org.eclipse.debug.ui/ui/org/eclipse/debug/internal/ui/viewers/breadcrumb/BreadcrumbItemDropDown.java - gerrit/platform/eclipse.platform.debug - Git at Google

 /*******************************************************************************
  * Copyright (c) 2008, 2017 IBM Corporation and others.
  *
  * This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
  * which accompanies this distribution, and is available at
  * https://www.eclipse.org/legal/epl-2.0/
  *
  * SPDX-License-Identifier: EPL-2.0
  *
  * Contributors:
  *     IBM Corporation - initial API and implementation
  *     Pawel Piech (Wind River) - adapted breadcrumb for use in Debug view (Bug 252677)
  *******************************************************************************/
 package org.eclipse.debug.internal.ui.viewers.breadcrumb;

 import org.eclipse.core.runtime.Assert;
 import org.eclipse.debug.internal.ui.DebugUIPlugin;
 import org.eclipse.jface.action.Action;
 import org.eclipse.jface.action.ToolBarManager;
 import org.eclipse.jface.dialogs.IDialogSettings;
 import org.eclipse.jface.resource.CompositeImageDescriptor;
 import org.eclipse.jface.util.Util;
 import org.eclipse.jface.viewers.ISelection;
 import org.eclipse.jface.viewers.TreePath;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.accessibility.AccessibleAdapter;
 import org.eclipse.swt.accessibility.AccessibleEvent;
 import org.eclipse.swt.events.ControlAdapter;
 import org.eclipse.swt.events.ControlEvent;
 import org.eclipse.swt.events.ControlListener;
 import org.eclipse.swt.events.DisposeEvent;
 import org.eclipse.swt.events.DisposeListener;
 import org.eclipse.swt.events.MouseAdapter;
 import org.eclipse.swt.events.MouseEvent;
 import org.eclipse.swt.events.ShellEvent;
 import org.eclipse.swt.events.ShellListener;
 import org.eclipse.swt.graphics.Color;
 import org.eclipse.swt.graphics.GC;
 import org.eclipse.swt.graphics.Image;
 import org.eclipse.swt.graphics.ImageData;
 import org.eclipse.swt.graphics.ImageDataProvider;
 import org.eclipse.swt.graphics.Point;
 import org.eclipse.swt.graphics.RGB;
 import org.eclipse.swt.graphics.Rectangle;
 import org.eclipse.swt.layout.GridData;
 import org.eclipse.swt.layout.GridLayout;
 import org.eclipse.swt.widgets.Composite;
 import org.eclipse.swt.widgets.Control;
 import org.eclipse.swt.widgets.Display;
 import org.eclipse.swt.widgets.Event;
 import org.eclipse.swt.widgets.Listener;
 import org.eclipse.swt.widgets.Shell;
 import org.eclipse.swt.widgets.ToolBar;
 import org.eclipse.swt.widgets.Widget;


 /**
  * The part of the breadcrumb item with the drop down menu.
  *
  * @since 3.5
  */
 class BreadcrumbItemDropDown implements IBreadcrumbDropDownSite {

 	private static final boolean IS_MAC_WORKAROUND= "carbon".equals(SWT.getPlatform()); //$NON-NLS-1$

 	/**
 	 * An arrow image descriptor. The images color is related to the list
 	 * fore- and background color. This makes the arrow visible even in high contrast
 	 * mode. If <code>ltr</code> is true the arrow points to the right, otherwise it
 	 * points to the left.
 	 */
 	private final class AccessibleArrowImage extends CompositeImageDescriptor {

 		private final static int ARROW_SIZE= 5;

 		private final boolean fLTR;

 		public AccessibleArrowImage(boolean ltr) {
 			fLTR= ltr;
 		}

 		/*
 		 * @see org.eclipse.jface.resource.CompositeImageDescriptor#drawCompositeImage(int, int)
 		 */
 		@Override
 		protected void drawCompositeImage(int width, int height) {
 			Display display= fParentComposite.getDisplay();
 			ImageDataProvider imageProvider = zoom -> {
 				Image image = new Image(display, ARROW_SIZE, ARROW_SIZE * 2);

 				GC gc = new GC(image, fLTR ? SWT.LEFT_TO_RIGHT : SWT.RIGHT_TO_LEFT);
 				gc.setAntialias(SWT.ON);

 				Color triangleColor = createColor(SWT.COLOR_LIST_FOREGROUND, SWT.COLOR_LIST_BACKGROUND, 20, display);
 				gc.setBackground(triangleColor);
 				gc.fillPolygon(new int[] {
 						0, 0, ARROW_SIZE, ARROW_SIZE, 0, ARROW_SIZE * 2 });
 				gc.dispose();
 				triangleColor.dispose();

 				ImageData imageData = image.getImageData(zoom);
 				image.dispose();
 				int zoomedArrowSize = ARROW_SIZE * zoom / 100;
 				for (int y1 = 0; y1 < zoomedArrowSize; y1++) {
 					// set opaque pixels for top half of the breadcrumb arrow
 					for (int x1 = 0; x1 <= y1; x1++) {
 						imageData.setAlpha(fLTR ? x1 : zoomedArrowSize - x1 - 1, y1, 255);
 					}
 					// set transparent pixels for top half of the breadcrumbe arrow
 					for (int x1 = y1 + 1; x1 < zoomedArrowSize; x1++) {
 						imageData.setAlpha(fLTR ? x1 : zoomedArrowSize - x1 - 1, y1, 0);
 					}
 				}
 				for (int y2 = 0; y2 < zoomedArrowSize; y2++) {
 					// set opaque pixels for bottom half of the breadcrumb arrow
 					for (int x2 = 0; x2 <= y2; x2++) {
 						imageData.setAlpha(fLTR ? x2 : zoomedArrowSize - x2 - 1, zoomedArrowSize * 2 - y2 - 1, 255);
 					}
 					// set transparent pixels for bottom half of the breadcrumbe arrow
 					for (int x2 = y2 + 1; x2 < zoomedArrowSize; x2++) {
 						imageData.setAlpha(fLTR ? x2 : zoomedArrowSize - x2 - 1, zoomedArrowSize * 2 - y2 - 1, 0);
 					}
 				}
 				return imageData;
 			};
 			drawImage(imageProvider, (width / 2) - (ARROW_SIZE / 2), (height / 2) - ARROW_SIZE);

 		}

 		/*
 		 * @see org.eclipse.jface.resource.CompositeImageDescriptor#getSize()
 		 */
 		@Override
 		protected Point getSize() {
 			return new Point(10, 16);
 		}

 		private Color createColor(int color1, int color2, int ratio, Display display) {
 			RGB rgb1= display.getSystemColor(color1).getRGB();
 			RGB rgb2= display.getSystemColor(color2).getRGB();

 			RGB blend= BreadcrumbViewer.blend(rgb2, rgb1, ratio);

 			return new Color(display, blend);
 		}
 	}

 	// Workaround for bug 258196: set the minimum size to 500 because on Linux
 	// the size is not adjusted correctly in a virtual tree.
 	private static final int DROP_DOWN_MIN_WIDTH= 500;
 	private static final int DROP_DOWN_MAX_WIDTH= 501;

 	private static final int DROP_DOWN_DEFAULT_MIN_HEIGHT= 100;
 	private static final int DROP_DOWN_DEFAULT_MAX_HEIGHT= 500;

 	private static final String DIALOG_SETTINGS= "BreadcrumbItemDropDown"; //$NON-NLS-1$
 	private static final String DIALOG_HEIGHT= "height"; //$NON-NLS-1$
 	private static final String DIALOG_WIDTH= "width"; //$NON-NLS-1$

 	private final BreadcrumbItem fParent;
 	private final Composite fParentComposite;
 	private final ToolBar fToolBar;

 	private boolean fMenuIsShown;
 	private boolean fEnabled;
 	private Shell fShell;
 	private boolean fIsResizingProgrammatically;
 	private int fCurrentWidth = -1;
 	private int fCurrentHeight = -1;


 	public BreadcrumbItemDropDown(BreadcrumbItem parent, Composite composite) {
 		fParent= parent;
 		fParentComposite= composite;
 		fMenuIsShown= false;
 		fEnabled= true;

 		fToolBar= new ToolBar(composite, SWT.FLAT);
 		fToolBar.setLayoutData(new GridData(SWT.END, SWT.CENTER, false, false));
 		fToolBar.getAccessible().addAccessibleListener(new AccessibleAdapter() {
 			@Override
 			public void getName(AccessibleEvent e) {
 				e.result= BreadcrumbMessages.BreadcrumbItemDropDown_showDropDownMenu_action_toolTip;
 			}
 		});
 		ToolBarManager manager= new ToolBarManager(fToolBar);

 		final Action showDropDownMenuAction= new Action(null, SWT.NONE) {
 			@Override
 			public void run() {
 				Shell shell= fParent.getDropDownShell();
 				if (shell != null) {
 					return;
 				}

 				shell= fParent.getViewer().getDropDownShell();
 				if (shell != null && !shell.isDisposed()) {
 					shell.close();
 				}

 				showMenu();

 				fShell.setFocus();
 			}
 		};

 		showDropDownMenuAction.setImageDescriptor(new AccessibleArrowImage(isLeft()));
 		showDropDownMenuAction.setToolTipText(BreadcrumbMessages.BreadcrumbItemDropDown_showDropDownMenu_action_toolTip);
 		manager.add(showDropDownMenuAction);

 		manager.update(true);
 		if (IS_MAC_WORKAROUND) {
 			manager.getControl().addMouseListener(new MouseAdapter() {
 				// see also BreadcrumbItemDetails#addElementListener(Control)
 				@Override
 				public void mouseDown(MouseEvent e) {
 					showDropDownMenuAction.run();
 				}
 			});
 		}
 		fToolBar.setData("org.eclipse.e4.ui.css.id", "DebugBreadcrumbItemDropDownToolBar"); //$NON-NLS-1$ //$NON-NLS-2$
 	}

 	/**
 	 * Return the width of this element.
 	 *
 	 * @return the width of this element
 	 */
 	public int getWidth() {
 		return fToolBar.computeSize(SWT.DEFAULT, SWT.DEFAULT).x;
 	}

 	/**
 	 * Set whether the drop down menu is available.
 	 *
 	 * @param enabled true if available
 	 */
 	public void setEnabled(boolean enabled) {
 		fEnabled= enabled;

 		fToolBar.setVisible(enabled);
 	}

 	/**
 	 * Tells whether the menu is shown.
 	 *
 	 * @return true if the menu is open
 	 */
 	public boolean isMenuShown() {
 		return fMenuIsShown;
 	}

 	/**
 	 * Returns the shell used for the drop down menu if it is shown.
 	 *
 	 * @return the drop down shell or <code>null</code>
 	 */
 	public Shell getDropDownShell() {
 		if (!isMenuShown()) {
 			return null;
 		}

 		return fShell;
 	}

 	/**
 	 * Opens the drop down menu.
 	 */
 	public void showMenu() {
 		if (DebugUIPlugin.DEBUG_BREADCRUMB) {
 			DebugUIPlugin.trace("BreadcrumbItemDropDown.showMenu()"); //$NON-NLS-1$
 		}

 		if (!fEnabled || fMenuIsShown) {
 			return;
 		}

 		fMenuIsShown= true;

 		fShell= new Shell(fToolBar.getShell(), SWT.RESIZE | SWT.TOOL | SWT.ON_TOP);
 		if (DebugUIPlugin.DEBUG_BREADCRUMB) {
 			DebugUIPlugin.trace("	creating new shell"); //$NON-NLS-1$
 		}

 		fShell.addControlListener(new ControlAdapter() {
 			/*
 			 * @see org.eclipse.swt.events.ControlAdapter#controlResized(org.eclipse.swt.events.ControlEvent)
 			 */
 			@Override
 			public void controlResized(ControlEvent e) {
 				if (fIsResizingProgrammatically) {
 					return;
 				}

 				Point size= fShell.getSize();
 				fCurrentWidth = size.x;
 				fCurrentHeight = size.y;
 				getDialogSettings().put(DIALOG_WIDTH, size.x);
 				getDialogSettings().put(DIALOG_HEIGHT, size.y);
 			}
 		});

 		GridLayout layout= new GridLayout(1, false);
 		layout.marginHeight= 0;
 		layout.marginWidth= 0;
 		fShell.setLayout(layout);

 		Composite composite= new Composite(fShell, SWT.NONE);
 		composite.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));
 		GridLayout gridLayout= new GridLayout(1, false);
 		gridLayout.marginHeight= 0;
 		gridLayout.marginWidth= 0;
 		composite.setLayout(gridLayout);

 		TreePath path= fParent.getPath();

 		Control control = fParent.getViewer().createDropDown(composite, this, path);

 		control.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));

 		setShellBounds(fShell);
 		fShell.setVisible(true);
 		installCloser(fShell);
 	}

 	/**
 	 * The closer closes the given shell when the focus is lost.
 	 *
 	 * @param shell the shell to install the closer to
 	 */
 	private void installCloser(final Shell shell) {
 		final Listener focusListener= new Listener() {
 			@Override
 			public void handleEvent(Event event) {
 				Widget focusElement= event.widget;
 				boolean isFocusBreadcrumbTreeFocusWidget= focusElement == shell || focusElement instanceof Control && ((Control)focusElement).getShell() == shell;
 				boolean isFocusWidgetParentShell= focusElement instanceof Control && ((Control)focusElement).getShell().getParent() == shell;

 				switch (event.type) {
 					case SWT.FocusIn:
 						if (DebugUIPlugin.DEBUG_BREADCRUMB) {
 							DebugUIPlugin.trace("focusIn - is breadcrumb tree: " + isFocusBreadcrumbTreeFocusWidget); //$NON-NLS-1$
 						}

 						if (!isFocusBreadcrumbTreeFocusWidget && !isFocusWidgetParentShell) {
 							if (DebugUIPlugin.DEBUG_BREADCRUMB) {
 								DebugUIPlugin.trace("==> closing shell since focus in other widget"); //$NON-NLS-1$
 							}
 							shell.close();
 						}
 						break;

 					case SWT.FocusOut:
 						if (DebugUIPlugin.DEBUG_BREADCRUMB) {
 							DebugUIPlugin.trace("focusOut - is breadcrumb tree: " + isFocusBreadcrumbTreeFocusWidget); //$NON-NLS-1$
 						}
 						if (event.display.getActiveShell() == null) {
 							if (DebugUIPlugin.DEBUG_BREADCRUMB) {
 								DebugUIPlugin.trace("==> closing shell since event.display.getActiveShell() != shell"); //$NON-NLS-1$
 							}
 							shell.close();
 						}
 						break;

 					default:
 						Assert.isTrue(false);
 				}
 			}
 		};

 		final Display display= shell.getDisplay();
 		display.addFilter(SWT.FocusIn, focusListener);
 		display.addFilter(SWT.FocusOut, focusListener);

 		final ControlListener controlListener= new ControlListener() {
 			@Override
 			public void controlMoved(ControlEvent e) {
 				if (!shell.isDisposed()) {
 					shell.close();
 				}
 			}

 			@Override
 			public void controlResized(ControlEvent e) {
 				if (!shell.isDisposed()) {
 					shell.close();
 				}
 			}
 		};
 		fToolBar.getShell().addControlListener(controlListener);

 		shell.addDisposeListener(new DisposeListener() {
 			@Override
 			public void widgetDisposed(DisposeEvent e) {
 				if (DebugUIPlugin.DEBUG_BREADCRUMB) {
 					DebugUIPlugin.trace("==> shell disposed"); //$NON-NLS-1$
 				}

 				display.removeFilter(SWT.FocusIn, focusListener);
 				display.removeFilter(SWT.FocusOut, focusListener);

 				if (!fToolBar.isDisposed()) {
 					fToolBar.getShell().removeControlListener(controlListener);
 				}
 			}
 		});
 		shell.addShellListener(new ShellListener() {
 			@Override
 			public void shellActivated(ShellEvent e) {
 			}

 			@Override
 			public void shellClosed(ShellEvent e) {
 				if (DebugUIPlugin.DEBUG_BREADCRUMB) {
 					DebugUIPlugin.trace("==> shellClosed"); //$NON-NLS-1$
 				}
 				if (!fMenuIsShown) {
 					return;
 				}

 				fMenuIsShown= false;
 			}

 			@Override
 			public void shellDeactivated(ShellEvent e) {
 			}

 			@Override
 			public void shellDeiconified(ShellEvent e) {
 			}

 			@Override
 			public void shellIconified(ShellEvent e) {
 			}
 		});
 	}

 	private IDialogSettings getDialogSettings() {
 		IDialogSettings javaSettings= DebugUIPlugin.getDefault().getDialogSettings();
 		IDialogSettings settings= javaSettings.getSection(DIALOG_SETTINGS);
 		if (settings == null) {
 			settings= javaSettings.addNewSection(DIALOG_SETTINGS);
 		}
 		return settings;
 	}

 	private int getMaxWidth() {
 		try {
 			return getDialogSettings().getInt(DIALOG_WIDTH);
 		} catch (NumberFormatException e) {
 			return DROP_DOWN_MAX_WIDTH;
 		}
 	}

 	private int getMaxHeight() {
 		try {
 			return getDialogSettings().getInt(DIALOG_HEIGHT);
 		} catch (NumberFormatException e) {
 			return DROP_DOWN_DEFAULT_MAX_HEIGHT;
 		}
 	}

 	/**
 	 * Calculates a useful size for the given shell.
 	 *
 	 * @param shell the shell to calculate the size for.
 	 */
 	private void setShellBounds(Shell shell) {

 		Rectangle rect= fParentComposite.getBounds();
 		Rectangle toolbarBounds= fToolBar.getBounds();

 		Point size = shell.computeSize(SWT.DEFAULT, SWT.DEFAULT, false);
 		int height= Math.max(Math.min(size.y, getMaxHeight()), DROP_DOWN_DEFAULT_MIN_HEIGHT);
 		int width= Math.max(getMaxWidth(), DROP_DOWN_MIN_WIDTH);

 		int imageBoundsX= 0;
 		if (fParent.getImage() != null) {
 			imageBoundsX= fParent.getImage().getImageData().width;
 		}

 		Rectangle trim= fShell.computeTrim(0, 0, width, height);
 		int x= toolbarBounds.x + toolbarBounds.width + 2 + trim.x - imageBoundsX;
 		if (!isLeft()) {
 			x+= width;
 		}

 		int y = rect.y;
 		if (isTop()) {
 			y+= rect.height;
 		} else {
 			y-= height;
 		}

 		Point pt= new Point(x, y);
 		pt= fParentComposite.toDisplay(pt);

 		Rectangle monitor = Util.getClosestMonitor(shell.getDisplay(), pt).getClientArea();
 		int overlap= (pt.x + width) - (monitor.x + monitor.width);
 		if (overlap > 0) {
 			pt.x-= overlap;
 		}
 		if (pt.x < monitor.x) {
 			pt.x= monitor.x;
 		}

 		shell.setLocation(pt);
 		fIsResizingProgrammatically= true;
 		try {
 			shell.setSize(width, height);
 			fCurrentWidth = width;
 			fCurrentHeight = height;
 		} finally {
 			fIsResizingProgrammatically= false;
 		}
 	}

 	/**
 	 * Set the size of the given shell such that more content can be shown. The shell size does not
 	 * exceed a user-configurable maximum.
 	 *
 	 * @param shell the shell to resize
 	 */
 	private void resizeShell(final Shell shell) {
 		int maxHeight= getMaxHeight();
 		int maxWidth = getMaxWidth();

 		if (fCurrentHeight >= maxHeight && fCurrentWidth >= maxWidth) {
 			return;
 		}

 		Point preferedSize= shell.computeSize(SWT.DEFAULT, SWT.DEFAULT, true);

 		int newWidth;
 		if (fCurrentWidth >= DROP_DOWN_MAX_WIDTH) {
 			newWidth= fCurrentWidth;
 		} else {
 			// Workaround for bug 319612: Do not resize width below the
 			// DROP_DOWN_MIN_WIDTH.  This can happen because the Shell.getSize()
 			// is incorrectly small on Linux.
 			newWidth= Math.min(Math.max(Math.max(preferedSize.x, fCurrentWidth), DROP_DOWN_MIN_WIDTH), maxWidth);
 		}
 		int newHeight;
 		if (fCurrentHeight >= maxHeight) {
 			newHeight= fCurrentHeight;
 		} else {
 			newHeight= Math.min(Math.max(preferedSize.y, fCurrentHeight), maxHeight);
 		}

 		if (newHeight != fCurrentHeight || newWidth != fCurrentWidth) {
 			shell.setRedraw(false);
 			try {
 				fIsResizingProgrammatically= true;
 				shell.setSize(newWidth, newHeight);
 				fCurrentWidth = newWidth;
 				fCurrentHeight = newHeight;

 				Point location = shell.getLocation();
 				Point newLocation = location;
 				if (!isLeft()) {
 					newLocation = new Point(newLocation.x - (newWidth - fCurrentWidth), newLocation.y);
 				}
 				if (!isTop()) {
 					newLocation = new Point(newLocation.x, newLocation.y - (newHeight - fCurrentHeight));
 				}
 				if (!location.equals(newLocation)) {
 					shell.setLocation(newLocation.x, newLocation.y);
 				}
 			} finally {
 				fIsResizingProgrammatically= false;
 				shell.setRedraw(true);
 			}
 		}
 	}

 	/**
 	 * Tells whether this the breadcrumb is in LTR mode or RTL mode.  Or whether the breadcrumb
 	 * is on the right-side status coolbar, which has the same effect on layout.
 	 *
 	 * @return <code>true</code> if the breadcrumb in left-to-right mode, <code>false</code>
 	 *         otherwise
 	 */
 	private boolean isLeft() {
 		return (fParentComposite.getStyle() & SWT.RIGHT_TO_LEFT) == 0 &&
 			(fParent.getViewer().getStyle() & SWT.RIGHT) == 0;
 	}

 	/**
 	 * Tells whether this the breadcrumb is in LTR mode or RTL mode.  Or whether the breadcrumb
 	 * is on the right-side status coolbar, which has the same effect on layout.
 	 *
 	 * @return <code>true</code> if the breadcrumb in left-to-right mode, <code>false</code>
 	 *         otherwise
 	 */
 	private boolean isTop() {
 		return (fParent.getViewer().getStyle() & SWT.BOTTOM) == 0;
 	}

 	@Override
 	public void close() {
 		if (fShell != null && !fShell.isDisposed()) {
 			fShell.close();
 		}
 	}

 	@Override
 	public void notifySelection(ISelection selection) {
 		fParent.getViewer().fireMenuSelection(selection);
 	}

 	@Override
 	public void updateSize() {
 		if (fShell != null && !fShell.isDisposed()) {
 			resizeShell(fShell);
 		}
 	}
 }
	/*******************************************************************************
	* Copyright (c) 2008, 2017 IBM Corporation and others.
	*
	* This program and the accompanying materials
	* are made available under the terms of the Eclipse Public License 2.0
	* which accompanies this distribution, and is available at
	* https://www.eclipse.org/legal/epl-2.0/
	*
	* SPDX-License-Identifier: EPL-2.0
	*
	* Contributors:
	* IBM Corporation - initial API and implementation
	* Pawel Piech (Wind River) - adapted breadcrumb for use in Debug view (Bug 252677)
	*******************************************************************************/
	package org.eclipse.debug.internal.ui.viewers.breadcrumb;

	import org.eclipse.core.runtime.Assert;
	import org.eclipse.debug.internal.ui.DebugUIPlugin;
	import org.eclipse.jface.action.Action;
	import org.eclipse.jface.action.ToolBarManager;
	import org.eclipse.jface.dialogs.IDialogSettings;
	import org.eclipse.jface.resource.CompositeImageDescriptor;
	import org.eclipse.jface.util.Util;
	import org.eclipse.jface.viewers.ISelection;
	import org.eclipse.jface.viewers.TreePath;
	import org.eclipse.swt.SWT;
	import org.eclipse.swt.accessibility.AccessibleAdapter;
	import org.eclipse.swt.accessibility.AccessibleEvent;
	import org.eclipse.swt.events.ControlAdapter;
	import org.eclipse.swt.events.ControlEvent;
	import org.eclipse.swt.events.ControlListener;
	import org.eclipse.swt.events.DisposeEvent;
	import org.eclipse.swt.events.DisposeListener;
	import org.eclipse.swt.events.MouseAdapter;
	import org.eclipse.swt.events.MouseEvent;
	import org.eclipse.swt.events.ShellEvent;
	import org.eclipse.swt.events.ShellListener;
	import org.eclipse.swt.graphics.Color;
	import org.eclipse.swt.graphics.GC;
	import org.eclipse.swt.graphics.Image;
	import org.eclipse.swt.graphics.ImageData;
	import org.eclipse.swt.graphics.ImageDataProvider;
	import org.eclipse.swt.graphics.Point;
	import org.eclipse.swt.graphics.RGB;
	import org.eclipse.swt.graphics.Rectangle;
	import org.eclipse.swt.layout.GridData;
	import org.eclipse.swt.layout.GridLayout;
	import org.eclipse.swt.widgets.Composite;
	import org.eclipse.swt.widgets.Control;
	import org.eclipse.swt.widgets.Display;
	import org.eclipse.swt.widgets.Event;
	import org.eclipse.swt.widgets.Listener;
	import org.eclipse.swt.widgets.Shell;
	import org.eclipse.swt.widgets.ToolBar;
	import org.eclipse.swt.widgets.Widget;


	/**
	* The part of the breadcrumb item with the drop down menu.
	*
	* @since 3.5
	*/
	class BreadcrumbItemDropDown implements IBreadcrumbDropDownSite {

	private static final boolean IS_MAC_WORKAROUND= "carbon".equals(SWT.getPlatform()); //$NON-NLS-1$

	/**
	* An arrow image descriptor. The images color is related to the list
	* fore- and background color. This makes the arrow visible even in high contrast
	* mode. If <code>ltr</code> is true the arrow points to the right, otherwise it
	* points to the left.
	*/
	private final class AccessibleArrowImage extends CompositeImageDescriptor {

	private final static int ARROW_SIZE= 5;

	private final boolean fLTR;

	public AccessibleArrowImage(boolean ltr) {
	fLTR= ltr;
	}

	/*
	* @see org.eclipse.jface.resource.CompositeImageDescriptor#drawCompositeImage(int, int)
	*/
	@Override
	protected void drawCompositeImage(int width, int height) {
	Display display= fParentComposite.getDisplay();
	ImageDataProvider imageProvider = zoom -> {
	Image image = new Image(display, ARROW_SIZE, ARROW_SIZE * 2);

	GC gc = new GC(image, fLTR ? SWT.LEFT_TO_RIGHT : SWT.RIGHT_TO_LEFT);
	gc.setAntialias(SWT.ON);

	Color triangleColor = createColor(SWT.COLOR_LIST_FOREGROUND, SWT.COLOR_LIST_BACKGROUND, 20, display);
	gc.setBackground(triangleColor);
	gc.fillPolygon(new int[] {
	0, 0, ARROW_SIZE, ARROW_SIZE, 0, ARROW_SIZE * 2 });
	gc.dispose();
	triangleColor.dispose();

	ImageData imageData = image.getImageData(zoom);
	image.dispose();
	int zoomedArrowSize = ARROW_SIZE * zoom / 100;
	for (int y1 = 0; y1 < zoomedArrowSize; y1++) {
	// set opaque pixels for top half of the breadcrumb arrow
	for (int x1 = 0; x1 <= y1; x1++) {
	imageData.setAlpha(fLTR ? x1 : zoomedArrowSize - x1 - 1, y1, 255);
	}
	// set transparent pixels for top half of the breadcrumbe arrow
	for (int x1 = y1 + 1; x1 < zoomedArrowSize; x1++) {
	imageData.setAlpha(fLTR ? x1 : zoomedArrowSize - x1 - 1, y1, 0);
	}
	}
	for (int y2 = 0; y2 < zoomedArrowSize; y2++) {
	// set opaque pixels for bottom half of the breadcrumb arrow
	for (int x2 = 0; x2 <= y2; x2++) {
	imageData.setAlpha(fLTR ? x2 : zoomedArrowSize - x2 - 1, zoomedArrowSize * 2 - y2 - 1, 255);
	}
	// set transparent pixels for bottom half of the breadcrumbe arrow
	for (int x2 = y2 + 1; x2 < zoomedArrowSize; x2++) {
	imageData.setAlpha(fLTR ? x2 : zoomedArrowSize - x2 - 1, zoomedArrowSize * 2 - y2 - 1, 0);
	}
	}
	return imageData;
	};
	drawImage(imageProvider, (width / 2) - (ARROW_SIZE / 2), (height / 2) - ARROW_SIZE);

	}

	/*
	* @see org.eclipse.jface.resource.CompositeImageDescriptor#getSize()
	*/
	@Override
	protected Point getSize() {
	return new Point(10, 16);
	}

	private Color createColor(int color1, int color2, int ratio, Display display) {
	RGB rgb1= display.getSystemColor(color1).getRGB();
	RGB rgb2= display.getSystemColor(color2).getRGB();

	RGB blend= BreadcrumbViewer.blend(rgb2, rgb1, ratio);

	return new Color(display, blend);
	}
	}

	// Workaround for bug 258196: set the minimum size to 500 because on Linux
	// the size is not adjusted correctly in a virtual tree.
	private static final int DROP_DOWN_MIN_WIDTH= 500;
	private static final int DROP_DOWN_MAX_WIDTH= 501;

	private static final int DROP_DOWN_DEFAULT_MIN_HEIGHT= 100;
	private static final int DROP_DOWN_DEFAULT_MAX_HEIGHT= 500;

	private static final String DIALOG_SETTINGS= "BreadcrumbItemDropDown"; //$NON-NLS-1$
	private static final String DIALOG_HEIGHT= "height"; //$NON-NLS-1$
	private static final String DIALOG_WIDTH= "width"; //$NON-NLS-1$

	private final BreadcrumbItem fParent;
	private final Composite fParentComposite;
	private final ToolBar fToolBar;

	private boolean fMenuIsShown;
	private boolean fEnabled;
	private Shell fShell;
	private boolean fIsResizingProgrammatically;
	private int fCurrentWidth = -1;
	private int fCurrentHeight = -1;


	public BreadcrumbItemDropDown(BreadcrumbItem parent, Composite composite) {
	fParent= parent;
	fParentComposite= composite;
	fMenuIsShown= false;
	fEnabled= true;

	fToolBar= new ToolBar(composite, SWT.FLAT);
	fToolBar.setLayoutData(new GridData(SWT.END, SWT.CENTER, false, false));
	fToolBar.getAccessible().addAccessibleListener(new AccessibleAdapter() {
	@Override
	public void getName(AccessibleEvent e) {
	e.result= BreadcrumbMessages.BreadcrumbItemDropDown_showDropDownMenu_action_toolTip;
	}
	});
	ToolBarManager manager= new ToolBarManager(fToolBar);

	final Action showDropDownMenuAction= new Action(null, SWT.NONE) {
	@Override
	public void run() {
	Shell shell= fParent.getDropDownShell();
	if (shell != null) {
	return;
	}

	shell= fParent.getViewer().getDropDownShell();
	if (shell != null && !shell.isDisposed()) {
	shell.close();
	}

	showMenu();

	fShell.setFocus();
	}
	};

	showDropDownMenuAction.setImageDescriptor(new AccessibleArrowImage(isLeft()));
	showDropDownMenuAction.setToolTipText(BreadcrumbMessages.BreadcrumbItemDropDown_showDropDownMenu_action_toolTip);
	manager.add(showDropDownMenuAction);

	manager.update(true);
	if (IS_MAC_WORKAROUND) {
	manager.getControl().addMouseListener(new MouseAdapter() {
	// see also BreadcrumbItemDetails#addElementListener(Control)
	@Override
	public void mouseDown(MouseEvent e) {
	showDropDownMenuAction.run();
	}
	});
	}
	fToolBar.setData("org.eclipse.e4.ui.css.id", "DebugBreadcrumbItemDropDownToolBar"); //$NON-NLS-1$ //$NON-NLS-2$
	}

	/**
	* Return the width of this element.
	*
	* @return the width of this element
	*/
	public int getWidth() {
	return fToolBar.computeSize(SWT.DEFAULT, SWT.DEFAULT).x;
	}

	/**
	* Set whether the drop down menu is available.
	*
	* @param enabled true if available
	*/
	public void setEnabled(boolean enabled) {
	fEnabled= enabled;

	fToolBar.setVisible(enabled);
	}

	/**
	* Tells whether the menu is shown.
	*
	* @return true if the menu is open
	*/
	public boolean isMenuShown() {
	return fMenuIsShown;
	}

	/**
	* Returns the shell used for the drop down menu if it is shown.
	*
	* @return the drop down shell or <code>null</code>
	*/
	public Shell getDropDownShell() {
	if (!isMenuShown()) {
	return null;
	}

	return fShell;
	}

	/**
	* Opens the drop down menu.
	*/
	public void showMenu() {
	if (DebugUIPlugin.DEBUG_BREADCRUMB) {
	DebugUIPlugin.trace("BreadcrumbItemDropDown.showMenu()"); //$NON-NLS-1$
	}

	if (!fEnabled \|\| fMenuIsShown) {
	return;
	}

	fMenuIsShown= true;

	fShell= new Shell(fToolBar.getShell(), SWT.RESIZE \| SWT.TOOL \| SWT.ON_TOP);
	if (DebugUIPlugin.DEBUG_BREADCRUMB) {
	DebugUIPlugin.trace(" creating new shell"); //$NON-NLS-1$
	}

	fShell.addControlListener(new ControlAdapter() {
	/*
	* @see org.eclipse.swt.events.ControlAdapter#controlResized(org.eclipse.swt.events.ControlEvent)
	*/
	@Override
	public void controlResized(ControlEvent e) {
	if (fIsResizingProgrammatically) {
	return;
	}

	Point size= fShell.getSize();
	fCurrentWidth = size.x;
	fCurrentHeight = size.y;
	getDialogSettings().put(DIALOG_WIDTH, size.x);
	getDialogSettings().put(DIALOG_HEIGHT, size.y);
	}
	});

	GridLayout layout= new GridLayout(1, false);
	layout.marginHeight= 0;
	layout.marginWidth= 0;
	fShell.setLayout(layout);

	Composite composite= new Composite(fShell, SWT.NONE);
	composite.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));
	GridLayout gridLayout= new GridLayout(1, false);
	gridLayout.marginHeight= 0;
	gridLayout.marginWidth= 0;
	composite.setLayout(gridLayout);

	TreePath path= fParent.getPath();

	Control control = fParent.getViewer().createDropDown(composite, this, path);

	control.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));

	setShellBounds(fShell);
	fShell.setVisible(true);
	installCloser(fShell);
	}

	/**
	* The closer closes the given shell when the focus is lost.
	*
	* @param shell the shell to install the closer to
	*/
	private void installCloser(final Shell shell) {
	final Listener focusListener= new Listener() {
	@Override
	public void handleEvent(Event event) {
	Widget focusElement= event.widget;
	boolean isFocusBreadcrumbTreeFocusWidget= focusElement == shell \|\| focusElement instanceof Control && ((Control)focusElement).getShell() == shell;
	boolean isFocusWidgetParentShell= focusElement instanceof Control && ((Control)focusElement).getShell().getParent() == shell;

	switch (event.type) {
	case SWT.FocusIn:
	if (DebugUIPlugin.DEBUG_BREADCRUMB) {
	DebugUIPlugin.trace("focusIn - is breadcrumb tree: " + isFocusBreadcrumbTreeFocusWidget); //$NON-NLS-1$
	}

	if (!isFocusBreadcrumbTreeFocusWidget && !isFocusWidgetParentShell) {
	if (DebugUIPlugin.DEBUG_BREADCRUMB) {
	DebugUIPlugin.trace("==> closing shell since focus in other widget"); //$NON-NLS-1$
	}
	shell.close();
	}
	break;

	case SWT.FocusOut:
	if (DebugUIPlugin.DEBUG_BREADCRUMB) {
	DebugUIPlugin.trace("focusOut - is breadcrumb tree: " + isFocusBreadcrumbTreeFocusWidget); //$NON-NLS-1$
	}
	if (event.display.getActiveShell() == null) {
	if (DebugUIPlugin.DEBUG_BREADCRUMB) {
	DebugUIPlugin.trace("==> closing shell since event.display.getActiveShell() != shell"); //$NON-NLS-1$
	}
	shell.close();
	}
	break;

	default:
	Assert.isTrue(false);
	}
	}
	};

	final Display display= shell.getDisplay();
	display.addFilter(SWT.FocusIn, focusListener);
	display.addFilter(SWT.FocusOut, focusListener);

	final ControlListener controlListener= new ControlListener() {
	@Override
	public void controlMoved(ControlEvent e) {
	if (!shell.isDisposed()) {
	shell.close();
	}
	}

	@Override
	public void controlResized(ControlEvent e) {
	if (!shell.isDisposed()) {
	shell.close();
	}
	}
	};
	fToolBar.getShell().addControlListener(controlListener);

	shell.addDisposeListener(new DisposeListener() {
	@Override
	public void widgetDisposed(DisposeEvent e) {
	if (DebugUIPlugin.DEBUG_BREADCRUMB) {
	DebugUIPlugin.trace("==> shell disposed"); //$NON-NLS-1$
	}

	display.removeFilter(SWT.FocusIn, focusListener);
	display.removeFilter(SWT.FocusOut, focusListener);

	if (!fToolBar.isDisposed()) {
	fToolBar.getShell().removeControlListener(controlListener);
	}
	}
	});
	shell.addShellListener(new ShellListener() {
	@Override
	public void shellActivated(ShellEvent e) {
	}

	@Override
	public void shellClosed(ShellEvent e) {
	if (DebugUIPlugin.DEBUG_BREADCRUMB) {
	DebugUIPlugin.trace("==> shellClosed"); //$NON-NLS-1$
	}
	if (!fMenuIsShown) {
	return;
	}

	fMenuIsShown= false;
	}

	@Override
	public void shellDeactivated(ShellEvent e) {
	}

	@Override
	public void shellDeiconified(ShellEvent e) {
	}

	@Override
	public void shellIconified(ShellEvent e) {
	}
	});
	}

	private IDialogSettings getDialogSettings() {
	IDialogSettings javaSettings= DebugUIPlugin.getDefault().getDialogSettings();
	IDialogSettings settings= javaSettings.getSection(DIALOG_SETTINGS);
	if (settings == null) {
	settings= javaSettings.addNewSection(DIALOG_SETTINGS);
	}
	return settings;
	}

	private int getMaxWidth() {
	try {
	return getDialogSettings().getInt(DIALOG_WIDTH);
	} catch (NumberFormatException e) {
	return DROP_DOWN_MAX_WIDTH;
	}
	}

	private int getMaxHeight() {
	try {
	return getDialogSettings().getInt(DIALOG_HEIGHT);
	} catch (NumberFormatException e) {
	return DROP_DOWN_DEFAULT_MAX_HEIGHT;
	}
	}

	/**
	* Calculates a useful size for the given shell.
	*
	* @param shell the shell to calculate the size for.
	*/
	private void setShellBounds(Shell shell) {

	Rectangle rect= fParentComposite.getBounds();
	Rectangle toolbarBounds= fToolBar.getBounds();

	Point size = shell.computeSize(SWT.DEFAULT, SWT.DEFAULT, false);
	int height= Math.max(Math.min(size.y, getMaxHeight()), DROP_DOWN_DEFAULT_MIN_HEIGHT);
	int width= Math.max(getMaxWidth(), DROP_DOWN_MIN_WIDTH);

	int imageBoundsX= 0;
	if (fParent.getImage() != null) {
	imageBoundsX= fParent.getImage().getImageData().width;
	}

	Rectangle trim= fShell.computeTrim(0, 0, width, height);
	int x= toolbarBounds.x + toolbarBounds.width + 2 + trim.x - imageBoundsX;
	if (!isLeft()) {
	x+= width;
	}

	int y = rect.y;
	if (isTop()) {
	y+= rect.height;
	} else {
	y-= height;
	}

	Point pt= new Point(x, y);
	pt= fParentComposite.toDisplay(pt);

	Rectangle monitor = Util.getClosestMonitor(shell.getDisplay(), pt).getClientArea();
	int overlap= (pt.x + width) - (monitor.x + monitor.width);
	if (overlap > 0) {
	pt.x-= overlap;
	}
	if (pt.x < monitor.x) {
	pt.x= monitor.x;
	}

	shell.setLocation(pt);
	fIsResizingProgrammatically= true;
	try {
	shell.setSize(width, height);
	fCurrentWidth = width;
	fCurrentHeight = height;
	} finally {
	fIsResizingProgrammatically= false;
	}
	}

	/**
	* Set the size of the given shell such that more content can be shown. The shell size does not
	* exceed a user-configurable maximum.
	*
	* @param shell the shell to resize
	*/
	private void resizeShell(final Shell shell) {
	int maxHeight= getMaxHeight();
	int maxWidth = getMaxWidth();

	if (fCurrentHeight >= maxHeight && fCurrentWidth >= maxWidth) {
	return;
	}

	Point preferedSize= shell.computeSize(SWT.DEFAULT, SWT.DEFAULT, true);

	int newWidth;
	if (fCurrentWidth >= DROP_DOWN_MAX_WIDTH) {
	newWidth= fCurrentWidth;
	} else {
	// Workaround for bug 319612: Do not resize width below the
	// DROP_DOWN_MIN_WIDTH. This can happen because the Shell.getSize()
	// is incorrectly small on Linux.
	newWidth= Math.min(Math.max(Math.max(preferedSize.x, fCurrentWidth), DROP_DOWN_MIN_WIDTH), maxWidth);
	}
	int newHeight;
	if (fCurrentHeight >= maxHeight) {
	newHeight= fCurrentHeight;
	} else {
	newHeight= Math.min(Math.max(preferedSize.y, fCurrentHeight), maxHeight);
	}

	if (newHeight != fCurrentHeight \|\| newWidth != fCurrentWidth) {
	shell.setRedraw(false);
	try {
	fIsResizingProgrammatically= true;
	shell.setSize(newWidth, newHeight);
	fCurrentWidth = newWidth;
	fCurrentHeight = newHeight;

	Point location = shell.getLocation();
	Point newLocation = location;
	if (!isLeft()) {
	newLocation = new Point(newLocation.x - (newWidth - fCurrentWidth), newLocation.y);
	}
	if (!isTop()) {
	newLocation = new Point(newLocation.x, newLocation.y - (newHeight - fCurrentHeight));
	}
	if (!location.equals(newLocation)) {
	shell.setLocation(newLocation.x, newLocation.y);
	}
	} finally {
	fIsResizingProgrammatically= false;
	shell.setRedraw(true);
	}
	}
	}

	/**
	* Tells whether this the breadcrumb is in LTR mode or RTL mode. Or whether the breadcrumb
	* is on the right-side status coolbar, which has the same effect on layout.
	*
	* @return <code>true</code> if the breadcrumb in left-to-right mode, <code>false</code>
	* otherwise
	*/
	private boolean isLeft() {
	return (fParentComposite.getStyle() & SWT.RIGHT_TO_LEFT) == 0 &&
	(fParent.getViewer().getStyle() & SWT.RIGHT) == 0;
	}

	/**
	* Tells whether this the breadcrumb is in LTR mode or RTL mode. Or whether the breadcrumb
	* is on the right-side status coolbar, which has the same effect on layout.
	*
	* @return <code>true</code> if the breadcrumb in left-to-right mode, <code>false</code>
	* otherwise
	*/
	private boolean isTop() {
	return (fParent.getViewer().getStyle() & SWT.BOTTOM) == 0;
	}

	@Override
	public void close() {
	if (fShell != null && !fShell.isDisposed()) {
	fShell.close();
	}
	}

	@Override
	public void notifySelection(ISelection selection) {
	fParent.getViewer().fireMenuSelection(selection);
	}

	@Override
	public void updateSize() {
	if (fShell != null && !fShell.isDisposed()) {
	resizeShell(fShell);
	}
	}
	}