The attached sample program produces a memory leak when the screen lock is active on windows.


package com.thalesgroup.de.gsr.test.testplugin.javafx.regionimage;

import java.nio.ByteBuffer;
import java.util.LinkedList;
import java.util.List;

import javafx.embed.swt.FXCanvas;
import javafx.geometry.Rectangle2D;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.canvas.Canvas;
import javafx.scene.canvas.GraphicsContext;
import javafx.scene.image.PixelFormat;
import javafx.scene.image.PixelWriter;
import javafx.scene.paint.Color;

import org.apache.log4j.BasicConfigurator;
import org.apache.log4j.Logger;
import org.eclipse.swt.SWT;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;

/**
 * @author Jochen Mönch
 */
public class StandaloneTestJavaFX {

    private static final Logger log = Logger.getLogger( StandaloneTestJavaFX.class );
    private static final int WIDTH = 1280;
    private static final int HEIGHT = 1000;
    private FXCanvas fxCanvas;
    public Color color = Color.rgb( 255, 0, 0 );
    private Canvas canvas;
    private PixelFormat<ByteBuffer> pixelFormat;
    private byte[] imageData;
    private int cycles = 0;
    private long lastCycleRateLog = System.currentTimeMillis();
    private int overallCycles = 0;
    private final byte blueByte;
    private final byte greenByte;
    private final byte redByte;
    private final byte alphaByte;
    private long lastUpdate = System.currentTimeMillis();
    private long lastAdd = System.currentTimeMillis();
    private final List<Rectangle2D> pendingRectangles = new LinkedList<Rectangle2D>();
    private boolean changed = false;
    private boolean stop = false;
    private Shell shell;

    public static void main(final String[] args) {

        BasicConfigurator.configure();
        StandaloneTestJavaFX test = new StandaloneTestJavaFX();
        test.run();
    }

    /**
     * Constructor. Opens Gui.
     *
     * @param parent
     */
    public StandaloneTestJavaFX() {

        createShell();
        createGUI( shell );
        createImageData();
        blueByte = (byte) (Math.round( color.getBlue() * 255 ) & 0xff);
        greenByte = (byte) (Math.round( color.getGreen() * 255 ) & 0xff);
        redByte = (byte) (Math.round( color.getRed() * 255 ) & 0xff);
        alphaByte = (byte) 0xff;
    }

    public void run() {

        shell.open();

        new Thread( new Runnable() {

            @Override
            public void run() {

                while( !stop ) {
                    doWork();
                }
            }
        }, "FXPainter" ).start();
        while( !shell.isDisposed() ) {
            if( !shell.getDisplay().readAndDispatch() ) {
                shell.getDisplay().sleep();
            }
        }
    }

    private void createShell() {

        shell = new Shell( Display.getDefault() );
        shell.setSize( WIDTH, HEIGHT );
        shell.setLayout( new FillLayout() );
    }

    private void createGUI(final Composite parent) {

        fxCanvas = new FXCanvas( parent, SWT.NONE );
        Group rootGroup = new Group();
        rootGroup.setCache( false );
        Scene scene = new Scene( rootGroup, Color.TRANSPARENT );
        fxCanvas.setScene( scene );
        canvas = createCanvas();
        rootGroup.getChildren().add( canvas );
    }

    private void createImageData() {

        imageData = new byte[WIDTH * 4 * HEIGHT];
        pixelFormat = PixelFormat.getByteBgraInstance();
        for( int y = 0; y < HEIGHT; y++ ) {
            for( int x = 0; x < WIDTH; x++ ) {
                int startIdx = getStartIndex( y, x );
                imageData[startIdx] = 0x0;
                imageData[startIdx + 1] = 0x0;
                imageData[startIdx + 2] = 0x0;
                imageData[startIdx + 3] = 0x0;
            }
        }
    }

    private Canvas createCanvas() {

        Canvas canvas = new Canvas();
        canvas.setCache( true );
        canvas.setWidth( WIDTH );
        canvas.setHeight( HEIGHT );
        canvas.setVisible( true );
        return canvas;
    }

    private void doWork() {

        final long now = System.currentTimeMillis();
        if( now - lastAdd >= 1 ) {
            addNewData( 1000 );
            lastAdd = now;
        }
        if( now - lastUpdate >= 50 ) {
            updateContent( (int) Math.round( 255.0 / 30.0 ) );
            lastUpdate = now;
        }

        if( !fxCanvas.isDisposed() ) {
            if( now - lastCycleRateLog > 1000 ) {
                double timeSpend = (now - lastCycleRateLog) / 1000.0;
                double cycleRate = cycles / timeSpend;
                log.info( "CycleRate: " + cycleRate + ", total cycles: " + cycles );
                lastCycleRateLog = now;
                cycles = 0;
            }
            paintContent( overallCycles );
            cycles++;
            overallCycles++;
        } else {
            stopWork();
        }
    }

    private void stopWork() {

        stop = true;
    }

    private void addNewData(final int numRects) {

        synchronized( imageData ) {
            for( int i = 0; i < numRects; i++ ) {
                int x = (int) Math.round( Math.random() * (WIDTH - 5) );
                int y = (int) Math.round( Math.random() * (HEIGHT - 5) );
                pendingRectangles.add( new Rectangle2D( x, y, 5, 5 ) );
            }
        }
    }

    private void updateContent(final int decreaseAlphaBy) {

        synchronized( imageData ) {
            adjustAlpha( imageData, decreaseAlphaBy );
            for( Rectangle2D rectangle : pendingRectangles ) {
                fillRect( imageData, color, (int) Math.round( rectangle.getMinX() ),
                        (int) Math.round( rectangle.getMinY() ), (int) Math.round( rectangle.getWidth() ),
                        (int) Math.round( rectangle.getHeight() ) );
            }
            pendingRectangles.clear();
            changed = true;
        }
    }

    private void paintContent(final int cycle) {

        synchronized( imageData ) {
            if( changed ) {
                GraphicsContext gc = canvas.getGraphicsContext2D();
                PixelWriter pixelWriter = gc.getPixelWriter();
                pixelWriter.setPixels( 0, 0, WIDTH, HEIGHT, pixelFormat, imageData, 0, WIDTH * 4 );
                changed = false;
            }
        }
    }

    private void adjustAlpha(final byte[] imageData, final int decreaseBy) {

        for( int i = 0; i < imageData.length; i += 4 ) {
            imageData[i + 3] = (byte) Math.max( (imageData[i + 3] & 0xff) - decreaseBy, 0x0 );
        }
    }

    private void fillRect(final byte[] imageData, final Color color, final int startX, final int startY,
            final int width, final int height) {

        for( int y = startY; y < startY + height; y++ ) {
            for( int x = startX; x < startX + width; x++ ) {
                int index = getStartIndex( y, x );
                imageData[index] = blueByte;
                imageData[index + 1] = greenByte;
                imageData[index + 2] = redByte;
                imageData[index + 3] = alphaByte;
            }
        }
    }

    private int getStartIndex(final int row, final int column) {

        return row * WIDTH * 4 + column * 4;
    }
}