Need help drawing!

google java spiral swing (or applet)

http://www.java-tips.org/java-se-tips/java.awt/how-to-create-a-hypnosis-spiral-in-java.html

http://www.cs.princeton.edu/introcs/14array/Spiral.java.html

import java.awt.BasicStroke;

import java.awt.BorderLayout;

import java.awt.Color;

import java.awt.Graphics;

import java.awt.Graphics2D;

import java.awt.Rectangle;

import java.awt.RenderingHints;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import java.awt.image.BufferedImage;

import javax.swing.JComponent;

import javax.swing.JFrame;

import javax.swing.Timer;

/**

* A Swing component that smoothly animates a spiral in a hypnotic way.

*/

public class Hypnosis extends JComponent implements ActionListener {

double x, y; // The center of the spiral

double r1, r2; // The inner and outer radii of the spiral

double a1, a2; // The start and end angles of the spiral

double deltaA; // How much the angle changes each frame

double deltaX, deltaY; // The trajectory of the center

float linewidth; // How wide the lines are

Timer timer; // The object that triggers the animation

BufferedImage buffer; // The image we use for double-buffering

Graphics2D osg; // Graphics2D object for drawing into the buffer

public Hypnosis(double x, double y, double r1, double r2, double a1,

double a2, float linewidth, int delay, double deltaA,

double deltaX, double deltaY) {

this.x = x;

this.y = y;

this.r1 = r1;

this.r2 = r2;

this.a1 = a1;

this.a2 = a2;

this.linewidth = linewidth;

this.deltaA = deltaA;

this.deltaX = deltaX;

this.deltaY = deltaY;

// Set up a timer to call actionPerformed() every delay milliseconds

timer = new Timer(delay, this);

// Create a buffer for double-buffering

buffer = new BufferedImage((int) (2 * r2 + linewidth),

(int) (2 * r2 + linewidth), BufferedImage.TYPE_INT_RGB);

// Create a Graphics object for the buffer, and set the linewidth

// and request antialiasing when drawing with it

osg = buffer.createGraphics();

osg.setStroke(new BasicStroke(linewidth, BasicStroke.CAP_ROUND,

BasicStroke.JOIN_ROUND));

osg.setRenderingHint(RenderingHints.KEY_ANTIALIASING,

RenderingHints.VALUE_ANTIALIAS_ON);

}

// Start and stop the animation by starting and stopping the timer

public void start() {

timer.start();

}

public void stop() {

timer.stop();

}

/**

* Swing calls this method to ask the component to redraw itself. This

* method uses double-buffering to make the animation smoother. Swing does

* double-buffering automatically, so this may not actually make much

* difference, but it is important to understand the technique.

*/

public void paintComponent(Graphics g) {

// Clear the background of the off-screen image

osg.setColor(getBackground());

osg.fillRect(0, 0, buffer.getWidth(), buffer.getHeight());

// Now draw a black spiral into the off-screen image

osg.setColor(Color.black);

osg.draw(new Spiral(r2 + linewidth / 2, r2 + linewidth / 2, r1, a1, r2,

a2));

// Now copy that off-screen image onto the screen

g.drawImage(buffer, (int) (x - r2), (int) (y - r2), this);

}

/**

* This method implements the ActionListener interface. Our Timer object

* calls this method periodically. It updates the position and angles of the

* spiral and requests a redraw. Instead of redrawing the entire component,

* however, this method requests a redraw only for the area that has

* changed.

*/

public void actionPerformed(ActionEvent e) {

// Ask to have the old bounding box of the spiral redrawn.

// Nothing else has anything drawn in it, so it doesn't need a redraw

repaint((int) (x - r2 - linewidth), (int) (y - r2 - linewidth),

(int) (2 * (r2 + linewidth)), (int) (2 * (r2 + linewidth)));

// Now animate: update the position and angles of the spiral

// Bounce if we've hit an edge

Rectangle bounds = getBounds();

if ((x - r2 + deltaX < 0) || (x + r2 + deltaX > bounds.width))

deltaX = -deltaX;

if ((y - r2 + deltaY < 0) || (y + r2 + deltaY > bounds.height))

deltaY = -deltaY;

// Move the center of the spiral

x += deltaX;

y += deltaY;

// Increment the start and end angles;

a1 += deltaA;

a2 += deltaA;

if (a1 > 2 * Math.PI) { // Don't let them get too big

a1 -= 2 * Math.PI;

a2 -= 2 * Math.PI;

}

// Now ask to have the new bounding box of the spiral redrawn. This

// rectangle will be intersected with the redraw rectangle requested

// above, and only the combined region will be redrawn

repaint((int) (x - r2 - linewidth), (int) (y - r2 - linewidth),

(int) (2 * (r2 + linewidth)), (int) (2 * (r2 + linewidth)));

}

/** Tell Swing not to double-buffer for us, since we do our own */

public boolean isDoubleBuffered() {

return false;

}

/** This is a main() method for testing the component */

public static void main(String[] args) {

JFrame f = new JFrame("Hypnosis");

Hypnosis h = new Hypnosis(200, 200, 10, 100, 0, 11 * Math.PI, 7, 100,

2 * Math.PI / 30, 3, 5);

f.getContentPane().add(h, BorderLayout.CENTER);

f.setSize(400, 400);

f.show();

h.start();

}

}

hope that helps

java_2006a at 2007-7-12 1:27:13 >