import org.eclipse.swt.events.MouseEvent;

import org.eclipse.swt.events.MouseListener;

import org.eclipse.swt.events.MouseMoveListener;

import org.eclipse.swt.graphics.Cursor;

	private Button cropShotButton;

				cropShotButton.setEnabled(true);

		cropShotButton = new Button(composite, SWT.PUSH);

		cropShotButton.setText("Crop a region");

		cropShotButton.addSelectionListener(new SelectionListener() {

			public void widgetSelected(SelectionEvent e) {

				cropScreenshotContent();

			}

			public void widgetDefaultSelected(SelectionEvent e) {

			}

		});

					cropShotButton.setEnabled(false);

				gc.drawRectangle(0, 0, displayBounds.width - 1, displayBounds.height - 1);

	private void cropScreenshotContent() {

		final Point downPoint = new Point(-1, -1);

		final Rectangle newImageBounds = new Rectangle(-1, -1, -1, -1);

		final Display display = Display.getDefault();

		final Rectangle displayBounds = display.getBounds();

		final Shell popup = new Shell(display.getActiveShell(), SWT.SHELL_TRIM);

		popup.setLayout(new GridLayout());

		popup.setText("Crop a region of the screenshot");

		Point dialogSize = new Point(0, 0);

		dialogSize.x = displayBounds.width - 100;

		dialogSize.y = displayBounds.height - 100;

		Point dialoglocation = new Point(0, 0);

		dialoglocation.x = displayBounds.x + displayBounds.width / 2 - dialogSize.x / 2;

		dialoglocation.y = displayBounds.y + displayBounds.height / 2 - dialogSize.y / 2;

		popup.setSize(dialogSize);

		popup.setLocation(dialoglocation);

		final Rectangle originalBounds = screenshotImage.getBounds();

		final Image bufferedImage = new Image(display, originalBounds);

		GC gc = new GC(bufferedImage);

		gc.setBackground(popup.getBackground());

		gc.fillRectangle(originalBounds);

		gc.drawImage(screenshotImage, 0, 0);

		gc.dispose();

		Composite bc = new Composite(popup, SWT.NONE);

		bc.setLayout(new GridLayout(2, false));

		final Button saveButton = new Button(bc, SWT.PUSH);

		saveButton.setText("Save");

		saveButton.addSelectionListener(new SelectionListener() {

			public void widgetSelected(SelectionEvent e) {

				if (newImageBounds.x != -1 && newImageBounds.y != -1) {

					screenshotImage = new Image(display, newImageBounds);

					GC drawGc = new GC(screenshotImage);

					drawGc.drawImage(bufferedImage, newImageBounds.x, newImageBounds.y, newImageBounds.width,

							newImageBounds.height, 0, 0, newImageBounds.width, newImageBounds.height);

					drawGc.drawRectangle(0, 0, newImageBounds.width - 1, newImageBounds.height - 1);

					drawGc.dispose();

					canvas.redraw();

					popup.close();

				}

			}

			public void widgetDefaultSelected(SelectionEvent e) {

				// ignore		

			}

		});

		saveButton.setEnabled(false);

		final Button cancelButton = new Button(bc, SWT.PUSH);

		cancelButton.setText("Cancel");

		cancelButton.addSelectionListener(new SelectionListener() {

			public void widgetSelected(SelectionEvent e) {

				popup.close();

			}

			public void widgetDefaultSelected(SelectionEvent e) {

				// ignore		

			}

		});

		final ScrolledComposite sc = new ScrolledComposite(popup, SWT.V_SCROLL | SWT.H_SCROLL | SWT.BORDER);

		sc.setLayoutData(GridDataFactory.fillDefaults().align(SWT.FILL, SWT.FILL).grab(true, true).create());

		final Canvas scCanvas = new Canvas(sc, SWT.DOUBLE_BUFFERED | SWT.NONE);

		scCanvas.setBounds(originalBounds);

		scCanvas.addPaintListener(new PaintListener() {

			public void paintControl(PaintEvent e) {

				if (screenshotImage != null)

					e.gc.drawImage(bufferedImage, 0, 0);

			}

		});

		sc.setContent(scCanvas);

		final GC selectionGc = new GC(scCanvas);

		final MouseMoveListener mouseMoveListener = new MouseMoveListener() {

			public void mouseMove(MouseEvent e) {

				if (downPoint.x != -1 && downPoint.y != -1) {

					int width = e.x - downPoint.x;

					int height = e.y - downPoint.y;

					scCanvas.redraw();

					selectionGc.drawRectangle(downPoint.x, downPoint.y, width, height);

				}

			}

		};

		final MouseListener mouseListener = new MouseListener() {

			public void mouseUp(MouseEvent e) {

				if (downPoint.x != -1 && downPoint.y != -1) {

					int width;

					if (e.x > originalBounds.width)

						width = originalBounds.width - downPoint.x;

					else if (e.x < 0) {

						width = downPoint.x;

						downPoint.x = 0;

					}

					else

						width = e.x - downPoint.x;

					int height;

					if (e.y > originalBounds.height)

						height = originalBounds.height - downPoint.y;

					else if (e.y < 0) {

						height = downPoint.y;

						downPoint.y = 0;

					} else

						height = e.y - downPoint.y;

					display.getActiveShell().setCursor(new Cursor(null, SWT.CURSOR_ARROW));

					selectionGc.drawRectangle(downPoint.x, downPoint.y, width, height);

					newImageBounds.x = downPoint.x;

					newImageBounds.y = downPoint.y;

					newImageBounds.width = width;

					newImageBounds.height = height;

					sc.removeMouseMoveListener(mouseMoveListener);

					sc.removeMouseListener(this);

					downPoint.x = -1;

					downPoint.y = -1;

					saveButton.setEnabled(true);

				}

			}

			public void mouseDown(MouseEvent e) {

				if (downPoint.x == -1 && downPoint.y == -1) {

					display.getActiveShell().setCursor(new Cursor(null, SWT.CURSOR_CROSS));

					downPoint.x = e.x;

					downPoint.y = e.y;

					selectionGc.setLineStyle(SWT.LINE_DASH);

					scCanvas.addMouseMoveListener(mouseMoveListener);

				}

			}

			public void mouseDoubleClick(MouseEvent e) {

				// ignore

			}

		};

		scCanvas.addMouseListener(mouseListener);

		popup.open();

	}