DrawMessage.java

package ch.rasc.s4ws.drawboard;

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.geom.Arc2D;
import java.awt.geom.Line2D;
import java.awt.geom.Rectangle2D;

public final class DrawMessage {

	private int type;

	private byte colorR, colorG, colorB, colorA;

	private double thickness;

	private double x1, y1, x2, y2;

	private boolean lastInChain;

	/**
	 * The type.<br>
	 * 1: Brush<br>
	 * 2: Line<br>
	 * 3: Rectangle<br>
	 * 4: Ellipse
	 */
	public int getType() {
		return this.type;
	}

	public void setType(int type) {
		this.type = type;
	}

	public double getThickness() {
		return this.thickness;
	}

	public void setThickness(double thickness) {
		this.thickness = thickness;
	}

	public byte getColorR() {
		return this.colorR;
	}

	public void setColorR(byte colorR) {
		this.colorR = colorR;
	}

	public byte getColorG() {
		return this.colorG;
	}

	public void setColorG(byte colorG) {
		this.colorG = colorG;
	}

	public byte getColorB() {
		return this.colorB;
	}

	public void setColorB(byte colorB) {
		this.colorB = colorB;
	}

	public byte getColorA() {
		return this.colorA;
	}

	public void setColorA(byte colorA) {
		this.colorA = colorA;
	}

	public double getX1() {
		return this.x1;
	}

	public void setX1(double x1) {
		this.x1 = x1;
	}

	public double getX2() {
		return this.x2;
	}

	public void setX2(double x2) {
		this.x2 = x2;
	}

	public double getY1() {
		return this.y1;
	}

	public void setY1(double y1) {
		this.y1 = y1;
	}

	public double getY2() {
		return this.y2;
	}

	public void setY2(double y2) {
		this.y2 = y2;
	}

	/**
	 * Specifies if this DrawMessage is the last one in a chain (e.g. a chain of brush
	 * paths).<br>
	 * Currently it is unused.
	 */
	public boolean isLastInChain() {
		return this.lastInChain;
	}

	public void setLastInChain(boolean lastInChain) {
		this.lastInChain = lastInChain;
	}

	public DrawMessage(int type, byte colorR, byte colorG, byte colorB, byte colorA,
			double thickness, double x1, double x2, double y1, double y2,
			boolean lastInChain) {

		this.type = type;
		this.colorR = colorR;
		this.colorG = colorG;
		this.colorB = colorB;
		this.colorA = colorA;
		this.thickness = thickness;
		this.x1 = x1;
		this.x2 = x2;
		this.y1 = y1;
		this.y2 = y2;
		this.lastInChain = lastInChain;
	}

	/**
	 * Draws this DrawMessage onto the given Graphics2D.
	 *
	 * @param g
	 */
	public void draw(Graphics2D g) {

		g.setStroke(new BasicStroke((float) this.thickness, BasicStroke.CAP_ROUND,
				BasicStroke.JOIN_MITER));
		g.setColor(new Color(this.colorR & 0xFF, this.colorG & 0xFF, this.colorB & 0xFF,
				this.colorA & 0xFF));

		if (this.x1 == this.x2 && this.y1 == this.y2) {
			// Always draw as arc to meet the behavior in the HTML5 Canvas.
			Arc2D arc = new Arc2D.Double(this.x1, this.y1, 0, 0, 0d, 360d, Arc2D.OPEN);
			g.draw(arc);

		}
		else if (this.type == 1 || this.type == 2) {
			// Draw a line.
			Line2D line = new Line2D.Double(this.x1, this.y1, this.x2, this.y2);
			g.draw(line);

		}
		else if (this.type == 3 || this.type == 4) {
			double x1 = this.x1, x2 = this.x2, y1 = this.y1, y2 = this.y2;
			if (x1 > x2) {
				x1 = this.x2;
				x2 = this.x1;
			}
			if (y1 > y2) {
				y1 = this.y2;
				y2 = this.y1;
			}

			// TODO: If (x1 == x2 || y1 == y2) draw as line.

			if (this.type == 3) {
				// Draw a rectangle.
				Rectangle2D rect = new Rectangle2D.Double(x1, y1, x2 - x1, y2 - y1);
				g.draw(rect);

			}
			else if (this.type == 4) {
				// Draw an ellipse.
				Arc2D arc = new Arc2D.Double(x1, y1, x2 - x1, y2 - y1, 0d, 360d,
						Arc2D.OPEN);
				g.draw(arc);

			}
		}
	}

	/**
	 * Converts this message into a String representation that can be sent over WebSocket.
	 * <br>
	 * Since a DrawMessage consists only of numbers, we concatenate those numbers with a
	 * ",".
	 */
	@Override
	public String toString() {

		return this.type + "," + (this.colorR & 0xFF) + "," + (this.colorG & 0xFF) + ","
				+ (this.colorB & 0xFF) + "," + (this.colorA & 0xFF) + "," + this.thickness
				+ "," + this.x1 + "," + this.y1 + "," + this.x2 + "," + this.y2 + ","
				+ (this.lastInChain ? "1" : "0");
	}

	public static DrawMessage parseFromString(String str) throws ParseException {

		int type;
		byte[] colors = new byte[4];
		double thickness;
		double[] coords = new double[4];
		boolean last;

		try {
			String[] elements = str.split(",");

			type = Integer.parseInt(elements[0]);
			if (!(type >= 1 && type <= 4)) {
				throw new ParseException("Invalid type: " + type);
			}

			for (int i = 0; i < colors.length; i++) {
				colors[i] = (byte) Integer.parseInt(elements[1 + i]);
			}

			thickness = Double.parseDouble(elements[5]);
			if (Double.isNaN(thickness) || thickness < 0 || thickness > 100) {
				throw new ParseException("Invalid thickness: " + thickness);
			}

			for (int i = 0; i < coords.length; i++) {
				coords[i] = Double.parseDouble(elements[6 + i]);
				if (Double.isNaN(coords[i])) {
					throw new ParseException("Invalid coordinate: " + coords[i]);
				}
			}

			last = !"0".equals(elements[10]);

		}
		catch (RuntimeException ex) {
			throw new ParseException(ex);
		}

		DrawMessage m = new DrawMessage(type, colors[0], colors[1], colors[2], colors[3],
				thickness, coords[0], coords[2], coords[1], coords[3], last);

		return m;
	}

	public static class ParseException extends Exception {
		private static final long serialVersionUID = -6651972769789842960L;

		public ParseException(Throwable root) {
			super(root);
		}

		public ParseException(String message) {
			super(message);
		}
	}

}