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Wicket Extensions is a rich component library for the Wicket framework.
/*
* 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.wicket.extensions.captcha.kittens;
import java.awt.Dimension;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.image.BufferedImage;
import java.awt.image.RescaleOp;
import java.io.IOException;
import java.io.Serializable;
import java.lang.ref.SoftReference;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.imageio.stream.MemoryCacheImageInputStream;
import org.apache.wicket.IResourceListener;
import org.apache.wicket.ajax.AjaxEventBehavior;
import org.apache.wicket.ajax.AjaxRequestTarget;
import org.apache.wicket.markup.html.basic.Label;
import org.apache.wicket.markup.html.image.Image;
import org.apache.wicket.markup.html.image.NonCachingImage;
import org.apache.wicket.markup.html.panel.Panel;
import org.apache.wicket.model.AbstractReadOnlyModel;
import org.apache.wicket.request.Request;
import org.apache.wicket.request.cycle.RequestCycle;
import org.apache.wicket.request.http.WebResponse;
import org.apache.wicket.request.resource.DynamicImageResource;
import org.apache.wicket.util.time.Time;
/**
* A unique and fun-to-use captcha technique I developed at Thoof.
*
* @author Jonathan Locke
*/
public class KittenCaptchaPanel extends Panel
{
private static final long serialVersionUID = 2711167040323855070L;
// The background grass area
private static BufferedImage grass = load("images/grass.png");
// The kittens and other animals
private static final List kittens = new ArrayList();
private static final List nonKittens = new ArrayList();
// Random number generator
private static Random random = new Random(-1);
// Load animals
static
{
kittens.add(new Animal("kitten_01", true));
kittens.add(new Animal("kitten_02", true));
kittens.add(new Animal("kitten_03", true));
kittens.add(new Animal("kitten_04", true));
nonKittens.add(new Animal("chick", false));
nonKittens.add(new Animal("guinea_pig", false));
nonKittens.add(new Animal("hamster", false));
nonKittens.add(new Animal("puppy", false));
nonKittens.add(new Animal("rabbit", false));
}
/**
* @param filename
* The name of the file to load
* @return The image read form the file
*/
private static BufferedImage load(final String filename)
{
try
{
return ImageIO.read(new MemoryCacheImageInputStream(
KittenCaptchaPanel.class.getResourceAsStream(filename)));
}
catch (IOException e)
{
e.printStackTrace();
return null;
}
}
/**
* The various animals as placed animals
*/
private final PlacedAnimalList animals;
/**
* Label that shows request status
*/
private final Label animalSelectionLabel;
/**
* The image component
*/
private final Image image;
/**
* The image resource referenced by the Image component
*/
private final CaptchaImageResource imageResource;
/**
* Size of this kitten panel's image
*/
private final Dimension imageSize;
/**
* @param id
* Component id
* @param imageSize
* Size of kitten captcha image
*/
public KittenCaptchaPanel(final String id, final Dimension imageSize)
{
super(id);
// Save image size
this.imageSize = imageSize;
// Create animal list
animals = new PlacedAnimalList();
// Need to ajax refresh
setOutputMarkupId(true);
// Show how many animals have been selected
animalSelectionLabel = new Label("animalSelectionLabel",
new AbstractReadOnlyModel()
{
private static final long serialVersionUID = 6792322972316712326L;
@Override
public String getObject()
{
return imageResource.selectString();
}
});
animalSelectionLabel.setOutputMarkupId(true);
add(animalSelectionLabel);
// Image referencing captcha image resource
image = new NonCachingImage("image", imageResource = new CaptchaImageResource(animals));
image.add(new AjaxEventBehavior("onclick")
{
private static final long serialVersionUID = 7480352029955897654L;
@Override
protected CharSequence getCallbackScript()
{
// Call-back script shows loading indicator and makes wicket
// ajax request passing in mouse co-ordinates
return generateCallbackScript("showLoadingIndicator(); wicketAjaxGet('" +
getCallbackUrl() +
"&x=' + getEventX(this, event) + '&y=' + getEventY(this, event)");
}
@Override
protected void onEvent(final AjaxRequestTarget target)
{
// Get clicked cursor position
final Request request = RequestCycle.get().getRequest();
final int x = request.getRequestParameters().getParameterValue("x").toInt(0);
final int y = request.getRequestParameters().getParameterValue("y").toInt(0);
// Force refresh
imageResource.clearData();
// Find any animal at the clicked location
final PlacedAnimal animal = animals.atLocation(new Point(x, y));
// If the user clicked on an animal
if (animal != null)
{
// Toggle the animal's highlighting
animal.isHighlighted = !animal.isHighlighted;
// Instead of reload entire image just change the src
// attribute, this reduces the flicker
final StringBuilder javascript = new StringBuilder();
javascript.append("Wicket.$('")
.append(image.getMarkupId())
.append("').src = '");
CharSequence url = image.urlFor(IResourceListener.INTERFACE);
javascript.append(url);
javascript.append(url.toString().indexOf('?') > -1 ? "&" : "?")
.append("rand=")
.append(Math.random());
javascript.append("'");
target.appendJavaScript(javascript.toString());
}
else
{
// The user didn't click on an animal, so hide the loading
// indicator
target.appendJavaScript(" hideLoadingIndicator();");
}
// Update the selection label
target.add(animalSelectionLabel);
}
});
add(image);
}
/**
* @return True if all (three) kittens have been selected
*/
public boolean allKittensSelected()
{
return imageResource.allKittensSelected();
}
/**
* Resets for another go-around
*/
public void reset()
{
imageResource.reset();
}
/**
* @param animals
* List of animals
* @param newAnimal
* New animal to place
* @return The placed animal
*/
private PlacedAnimal placeAnimal(final List animals, final Animal newAnimal)
{
// Try 100 times
for (int iter = 0; iter < 100; iter++)
{
// Get the new animal's width and height
final int width = newAnimal.image.getWidth();
final int height = newAnimal.image.getHeight();
// Pick a random position
final int x = random(imageSize.width - width);
final int y = random(imageSize.height - height);
final Point point = new Point(x, y);
// Determine if there is too much overlap with other animals
final double tooClose = new Point(width, height).distance(new Point(0, 0)) / 2.0;
boolean tooMuchOverlap = false;
for (final PlacedAnimal animal : animals)
{
if (point.distance(animal.location) < tooClose)
{
tooMuchOverlap = true;
break;
}
}
// If there was not too much overlap
if (!tooMuchOverlap)
{
// The animal is now placed at x, y
return new PlacedAnimal(newAnimal, new Point(x, y));
}
}
// Could not place animal
return null;
}
/**
* @param max
* Maximum size of random value
* @return A random number between 0 and max - 1
*/
private int random(final int max)
{
return Math.abs(random.nextInt(max));
}
/**
* @return A random kitten
*/
private Animal randomKitten()
{
return kittens.get(random(kittens.size()));
}
/**
* @return A random other animal
*/
private Animal randomNonKitten()
{
return nonKittens.get(random(nonKittens.size()));
}
/**
* Animal, whether kitten or non-kitten
*/
private static class Animal
{
/**
* The highlighted image
*/
private final BufferedImage highlightedImage;
/**
* The normal image
*/
private final BufferedImage image;
/**
* True if the animal is a kitten
*/
private final boolean isKitten;
/**
* The visible region of the animal
*/
private final OpaqueRegion visibleRegion;
/**
* @param filename
* The filename
* @param isKitten
* True if the animal is a kitten
*/
private Animal(final String filename, final boolean isKitten)
{
this.isKitten = isKitten;
image = load("images/" + filename);
highlightedImage = load("images/" + filename + "_highlight");
visibleRegion = new OpaqueRegion(image);
}
/**
* @param filename
* The file to load
* @return The image in the file
*/
private BufferedImage load(final String filename)
{
try
{
final BufferedImage loadedImage = ImageIO.read(new MemoryCacheImageInputStream(
KittenCaptchaPanel.class.getResourceAsStream(filename + ".png")));
final BufferedImage image = new BufferedImage(loadedImage.getWidth(),
loadedImage.getHeight(), BufferedImage.TYPE_INT_ARGB);
final Graphics2D graphics = image.createGraphics();
graphics.drawImage(loadedImage, 0, 0, null);
graphics.dispose();
return image;
}
catch (IOException e)
{
e.printStackTrace();
return null;
}
}
}
/**
* Resource which renders the actual captcha image
*/
private static class CaptchaImageResource extends DynamicImageResource
{
private static final long serialVersionUID = -1560784998742404278L;
/**
* The placed animals
*/
private final PlacedAnimalList animals;
/**
* Image data array
*/
private transient SoftReference data = null;
@Override
protected void configureResponse(final ResourceResponse response,
final Attributes attributes)
{
super.configureResponse(response, attributes);
response.disableCaching();
}
/**
* @param animals
* The positioned animals
*/
private CaptchaImageResource(final PlacedAnimalList animals)
{
this.animals = animals;
setFormat("jpg");
}
/**
* @return Rendered image data
*/
@Override
protected byte[] getImageData(final Attributes attributes)
{
// Handle caching
setLastModifiedTime(Time.now());
final WebResponse response = (WebResponse)RequestCycle.get().getResponse();
response.setHeader("Cache-Control", "no-cache, must-revalidate, max-age=0, no-store");
// If we don't have data
if ((data == null) || (data.get() == null))
{
// Create the image and turn it into data
final BufferedImage composedImage = animals.createImage();
data = new SoftReference(toImageData(composedImage));
}
// Return image data
return data.get();
}
/**
* Invalidates the image data
*/
protected void invalidate()
{
data = null;
}
/**
* @return True if all kittens have been selected
*/
private boolean allKittensSelected()
{
return animals.allKittensSelected();
}
/**
* Clears out image data
*/
private void clearData()
{
invalidate();
setLastModifiedTime(Time.now());
}
/**
* Resets animals to default states
*/
private void reset()
{
animals.reset();
}
/**
* @return Selection state string for animals
*/
private String selectString()
{
return animals.selectString();
}
}
/**
* An animal that has a location
*/
private static class PlacedAnimal implements Serializable
{
private static final long serialVersionUID = -6703909440564862486L;
/**
* The animal
*/
private transient Animal animal;
/**
* Index in kitten or nonKitten list
*/
private final int index;
/**
* True if the animal is highlighted
*/
private boolean isHighlighted;
/**
* True if this animal is a kitten
*/
private final boolean isKitten;
/**
* The location of the animal
*/
private final Point location;
/**
* Scaling values
*/
private final float[] scales = { 1f, 1f, 1f, 1f };
/**
* @param animal
* The animal
* @param location
* Where to put it
*/
public PlacedAnimal(final Animal animal, final Point location)
{
this.animal = animal;
this.location = location;
isKitten = animal.isKitten;
if (isKitten)
{
index = kittens.indexOf(animal);
}
else
{
index = nonKittens.indexOf(animal);
}
for (int i = 0; i < 3; i++)
{
scales[i] = random(0.9f, 1.0f);
}
scales[3] = random(0.7f, 1.0f);
}
/**
* {@inheritDoc}
*/
@Override
public String toString()
{
return (isKitten ? "kitten at " : "other at ") + location.x + ", " + location.y;
}
/**
* @param point
* The point
* @return True if this placed animal contains the given point
*/
private boolean contains(final Point point)
{
final Point relativePoint = new Point(point.x - location.x, point.y - location.y);
return getAnimal().visibleRegion.contains(relativePoint);
}
/**
* @param graphics
* The graphics to draw on
*/
private void draw(final Graphics2D graphics)
{
final float[] offsets = new float[4];
final RescaleOp rop = new RescaleOp(scales, offsets, null);
if (isHighlighted)
{
graphics.drawImage(getAnimal().highlightedImage, rop, location.x, location.y);
}
else
{
graphics.drawImage(getAnimal().image, rop, location.x, location.y);
}
}
/**
* @return The animal that is placed
*/
private Animal getAnimal()
{
if (animal == null)
{
if (isKitten)
{
animal = kittens.get(index);
}
else
{
animal = nonKittens.get(index);
}
}
return animal;
}
/**
* @param min
* Minimum random value
* @param max
* Maximum random value
* @return A random value in the given range
*/
private float random(final float min, final float max)
{
return min + Math.abs(random.nextFloat() * (max - min));
}
}
/**
* Holds a list of placed animals
*/
private class PlacedAnimalList implements Serializable
{
private static final long serialVersionUID = 6335852594326213439L;
/**
* List of placed animals
*/
private final List animals = new ArrayList();
/**
* Arrange random animals and kittens
*/
private PlacedAnimalList()
{
// Place the three kittens
animals.add(placeAnimal(animals, randomKitten()));
animals.add(placeAnimal(animals, randomKitten()));
animals.add(placeAnimal(animals, randomKitten()));
// Try a few times
for (int iter = 0; iter < 500; iter++)
{
// Place a non kitten
final PlacedAnimal animal = placeAnimal(animals, randomNonKitten());
// If we were able to place the animal
if (animal != null)
{
// add it to the list
animals.add(animal);
}
// 15 non-kittens is enough
if (animals.size() > 15)
{
break;
}
}
// Shuffle the animal order
Collections.shuffle(animals);
// Ensure kittens are visible enough
List strayKittens = new ArrayList();
for (final PlacedAnimal animal : animals)
{
// If it's a kitten
if (animal.isKitten)
{
// Compute the area of the visible region in pixels
final int kittenArea = animal.getAnimal().visibleRegion.areaInPixels();
// If at least 4/5ths of the given kitten is not visible
// (because it is obscured by other animal(s))
if (visibleRegion(animal).areaInPixels() < kittenArea * 4 / 5)
{
// The user probably can't identify it, so add to the
// stray kittens list
strayKittens.add(animal);
}
}
}
// Remove any the stray kittens and then re-add them so they move to
// the top of the z-order
animals.removeAll(strayKittens);
animals.addAll(strayKittens);
}
/**
* @return True if all kittens are selected
*/
private boolean allKittensSelected()
{
for (final PlacedAnimal animal : animals)
{
if (animal.isKitten != animal.isHighlighted)
{
return false;
}
}
return true;
}
/**
* @param location
* The cursor location that was clicked
* @return Any animal that might be at the given location or null if none found (the user
* clicked on grass)
*/
private PlacedAnimal atLocation(final Point location)
{
// Reverse list for z-ordered hit-testing
final List reversedAnimals = new ArrayList(animals);
Collections.reverse(reversedAnimals);
// Return any animal at the given location
for (final PlacedAnimal animal : reversedAnimals)
{
if (animal.contains(location))
{
return animal;
}
}
// No animal found
return null;
}
/**
* @return The kitten captcha image
*/
private BufferedImage createImage()
{
// Create image of the right size
final BufferedImage newImage = new BufferedImage(imageSize.width, imageSize.height,
BufferedImage.TYPE_INT_RGB);
// Draw the grass
final Graphics2D graphics = newImage.createGraphics();
graphics.drawImage(grass, 0, 0, null);
// Draw each animal in order
for (final PlacedAnimal animal : animals)
{
animal.draw(graphics);
}
// Clean up graphics resource
graphics.dispose();
// Return the rendered animals
return newImage;
}
/**
* Undo highlight states of animals
*/
private void reset()
{
for (final PlacedAnimal animal : animals)
{
animal.isHighlighted = false;
}
}
/**
* @return Selection string to show
*/
private String selectString()
{
int selected = 0;
for (final PlacedAnimal animal : animals)
{
if (animal.isHighlighted)
{
selected++;
}
}
if (selected == 0)
{
return getString("instructions");
}
else
{
return selected + " " + getString("animalsSelected");
}
}
/**
* @param animal
* The animal
* @return The visible region of the animal
*/
private OpaqueRegion visibleRegion(final PlacedAnimal animal)
{
// The index of the animal in the animal list
int index = animals.indexOf(animal);
// Check sanity
if (index == -1)
{
// Invalid animal somehow
throw new IllegalArgumentException("animal not in list");
}
else
{
// Get the animal's visible region
OpaqueRegion visible = animal.getAnimal().visibleRegion;
// Go through the animals above the given animal
for (index++; index < animals.size(); index++)
{
// Remove the higher animal's visible region
final PlacedAnimal remove = animals.get(index);
visible = visible.subtract(remove.getAnimal().visibleRegion, new Point(
remove.location.x - animal.location.x, remove.location.y -
animal.location.y));
}
return visible;
}
}
}
}