Re: [JAVA3D] Screen Capturing resulting in Blank images

[Kasparian, Raffi J.]

Hi Stam,

I've had that same problem and now I don't. I don't understand why I did and
I don't understand why I don't. There seems to be some *magic* involved.
Serioiusly, though, maybe someone on this list knows what causes the
problem. Anyway, below you will find my working solution.

Raffi

-----Original Message-----
From: stam echad [mailto:[EMAIL PROTECTED]]
Sent: Wednesday, September 25, 2002 6:25 AM
To: [EMAIL PROTECTED]
Subject: [JAVA3D] Screen Capturing resulting in Blank images


Hi,

I've tried to use the screen capturing functions as described in
http://www.j3d.org/faq/capturing.html.
Whenever I run my program and press the 'capture' button, the Canvas flashes
grey for a few seconds and then a picture is saved as Jpg file. The problem
is that the saved Jpg's are very often the blank grey flash instead of the
contents of the Canvas3D I wanted to save. Has anyone encountered this
problem and could anyone please provide me with some help in the matter?

Thank You

/*******************************************************************
Copyright 2002. Science Applications International Corportion (SAIC)
Raffi J. Kasparian
1525 WILSON BOULEVARD
SUITE 800
ARLINGTON, VA 22209
*******************************************************************/

package orbiter;

import com.sun.j3d.utils.image.*;
import java.awt.*;
import java.io.*;
import javax.media.j3d.*;
import javax.vecmath.*;
import java.awt.image.BufferedImage;
import com.sun.image.codec.jpeg.*;
import java.util.*;

public class CaptureCanvas3D extends Canvas3D{
    private Timer timer = new Timer();

    private Vector captureRequests = new Vector();

    public CaptureCanvas3D( GraphicsConfiguration gc ){
        super( gc );
    }
    public void captureOne( File file ){
        ImageHandler request = createRequest( file );
        synchronized( captureRequests ){
            captureRequests.add( request );
        }
        getView().repaint();
    }
    public void postSwap(){
        boolean pendingRequests = false;
        synchronized( captureRequests ){
            if( captureRequests.size() > 0 ){
                pendingRequests = true;
            }
        }
        if( pendingRequests ){
            BufferedImage img = createBufferedImage();
            handleRequests( img );
        }
    }
    private void handleRequests( BufferedImage img ){
        ImageHandler[] requests;
        synchronized( captureRequests ){
            requests = (ImageHandler[])captureRequests.toArray( new
ImageHandler[captureRequests.size()] );
            captureRequests.clear();
        }
        for( int i = 0; i < requests.length; ++i ){
            requests[i].handleImage( img );
        }
    }
    private ImageHandler createRequest( final File f ){//must be called from
postSwap
        ImageHandler request = new ImageHandler(){
            public void handleImage( BufferedImage img ){
                writeToFile( img, f );
            }
        };
        return request;
    }
    private void writeToFile( BufferedImage image, File file ){
        try{
            FileOutputStream out = new FileOutputStream( file );
            JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder( out );
            JPEGEncodeParam param = encoder.getDefaultJPEGEncodeParam( image
);
            param.setQuality( 1.0f, false );
            encoder.setJPEGEncodeParam( param );
            encoder.encode( image );
            out.close();
        }catch ( IOException e ){
            e.printStackTrace();
        }
    }
    private BufferedImage createBufferedImage(){
        GraphicsContext3D  ctx = getGraphicsContext3D();
        int w = getWidth();
        int h = getHeight();
        //BufferedImage bi = new BufferedImage( w, h,
BufferedImage.TYPE_INT_RGB );
        //BufferedImage bi = new BufferedImage( w, h,
BufferedImage.TYPE_BYTE_INDEXED );
        BufferedImage bi = new BufferedImage( w, h,
BufferedImage.TYPE_BYTE_BINARY );
        ImageComponent2D im = new ImageComponent2D(
ImageComponent.FORMAT_R3_G3_B2, bi );
        Raster ras = new Raster( new Point3f( -1.0f, -1.0f, -1.0f ),
Raster.RASTER_COLOR, 0, 0, w, h, im, null );
        ctx.readRaster( ras );
        return ras.getImage().getImage();
    }
    interface ImageHandler{
        public void handleImage( BufferedImage img );
    }
}





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