Color sample plotter

PlotColorSamples.java

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.geom.Arc2D;
import java.awt.geom.Ellipse2D;
import java.awt.geom.Line2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

import javax.imageio.ImageIO;

import com.tomgibara.graphics.util.ImageUtil;


public class PlotColorSamples {

	public static void main(String[] args) throws IOException {
		String path = args[0];
		BufferedImage image = ImageIO.read(new File(path, "samples.png"));
		int[] rgb = ImageUtil.toIntRGB(image);
		ImageIO.write(plot(rgb, true), "PNG", new File(path, "brightness-plot.png"));
		ImageIO.write(plot(rgb, false), "PNG", new File(path, "saturation-plot.png"));
	}
	
	private static BufferedImage plot(int[] rgb, boolean brightness) {
		String name = brightness ? "Brightness" : "Saturation";
		
		int size = 300;
		BufferedImage img = new BufferedImage(size, size, BufferedImage.TYPE_INT_RGB);
		Graphics2D g = img.createGraphics();
		g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
		g.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
		g.setRenderingHint(RenderingHints.KEY_FRACTIONALMETRICS, RenderingHints.VALUE_FRACTIONALMETRICS_ON);
		g.setBackground(Color.WHITE);
		g.clearRect(0, 0, size, size);
		g.setColor(Color.GRAY);
		
		float[] hsb = new float[3];
		double radius = size *.5f;
		g.translate(radius, radius);
		g.scale(radius, radius);
		
		int steps = 30;
		double angleStep = 360.0 / steps * 0.8;
		float strokeWidth = 0.05f;
		g.setStroke(new BasicStroke(strokeWidth, BasicStroke.CAP_BUTT, BasicStroke.JOIN_MITER));
		double outerRadius = 1 - strokeWidth;
		for (int i = 0; i < steps; i++) {
			double angle = i * 360.0 / steps;
			Color c = Color.getHSBColor(i / (float) steps, 0.5f, 0.5f);
			g.setColor(c);
			g.draw(new Arc2D.Double(-outerRadius, -outerRadius, 2 * outerRadius, 2 * outerRadius, angle - angleStep/2, angleStep, Arc2D.OPEN));
		}
		
		double innerRadius = 1 - 1.5 * strokeWidth;
		g.setColor(Color.BLACK);
		g.setStroke(new BasicStroke(0.01f, BasicStroke.CAP_BUTT, BasicStroke.JOIN_MITER));
		g.rotate(Math.PI/6);
		g.draw(new Line2D.Double(0, 0, innerRadius, 0));
		g.draw(new Line2D.Double(innerRadius, 0, innerRadius - 0.04, -0.02));
		g.draw(new Line2D.Double(innerRadius, 0, innerRadius - 0.04,  0.02));
		g.setFont(new Font("Arial", Font.PLAIN, 1).deriveFont(0.11f));
		g.drawString(name, 0.20f, 0.12f);
		g.rotate(-Math.PI/6);
		
		for (int i = 0; i < rgb.length; i++) {
			Color c = new Color(rgb[i]);
			Color.RGBtoHSB(c.getRed(), c.getGreen(), c.getBlue(), hsb);
			double a = -hsb[0] * 2.0 * Math.PI;
			double r = hsb[brightness ? 2 : 1] * 0.9;
			double x = Math.cos(a) * r;
			double y = Math.sin(a) * r;
			double ptr = 0.03;
			g.setColor(c);
			g.fill(new Ellipse2D.Double(x-ptr, y-ptr, ptr*2, ptr*2));
		}
		
		ImageUtil.showImage(name + " Plot", img);
		return img;
	}
	
}