boofcv.misc.DiscretizedCircle Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of ip Show documentation

BoofCV is an open source Java library for real-time computer vision and robotics applications.

There is a newer version: 0.26

/*
 * Copyright (c) 2011-2013, Peter Abeles. All Rights Reserved.
 *
 * This file is part of BoofCV (http://boofcv.org).
 *
 * 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.
 */

package boofcv.misc;

/**
 * Functions related to discretized circles for image processing
 *
 * @author Peter Abeles
 */
public class DiscretizedCircle {

	/**
	 * Computes the offsets for a discretized circle of the specified radius for an
	 * image with the specified width.
	 *
	 * @param radius   The radius of the circle in pixels.
	 * @param imgWidth The row step of the image
	 * @return A list of offsets that describe the circle
	 */
	public static int[] imageOffsets(double radius, int imgWidth) {


		double PI2 = Math.PI * 2.0;

		double circumference = PI2 * radius;
		int num = (int) Math.ceil(circumference);
		num = num - num % 4;

		double angleStep = PI2 / num;


		int temp[] = new int[(int) Math.ceil(circumference)];
		int i = 0;

		int prev = 0;

		for (double ang = 0; ang < PI2; ang += angleStep) {
			int x = (int) Math.round(Math.cos(ang) * radius);
			int y = (int) Math.round(Math.sin(ang) * radius);

			int pixel = y * imgWidth + x;

			if (pixel != prev) {
//                System.out.println("i = "+i+"  x = "+x+"  y = "+y);
				temp[i++] = pixel;
			}
			prev = pixel;
		}

		if (i == temp.length)
			return temp;
		else {
			int ret[] = new int[i];
			System.arraycopy(temp, 0, ret, 0, i);

			return ret;
		}
	}

	public static int[][] imageOffsets2(double radius) {


		double PI2 = Math.PI * 2.0;

		double circumference = PI2 * radius;
		int num = (int) Math.ceil(circumference);
		num = num - num % 4;

		double angleStep = PI2 / num;


		int temp[][] = new int[num][2];

		for (int i = 0; i < num; i++) {
			double ang = angleStep * i;
			int x = (int) Math.round(Math.cos(ang) * radius);
			int y = (int) Math.round(Math.sin(ang) * radius);

			temp[i][0] = x;
			temp[i][1] = y;


//            System.out.println("i = "+i+"  x = "+x+"  y = "+y);
		}

		return temp;
	}
}