package com.darwinsys.graphics;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;
import java.io.Serializable;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.imageio.stream.ImageOutputStream;
/**
* Write a ransom-note-style string to an OutputStream as
* an Image file (jpeg for now). Designed for use in
* e.g., a servlet for verifying that a user is a person
* and not a spambot.
* But, deliberately, does not know about the Servlet API.
*/
public class JigglyTextImageWriter implements Serializable {
private final int width, height;
private final Font font;
private int nextColor;
private final Random random = new Random();
public JigglyTextImageWriter(Font font, int width, int height) {
super();
this.font = font;
this.width = width;
this.height = height;
}
/** generate the image and output it. */
public void write(String msg, OutputStream os) throws IOException{
BufferedImage img =
new BufferedImage(width, height,
BufferedImage.TYPE_INT_RGB);
// Get the Image's Graphics context
Graphics2D g = img.createGraphics();
g.setFont(font);
// Start with a clear screen
g.setColor(Color.WHITE);
g.fillRect(0,0, width, height);
// Fill the background with hashes
// XXX maybe use fanOfLines here
g.setColor(Color.GRAY);
g.drawLine(0, height / 2, width-1, height / 2);
// Draw the text
char[] msgChars = msg.toCharArray();
int y = height / 2, x = 0;
for (int i = 0; i < msgChars.length; i++) {
g.setColor(randomColor());
int xPermute = random.nextInt(5);
int yPermute = random.nextInt(5);
// XXX pick a rotation transform
g.drawChars(msgChars, i, 1, (x += 20) + xPermute, y + yPermute);
}
// Write the output
ImageOutputStream ios = ImageIO.createImageOutputStream(os);
if (!ImageIO.write(img, "jpeg", ios)) {
throw new IOException("Write Failed");
}
}
private static Color[] colors = {
Color.BLUE, Color.RED, Color.BLACK, Color.GREEN
};
private Color randomColor() {
return colors[nextColor++ % colors.length];
}
}