CustomColorRamp.java

/* (c) 2014 Open Source Geospatial Foundation - all rights reserved
 * Copyright (C) 2007-2008-2009 GeoSolutions S.A.S.
 *  http://www.geo-solutions.it
 * This code is licensed under the GPL 2.0 license, available at the root
 * application directory.
 */
package org.geoserver.sldservice.utils.classifier.impl;

import java.awt.Color;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import org.geoserver.sldservice.utils.classifier.ColorRamp;

/**
 * Custom Color Ramp Implementation
 * 
 * @author Alessio Fabiani, GeoSolutions SAS
 *
 */
public class CustomColorRamp implements ColorRamp {

	private int classNum = 0;
	private List<Color> colors = new ArrayList<Color>();
	private Color startColor = null;
	private Color endColor = null;
	private Color midColor = null;

	public int getNumClasses() {
		return classNum;
	}

	public List<Color> getRamp() throws Exception {
		if (colors == null)
			throw new Exception("Class num not setted, color ramp null");
		return colors;
	}

	public void revert() {
        Collections.reverse(colors);
	}

	public void setNumClasses(int numClass) {
		classNum = numClass+1;//+1 for transparent
		try {
			createRamp();
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	public void setStartColor(Color start) {
		startColor = start;
	}

	public void setEndColor(Color end) {
		endColor = end;
	}

	public void setMid(Color mid) {
		midColor = mid;
	}

	protected void createRamp() throws Exception {
		int red, green, blue;
		double sRed, sGreen, sBlue;
		int mid;
		if (startColor == null || endColor == null)
			throw new Exception(
					"Start or end color not setted unable to build color ramp");

		if (midColor == null) {
			sRed = ((double) endColor.getRed() - startColor.getRed())
					/ (double) (classNum - 1);
			sGreen = ((double) endColor.getGreen() - startColor.getGreen())
					/ (double) (classNum - 1);
			sBlue = ((double) endColor.getBlue() - startColor.getBlue())
					/ (double) (classNum - 1);
			for (int i = 0; i < classNum -1; i++) {
				red = (int) (sRed * i + startColor.getRed());
				green = (int) (sGreen * i + startColor.getGreen());
				blue = (int) (sBlue * i + startColor.getBlue());
				colors.add(new Color(red, green, blue));
			}
		} else {
			mid = (classNum-1) / 2;
			int rest = (classNum-1) % 2;
			sRed = ((double) midColor.getRed() - startColor.getRed())
					/ (double) (mid);
			sGreen = ((double) midColor.getGreen() - startColor.getGreen())
					/ (double) (mid);
			sBlue = ((double) midColor.getBlue() - startColor.getBlue())
					/ (double) (mid);
			for (int i = 0; i < mid; i++) {
				red = (int) (sRed * i + startColor.getRed());
				green = (int) (sGreen * i + startColor.getGreen());
				blue = (int) (sBlue * i + startColor.getBlue());
				colors.add(new Color(red, green, blue));
			}
			int count = mid;
			sRed = ((double) endColor.getRed() - midColor.getRed())
					/ (double) (mid + rest - 1);
			sGreen = ((double) endColor.getGreen() - midColor.getGreen())
					/ (double) (mid + rest - 1);
			sBlue = ((double) endColor.getBlue() - midColor.getBlue())
					/ (double) (mid + rest - 1);
			for (int i = 0; i < (mid + rest); i++) {
				red = (int) (sRed * i + midColor.getRed());
				green = (int) (sGreen * i + midColor.getGreen());
				blue = (int) (sBlue * i + midColor.getBlue());
				colors.add(new Color(red, green, blue));
				count++;
			}
		}
	}

}