Add possibility to set view size + example

src/example/java/com/github/sarxos/webcam/TakePictureDifferentSizeExample.java

@@ -0,0 +1,26 @@
+package com.github.sarxos.webcam;
+
+import java.awt.Dimension;
+import java.io.File;
+import java.io.IOException;
+
+import javax.imageio.ImageIO;
+
+
+/**
+ * Set view size before taking picture. It's worth to mention that size has to
+ * be set before opening camera.
+ * 
+ * @author Bartosz Firyn (SarXos)
+ */
+public class TakePictureDifferentSizeExample {
+
+	public static void main(String[] args) throws IOException {
+		Webcam webcam = Webcam.getDefault();
+		webcam.setViewSize(new Dimension(176, 144));
+		webcam.open();
+		ImageIO.write(webcam.getImage(), "PNG", new File("test.png"));
+		webcam.close();
+	}
+
+}

src/example/java/com/github/sarxos/webcam/TakePictureExample.java

@@ -7,14 +7,12 @@
 
 
 /**
- * Proof of concept of how to handle webcam video stream from Java
- * 
  * @author Bartosz Firyn (SarXos)
  */
 public class TakePictureExample {
 
 	public static void main(String[] args) throws IOException {
-		Webcam webcam = Webcam.getWebcams().get(0);
+		Webcam webcam = Webcam.getDefault();
 		webcam.open();
 		ImageIO.write(webcam.getImage(), "PNG", new File("test.png"));
 		webcam.close();

src/example/java/com/github/sarxos/webcam/TakePictureFromTwoCamsExample.java

@@ -0,0 +1,29 @@
+package com.github.sarxos.webcam;
+
+import java.io.File;
+import java.io.IOException;
+
+import javax.imageio.ImageIO;
+
+
+/**
+ * @author Bartosz Firyn (SarXos)
+ */
+public class TakePictureFromTwoCamsExample {
+
+	public static void main(String[] args) throws IOException {
+
+		Webcam webcam1 = Webcam.getWebcams().get(0);
+		Webcam webcam2 = Webcam.getWebcams().get(1);
+
+		webcam1.open();
+		webcam2.open();
+
+		ImageIO.write(webcam1.getImage(), "PNG", new File("test1.png"));
+		ImageIO.write(webcam2.getImage(), "PNG", new File("test2.png"));
+
+		webcam1.close();
+		webcam2.close();
+	}
+
+}

src/main/java/com/github/sarxos/webcam/Webcam.java

@@ -136,6 +136,7 @@ public void controllerUpdate(ControllerEvent ce) {
 
 	private PlayerStarter starter = null;
 	private Semaphore semaphore = new Semaphore(0, true);
+	private Dimension viewSize = null;
 
 	/**
 	 * Webcam class.
@@ -146,6 +147,14 @@ public Webcam(CaptureDeviceInfo device) {
 		this.device = device;
 	}
 
+	private VideoFormat createFormat(Dimension size) {
+		if (size == null) {
+			return getLargestVideoFormat();
+		} else {
+			return getSizedVideoFormat(size);
+		}
+	}
+
 	/**
 	 * Open webcam.
 	 */
@@ -159,7 +168,7 @@ public synchronized void open() {
 		LOG.debug("Opening webcam");
 
 		locator = device.getLocator();
-		format = getVideoFormat(device);
+		format = createFormat(viewSize);
 		converter = new BufferToImage(format);
 
 		try {
@@ -254,10 +263,83 @@ private Control getControl(String name) {
 	 * @return Webcam view size (picture size) in pixels.
 	 */
 	public Dimension getViewSize() {
-		if (!isOpen()) {
-			throw new RuntimeException("Webcam has to be open to get video size");
+		if (viewSize == null) {
+			return getLargestVideoFormat().getSize();
+		}
+		return viewSize;
+	}
+
+	public Dimension[] getViewSizes() {
+
+		List<Dimension> dimensions = new ArrayList<Dimension>();
+
+		Format[] formats = device.getFormats();
+		for (Format format : formats) {
+			if ("RGB".equalsIgnoreCase(format.getEncoding())) {
+				VideoFormat rgb = (VideoFormat) format;
+				dimensions.add(rgb.getSize());
+			}
 		}
-		return format.getSize();
+		return dimensions.toArray(new Dimension[dimensions.size()]);
+	}
+
+	public void setViewSize(Dimension size) {
+
+		// check if dimension is valid one
+		boolean ok = false;
+		Dimension[] sizes = getViewSizes();
+		for (Dimension d : sizes) {
+			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 : sizes) {
+				sb.append("[").append(d.width).append("x").append(d.height).append("] ");
+			}
+			throw new IllegalArgumentException(sb.toString());
+		}
+
+		viewSize = size;
+	}
+
+	public static void main(String[] args) {
+		for (Dimension d : Webcam.getDefault().getViewSizes()) {
+			System.out.println(d);
+		}
+	}
+
+	/**
+	 * Get video format for size.
+	 * 
+	 * @param device device to get format from
+	 * @param size specific size to search
+	 * @return VideoFormat
+	 */
+	private VideoFormat getSizedVideoFormat(Dimension size) {
+
+		Format[] formats = device.getFormats();
+		VideoFormat format = null;
+
+		for (Format f : formats) {
+
+			if (!"RGB".equalsIgnoreCase(f.getEncoding()) || !(f instanceof VideoFormat)) {
+				continue;
+			}
+
+			Dimension d = ((VideoFormat) f).getSize();
+			if (d.width == size.width && d.height == size.height) {
+				format = (VideoFormat) f;
+				break;
+			}
+		}
+
+		return format;
 	}
 
 	/**
@@ -267,7 +349,7 @@ public Dimension getViewSize() {
 	 * @param device device to get video format for
 	 * @return Suitable video format
 	 */
-	protected VideoFormat getVideoFormat(CaptureDeviceInfo device) {
+	private VideoFormat getLargestVideoFormat() {
 
 		Format[] formats = device.getFormats();
 		VideoFormat format = null;