68 lines
2.2 KiB
Java
68 lines
2.2 KiB
Java
package lc.captchas;
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import javax.imageio.ImageIO;
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import java.awt.Graphics2D;
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import java.awt.RenderingHints;
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import java.awt.Color;
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import java.awt.Font;
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import java.awt.font.TextLayout;
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import java.awt.image.BufferedImage;
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import java.awt.image.ConvolveOp;
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import java.awt.image.Kernel;
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import java.io.ByteArrayOutputStream;
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import lc.misc.HelperFunctions;
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import lc.captchas.interfaces.Challenge;
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import lc.captchas.interfaces.ChallengeProvider;
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public class ShadowTextCaptcha implements ChallengeProvider {
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public String getId() {
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return "ShadowTextCaptcha";
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}
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public boolean checkAnswer(String secret, String answer) {
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return answer.toLowerCase().equals(secret);
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}
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private byte[] shadowText(String text) {
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BufferedImage img = new BufferedImage(350, 100, BufferedImage.TYPE_INT_RGB);
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Font font = new Font("Arial", Font.ROMAN_BASELINE, 48);
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Graphics2D graphics2D = img.createGraphics();
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graphics2D.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
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graphics2D.setRenderingHint(
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RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
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TextLayout textLayout = new TextLayout(text, font, graphics2D.getFontRenderContext());
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HelperFunctions.setRenderingHints(graphics2D);
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graphics2D.setPaint(Color.WHITE);
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graphics2D.fillRect(0, 0, 350, 100);
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graphics2D.setPaint(Color.BLACK);
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textLayout.draw(graphics2D, 15, 50);
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graphics2D.dispose();
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float[] kernel = {
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1f / 9f, 1f / 9f, 1f / 9f,
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1f / 9f, 1f / 9f, 1f / 9f,
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1f / 9f, 1f / 9f, 1f / 9f
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};
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ConvolveOp op = new ConvolveOp(new Kernel(3, 3, kernel), ConvolveOp.EDGE_NO_OP, null);
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BufferedImage img2 = op.filter(img, null);
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Graphics2D g2d = img2.createGraphics();
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HelperFunctions.setRenderingHints(g2d);
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g2d.setPaint(Color.WHITE);
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textLayout.draw(g2d, 13, 50);
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g2d.dispose();
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ByteArrayOutputStream baos = new ByteArrayOutputStream();
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try {
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ImageIO.write(img2, "png", baos);
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} catch (Exception e) {
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e.printStackTrace();
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}
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return baos.toByteArray();
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}
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public Challenge returnChallenge() {
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String secret = HelperFunctions.randomString(6);
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return new Challenge(shadowText(secret), "image/png", secret.toLowerCase());
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}
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}
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