wikitext/ui/org.eclipse.mylyn.wikitext.ui/src/org/eclipse/mylyn/internal/wikitext/ui/viewer/ImageManager.java - mylyn/org.eclipse.mylyn.docs - Git at Google

 /*******************************************************************************
  * Copyright (c) 2007, 2009 David Green and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v2.0
  * which accompanies this distribution, and is available at
  * https://www.eclipse.org/legal/epl-2.0/
  *
  * SPDX-License-Identifier: EPL-2.0
  *
  * Contributors:
  *     David Green - initial API and implementation
  *******************************************************************************/

 package org.eclipse.mylyn.internal.wikitext.ui.viewer;

 import java.io.BufferedInputStream;
 import java.io.InputStream;
 import java.net.MalformedURLException;
 import java.net.URL;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.atomic.AtomicInteger;

 import org.eclipse.core.runtime.IStatus;
 import org.eclipse.jface.resource.ImageDescriptor;
 import org.eclipse.jface.text.BadLocationException;
 import org.eclipse.jface.text.DocumentEvent;
 import org.eclipse.jface.text.IDocument;
 import org.eclipse.jface.text.IDocumentListener;
 import org.eclipse.jface.text.ITextInputListener;
 import org.eclipse.jface.text.Position;
 import org.eclipse.jface.text.TextPresentation;
 import org.eclipse.jface.text.hyperlink.IHyperlink;
 import org.eclipse.jface.text.source.Annotation;
 import org.eclipse.jface.text.source.AnnotationModel;
 import org.eclipse.jface.text.source.AnnotationPainter;
 import org.eclipse.jface.viewers.ISelectionChangedListener;
 import org.eclipse.jface.viewers.SelectionChangedEvent;
 import org.eclipse.mylyn.internal.wikitext.ui.WikiTextUiPlugin;
 import org.eclipse.mylyn.internal.wikitext.ui.util.ImageCache;
 import org.eclipse.mylyn.internal.wikitext.ui.viewer.annotation.ImageAnnotation;
 import org.eclipse.mylyn.internal.wikitext.ui.viewer.annotation.ImageDrawingStrategy;
 import org.eclipse.mylyn.wikitext.ui.viewer.HtmlViewer;
 import org.eclipse.osgi.util.NLS;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.SWTException;
 import org.eclipse.swt.custom.StyleRange;
 import org.eclipse.swt.events.DisposeEvent;
 import org.eclipse.swt.events.DisposeListener;
 import org.eclipse.swt.events.MouseEvent;
 import org.eclipse.swt.events.MouseListener;
 import org.eclipse.swt.events.MouseMoveListener;
 import org.eclipse.swt.events.PaintEvent;
 import org.eclipse.swt.graphics.Cursor;
 import org.eclipse.swt.graphics.Font;
 import org.eclipse.swt.graphics.GC;
 import org.eclipse.swt.graphics.Image;
 import org.eclipse.swt.graphics.ImageData;
 import org.eclipse.swt.graphics.Point;
 import org.eclipse.swt.graphics.Rectangle;
 import org.eclipse.swt.widgets.Display;
 import org.eclipse.swt.widgets.Event;

 /**
  * Manages all aspects of image download/display in an {@link HtmlViewer}. Manages the download of images for viewing in
  * an {@link HtmlViewer}, and creates appropriate space for their display. Downloads image data in a background thread,
  * instantiates the corresopnding images, and ensures that enough vertical space exists in the viewer to display the
  * images.
  *
  * @see ImageAnnotation
  * @see ImageDrawingStrategy
  * @see ImageCache
  * @see HtmlViewer
  * @author David Green
  */
 public class ImageManager implements ITextInputListener, DisposeListener, IDocumentListener, ISelectionChangedListener {
 	private class HyperlinkMouseListener implements MouseMoveListener, MouseListener {
 		@SuppressWarnings("unused")
 		public void mouseEnter(MouseEvent e) {
 			// ignore
 		}

 		@SuppressWarnings("unused")
 		public void mouseExit(MouseEvent e) {
 			disarm();
 		}

 		public void mouseMove(MouseEvent e) {
 			adjust(e);
 		}

 		public void mouseDoubleClick(MouseEvent e) {
 			// ignore
 		}

 		public void mouseDown(MouseEvent e) {
 			// ignore
 		}

 		public void mouseUp(MouseEvent e) {
 			clicked(e);
 		}
 	}

 	private final HtmlViewer viewer;

 	private final Display display;

 	private final ImageCache imageCache;

 	private final Set<ImageAnnotation> annotations = new HashSet<>();

 	private ImageResolver imageResolver;

 	private boolean computingChanges;

 	private final AnnotationPainter painter;

 	private boolean armed = false;

 	private Cursor cursor;

 	private Cursor previousCursor;

 	public ImageManager(HtmlViewer viewer, ImageCache imageCache, AnnotationPainter painter) {
 		this.viewer = viewer;
 		this.painter = painter;
 		display = viewer.getTextWidget().getDisplay();
 		this.imageCache = imageCache;
 		inspect();
 		viewer.getTextWidget().addDisposeListener(this);
 		viewer.addTextInputListener(this);
 		if (viewer.getDocument() != null) {
 			viewer.getDocument().addDocumentListener(this);
 		}
 		viewer.addSelectionChangedListener(this);
 		viewer.addPostSelectionChangedListener(this);

 		// bug 257868 support image hyperlinks
 		HyperlinkMouseListener mouseListener = new HyperlinkMouseListener();
 		viewer.getTextWidget().addMouseMoveListener(mouseListener);
 		viewer.getTextWidget().addMouseListener(mouseListener);

 	}

 	private IHyperlink getHyperlink(MouseEvent e) {
 		// bug 257868 support image hyperlinks
 		if (annotations.isEmpty()) {
 			return null;
 		}
 		Point point = new Point(e.x, e.y);
 		for (ImageAnnotation annotation : annotations) {
 			if (annotation.getHyperlnkAnnotation() == null) {
 				continue;
 			}
 			Rectangle region = getRegion(annotation);
 			if (region != null) {
 				if (region.contains(point)) {
 					AnnotationHyperlinkDetector detector = (AnnotationHyperlinkDetector) viewer.getTextWidget()
 							.getData(AnnotationHyperlinkDetector.class.getName());
 					if (detector != null) {
 						IHyperlink hyperlink = detector.createHyperlink(viewer, viewer.getAnnotationModel(),
 								annotation.getHyperlnkAnnotation());
 						return hyperlink;
 					}
 				}
 			}
 		}
 		return null;
 	}

 	public void clicked(MouseEvent e) {
 		IHyperlink hyperlink = getHyperlink(e);
 		if (hyperlink != null) {
 			disarm();
 			hyperlink.open();
 		}
 	}

 	/**
 	 * get the widget-relative region of the given annotation
 	 *
 	 * @return the region, or null if it is unknown
 	 */
 	private Rectangle getRegion(ImageAnnotation annotation) {
 		if (annotation.getImage() == null) {
 			return null;
 		}
 		Position position = viewer.getAnnotationModel().getPosition(annotation);
 		Point locationAtOffset = viewer.getTextWidget().getLocationAtOffset(position.offset);
 		Rectangle bounds = annotation.getImage().getBounds();
 		Rectangle rectange = new Rectangle(locationAtOffset.x, locationAtOffset.y, bounds.width, bounds.height);
 		return rectange;
 	}

 	void adjust(MouseEvent e) {
 		IHyperlink hyperlink = getHyperlink(e);
 		if (hyperlink == null) {
 			disarm();
 		} else {
 			// always arm here even if already armed, otherwise the cursor
 			// setting interacts poorly with other things that set the cursor.
 			armed = true;
 			Cursor currentCursor = viewer.getTextWidget().getCursor();
 			if (cursor == null || currentCursor != cursor) {
 				previousCursor = currentCursor;
 				if (cursor == null) {
 					cursor = new Cursor(viewer.getTextWidget().getDisplay(), SWT.CURSOR_HAND);
 				}
 				viewer.getTextWidget().setCursor(cursor);
 			}
 		}
 	}

 	void disarm() {
 		if (armed) {
 			if (previousCursor != null) {
 				viewer.getTextWidget().setCursor(previousCursor);
 			}
 			armed = false;
 		}
 	}

 	public void inputDocumentAboutToBeChanged(IDocument oldInput, IDocument newInput) {
 		stop();
 	}

 	public void inputDocumentChanged(IDocument oldInput, IDocument newInput) {
 		if (oldInput != null) {
 			oldInput.removeDocumentListener(this);
 		}
 		if (newInput != null) {
 			newInput.addDocumentListener(this);
 		}
 		inspect();
 	}

 	@SuppressWarnings("unchecked")
 	private void inspect() {
 		synchronized (this) {
 			annotations.clear();
 			if (viewer.getAnnotationModel() != null) {
 				Iterator<Annotation> iterator = viewer.getAnnotationModel().getAnnotationIterator();
 				while (iterator.hasNext()) {
 					Annotation annotation = iterator.next();
 					if (annotation instanceof ImageAnnotation) {
 						annotations.add((ImageAnnotation) annotation);
 					}
 				}
 			}
 		}
 		if (!annotations.isEmpty()) {
 			ImageResolver resolver;
 			synchronized (this) {
 				resolver = imageResolver;
 			}
 			if (resolver != null) {
 				try {
 					resolver.join();
 				} catch (InterruptedException e) {
 					return;
 				}
 			}
 			imageResolver = new ImageResolver();
 			imageResolver.start();
 		}
 	}

 	private synchronized void stop() {
 		ImageResolver resolver = imageResolver;
 		if (resolver != null) {
 			resolver.interrupt();
 		}
 	}

 	public void widgetDisposed(DisposeEvent e) {
 		if (cursor != null) {
 			cursor.dispose();
 			cursor = null;
 		}
 		stop();
 	}

 	@SuppressWarnings("unchecked")
 	private void updateImage(String imgSrc, ImageData imageData) {
 		if (display.isDisposed() || viewer.getTextWidget().isDisposed()) {
 			return;
 		}
 		Image image = imageData == null
 				? imageCache.getMissingImage()
 				: ImageDescriptor.createFromImageData(imageData).createImage();
 		imageCache.putImage(imgSrc, image);

 		Set<ImageAnnotation> modifiedAnnotations = new HashSet<>();

 		AnnotationModel annotationModel = (AnnotationModel) viewer.getAnnotationModel();
 		Object annotationLockObject = annotationModel.getLockObject();
 		if (annotationLockObject == null) {
 			annotationLockObject = annotationModel;
 		}
 		synchronized (annotationLockObject) {
 			Iterator<Annotation> iterator = annotationModel.getAnnotationIterator();
 			while (iterator.hasNext()) {
 				Annotation annotation = iterator.next();
 				if (annotation instanceof ImageAnnotation) {
 					ImageAnnotation imageAnnotation = (ImageAnnotation) annotation;
 					if (imgSrc.equals(imageAnnotation.getUrl())) {
 						imageAnnotation.setImage(image);
 						modifiedAnnotations.add(imageAnnotation);
 					}
 				}
 			}
 		}

 		if (!modifiedAnnotations.isEmpty()) {
 			computingChanges = true;
 			try {
 				boolean rangesAdjusted = false;
 				List<StyleRange> ranges = new ArrayList<>();

 				Iterator<?> allStyleRangeIterator = viewer.getTextPresentation().getAllStyleRangeIterator();
 				while (allStyleRangeIterator.hasNext()) {
 					StyleRange range = (StyleRange) allStyleRangeIterator.next();
 					ranges.add((StyleRange) range.clone());
 				}

 				GC gc = new GC(viewer.getTextWidget());
 				try {
 					viewer.getTextWidget().setRedraw(false);
 					TextPresentation textPresentation = viewer.getTextPresentation();
 					//			textPresentation.
 					for (ImageAnnotation annotation : modifiedAnnotations) {
 						int height = annotation.getImage().getBounds().height;
 						Position position = annotationModel.getPosition(annotation);
 						String widgetText = viewer.getTextWidget().getText();
 						Font font = null;
 						if (widgetText.length() > 0 && widgetText.length() > position.offset) {
 							StyleRange styleRange = viewer.getTextWidget().getStyleRangeAtOffset(position.offset);
 							if (styleRange != null) {
 								font = styleRange.font;
 							}
 						}
 						if (font == null) {
 							font = viewer.getTextWidget().getFont();
 						}
 						gc.setFont(font);
 						Point extent = gc.textExtent("\n"); //$NON-NLS-1$
 						if (extent.y > 0) {
 							int numNewlines = (int) Math.ceil(((double) height) / ((double) extent.y));
 							final int originalNewlines = numNewlines;
 							IDocument document = viewer.getDocument();
 							try {
 								for (int x = position.offset; x < document.getLength(); ++x) {
 									if (document.getChar(x) == '\n') {
 										if (x != position.offset
 												&& Util.annotationsIncludeOffset(viewer.getAnnotationModel(), x)) {
 											break;
 										}
 										--numNewlines;
 									} else {
 										break;
 									}
 								}
 								if (numNewlines > 0) {
 									String newlines = ""; //$NON-NLS-1$
 									for (int x = 0; x < numNewlines; ++x) {
 										newlines += "\n"; //$NON-NLS-1$
 									}
 									document.replace(position.offset + 1, 0, newlines);
 								} else if (numNewlines < 0) {
 									document.replace(position.offset, -numNewlines, ""); //$NON-NLS-1$
 								}
 								if (numNewlines != 0) {
 									// no need to fixup other annotation positions, since the annotation model is hooked into the document.

 									// fix up styles
 									for (StyleRange range : ranges) {
 										if (range.start > position.offset) {
 											range.start += numNewlines;
 											rangesAdjusted = true;
 										} else if (range.start + range.length > position.offset) {
 											range.length += numNewlines;
 											rangesAdjusted = true;
 										}
 									}
 								}

 								// bug# 248643: update the annotation size to reflect the full size of the image
 								//              so that it gets repainted when some portion of the image is exposed
 								//              as a result of scrolling
 								if (position.getLength() != originalNewlines) {
 									annotationModel.modifyAnnotationPosition(annotation,
 											new Position(position.offset, originalNewlines));
 								}
 							} catch (BadLocationException e) {
 								// ignore
 							}
 						}
 					}
 					if (rangesAdjusted) {
 						TextPresentation presentation = new TextPresentation();
 						if (textPresentation.getDefaultStyleRange() != null) {
 							StyleRange defaultStyleRange = (StyleRange) textPresentation.getDefaultStyleRange().clone();
 							if (viewer.getDocument() != null) {
 								if (defaultStyleRange.length < viewer.getDocument().getLength()) {
 									defaultStyleRange.length = viewer.getDocument().getLength();
 								}
 							}
 							presentation.setDefaultStyleRange(defaultStyleRange);
 						}
 						for (StyleRange range : ranges) {
 							presentation.addStyleRange(range);
 						}
 						viewer.setTextPresentation(presentation);
 						viewer.invalidateTextPresentation();
 					}
 				} finally {
 					viewer.getTextWidget().setRedraw(true);
 					gc.dispose();
 				}
 				viewer.getTextWidget().redraw();
 			} finally {
 				computingChanges = false;
 			}
 		}
 	}

 	private static final AtomicInteger resolverIdSeed = new AtomicInteger(1);

 	private class ImageResolver extends Thread {

 		public ImageResolver() {
 			setName(ImageResolver.class.getSimpleName() + '-' + resolverIdSeed.getAndIncrement());
 			setDaemon(true);
 		}

 		@Override
 		public void run() {
 			try {
 				final Map<String, ImageData> urlToImageData = new HashMap<>();
 				for (ImageAnnotation annotation : annotations) {
 					final String imgSrc = annotation.getUrl();
 					if (imgSrc != null && !urlToImageData.containsKey(imgSrc)) {
 						try {
 							URL location = imageCache.getBase() == null
 									? new URL(imgSrc)
 									: new URL(imageCache.getBase(), imgSrc);

 							try {
 								InputStream in = new BufferedInputStream(location.openStream());
 								try {
 									urlToImageData.put(imgSrc, new ImageData(in));
 								} catch (SWTException e) {
 									if (e.code != SWT.ERROR_INVALID_IMAGE) {
 										throw e;
 									}
 									urlToImageData.put(imgSrc, null);
 								} finally {
 									in.close();
 								}
 							} catch (Exception e) {
 								if (WikiTextUiPlugin.getDefault() != null) {
 									WikiTextUiPlugin.getDefault().log(IStatus.ERROR,
 											NLS.bind(Messages.ImageManager_accessFailed, new Object[] { location }), e);
 								}
 								urlToImageData.put(imgSrc, null);
 							}
 						} catch (MalformedURLException e) {
 							urlToImageData.put(imgSrc, null);
 						}
 						display.asyncExec(new Runnable() {
 							public void run() {
 								updateImage(imgSrc, urlToImageData.get(imgSrc));
 							}
 						});
 					}
 					if (Thread.currentThread().isInterrupted()) {
 						break;
 					}
 				}
 			} finally {
 				imageResolver = null;
 			}
 		}
 	}

 	public void documentAboutToBeChanged(DocumentEvent event) {
 		if (computingChanges) {
 			return;
 		}
 		stop();
 	}

 	public void documentChanged(DocumentEvent event) {
 		if (computingChanges) {
 			return;
 		}
 		inspect();
 	}

 	public void selectionChanged(SelectionChangedEvent event) {
 		GC gc = new GC(viewer.getTextWidget());
 		try {
 			Event e = new Event();
 			e.gc = gc;
 			e.widget = viewer.getTextWidget();
 			Rectangle bounds = viewer.getTextWidget().getBounds();
 			e.height = bounds.height;
 			e.width = bounds.width;
 			e.x = 0;
 			e.y = 0;
 			PaintEvent paintEvent = new PaintEvent(e);
 			painter.paintControl(paintEvent);
 		} finally {
 			gc.dispose();
 		}
 	}

 }
	/*******************************************************************************
	* Copyright (c) 2007, 2009 David Green and others.
	* All rights reserved. This program and the accompanying materials
	* are made available under the terms of the Eclipse Public License v2.0
	* which accompanies this distribution, and is available at
	* https://www.eclipse.org/legal/epl-2.0/
	*
	* SPDX-License-Identifier: EPL-2.0
	*
	* Contributors:
	* David Green - initial API and implementation
	*******************************************************************************/

	package org.eclipse.mylyn.internal.wikitext.ui.viewer;

	import java.io.BufferedInputStream;
	import java.io.InputStream;
	import java.net.MalformedURLException;
	import java.net.URL;
	import java.util.ArrayList;
	import java.util.HashMap;
	import java.util.HashSet;
	import java.util.Iterator;
	import java.util.List;
	import java.util.Map;
	import java.util.Set;
	import java.util.concurrent.atomic.AtomicInteger;

	import org.eclipse.core.runtime.IStatus;
	import org.eclipse.jface.resource.ImageDescriptor;
	import org.eclipse.jface.text.BadLocationException;
	import org.eclipse.jface.text.DocumentEvent;
	import org.eclipse.jface.text.IDocument;
	import org.eclipse.jface.text.IDocumentListener;
	import org.eclipse.jface.text.ITextInputListener;
	import org.eclipse.jface.text.Position;
	import org.eclipse.jface.text.TextPresentation;
	import org.eclipse.jface.text.hyperlink.IHyperlink;
	import org.eclipse.jface.text.source.Annotation;
	import org.eclipse.jface.text.source.AnnotationModel;
	import org.eclipse.jface.text.source.AnnotationPainter;
	import org.eclipse.jface.viewers.ISelectionChangedListener;
	import org.eclipse.jface.viewers.SelectionChangedEvent;
	import org.eclipse.mylyn.internal.wikitext.ui.WikiTextUiPlugin;
	import org.eclipse.mylyn.internal.wikitext.ui.util.ImageCache;
	import org.eclipse.mylyn.internal.wikitext.ui.viewer.annotation.ImageAnnotation;
	import org.eclipse.mylyn.internal.wikitext.ui.viewer.annotation.ImageDrawingStrategy;
	import org.eclipse.mylyn.wikitext.ui.viewer.HtmlViewer;
	import org.eclipse.osgi.util.NLS;
	import org.eclipse.swt.SWT;
	import org.eclipse.swt.SWTException;
	import org.eclipse.swt.custom.StyleRange;
	import org.eclipse.swt.events.DisposeEvent;
	import org.eclipse.swt.events.DisposeListener;
	import org.eclipse.swt.events.MouseEvent;
	import org.eclipse.swt.events.MouseListener;
	import org.eclipse.swt.events.MouseMoveListener;
	import org.eclipse.swt.events.PaintEvent;
	import org.eclipse.swt.graphics.Cursor;
	import org.eclipse.swt.graphics.Font;
	import org.eclipse.swt.graphics.GC;
	import org.eclipse.swt.graphics.Image;
	import org.eclipse.swt.graphics.ImageData;
	import org.eclipse.swt.graphics.Point;
	import org.eclipse.swt.graphics.Rectangle;
	import org.eclipse.swt.widgets.Display;
	import org.eclipse.swt.widgets.Event;

	/**
	* Manages all aspects of image download/display in an {@link HtmlViewer}. Manages the download of images for viewing in
	* an {@link HtmlViewer}, and creates appropriate space for their display. Downloads image data in a background thread,
	* instantiates the corresopnding images, and ensures that enough vertical space exists in the viewer to display the
	* images.
	*
	* @see ImageAnnotation
	* @see ImageDrawingStrategy
	* @see ImageCache
	* @see HtmlViewer
	* @author David Green
	*/
	public class ImageManager implements ITextInputListener, DisposeListener, IDocumentListener, ISelectionChangedListener {
	private class HyperlinkMouseListener implements MouseMoveListener, MouseListener {
	@SuppressWarnings("unused")
	public void mouseEnter(MouseEvent e) {
	// ignore
	}

	@SuppressWarnings("unused")
	public void mouseExit(MouseEvent e) {
	disarm();
	}

	public void mouseMove(MouseEvent e) {
	adjust(e);
	}

	public void mouseDoubleClick(MouseEvent e) {
	// ignore
	}

	public void mouseDown(MouseEvent e) {
	// ignore
	}

	public void mouseUp(MouseEvent e) {
	clicked(e);
	}
	}

	private final HtmlViewer viewer;

	private final Display display;

	private final ImageCache imageCache;

	private final Set<ImageAnnotation> annotations = new HashSet<>();

	private ImageResolver imageResolver;

	private boolean computingChanges;

	private final AnnotationPainter painter;

	private boolean armed = false;

	private Cursor cursor;

	private Cursor previousCursor;

	public ImageManager(HtmlViewer viewer, ImageCache imageCache, AnnotationPainter painter) {
	this.viewer = viewer;
	this.painter = painter;
	display = viewer.getTextWidget().getDisplay();
	this.imageCache = imageCache;
	inspect();
	viewer.getTextWidget().addDisposeListener(this);
	viewer.addTextInputListener(this);
	if (viewer.getDocument() != null) {
	viewer.getDocument().addDocumentListener(this);
	}
	viewer.addSelectionChangedListener(this);
	viewer.addPostSelectionChangedListener(this);

	// bug 257868 support image hyperlinks
	HyperlinkMouseListener mouseListener = new HyperlinkMouseListener();
	viewer.getTextWidget().addMouseMoveListener(mouseListener);
	viewer.getTextWidget().addMouseListener(mouseListener);

	}

	private IHyperlink getHyperlink(MouseEvent e) {
	// bug 257868 support image hyperlinks
	if (annotations.isEmpty()) {
	return null;
	}
	Point point = new Point(e.x, e.y);
	for (ImageAnnotation annotation : annotations) {
	if (annotation.getHyperlnkAnnotation() == null) {
	continue;
	}
	Rectangle region = getRegion(annotation);
	if (region != null) {
	if (region.contains(point)) {
	AnnotationHyperlinkDetector detector = (AnnotationHyperlinkDetector) viewer.getTextWidget()
	.getData(AnnotationHyperlinkDetector.class.getName());
	if (detector != null) {
	IHyperlink hyperlink = detector.createHyperlink(viewer, viewer.getAnnotationModel(),
	annotation.getHyperlnkAnnotation());
	return hyperlink;
	}
	}
	}
	}
	return null;
	}

	public void clicked(MouseEvent e) {
	IHyperlink hyperlink = getHyperlink(e);
	if (hyperlink != null) {
	disarm();
	hyperlink.open();
	}
	}

	/**
	* get the widget-relative region of the given annotation
	*
	* @return the region, or null if it is unknown
	*/
	private Rectangle getRegion(ImageAnnotation annotation) {
	if (annotation.getImage() == null) {
	return null;
	}
	Position position = viewer.getAnnotationModel().getPosition(annotation);
	Point locationAtOffset = viewer.getTextWidget().getLocationAtOffset(position.offset);
	Rectangle bounds = annotation.getImage().getBounds();
	Rectangle rectange = new Rectangle(locationAtOffset.x, locationAtOffset.y, bounds.width, bounds.height);
	return rectange;
	}

	void adjust(MouseEvent e) {
	IHyperlink hyperlink = getHyperlink(e);
	if (hyperlink == null) {
	disarm();
	} else {
	// always arm here even if already armed, otherwise the cursor
	// setting interacts poorly with other things that set the cursor.
	armed = true;
	Cursor currentCursor = viewer.getTextWidget().getCursor();
	if (cursor == null \|\| currentCursor != cursor) {
	previousCursor = currentCursor;
	if (cursor == null) {
	cursor = new Cursor(viewer.getTextWidget().getDisplay(), SWT.CURSOR_HAND);
	}
	viewer.getTextWidget().setCursor(cursor);
	}
	}
	}

	void disarm() {
	if (armed) {
	if (previousCursor != null) {
	viewer.getTextWidget().setCursor(previousCursor);
	}
	armed = false;
	}
	}

	public void inputDocumentAboutToBeChanged(IDocument oldInput, IDocument newInput) {
	stop();
	}

	public void inputDocumentChanged(IDocument oldInput, IDocument newInput) {
	if (oldInput != null) {
	oldInput.removeDocumentListener(this);
	}
	if (newInput != null) {
	newInput.addDocumentListener(this);
	}
	inspect();
	}

	@SuppressWarnings("unchecked")
	private void inspect() {
	synchronized (this) {
	annotations.clear();
	if (viewer.getAnnotationModel() != null) {
	Iterator<Annotation> iterator = viewer.getAnnotationModel().getAnnotationIterator();
	while (iterator.hasNext()) {
	Annotation annotation = iterator.next();
	if (annotation instanceof ImageAnnotation) {
	annotations.add((ImageAnnotation) annotation);
	}
	}
	}
	}
	if (!annotations.isEmpty()) {
	ImageResolver resolver;
	synchronized (this) {
	resolver = imageResolver;
	}
	if (resolver != null) {
	try {
	resolver.join();
	} catch (InterruptedException e) {
	return;
	}
	}
	imageResolver = new ImageResolver();
	imageResolver.start();
	}
	}

	private synchronized void stop() {
	ImageResolver resolver = imageResolver;
	if (resolver != null) {
	resolver.interrupt();
	}
	}

	public void widgetDisposed(DisposeEvent e) {
	if (cursor != null) {
	cursor.dispose();
	cursor = null;
	}
	stop();
	}

	@SuppressWarnings("unchecked")
	private void updateImage(String imgSrc, ImageData imageData) {
	if (display.isDisposed() \|\| viewer.getTextWidget().isDisposed()) {
	return;
	}
	Image image = imageData == null
	? imageCache.getMissingImage()
	: ImageDescriptor.createFromImageData(imageData).createImage();
	imageCache.putImage(imgSrc, image);

	Set<ImageAnnotation> modifiedAnnotations = new HashSet<>();

	AnnotationModel annotationModel = (AnnotationModel) viewer.getAnnotationModel();
	Object annotationLockObject = annotationModel.getLockObject();
	if (annotationLockObject == null) {
	annotationLockObject = annotationModel;
	}
	synchronized (annotationLockObject) {
	Iterator<Annotation> iterator = annotationModel.getAnnotationIterator();
	while (iterator.hasNext()) {
	Annotation annotation = iterator.next();
	if (annotation instanceof ImageAnnotation) {
	ImageAnnotation imageAnnotation = (ImageAnnotation) annotation;
	if (imgSrc.equals(imageAnnotation.getUrl())) {
	imageAnnotation.setImage(image);
	modifiedAnnotations.add(imageAnnotation);
	}
	}
	}
	}

	if (!modifiedAnnotations.isEmpty()) {
	computingChanges = true;
	try {
	boolean rangesAdjusted = false;
	List<StyleRange> ranges = new ArrayList<>();

	Iterator<?> allStyleRangeIterator = viewer.getTextPresentation().getAllStyleRangeIterator();
	while (allStyleRangeIterator.hasNext()) {
	StyleRange range = (StyleRange) allStyleRangeIterator.next();
	ranges.add((StyleRange) range.clone());
	}

	GC gc = new GC(viewer.getTextWidget());
	try {
	viewer.getTextWidget().setRedraw(false);
	TextPresentation textPresentation = viewer.getTextPresentation();
	// textPresentation.
	for (ImageAnnotation annotation : modifiedAnnotations) {
	int height = annotation.getImage().getBounds().height;
	Position position = annotationModel.getPosition(annotation);
	String widgetText = viewer.getTextWidget().getText();
	Font font = null;
	if (widgetText.length() > 0 && widgetText.length() > position.offset) {
	StyleRange styleRange = viewer.getTextWidget().getStyleRangeAtOffset(position.offset);
	if (styleRange != null) {
	font = styleRange.font;
	}
	}
	if (font == null) {
	font = viewer.getTextWidget().getFont();
	}
	gc.setFont(font);
	Point extent = gc.textExtent("\n"); //$NON-NLS-1$
	if (extent.y > 0) {
	int numNewlines = (int) Math.ceil(((double) height) / ((double) extent.y));
	final int originalNewlines = numNewlines;
	IDocument document = viewer.getDocument();
	try {
	for (int x = position.offset; x < document.getLength(); ++x) {
	if (document.getChar(x) == '\n') {
	if (x != position.offset
	&& Util.annotationsIncludeOffset(viewer.getAnnotationModel(), x)) {
	break;
	}
	--numNewlines;
	} else {
	break;
	}
	}
	if (numNewlines > 0) {
	String newlines = ""; //$NON-NLS-1$
	for (int x = 0; x < numNewlines; ++x) {
	newlines += "\n"; //$NON-NLS-1$
	}
	document.replace(position.offset + 1, 0, newlines);
	} else if (numNewlines < 0) {
	document.replace(position.offset, -numNewlines, ""); //$NON-NLS-1$
	}
	if (numNewlines != 0) {
	// no need to fixup other annotation positions, since the annotation model is hooked into the document.

	// fix up styles
	for (StyleRange range : ranges) {
	if (range.start > position.offset) {
	range.start += numNewlines;
	rangesAdjusted = true;
	} else if (range.start + range.length > position.offset) {
	range.length += numNewlines;
	rangesAdjusted = true;
	}
	}
	}

	// bug# 248643: update the annotation size to reflect the full size of the image
	// so that it gets repainted when some portion of the image is exposed
	// as a result of scrolling
	if (position.getLength() != originalNewlines) {
	annotationModel.modifyAnnotationPosition(annotation,
	new Position(position.offset, originalNewlines));
	}
	} catch (BadLocationException e) {
	// ignore
	}
	}
	}
	if (rangesAdjusted) {
	TextPresentation presentation = new TextPresentation();
	if (textPresentation.getDefaultStyleRange() != null) {
	StyleRange defaultStyleRange = (StyleRange) textPresentation.getDefaultStyleRange().clone();
	if (viewer.getDocument() != null) {
	if (defaultStyleRange.length < viewer.getDocument().getLength()) {
	defaultStyleRange.length = viewer.getDocument().getLength();
	}
	}
	presentation.setDefaultStyleRange(defaultStyleRange);
	}
	for (StyleRange range : ranges) {
	presentation.addStyleRange(range);
	}
	viewer.setTextPresentation(presentation);
	viewer.invalidateTextPresentation();
	}
	} finally {
	viewer.getTextWidget().setRedraw(true);
	gc.dispose();
	}
	viewer.getTextWidget().redraw();
	} finally {
	computingChanges = false;
	}
	}
	}

	private static final AtomicInteger resolverIdSeed = new AtomicInteger(1);

	private class ImageResolver extends Thread {

	public ImageResolver() {
	setName(ImageResolver.class.getSimpleName() + '-' + resolverIdSeed.getAndIncrement());
	setDaemon(true);
	}

	@Override
	public void run() {
	try {
	final Map<String, ImageData> urlToImageData = new HashMap<>();
	for (ImageAnnotation annotation : annotations) {
	final String imgSrc = annotation.getUrl();
	if (imgSrc != null && !urlToImageData.containsKey(imgSrc)) {
	try {
	URL location = imageCache.getBase() == null
	? new URL(imgSrc)
	: new URL(imageCache.getBase(), imgSrc);

	try {
	InputStream in = new BufferedInputStream(location.openStream());
	try {
	urlToImageData.put(imgSrc, new ImageData(in));
	} catch (SWTException e) {
	if (e.code != SWT.ERROR_INVALID_IMAGE) {
	throw e;
	}
	urlToImageData.put(imgSrc, null);
	} finally {
	in.close();
	}
	} catch (Exception e) {
	if (WikiTextUiPlugin.getDefault() != null) {
	WikiTextUiPlugin.getDefault().log(IStatus.ERROR,
	NLS.bind(Messages.ImageManager_accessFailed, new Object[] { location }), e);
	}
	urlToImageData.put(imgSrc, null);
	}
	} catch (MalformedURLException e) {
	urlToImageData.put(imgSrc, null);
	}
	display.asyncExec(new Runnable() {
	public void run() {
	updateImage(imgSrc, urlToImageData.get(imgSrc));
	}
	});
	}
	if (Thread.currentThread().isInterrupted()) {
	break;
	}
	}
	} finally {
	imageResolver = null;
	}
	}
	}

	public void documentAboutToBeChanged(DocumentEvent event) {
	if (computingChanges) {
	return;
	}
	stop();
	}

	public void documentChanged(DocumentEvent event) {
	if (computingChanges) {
	return;
	}
	inspect();
	}

	public void selectionChanged(SelectionChangedEvent event) {
	GC gc = new GC(viewer.getTextWidget());
	try {
	Event e = new Event();
	e.gc = gc;
	e.widget = viewer.getTextWidget();
	Rectangle bounds = viewer.getTextWidget().getBounds();
	e.height = bounds.height;
	e.width = bounds.width;
	e.x = 0;
	e.y = 0;
	PaintEvent paintEvent = new PaintEvent(e);
	painter.paintControl(paintEvent);
	} finally {
	gc.dispose();
	}
	}

	}