lc-core/src/main/java/lc/GifCaptcha.java

package lc;

import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.Color;
import java.awt.image.BufferedImage;
import java.io.IOException;
import javax.imageio.stream.ImageOutputStream;
import javax.imageio.stream.MemoryCacheImageOutputStream;
import java.io.ByteArrayOutputStream;

public class GifCaptcha implements ChallengeProvider{

    private BufferedImage charToImg(String text){
        BufferedImage img = new BufferedImage(250, 100, BufferedImage.TYPE_INT_RGB);
        Font font = new Font("Bradley Hand", Font.ROMAN_BASELINE, 48);
        Graphics2D graphics2D = img.createGraphics();
        graphics2D.setFont(font);
        graphics2D.setColor(new Color((int)(Math.random() * 0x1000000)));
        graphics2D.drawString( text , 45, 45);
        graphics2D.dispose();
        return img;
    }

    private byte[] gifCaptcha(String text){
        try {
            ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
            ImageOutputStream output = new MemoryCacheImageOutputStream(byteArrayOutputStream);
            GifSequenceWriter writer = new GifSequenceWriter( output, 1,1000, true );
            for(int i=0; i< text.length(); i++){
                BufferedImage nextImage = charToImg(String.valueOf(text.charAt(i)));
                writer.writeToSequence(nextImage);
            }
            writer.close();
            output.close();
            return byteArrayOutputStream.toByteArray();
        } catch (IOException e){
            e.printStackTrace();
        }
        return null;
    }

    public Challenge returnChallenge() {
        String secret = HelperFunctions.randomString(6);
        return new Challenge(gifCaptcha(secret),"gif",secret.toLowerCase());
    }

    public boolean checkAnswer(String secret, String answer) {
        return answer.toLowerCase().equals(secret);
    }

    public String getId() {
        return "GifCaptcha";
    }
}