}
/**
Returns a value of 1.
*/
public int
getSampleLimit() {
return 1;
}
/**
The requirements for this curve are the group-iterator must be in-range and have a group size of at least 4.
If these requirements are not met then this method returns quietly.
*/
public void
appendTo(
MultiPath mp) {
if (!
gi.
isInRange(0,
cp.
numPoints()))
throw new
IllegalArgumentException("Group iterator not in range");;
if (
gi.
getGroupSize() < 4)
throw new
IllegalArgumentException("Group iterator size < 4");;
gi.
set(0, 0);
for (int
i = 0;
i < 4;
i++)
pt[
i] =
cp.
getPoint(
gi.
next()).
getLocation();
double[]
d = new double[
mp.
getDimension() + 1];
eval(
d);
if (
connect)
mp.
lineTo(
d);
else
mp.
moveTo(
d);
gi.
set(0, 0);
while (true) {
int
index_i =
gi.
index_i();
int
count_j =
gi.
count_j();
for (int
i = 0;
i < 4;
i++) {
if (!
gi.
hasNext())
throw new
IllegalArgumentException("Group iterator ended early");
pt[
i] =
cp.
getPoint(
gi.
next()).
getLocation();
}
gi.
set(
index_i,
count_j);
gi.
next();
BinaryCurveApproximationAlgorithm.
genPts(this, 0.0, 1.0,
mp);
}
}
}