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Open-source Java libraries, supporting generalized smart arrays and matrices with elements
of any types, including a wide set of 2D-, 3D- and multidimensional image processing
and other algorithms, working with arrays and matrices.
/*
* The MIT License (MIT)
*
* Copyright (c) 2007-2024 Daniel Alievsky, AlgART Laboratory (http://algart.net)
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
package net.algart.math.functions;
final class SelectFrom8Directions2DFunc implements Func {
private static final double COS_PI_DIV_8 = StrictMath.cos(StrictMath.PI / 8.0);
private static final double SIN_PI_DIV_8 = StrictMath.sin(StrictMath.PI / 8.0);
SelectFrom8Directions2DFunc() {
}
public double get(double... x) { // dx=x[0], dy=x[1]
double dx = COS_PI_DIV_8 * x[0] - SIN_PI_DIV_8 * x[1];
double dy = SIN_PI_DIV_8 * x[0] + COS_PI_DIV_8 * x[1];
// rotate anticlockwise by 22.5 degree
if (dy >= 0.0) {
return dx >= dy ? 0 : dx >= 0.0 ? 1 : dx >= -dy ? 2 : 3;
} else {
return dx <= dy ? 4 : dx <= 0.0 ? 5 : dx <= -dy ? 6 : 7;
}
}
public double get() {
throw new IndexOutOfBoundsException("At least 2 arguments required");
}
public double get(double x0) {
throw new IndexOutOfBoundsException("At least 2 arguments required");
}
public double get(double x0, double x1) {
double dx = COS_PI_DIV_8 * x0 - SIN_PI_DIV_8 * x1;
double dy = SIN_PI_DIV_8 * x0 + COS_PI_DIV_8 * x1;
// rotate anticlockwise by 22.5 degree
if (dy >= 0.0) {
return dx >= dy ? 0 : dx >= 0.0 ? 1 : dx >= -dy ? 2 : 3;
} else {
return dx <= dy ? 4 : dx <= 0.0 ? 5 : dx <= -dy ? 6 : 7;
}
}
public double get(double x0, double x1, double x2) {
return get(x0, x1);
}
public double get(double x0, double x1, double x2, double x3) {
return get(x0, x1);
}
/**
* Returns a brief string description of this object.
*
* @return a brief string description of this object.
*/
public String toString() {
return "select from 8 directions in 2D plane f(x,y)=0..7 (depending on x, y)";
}
}