Drawing a right-angled triangle

import java.awt.*;

import javax.swing.*;

public class DrawingATriangle extends JPanel {

Polygon[] triangles;

public DrawingATriangle() {

triangles = new Polygon[3];

triangles[0] = new Polygon();

triangles[0].addPoint(50,25);

triangles[0].addPoint(50,150);

triangles[0].addPoint(150,150);

triangles[1] = getPolygon(75, 250, 100, 200);

triangles[2] = getPolygon(300, 175, -150, -75);

}

protected void paintComponent(Graphics g) {

super.paintComponent(g);

Graphics2D g2 = (Graphics2D)g;

g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,

RenderingHints.VALUE_ANTIALIAS_ON);

for(int j = 0; j < triangles.length; j++)

g2.draw(triangles[j]);

}

private Polygon getPolygon(int x, int y, int s1, int s2) {

int sides = 3;

int[] xpoints = new int[sides];

int[] ypoints = new int[sides];

xpoints[0] = x;

ypoints[0] = y + s1;

xpoints[1] = x;

ypoints[1] = y;

xpoints[2] = x + s2;

ypoints[2] = y;

return new Polygon(xpoints, ypoints, sides);

}

public static void main(String[] args) {

JFrame f = new JFrame();

f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

f.getContentPane().add(new DrawingATriangle());

f.setSize(400,400);

f.setLocation(200,200);

f.setVisible(true);

}

}

crwooda at 2007-7-12 10:33:27 >

import java.awt.*;

import java.awt.geom.*;

import javax.swing.*;

public class FormingATriangle extends JPanel {

Line2D.Double line;

Point2D.Double[] vertices;

public FormingATriangle() {

line = new Line2D.Double(100,100,300,300);

vertices = getVertices(line);

}

protected void paintComponent(Graphics g) {

super.paintComponent(g);

Graphics2D g2 = (Graphics2D)g;

g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,

RenderingHints.VALUE_ANTIALIAS_ON);

g2.draw(line);

g2.setPaint(Color.blue);

for(int j = 0; j < vertices.length; j++) {

g2.draw(new Line2D.Double(vertices[j], line.getP1()));

g2.draw(new Line2D.Double(vertices[j], line.getP2()));

}

g2.setPaint(Color.red);

for(int j = 0; j < vertices.length; j++)

mark(vertices[j], g2);

}

private Point2D.Double[] getVertices(Line2D.Double line) {

Point2D.Double[] p = new Point2D.Double[2];

Point2D p1 = line.getP1();

Point2D p2 = line.getP2();

// Try horizontal line at p1 and vertical line at p2

p[0] = new Point2D.Double(p2.getX(), p1.getY());

//System.out.printf("p[0] = [%.1f, %.1f]%n", p[0].x, p[0].y);

// Try vertical line at p1 and horizontal line at p2

p[1] = new Point2D.Double(p1.getX(), p2.getY());

//System.out.printf("p[1] = [%.1f, %.1f]%n", p[1].x, p[1].y);

return p;

}

private void mark(Point2D.Double p, Graphics2D g2) {

g2.fill(new Ellipse2D.Double(p.x-2, p.y-2, 4, 4));

}

public static void main(String[] args) {

JFrame f = new JFrame();

f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

f.getContentPane().add(new FormingATriangle());

f.setSize(400,400);

f.setLocation(200,200);

f.setVisible(true);

}

}

crwooda at 2007-7-12 10:33:27 >