com.github.sarxos.webcam.Webcam Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of webcam-capture Show documentation
Show all versions of webcam-capture Show documentation
This library allows you to use your PC webcam, IP or network cameras directly from Java. It's compatible with most operating systems (Windows, Linux, MacOS).
package com.github.sarxos.webcam;
import java.awt.Dimension;
import java.awt.image.BufferedImage;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import java.util.concurrent.atomic.AtomicBoolean;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.github.sarxos.webcam.WebcamDevice.BufferAccess;
import com.github.sarxos.webcam.WebcamDevice.Configurable;
import com.github.sarxos.webcam.WebcamUpdater.DefaultDelayCalculator;
import com.github.sarxos.webcam.WebcamUpdater.DelayCalculator;
import com.github.sarxos.webcam.ds.buildin.WebcamDefaultDevice;
import com.github.sarxos.webcam.ds.buildin.WebcamDefaultDriver;
import com.github.sarxos.webcam.ds.cgt.WebcamCloseTask;
import com.github.sarxos.webcam.ds.cgt.WebcamDisposeTask;
import com.github.sarxos.webcam.ds.cgt.WebcamGetBufferTask;
import com.github.sarxos.webcam.ds.cgt.WebcamGetImageTask;
import com.github.sarxos.webcam.ds.cgt.WebcamOpenTask;
import com.github.sarxos.webcam.ds.cgt.WebcamReadBufferTask;
/**
* Webcam class. It wraps webcam device obtained from webcam driver.
*
* @author Bartosz Firyn (bfiryn)
*/
public class Webcam {
/**
* Class used to asynchronously notify all webcam listeners about new image available.
*
* @author Bartosz Firyn (sarxos)
*/
private static final class ImageNotification implements Runnable {
/**
* Camera.
*/
private final Webcam webcam;
/**
* Acquired image.
*/
private final BufferedImage image;
/**
* Create new notification.
*
* @param webcam the webcam from which image has been acquired
* @param image the acquired image
*/
public ImageNotification(Webcam webcam, BufferedImage image) {
this.webcam = webcam;
this.image = image;
}
@Override
public void run() {
if (image != null) {
WebcamEvent we = new WebcamEvent(WebcamEventType.NEW_IMAGE, webcam, image);
for (WebcamListener l : webcam.getWebcamListeners()) {
try {
l.webcamImageObtained(we);
} catch (Exception e) {
LOG.error(String.format("Notify image acquired, exception when calling listener %s", l.getClass()), e);
}
}
}
}
}
private final class NotificationThreadFactory implements ThreadFactory {
@Override
public Thread newThread(Runnable r) {
Thread t = new Thread(r, String.format("notificator-[%s]", getName()));
t.setUncaughtExceptionHandler(WebcamExceptionHandler.getInstance());
t.setDaemon(true);
return t;
}
}
/**
* Logger instance.
*/
private static final Logger LOG = LoggerFactory.getLogger(Webcam.class);
/**
* List of driver classes names to search for.
*/
private static final List DRIVERS_LIST = new ArrayList();
/**
* List of driver classes to search for.
*/
private static final List> DRIVERS_CLASS_LIST = new ArrayList>();
/**
* Discovery listeners.
*/
private static final List DISCOVERY_LISTENERS = Collections.synchronizedList(new ArrayList());
/**
* Webcam driver (LtiCivil, JMF, FMJ, JQT, OpenCV, VLCj, etc).
*/
private static volatile WebcamDriver driver = null;
/**
* Webcam discovery service.
*/
private static volatile WebcamDiscoveryService discovery = null;
/**
* Is automated deallocation on TERM signal enabled.
*/
private static boolean deallocOnTermSignal = false;
/**
* Is auto-open feature enabled?
*/
private static boolean autoOpen = false;
/**
* Webcam listeners.
*/
private List listeners = new CopyOnWriteArrayList();
/**
* List of custom resolution sizes supported by webcam instance.
*/
private List customSizes = new ArrayList();
/**
* Shutdown hook.
*/
private WebcamShutdownHook hook = null;
/**
* Underlying webcam device.
*/
private WebcamDevice device = null;
/**
* Is webcam open?
*/
private AtomicBoolean open = new AtomicBoolean(false);
/**
* Is webcam already disposed?
*/
private AtomicBoolean disposed = new AtomicBoolean(false);
/**
* Is non-blocking (asynchronous) access enabled?
*/
private volatile boolean asynchronous = false;
/**
* Current FPS.
*/
private volatile double fps = 0;
/**
* Webcam image updater.
*/
private volatile WebcamUpdater updater = null;
/**
* Image transformer.
*/
private volatile WebcamImageTransformer transformer = null;
/**
* Lock which denies access to the given webcam when it's already in use by other webcam capture
* API process or thread.
*/
private WebcamLock lock = null;
/**
* Executor service for image notifications.
*/
private ExecutorService notificator = null;
/**
* Webcam class.
*
* @param device - device to be used as webcam
* @throws IllegalArgumentException when device argument is null
*/
protected Webcam(WebcamDevice device) {
if (device == null) {
throw new IllegalArgumentException("Webcam device cannot be null");
}
this.device = device;
this.lock = new WebcamLock(this);
}
/**
* Asynchronously start new thread which will notify all webcam listeners about the new image
* available.
*/
protected void notifyWebcamImageAcquired(BufferedImage image) {
// notify webcam listeners of new image available, do that only if there
// are any webcam listeners available because there is no sense to start
// additional threads for no purpose
if (getWebcamListenersCount() > 0) {
notificator.execute(new ImageNotification(this, image));
}
}
/**
* Open the webcam in blocking (synchronous) mode.
*
* @return True if webcam has been open, false otherwise
* @see #open(boolean, DelayCalculator)
* @throws WebcamException when something went wrong
*/
public boolean open() {
return open(false);
}
/**
* Open the webcam in either blocking (synchronous) or non-blocking
* (asynchronous) mode. If the non-blocking mode is enabled the
* DefaultDelayCalculator is used for calculating delay between two image
* fetching.
*
* @param async true for non-blocking mode, false for blocking
* @return True if webcam has been open, false otherwise
* @see #open(boolean, DelayCalculator)
* @throws WebcamException when something went wrong
*/
public boolean open(boolean async) {
return open(async, new DefaultDelayCalculator());
}
/**
* Open the webcam in either blocking (synchronous) or non-blocking
* (asynchronous) mode.The difference between those two modes lies in the
* image acquisition mechanism.
*
* In blocking mode, when user calls {@link #getImage()} method, device is
* being queried for new image buffer and user have to wait for it to be
* available.
*
* In non-blocking mode, there is a special thread running in the background
* which constantly fetch new images and cache them internally for further
* use. This cached instance is returned every time when user request new
* image. Because of that it can be used when timeing is very important,
* because all users calls for new image do not have to wait on device
* response. By using this mode user should be aware of the fact that in
* some cases, when two consecutive calls to get new image are executed more
* often than webcam device can serve them, the same image instance will be
* returned. User should use {@link #isImageNew()} method to distinguish if
* returned image is not the same as the previous one.
* The background thread uses implementation of DelayCalculator interface to
* calculate delay between two image fetching. Custom implementation may be
* specified as parameter of this method. If the non-blocking mode is
* enabled and no DelayCalculator is specified, DefaultDelayCalculator will
* be used.
*
* @param async true for non-blocking mode, false for blocking
* @param delayCalculator responsible for calculating delay between two
* image fetching in non-blocking mode; It's ignored in blocking
* mode.
* @return True if webcam has been open
* @throws WebcamException when something went wrong
*/
public boolean open(boolean async, DelayCalculator delayCalculator) {
if (open.compareAndSet(false, true)) {
assert lock != null;
notificator = Executors.newSingleThreadExecutor(new NotificationThreadFactory());
// lock webcam for other Java (only) processes
lock.lock();
// open webcam device
WebcamOpenTask task = new WebcamOpenTask(driver, device);
try {
task.open();
} catch (InterruptedException e) {
lock.unlock();
open.set(false);
LOG.debug("Thread has been interrupted in the middle of webcam opening process!", e);
return false;
} catch (WebcamException e) {
lock.unlock();
open.set(false);
LOG.debug("Webcam exception when opening", e);
throw e;
}
LOG.debug("Webcam is now open {}", getName());
// install shutdown hook
try {
Runtime.getRuntime().addShutdownHook(hook = new WebcamShutdownHook(this));
} catch (IllegalStateException e) {
LOG.debug("Shutdown in progress, do not open device");
LOG.trace(e.getMessage(), e);
close();
return false;
}
// setup non-blocking configuration
if (asynchronous = async) {
if (updater == null) {
updater = new WebcamUpdater(this, delayCalculator);
}
updater.start();
}
// notify listeners
WebcamEvent we = new WebcamEvent(WebcamEventType.OPEN, this);
Iterator wli = listeners.iterator();
WebcamListener l = null;
while (wli.hasNext()) {
l = wli.next();
try {
l.webcamOpen(we);
} catch (Exception e) {
LOG.error(String.format("Notify webcam open, exception when calling listener %s", l.getClass()), e);
}
}
} else {
LOG.debug("Webcam is already open {}", getName());
}
return true;
}
/**
* Close the webcam.
*
* @return True if webcam has been open, false otherwise
*/
public boolean close() {
if (open.compareAndSet(true, false)) {
LOG.debug("Closing webcam {}", getName());
assert lock != null;
// close webcam
WebcamCloseTask task = new WebcamCloseTask(driver, device);
try {
task.close();
} catch (InterruptedException e) {
open.set(true);
LOG.debug("Thread has been interrupted before webcam was closed!", e);
return false;
} catch (WebcamException e) {
open.set(true);
throw e;
}
// stop updater
if (asynchronous) {
updater.stop();
}
// remove shutdown hook (it's not more necessary)
removeShutdownHook();
// unlock webcam so other Java processes can start using it
lock.unlock();
// notify listeners
WebcamEvent we = new WebcamEvent(WebcamEventType.CLOSED, this);
Iterator wli = listeners.iterator();
WebcamListener l = null;
while (wli.hasNext()) {
l = wli.next();
try {
l.webcamClosed(we);
} catch (Exception e) {
LOG.error(String.format("Notify webcam closed, exception when calling %s listener", l.getClass()), e);
}
}
notificator.shutdown();
while (!notificator.isTerminated()) {
try {
notificator.awaitTermination(100, TimeUnit.MILLISECONDS);
} catch (InterruptedException e) {
return false;
}
}
LOG.debug("Webcam {} has been closed", getName());
} else {
LOG.debug("Webcam {} is already closed", getName());
}
return true;
}
/**
* Return underlying webcam device. Depending on the driver used to discover devices, this
* method can return instances of different class. By default {@link WebcamDefaultDevice} is
* returned when no external driver is used.
*
* @return Underlying webcam device instance
*/
public WebcamDevice getDevice() {
assert device != null;
return device;
}
/**
* Completely dispose capture device. After this operation webcam cannot be used any more and
* full reinstantiation is required.
*/
protected void dispose() {
assert disposed != null;
assert open != null;
assert driver != null;
assert device != null;
assert listeners != null;
if (!disposed.compareAndSet(false, true)) {
return;
}
open.set(false);
LOG.info("Disposing webcam {}", getName());
WebcamDisposeTask task = new WebcamDisposeTask(driver, device);
try {
task.dispose();
} catch (InterruptedException e) {
LOG.error("Processor has been interrupted before webcam was disposed!", e);
return;
}
WebcamEvent we = new WebcamEvent(WebcamEventType.DISPOSED, this);
Iterator wli = listeners.iterator();
WebcamListener l = null;
while (wli.hasNext()) {
l = wli.next();
try {
l.webcamClosed(we);
l.webcamDisposed(we);
} catch (Exception e) {
LOG.error(String.format("Notify webcam disposed, exception when calling %s listener", l.getClass()), e);
}
}
removeShutdownHook();
LOG.debug("Webcam disposed {}", getName());
}
private void removeShutdownHook() {
// hook can be null because there is a possibility that webcam has never
// been open and therefore hook was not created
if (hook != null) {
try {
Runtime.getRuntime().removeShutdownHook(hook);
} catch (IllegalStateException e) {
LOG.trace("Shutdown in progress, cannot remove hook");
}
}
}
/**
* TRansform image using image transformer. If image transformer has not been set, this method
* return instance passed in the argument, without any modifications.
*
* @param image the image to be transformed
* @return Transformed image (if transformer is set)
*/
protected BufferedImage transform(BufferedImage image) {
if (image != null) {
WebcamImageTransformer tr = getImageTransformer();
if (tr != null) {
return tr.transform(image);
}
}
return image;
}
/**
* Is webcam open?
*
* @return true if open, false otherwise
*/
public boolean isOpen() {
return open.get();
}
/**
* Get current webcam resolution in pixels.
*
* @return Webcam resolution (picture size) in pixels.
*/
public Dimension getViewSize() {
return device.getResolution();
}
/**
* Return list of supported view sizes. It can differ between vary webcam data sources.
*
* @return Array of supported dimensions
*/
public Dimension[] getViewSizes() {
return device.getResolutions();
}
/**
* Set custom resolution. If you are using this method you have to make sure that your webcam
* device can support this specific resolution.
*
* @param sizes the array of custom resolutions to be supported by webcam
*/
public void setCustomViewSizes(Dimension[] sizes) {
assert customSizes != null;
if (sizes == null) {
customSizes.clear();
return;
}
customSizes = Arrays.asList(sizes);
}
public Dimension[] getCustomViewSizes() {
assert customSizes != null;
return customSizes.toArray(new Dimension[customSizes.size()]);
}
/**
* Set new view size. New size has to exactly the same as one of the default sized or exactly
* the same as one of the custom ones.
*
* @param size the new view size to be set
* @see Webcam#setCustomViewSizes(Dimension[])
* @see Webcam#getViewSizes()
*/
public void setViewSize(Dimension size) {
if (size == null) {
throw new IllegalArgumentException("Resolution cannot be null!");
}
if (open.get()) {
throw new IllegalStateException("Cannot change resolution when webcam is open, please close it first");
}
// check if new resolution is the same as current one
Dimension current = getViewSize();
if (current != null && current.width == size.width && current.height == size.height) {
return;
}
// check if new resolution is valid
Dimension[] predefined = getViewSizes();
Dimension[] custom = getCustomViewSizes();
assert predefined != null;
assert custom != null;
boolean ok = false;
for (Dimension d : predefined) {
if (d.width == size.width && d.height == size.height) {
ok = true;
break;
}
}
if (!ok) {
for (Dimension d : custom) {
if (d.width == size.width && d.height == size.height) {
ok = true;
break;
}
}
}
if (!ok) {
StringBuilder sb = new StringBuilder("Incorrect dimension [");
sb.append(size.width).append("x").append(size.height).append("] ");
sb.append("possible ones are ");
for (Dimension d : predefined) {
sb.append("[").append(d.width).append("x").append(d.height).append("] ");
}
for (Dimension d : custom) {
sb.append("[").append(d.width).append("x").append(d.height).append("] ");
}
throw new IllegalArgumentException(sb.toString());
}
LOG.debug("Setting new resolution {}x{}", size.width, size.height);
device.setResolution(size);
}
/**
* Capture image from webcam and return it. Will return image object or null if webcam is closed
* or has been already disposed by JVM.
*
* IMPORTANT NOTE!!!
*
* There are two possible behaviors of what webcam should do when you try to get image and
* webcam is actually closed. Normally it will return null, but there is a special flag which
* can be statically set to switch all webcams to auto open mode. In this mode, webcam will be
* automatically open, when you try to get image from closed webcam. Please be aware of some
* side effects! In case of multi-threaded applications, there is no guarantee that one thread
* will not try to open webcam even if it was manually closed in different thread.
*
* @return Captured image or null if webcam is closed or disposed by JVM
*/
public BufferedImage getImage() {
if (!isReady()) {
return null;
}
long t1 = 0;
long t2 = 0;
if (asynchronous) {
return updater.getImage();
} else {
// get image
t1 = System.currentTimeMillis();
BufferedImage image = transform(new WebcamGetImageTask(driver, device).getImage());
t2 = System.currentTimeMillis();
if (image == null) {
return null;
}
// get FPS
if (device instanceof WebcamDevice.FPSSource) {
fps = ((WebcamDevice.FPSSource) device).getFPS();
} else {
// +1 to avoid division by zero
fps = (4 * fps + 1000 / (t2 - t1 + 1)) / 5;
}
// notify webcam listeners about new image available
notifyWebcamImageAcquired(image);
return image;
}
}
public boolean isImageNew() {
if (asynchronous) {
return updater.isImageNew();
}
return true;
}
public double getFPS() {
if (asynchronous) {
return updater.getFPS();
} else {
return fps;
}
}
/**
* Get RAW image ByteBuffer. It will always return buffer with 3 x 1 bytes per each pixel, where
* RGB components are on (0, 1, 2) and color space is sRGB.
*
* IMPORTANT!
* Some drivers can return direct ByteBuffer, so there is no guarantee that underlying bytes
* will not be released in next read image operation. Therefore, to avoid potential bugs you
* should convert this ByteBuffer to bytes array before you fetch next image.
*
* @return Byte buffer
*/
public ByteBuffer getImageBytes() {
if (!isReady()) {
return null;
}
assert driver != null;
assert device != null;
// some devices can support direct image buffers, and for those call
// processor task, and for those which does not support direct image
// buffers, just convert image to RGB byte array
if (device instanceof BufferAccess) {
return new WebcamGetBufferTask(driver, device).getBuffer();
} else {
throw new IllegalStateException(String.format("Driver %s does not support buffer access", driver.getClass().getName()));
}
}
/**
* Get RAW image ByteBuffer. It will always return buffer with 3 x 1 bytes per each pixel, where
* RGB components are on (0, 1, 2) and color space is sRGB.
*
* IMPORTANT!
* Some drivers can return direct ByteBuffer, so there is no guarantee that underlying bytes
* will not be released in next read image operation. Therefore, to avoid potential bugs you
* should convert this ByteBuffer to bytes array before you fetch next image.
*
* @param target the target {@link ByteBuffer} object to copy data into
*/
public void getImageBytes(ByteBuffer target) {
if (!isReady()) {
return;
}
assert driver != null;
assert device != null;
// some devices can support direct image buffers, and for those call
// processor task, and for those which does not support direct image
// buffers, just convert image to RGB byte array
if (device instanceof BufferAccess) {
new WebcamReadBufferTask(driver, device, target).readBuffer();
} else {
throw new IllegalStateException(String.format("Driver %s does not support buffer access", driver.getClass().getName()));
}
}
/**
* If the underlying device implements Configurable interface, specified
* parameters are passed to it. May be called before the open method or
* later in dependence of the device implementation.
*
* @param parameters - Map of parameters changing device defaults
* @see Configurable
*/
public void setParameters(Map parameters) {
WebcamDevice device = getDevice();
if (device instanceof Configurable) {
((Configurable) device).setParameters(parameters);
} else {
LOG.debug("Webcam device {} is not configurable", device);
}
}
/**
* Is webcam ready to be read.
*
* @return True if ready, false otherwise
*/
private boolean isReady() {
assert disposed != null;
assert open != null;
if (disposed.get()) {
LOG.warn("Cannot get image, webcam has been already disposed");
return false;
}
if (!open.get()) {
if (autoOpen) {
open();
} else {
return false;
}
}
return true;
}
/**
* Get list of webcams to use. This method will wait predefined time interval for webcam devices
* to be discovered. By default this time is set to 1 minute.
*
* @return List of webcams existing in the system
* @throws WebcamException when something is wrong
* @see Webcam#getWebcams(long, TimeUnit)
*/
public static List getWebcams() throws WebcamException {
// timeout exception below will never be caught since user would have to
// wait around three hundreds billion years for it to occur
try {
return getWebcams(Long.MAX_VALUE);
} catch (TimeoutException e) {
throw new RuntimeException(e);
}
}
/**
* Get list of webcams to use. This method will wait given time interval for webcam devices to
* be discovered. Time argument is given in milliseconds.
*
* @param timeout the time to wait for webcam devices to be discovered
* @return List of webcams existing in the ssytem
* @throws TimeoutException when timeout occurs
* @throws WebcamException when something is wrong
* @throws IllegalArgumentException when timeout is negative
* @see Webcam#getWebcams(long, TimeUnit)
*/
public static List getWebcams(long timeout) throws TimeoutException, WebcamException {
if (timeout < 0) {
throw new IllegalArgumentException(String.format("Timeout cannot be negative (%d)", timeout));
}
return getWebcams(timeout, TimeUnit.MILLISECONDS);
}
/**
* Get list of webcams to use. This method will wait given time interval for webcam devices to
* be discovered.
*
* @param timeout the devices discovery timeout
* @param tunit the time unit
* @return List of webcams
* @throws TimeoutException when timeout has been exceeded
* @throws WebcamException when something is wrong
* @throws IllegalArgumentException when timeout is negative or tunit null
*/
public static synchronized List getWebcams(long timeout, TimeUnit tunit) throws TimeoutException, WebcamException {
if (timeout < 0) {
throw new IllegalArgumentException(String.format("Timeout cannot be negative (%d)", timeout));
}
if (tunit == null) {
throw new IllegalArgumentException("Time unit cannot be null!");
}
WebcamDiscoveryService discovery = getDiscoveryService();
assert discovery != null;
List webcams = discovery.getWebcams(timeout, tunit);
if (!discovery.isRunning()) {
discovery.start();
}
return webcams;
}
/**
* Will discover and return first webcam available in the system.
*
* @return Default webcam (first from the list)
* @throws WebcamException if something is really wrong
* @see Webcam#getWebcams()
*/
public static Webcam getDefault() throws WebcamException {
try {
return getDefault(Long.MAX_VALUE);
} catch (TimeoutException e) {
// this should never happen since user would have to wait 300000000
// years for it to occur
throw new RuntimeException(e);
}
}
/**
* Will discover and return first webcam available in the system.
*
* @param timeout the webcam discovery timeout (1 minute by default)
* @return Default webcam (first from the list)
* @throws TimeoutException when discovery timeout has been exceeded
* @throws WebcamException if something is really wrong
* @throws IllegalArgumentException when timeout is negative
* @see Webcam#getWebcams(long)
*/
public static Webcam getDefault(long timeout) throws TimeoutException, WebcamException {
if (timeout < 0) {
throw new IllegalArgumentException(String.format("Timeout cannot be negative (%d)", timeout));
}
return getDefault(timeout, TimeUnit.MILLISECONDS);
}
/**
* Will discover and return first webcam available in the system.
*
* @param timeout the webcam discovery timeout (1 minute by default)
* @param tunit the time unit
* @return Default webcam (first from the list)
* @throws TimeoutException when discovery timeout has been exceeded
* @throws WebcamException if something is really wrong
* @throws IllegalArgumentException when timeout is negative or tunit null
* @see Webcam#getWebcams(long, TimeUnit)
*/
public static Webcam getDefault(long timeout, TimeUnit tunit) throws TimeoutException, WebcamException {
if (timeout < 0) {
throw new IllegalArgumentException(String.format("Timeout cannot be negative (%d)", timeout));
}
if (tunit == null) {
throw new IllegalArgumentException("Time unit cannot be null!");
}
List webcams = getWebcams(timeout, tunit);
assert webcams != null;
if (!webcams.isEmpty()) {
return webcams.get(0);
}
LOG.warn("No webcam has been detected!");
return null;
}
/**
* Get webcam name (device name). The name of device depends on the value returned by the
* underlying data source, so in some cases it can be human-readable value and sometimes it can
* be some strange number.
*
* @return Name
*/
public String getName() {
assert device != null;
return device.getName();
}
@Override
public String toString() {
return String.format("Webcam %s", getName());
}
/**
* Add webcam listener.
*
* @param l the listener to be added
* @return True if listener has been added, false if it was already there
* @throws IllegalArgumentException when argument is null
*/
public boolean addWebcamListener(WebcamListener l) {
if (l == null) {
throw new IllegalArgumentException("Webcam listener cannot be null!");
}
assert listeners != null;
return listeners.add(l);
}
/**
* @return All webcam listeners
*/
public WebcamListener[] getWebcamListeners() {
assert listeners != null;
return listeners.toArray(new WebcamListener[listeners.size()]);
}
/**
* @return Number of webcam listeners
*/
public int getWebcamListenersCount() {
assert listeners != null;
return listeners.size();
}
/**
* Removes webcam listener.
*
* @param l the listener to be removed
* @return True if listener has been removed, false otherwise
*/
public boolean removeWebcamListener(WebcamListener l) {
assert listeners != null;
return listeners.remove(l);
}
/**
* Return webcam driver. Perform search if necessary.
*
* This method is not thread-safe!
*
* @return Webcam driver
*/
public static synchronized WebcamDriver getDriver() {
if (driver != null) {
return driver;
}
if (driver == null) {
driver = WebcamDriverUtils.findDriver(DRIVERS_LIST, DRIVERS_CLASS_LIST);
}
if (driver == null) {
driver = new WebcamDefaultDriver();
}
LOG.info("{} capture driver will be used", driver.getClass().getSimpleName());
return driver;
}
/**
* Set new video driver to be used by webcam.
*
* This method is not thread-safe!
*
* @param wd new webcam driver to be used (e.g. LtiCivil, JFM, FMJ, QTJ)
* @throws IllegalArgumentException when argument is null
*/
public static void setDriver(WebcamDriver wd) {
if (wd == null) {
throw new IllegalArgumentException("Webcam driver cannot be null!");
}
LOG.debug("Setting new capture driver {}", wd);
resetDriver();
driver = wd;
}
/**
* Set new video driver class to be used by webcam. Class given in the argument shall extend
* {@link WebcamDriver} interface and should have public default constructor, so instance can be
* created by reflection.
*
* This method is not thread-safe!
*
* @param driverClass new video driver class to use
* @throws IllegalArgumentException when argument is null
*/
public static void setDriver(Class driverClass) {
if (driverClass == null) {
throw new IllegalArgumentException("Webcam driver class cannot be null!");
}
resetDriver();
try {
driver = driverClass.newInstance();
} catch (InstantiationException e) {
throw new WebcamException(e);
} catch (IllegalAccessException e) {
throw new WebcamException(e);
}
}
/**
* Reset webcam driver.
*
* This method is not thread-safe!
*/
public static void resetDriver() {
synchronized (DRIVERS_LIST) {
DRIVERS_LIST.clear();
}
if (discovery != null) {
discovery.shutdown();
discovery = null;
}
driver = null;
}
/**
* Register new webcam video driver.
*
* @param clazz webcam video driver class
* @throws IllegalArgumentException when argument is null
*/
public static void registerDriver(Class clazz) {
if (clazz == null) {
throw new IllegalArgumentException("Webcam driver class to register cannot be null!");
}
DRIVERS_CLASS_LIST.add(clazz);
registerDriver(clazz.getCanonicalName());
}
/**
* Register new webcam video driver.
*
* @param clazzName webcam video driver class name
* @throws IllegalArgumentException when argument is null
*/
public static void registerDriver(String clazzName) {
if (clazzName == null) {
throw new IllegalArgumentException("Webcam driver class name to register cannot be null!");
}
DRIVERS_LIST.add(clazzName);
}
/**
* CAUTION!!!
*
* This is experimental feature to be used mostly in in development phase. After you set handle
* term signal to true, and fetch capture devices, Webcam Capture API will listen for TERM
* signal and try to close all devices after it has been received. This feature can be
* unstable on some systems!
*
* @param on signal handling will be enabled if true, disabled otherwise
*/
public static void setHandleTermSignal(boolean on) {
if (on) {
LOG.warn("Automated deallocation on TERM signal is now enabled! Make sure to not use it in production!");
}
deallocOnTermSignal = on;
}
/**
* Is TERM signal handler enabled.
*
* @return True if enabled, false otherwise
*/
public static boolean isHandleTermSignal() {
return deallocOnTermSignal;
}
/**
* Switch all webcams to auto open mode. In this mode, each webcam will be automatically open
* whenever user will try to get image from instance which has not yet been open. Please be
* aware of some side effects! In case of multi-threaded applications, there is no guarantee
* that one thread will not try to open webcam even if it was manually closed in different
* thread.
*
* @param on true to enable, false to disable
*/
public static void setAutoOpenMode(boolean on) {
autoOpen = on;
}
/**
* Is auto open mode enabled. Auto open mode will will automatically open webcam whenever user
* will try to get image from instance which has not yet been open. Please be aware of some side
* effects! In case of multi-threaded applications, there is no guarantee that one thread will
* not try to open webcam even if it was manually closed in different thread.
*
* @return True if mode is enabled, false otherwise
*/
public static boolean isAutoOpenMode() {
return autoOpen;
}
/**
* Add new webcam discovery listener.
*
* @param l the listener to be added
* @return True, if listeners list size has been changed, false otherwise
* @throws IllegalArgumentException when argument is null
*/
public static boolean addDiscoveryListener(WebcamDiscoveryListener l) {
if (l == null) {
throw new IllegalArgumentException("Webcam discovery listener cannot be null!");
}
return DISCOVERY_LISTENERS.add(l);
}
public static WebcamDiscoveryListener[] getDiscoveryListeners() {
return DISCOVERY_LISTENERS.toArray(new WebcamDiscoveryListener[DISCOVERY_LISTENERS.size()]);
}
/**
* Remove discovery listener
*
* @param l the listener to be removed
* @return True if listeners list contained the specified element
*/
public static boolean removeDiscoveryListener(WebcamDiscoveryListener l) {
return DISCOVERY_LISTENERS.remove(l);
}
/**
* Return discovery service.
*
* @return Discovery service
*/
public static synchronized WebcamDiscoveryService getDiscoveryService() {
if (discovery == null) {
discovery = new WebcamDiscoveryService(getDriver());
}
return discovery;
}
/**
* Return discovery service without creating it if not exists.
*
* @return Discovery service or null if not yet created
*/
public static synchronized WebcamDiscoveryService getDiscoveryServiceRef() {
return discovery;
}
/**
* Return image transformer.
*
* @return Transformer instance
*/
public WebcamImageTransformer getImageTransformer() {
return transformer;
}
/**
* Set image transformer.
*
* @param transformer the transformer to be set
*/
public void setImageTransformer(WebcamImageTransformer transformer) {
this.transformer = transformer;
}
/**
* Return webcam lock.
*
* @return Webcam lock
*/
public WebcamLock getLock() {
return lock;
}
/**
* Shutdown webcam framework. This method should be used ONLY when you
* are exiting JVM, but please do not invoke it if you really don't
* need to.
*/
protected static void shutdown() {
// stop discovery service
WebcamDiscoveryService discovery = getDiscoveryServiceRef();
if (discovery != null) {
discovery.stop();
}
// stop processor
WebcamProcessor.getInstance().shutdown();
}
/**
* Return webcam with given name or null if no device with given name has
* been found. Please note that specific webcam name may depend on the order
* it was connected to the USB port (e.g. /dev/video0 vs /dev/video1).
*
* @param name the webcam name
* @return Webcam with given name or null if not found
* @throws IllegalArgumentException when name is null
*/
public static Webcam getWebcamByName(String name) {
if (name == null) {
throw new IllegalArgumentException("Webcam name cannot be null");
}
for (Webcam webcam : getWebcams()) {
if (webcam.getName().equals(name)) {
return webcam;
}
}
return null;
}
}
© 2015 - 2025 Weber Informatics LLC | Privacy Policy