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package test;
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import java.awt.image.*;
import javax.swing.*;
import javax.swing.event.*;
/**
* <p>Title: </p>
* <p>Description: </p>
* <p>Copyright: Copyright (c) 2005</p>
* <p>Company: </p>
* @author Fabrice Bouyé (fabriceb@spc.int)
* @version 1.0
*/
public class ArrowPanel extends JPanel implements ComponentListener, MouseInputListener {
/** Default width.
*/
public static final int DEFAULT_WIDTH = 300;
/** Default height.
*/
public static final int DEFAULT_HEIGHT = 300;
/** Default size.
*/
public static final Dimension DEFAULT_SIZE = new Dimension(DEFAULT_WIDTH, DEFAULT_HEIGHT);
/** Starting angle.
*/
public static final double DEFAULT_ANGLE = Math.PI / 4.0;
/** Labels for angles around the trigonometric circle.
*/
private static final String[] ANGLE_LABELS = new String[] {"0", "\u03C0/2", "\u03C0", "3*\u03C0/2"};
/** The trigonometric circle shape.
*/
private Ellipse2D.Double circle = new Ellipse2D.Double();
/** Current segment angle vs X axis.
*/
private double angle = DEFAULT_ANGLE;
/** Current segment.
*/
private Line2D.Double segment = new Line2D.Double();
/** Creates a new instance.
*/
public ArrowPanel() {
super();
addComponentListener(this);
addMouseListener(this);
addMouseMotionListener(this);
setPreferredSize(DEFAULT_SIZE);
setSize(DEFAULT_SIZE);
}
/** {@inheritDoc}
*/
@Override protected void paintComponent(Graphics graphics) {
super.paintComponent(graphics);
Dimension size = getSize();
Insets insets = getInsets();
int width = size.width - (insets.left + insets.right);
int height = size.height - (insets.top + insets.bottom);
Graphics2D g2 = (Graphics2D) graphics.create(insets.left, insets.top, width, height);
g2.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
try {
paintAxis(g2, width, height);
paintCircle(g2, width, height);
paintArrow(g2, width, height);
} finally {
g2.dispose();
}
}
/** Paint the axis.
* @param graphics The graphics context in which to render.
* @param width The width of the drawing area.
* @param height The height of the drawing area.
*/
private void paintAxis(Graphics2D graphics, int width, int height) {
graphics.setColor(Color.GRAY);
int centerX = (int) (circle.getX() + circle.getWidth() / 2.0);
int centerY = (int) (circle.getY() + circle.getHeight() / 2.0);
graphics.drawLine(0, centerY, width, centerY);
graphics.drawLine(centerX, 0, centerX, height);
}
/** Paint the circle.
* @param graphics The graphics context in which to render.
* @param width The width of the drawing area.
* @param height The height of the drawing area.
*/
private void paintCircle(Graphics2D graphics, int width, int height) {
graphics.setColor(Color.BLACK);
graphics.draw(circle);
int centerX = (int) (circle.getX() + circle.getWidth() / 2.0);
int centerY = (int) (circle.getY() + circle.getHeight() / 2.0);
int radius = (int) circle.getWidth() / 2;
// Draw angle labels around the circle.
graphics.translate(centerX, centerY);
AffineTransform transform = AffineTransform.getRotateInstance(Math.PI / 2.0);
Point2D.Double point = new Point2D.Double(radius + 20, 0);
for (int i = 0; i < 4; i++) {
graphics.drawString(ANGLE_LABELS[i], (float) point.x, (float) point.y);
transform.transform(point, point);
}
graphics.translate( -centerX, -centerY);
}
/** Paint the arrow.
* @param graphics The graphics context in which to render.
* @param width The width of the drawing area.
* @param height The height of the drawing area.
*/
private void paintArrow(Graphics2D graphics, int width, int height) {
graphics.setColor(Color.BLUE);
graphics.draw(segment);
drawArrowHeadAtLocation(graphics, segment.getX2(), segment.getY2(), angle);
}
/** Paint the arrow head at given location and angle.
* @param graphics The graphics context in which to render.
* @param x The X coordinate.
* @param y the Y coordinate.
* @param angle The angle (in radian).
*/
private void drawArrowHeadAtLocation(Graphics2D graphics, double x, double y, double angle) {
graphics.translate(x, y);
graphics.rotate(angle);
drawArrowHead(graphics);
graphics.rotate( -angle);
graphics.translate( -x, -y);
}
/** Draw a simple arrow head at (0, 0) that points to the right.
* @param graphics The graphics context in which to render.
*/
private void drawArrowHead(Graphics2D graphics) {
graphics.drawLine(0, 0, -10, 5);
graphics.drawLine(0, 0, -10, -5);
graphics.drawLine( -10, 5, -10, -5);
}
///////////////
// Geometry. //
///////////////
/** Recalculate all shapes with given drawing area dimension.
* @param width The width of the drawing area.
* @param height The height of the drawing area.
*/
private void recalculateShapes(double width, double height) {
double centerX = width / 2.0;
double centerY = height / 2.0;
double radius = Math.min(width / 2.0, height / 2.0) / 2.0;
circle.setFrameFromCenter(centerX, centerY, centerX + radius, centerY + radius);
double arrowLength = radius * 1.33;
double endX = centerX + arrowLength;
double endY = centerY;
AffineTransform transform = AffineTransform.getRotateInstance(angle, centerX, centerY);
Point2D endPoint = transform.transform(new Point2D.Double(endX, endY), null);
segment.setLine(centerX, centerY, endPoint.getX(), endPoint.getY());
}
/** Reset the segment's angle relative to a give mouse event.
* @param event The mouse event.
*/
private void resetAngleRelativeToEvent(MouseEvent event) {
Insets insets = getInsets();
int x = event.getX() - insets.left;
int y = event.getY() - insets.top;
resetAngleRelativeToLocation(x, y);
}
/** Reset the segment's angle relative to a given location.
* @param locationX The X coordinate.
* @param locationY The Y corrdinate.
*/
private void resetAngleRelativeToLocation(double locationX, double locationY) {
try {
int centerX = (int) (circle.getX() + circle.getWidth() / 2.0);
int centerY = (int) (circle.getY() + circle.getHeight() / 2.0);
// Angle between (center, location) and X axis.
double newAngle = calculateAngle(centerX, centerY, locationX, locationY);
AffineTransform transform = AffineTransform.getRotateInstance(newAngle - angle, centerX, centerY);
Point2D endPoint = transform.transform(segment.getP2(), null);
segment.setLine(centerX, centerY, endPoint.getX(), endPoint.getY());
angle = newAngle;
}
// Silently consume exception.
catch (Throwable t) {
}
}
/////////////////////
// static methods. //
/////////////////////
/** Self-test main.
* @param args Arguments from the command line.
*/
public static void main(String ...args) {
JFrame frame = new JFrame("Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new ArrowPanel(), BorderLayout.CENTER);
frame.pack();
frame.setVisible(true);
}
/** Gets the angle between the given vector and the horizontal axis.
* @param x1 The X coordinate of the first point.
* @param y1 The Y coordinate of the first point.
* @param x2 The X coordinate of the first point.
* @param y2 The Y coordinate of the first point.
* @return A value within the <CODE>[0, 2*PI[</CODE> range.
* @exception ValueNotDefinedException If the vector's length is zero, the angle is not defined.
* @since 1.1
*/
public static double calculateAngle(double x1, double y1, double x2, double y2) throws ValueNotDefinedException {
double a = (x2 - x1);
double b = (y2 - y1);
double length = Math.sqrt(Math.pow(a, 2) + Math.pow(b, 2));
if (length == 0) {
throw new ValueNotDefinedException();
}
double p = length; //Math.sqrt(a*a+b*b);
double theta = Math.asin(Math.abs(b) / p);
if (b < 0) {
theta = -theta;
}
if (a < 0) {
theta = Math.PI - theta;
}
// Rescale into [0, 2*PI[.
theta %= 2 * Math.PI;
if (theta < 0) {
theta += 2 * Math.PI;
}
return theta;
}
///////////////////////
// Event management. //
///////////////////////
// ComponentListener interface.
/** {@inheritDoc}
*/
public void componentResized(ComponentEvent event) {
Dimension size = getSize();
Insets insets = getInsets();
int width = size.width - (insets.left + insets.right);
int height = size.height - (insets.top + insets.bottom);
recalculateShapes(width, height);
repaint();
}
/** {@inheritDoc}
*/
public void componentMoved(ComponentEvent event) {
}
/** {@inheritDoc}
*/
public void componentShown(ComponentEvent event) {
}
/** {@inheritDoc}
*/
public void componentHidden(ComponentEvent event) {
}
// MouseInputListener interface.
/** {@inheritDoc}
*/
public void mouseClicked(MouseEvent event) {
}
/** {@inheritDoc}
*/
public void mousePressed(MouseEvent event) {
resetAngleRelativeToEvent(event);
repaint();
}
/** {@inheritDoc}
*/
public void mouseReleased(MouseEvent event) {
}
/** {@inheritDoc}
*/
public void mouseEntered(MouseEvent event) {
}
/** {@inheritDoc}
*/
public void mouseExited(MouseEvent event) {
}
/** {@inheritDoc}
*/
public void mouseDragged(MouseEvent event) {
resetAngleRelativeToEvent(event);
repaint();
}
/** {@inheritDoc}
*/
public void mouseMoved(MouseEvent event) {
}
////////////////////
// Inner classes. //
////////////////////
/**
* <p>Title: </p>
* <p>Description: </p>
* <p>Copyright: Copyright (c) 2005</p>
* <p>Company: </p>
* @author Fabrice Bouyé (fabriceb@spc.int)
* @version 1.0
*/
public static class ValueNotDefinedException extends Exception {}
} |
