/**
* Capture a part of the desktop screen using <tt>java.awt.Robot</tt>.
*
* @param x x position to start capture
* @param y y position to start capture
* @param width capture width
* @param height capture height
* @return <tt>BufferedImage</tt> of a part of the desktop screen or null if Robot problem
*/
public BufferedImage captureScreen(int x, int y, int width, int height) {
BufferedImage img = null;
Rectangle rect = null;
if (robot == null) {
/* Robot has not been created so abort */
return null;
}
if (logger.isInfoEnabled()) logger.info("Begin capture: " + System.nanoTime());
rect = new Rectangle(x, y, width, height);
img = robot.createScreenCapture(rect);
if (logger.isInfoEnabled()) logger.info("End capture: " + System.nanoTime());
return img;
}
/**
* Blocks and reads into a <tt>Buffer</tt> from this <tt>PullBufferStream</tt>.
*
* @param buffer the <tt>Buffer</tt> this <tt>PullBufferStream</tt> is to read into
* @throws IOException if an I/O error occurs while this <tt>PullBufferStream</tt> reads into the
* specified <tt>Buffer</tt>
* @see AbstractVideoPullBufferStream#doRead(Buffer)
*/
@Override
protected void doRead(Buffer buffer) throws IOException {
/*
* Determine the Format in which we're expected to output. We cannot
* rely on the Format always being specified in the Buffer because it is
* not its responsibility, the DataSource of this ImageStream knows the
* output Format.
*/
Format format = buffer.getFormat();
if (format == null) {
format = getFormat();
if (format != null) buffer.setFormat(format);
}
if (format instanceof AVFrameFormat) {
Object o = buffer.getData();
AVFrame frame;
if (o instanceof AVFrame) frame = (AVFrame) o;
else {
frame = new AVFrame();
buffer.setData(frame);
}
AVFrameFormat avFrameFormat = (AVFrameFormat) format;
Dimension size = avFrameFormat.getSize();
ByteBuffer data = readScreenNative(size);
if (data != null) {
if (frame.avpicture_fill(data, avFrameFormat) < 0) {
data.free();
throw new IOException("avpicture_fill");
}
} else {
/*
* This can happen when we disconnect a monitor from computer
* before or during grabbing.
*/
throw new IOException("Failed to grab screen.");
}
} else {
byte[] bytes = (byte[]) buffer.getData();
Dimension size = ((VideoFormat) format).getSize();
bytes = readScreen(bytes, size);
buffer.setData(bytes);
buffer.setOffset(0);
buffer.setLength(bytes.length);
}
buffer.setHeader(null);
buffer.setTimeStamp(System.nanoTime());
buffer.setSequenceNumber(seqNo);
buffer.setFlags(Buffer.FLAG_SYSTEM_TIME | Buffer.FLAG_LIVE_DATA);
seqNo++;
}