org.apache.myfaces.custom.captcha.util.CAPTCHAImageGenerator Maven / Gradle / Ivy
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JSF components and utilities that can be used with any JSF implementation.
This library is based on the JSF1.1 version of Tomahawk, but with minor source code and build
changes to take advantage of JSF2.1 features. A JSF2.1 implementation is required to use this
version of the Tomahawk library.
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/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.myfaces.custom.captcha.util;
import java.awt.Color;
import java.awt.Font;
import java.awt.GradientPaint;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.font.TextLayout;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Random;
import org.apache.batik.ext.awt.image.codec.PNGEncodeParam;
import org.apache.batik.ext.awt.image.codec.PNGImageEncoder;
/**
* This class is responsible for generating the CAPTCHA image.
*
* @since 1.1.7
*/
public class CAPTCHAImageGenerator
{
//private static final Color startingColor = new Color(150, 50, 150);
//private static final Color endingColor = new Color(255, 255, 255);
/*
* A helper method to draw the captcha text on the generated image.
*/
private void drawTextOnImage(Graphics2D graphics, String captchaText)
{
Font font;
TextLayout textLayout;
double currentFontStatus = Math.random();
// Generate random font status.
if (currentFontStatus >= 0.5)
{
font = new Font("Arial", Font.PLAIN, 60);
}
else
{
font = new Font("Arial", Font.BOLD, 60);
}
graphics.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
textLayout = new TextLayout(captchaText, font, graphics
.getFontRenderContext());
textLayout.draw(graphics, CAPTCHAConstants.TEXT_X_COORDINATE,
CAPTCHAConstants.TEXT_Y_COORDINATE);
}
/*
* A helper method to apply noise on the generated image.
*/
private void applyNoiseOnImage(Graphics2D graphics, int bufferedImageWidth,
int bufferedImageHeight, Color startingColor, Color endingColor)
{
// Applying shear.
applyShear(graphics, bufferedImageWidth, bufferedImageHeight,
startingColor, endingColor);
// Drawing a broken line on the image.
drawBrokenLineOnImage(graphics);
}
/*
* This helper method is used for applying current gradient paint to the
* Graphics2D object.
*/
private static void applyCurrentGradientPaint(Graphics2D graphics,
int width, int height, Color startingColor, Color endingColor)
{
GradientPaint gradientPaint = new GradientPaint(0, 0, startingColor,
width, height, endingColor);
graphics.setPaint(gradientPaint);
}
/**
* This method generates the CAPTCHA image.
* @param response
* @param captchaText
* @param startingColor
* @param endingColor
* @throws IOException
*/
public void generateImage(OutputStream out, String captchaText,
Color startingColor, Color endingColor) throws IOException
{
BufferedImage bufferedImage;
Graphics2D graphics;
PNGEncodeParam param;
PNGImageEncoder captchaPNGImage;
// Create the CAPTCHA Image.
bufferedImage = new BufferedImage(
CAPTCHAConstants.DEFAULT_CAPTCHA_WIDTH,
CAPTCHAConstants.DEFAULT_CAPTCHA_HEIGHT,
BufferedImage.TYPE_BYTE_INDEXED);
// Setup the graphics object.
graphics = bufferedImage.createGraphics();
applyCurrentGradientPaint(graphics, bufferedImage.getWidth(),
bufferedImage.getHeight(), startingColor, endingColor);
graphics.fillRect(0, 0, bufferedImage.getWidth(), bufferedImage
.getHeight());
graphics.setColor(Color.black);
// Draw text on the CAPTCHA image.
drawTextOnImage(graphics, captchaText);
// Apply noise on the CAPTCHA image.
applyNoiseOnImage(graphics, bufferedImage.getWidth(), bufferedImage
.getHeight(), startingColor, endingColor);
// Draw the image border.
drawBorders(graphics, bufferedImage.getWidth(), bufferedImage
.getHeight());
param = PNGEncodeParam.getDefaultEncodeParam(bufferedImage);
captchaPNGImage = new PNGImageEncoder(out, param);
captchaPNGImage.encode(bufferedImage);
}
/*
* This helper method is used for drawing a thick line on the image.
*/
private void drawThickLineOnImage(Graphics graphics, int x1, int y1,
int x2, int y2)
{
int dX = x2 - x1;
int dY = y2 - y1;
int xPoints[] = new int[4];
int yPoints[] = new int[4];
int thickness = 2;
double lineLength = Math.sqrt(dX * dX + dY * dY);
double scale = (double) (thickness) / (2 * lineLength);
double ddx = -scale * (double) dY;
double ddy = scale * (double) dX;
graphics.setColor(Color.black);
ddx += (ddx > 0) ? 0.5 : -0.5;
ddy += (ddy > 0) ? 0.5 : -0.5;
dX = (int) ddx;
dY = (int) ddy;
xPoints[0] = x1 + dX;
yPoints[0] = y1 + dY;
xPoints[1] = x1 - dX;
yPoints[1] = y1 - dY;
xPoints[2] = x2 - dX;
yPoints[2] = y2 - dY;
xPoints[3] = x2 + dX;
yPoints[3] = y2 + dY;
graphics.fillPolygon(xPoints, yPoints, 4);
}
/*
* This helper method is used for drawing a broken line on the image.
*/
private void drawBrokenLineOnImage(Graphics2D graphics)
{
int yPoint1;
int yPoint2;
int yPoint3;
int yPoint4;
int yPoint5;
Random random = new Random();
// Random Y Points.
yPoint1 = random.nextInt(CAPTCHAConstants.DEFAULT_CAPTCHA_HEIGHT);
yPoint2 = random.nextInt(CAPTCHAConstants.DEFAULT_CAPTCHA_HEIGHT);
yPoint3 = CAPTCHAConstants.DEFAULT_CAPTCHA_HEIGHT / 2;
yPoint4 = random.nextInt(CAPTCHAConstants.DEFAULT_CAPTCHA_HEIGHT);
yPoint5 = random.nextInt(CAPTCHAConstants.DEFAULT_CAPTCHA_HEIGHT);
// Draw the random broken line.
drawThickLineOnImage(graphics, 0, yPoint1,
CAPTCHAConstants.DEFAULT_CAPTCHA_WIDTH / 4, yPoint2);
drawThickLineOnImage(graphics,
CAPTCHAConstants.DEFAULT_CAPTCHA_WIDTH / 4, yPoint2,
CAPTCHAConstants.DEFAULT_CAPTCHA_WIDTH / 2, yPoint3);
drawThickLineOnImage(graphics,
CAPTCHAConstants.DEFAULT_CAPTCHA_WIDTH / 2, yPoint3,
3 * CAPTCHAConstants.DEFAULT_CAPTCHA_WIDTH / 4, yPoint4);
drawThickLineOnImage(graphics,
3 * CAPTCHAConstants.DEFAULT_CAPTCHA_WIDTH / 4, yPoint4,
CAPTCHAConstants.DEFAULT_CAPTCHA_WIDTH, yPoint5);
}
/*
* This helper method is used for calculating the delta of the shearing
* equation.
*/
private double getDelta(int period, double i, double phase, double frames)
{
return (double) (period / 2)
* Math.sin(i / (double) period
+ (2 * CAPTCHAConstants.PI * phase) / frames);
}
/*
* This helper method is used for applying shear on the image.
*/
private void applyShear(Graphics2D graphics, int bufferedImageWidth,
int bufferedImageHeight, Color startingColor, Color endingColor)
{
int periodValue = 20;
int numberOfFrames = 15;
int phaseNumber = 7;
double deltaX;
double deltaY;
applyCurrentGradientPaint(graphics, bufferedImageWidth,
bufferedImageHeight, startingColor, endingColor);
for (int i = 0; i < bufferedImageWidth; ++i)
{
deltaX = getDelta(periodValue, i, phaseNumber, numberOfFrames);
graphics.copyArea(i, 0, 1, bufferedImageHeight, 0, (int) deltaX);
graphics.drawLine(i, (int) deltaX, i, 0);
graphics.drawLine(i, (int) deltaX + bufferedImageHeight, i,
bufferedImageHeight);
}
for (int i = 0; i < bufferedImageHeight; ++i)
{
deltaY = getDelta(periodValue, i, phaseNumber, numberOfFrames);
graphics.copyArea(0, i, bufferedImageWidth, 1, (int) deltaY, 0);
graphics.drawLine((int) deltaY, i, 0, i);
graphics.drawLine((int) deltaY + bufferedImageWidth, i,
bufferedImageWidth, i);
}
}
/*
* This helper method is used for drawing the borders the image.
*/
private void drawBorders(Graphics2D graphics, int width, int height)
{
graphics.setColor(Color.black);
graphics.drawLine(0, 0, 0, width - 1);
graphics.drawLine(0, 0, width - 1, 0);
graphics.drawLine(0, height - 1, width, height - 1);
graphics.drawLine(width - 1, height - 1, width - 1, 0);
}
}