bundles/org.eclipse.wst.sse.ui/src/org/eclipse/wst/sse/ui/internal/hyperlink/HighlighterHyperlinkPresenter.java - sourceediting/webtools.sourceediting - Git at Google

 package org.eclipse.wst.sse.ui.internal.hyperlink;

 import org.eclipse.jface.preference.IPreferenceStore;
 import org.eclipse.jface.preference.PreferenceConverter;
 import org.eclipse.jface.text.Assert;
 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.IRegion;
 import org.eclipse.jface.text.ITextInputListener;
 import org.eclipse.jface.text.ITextViewer;
 import org.eclipse.jface.text.ITextViewerExtension2;
 import org.eclipse.jface.text.ITextViewerExtension5;
 import org.eclipse.jface.text.Position;
 import org.eclipse.jface.text.Region;
 import org.eclipse.jface.text.hyperlink.IHyperlink;
 import org.eclipse.jface.text.hyperlink.IHyperlinkPresenter;
 import org.eclipse.jface.util.IPropertyChangeListener;
 import org.eclipse.jface.util.PropertyChangeEvent;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.custom.StyleRange;
 import org.eclipse.swt.custom.StyledText;
 import org.eclipse.swt.events.PaintEvent;
 import org.eclipse.swt.events.PaintListener;
 import org.eclipse.swt.graphics.Color;
 import org.eclipse.swt.graphics.Cursor;
 import org.eclipse.swt.graphics.GC;
 import org.eclipse.swt.graphics.Point;
 import org.eclipse.swt.graphics.RGB;
 import org.eclipse.swt.graphics.Rectangle;
 import org.eclipse.swt.widgets.Display;


 /**
  * The is almost an exact copy of DefaultHyperlinkPresenter. However this
  * hyperlink presenter works with the StructuredTextEditor's Highlighter
  * instead of TextPresentation.
  *
  * The main difference is <code>text.redrawRange(offset, length, true);</code>
  * is called instead of passing false for clearBackground. Also all mention of
  * TextPresentation was removed since it does not really apply.
  *
  * @see org.eclipse.jface.text.hyperlink.DefaultHyperlinkPresenter
  */
 public class HighlighterHyperlinkPresenter implements IHyperlinkPresenter, PaintListener, ITextInputListener, IDocumentListener, IPropertyChangeListener {

 	/**
 	 * A named preference that holds the color used for hyperlinks.
 	 * <p>
 	 * Value is of type <code>String</code>. A RGB color value encoded as a
 	 * string using class <code>PreferenceConverter</code>
 	 * </p>
 	 *
 	 * @see org.eclipse.jface.resource.StringConverter
 	 * @see org.eclipse.jface.preference.PreferenceConverter
 	 */
 	public final static String HYPERLINK_COLOR = "hyperlinkColor"; //$NON-NLS-1$


 	/** The text viewer. */
 	private ITextViewer fTextViewer;
 	/** The hand cursor. */
 	private Cursor fCursor;
 	/** The link color. */
 	private Color fColor;
 	/** Tells whether to dispose the color on uninstall. */
 	private boolean fDisposeColor;
 	/** The currently active region. */
 	private IRegion fActiveRegion;
 	/** The currently active style range as position. */
 	private Position fRememberedPosition;
 	/** The optional preference store */
 	private IPreferenceStore fPreferenceStore;


 	/**
 	 * Creates a new default hyperlink presenter which uses
 	 * {@link #HYPERLINK_COLOR}to read the color from the given preference
 	 * store.
 	 *
 	 * @param store
 	 *            the preference store
 	 */
 	public HighlighterHyperlinkPresenter(IPreferenceStore store) {
 		fPreferenceStore = store;
 		fDisposeColor = true;
 	}

 	/**
 	 * Creates a new default hyperlink presenter.
 	 *
 	 * @param color
 	 *            the hyperlink color, to be disposed by the caller
 	 */
 	public HighlighterHyperlinkPresenter(Color color) {
 		fDisposeColor = false;
 		fColor = color;
 	}

 	public boolean canShowMultipleHyperlinks() {
 		return false;
 	}

 	public void showHyperlinks(IHyperlink[] hyperlinks) {
 		Assert.isLegal(hyperlinks != null && hyperlinks.length == 1);
 		highlightRegion(hyperlinks[0].getHyperlinkRegion());
 		activateCursor();
 	}

 	public void hideHyperlinks() {
 		repairRepresentation();
 		fRememberedPosition = null;
 	}

 	public void install(ITextViewer textViewer) {
 		Assert.isNotNull(textViewer);
 		fTextViewer = textViewer;
 		fTextViewer.addTextInputListener(this);

 		StyledText text = fTextViewer.getTextWidget();
 		if (text != null && !text.isDisposed()) {
 			text.addPaintListener(this);
 			if (fPreferenceStore != null)
 				fColor = createColor(fPreferenceStore, HYPERLINK_COLOR, text.getDisplay());
 		}

 		if (fPreferenceStore != null)
 			fPreferenceStore.addPropertyChangeListener(this);
 	}

 	public void uninstall() {
 		fTextViewer.removeTextInputListener(this);

 		if (fColor != null) {
 			if (fDisposeColor)
 				fColor.dispose();
 			fColor = null;
 		}

 		if (fCursor != null) {
 			fCursor.dispose();
 			fCursor = null;
 		}

 		StyledText text = fTextViewer.getTextWidget();
 		if (text != null && !text.isDisposed())
 			text.removePaintListener(this);

 		fTextViewer = null;

 		if (fPreferenceStore != null)
 			fPreferenceStore.removePropertyChangeListener(this);
 	}

 	public void setColor(Color color) {
 		Assert.isNotNull(fTextViewer);
 		fColor = color;
 	}

 	private void highlightRegion(IRegion region) {

 		if (region.equals(fActiveRegion))
 			return;

 		repairRepresentation();

 		StyledText text = fTextViewer.getTextWidget();
 		if (text == null || text.isDisposed())
 			return;


 		// Underline
 		int offset = 0;
 		int length = 0;
 		if (fTextViewer instanceof ITextViewerExtension5) {
 			ITextViewerExtension5 extension = (ITextViewerExtension5) fTextViewer;
 			IRegion widgetRange = extension.modelRange2WidgetRange(region);
 			if (widgetRange == null)
 				return;

 			offset = widgetRange.getOffset();
 			length = widgetRange.getLength();

 		}
 		else {
 			offset = region.getOffset() - fTextViewer.getVisibleRegion().getOffset();
 			length = region.getLength();
 		}

 		// needs to clean background due to StructuredTextEditor's highlighter
 		text.redrawRange(offset, length, true);

 		// Invalidate region ==> apply text presentation
 		fActiveRegion = region;

 		if (fTextViewer instanceof ITextViewerExtension2)
 			((ITextViewerExtension2) fTextViewer).invalidateTextPresentation(region.getOffset(), region.getLength());
 		else
 			fTextViewer.invalidateTextPresentation();
 	}

 	private void activateCursor() {
 		StyledText text = fTextViewer.getTextWidget();
 		if (text == null || text.isDisposed())
 			return;
 		Display display = text.getDisplay();
 		if (fCursor == null)
 			fCursor = new Cursor(display, SWT.CURSOR_HAND);
 		text.setCursor(fCursor);
 	}

 	private void resetCursor() {
 		StyledText text = fTextViewer.getTextWidget();
 		if (text != null && !text.isDisposed())
 			text.setCursor(null);

 		if (fCursor != null) {
 			fCursor.dispose();
 			fCursor = null;
 		}
 	}

 	private void repairRepresentation() {

 		if (fActiveRegion == null)
 			return;

 		int offset = fActiveRegion.getOffset();
 		int length = fActiveRegion.getLength();
 		fActiveRegion = null;

 		resetCursor();

 		// Invalidate ==> remove applied text presentation
 		if (fTextViewer instanceof ITextViewerExtension2)
 			((ITextViewerExtension2) fTextViewer).invalidateTextPresentation(offset, length);
 		else
 			fTextViewer.invalidateTextPresentation();

 		// Remove underline
 		if (fTextViewer instanceof ITextViewerExtension5) {
 			ITextViewerExtension5 extension = (ITextViewerExtension5) fTextViewer;
 			offset = extension.modelOffset2WidgetOffset(offset);
 		}
 		else {
 			offset -= fTextViewer.getVisibleRegion().getOffset();
 		}
 		try {
 			StyledText text = fTextViewer.getTextWidget();

 			// needs to clean background due to StructuredTextEditor's
 			// highlighter
 			text.redrawRange(offset, length, true);

 		}
 		catch (IllegalArgumentException x) {
 			// ignore - do not log
 		}
 	}

 	/*
 	 * @see PaintListener#paintControl(PaintEvent)
 	 */
 	public void paintControl(PaintEvent event) {
 		if (fActiveRegion == null)
 			return;

 		StyledText text = fTextViewer.getTextWidget();
 		if (text == null || text.isDisposed())
 			return;

 		int offset = 0;
 		int length = 0;

 		if (fTextViewer instanceof ITextViewerExtension5) {

 			ITextViewerExtension5 extension = (ITextViewerExtension5) fTextViewer;
 			IRegion widgetRange = extension.modelRange2WidgetRange(fActiveRegion);
 			if (widgetRange == null)
 				return;

 			offset = widgetRange.getOffset();
 			length = widgetRange.getLength();

 		}
 		else {

 			IRegion region = fTextViewer.getVisibleRegion();
 			if (!includes(region, fActiveRegion))
 				return;

 			offset = fActiveRegion.getOffset() - region.getOffset();
 			length = fActiveRegion.getLength();
 		}

 		// support for BIDI
 		Point minLocation = getMinimumLocation(text, offset, length);
 		Point maxLocation = getMaximumLocation(text, offset, length);

 		int x1 = minLocation.x;
 		int x2 = maxLocation.x - 1;
 		int y = minLocation.y + text.getLineHeight() - 1;

 		GC gc = event.gc;
 		if (fColor != null && !fColor.isDisposed())
 			gc.setForeground(fColor);
 		else if (fColor == null && !(offset < 0 && offset >= text.getCharCount())) {
 			StyleRange style = text.getStyleRangeAtOffset(offset);
 			if (style != null)
 				gc.setForeground(style.foreground);
 		}
 		gc.drawLine(x1, y, x2, y);
 	}

 	private Point getMinimumLocation(StyledText text, int offset, int length) {
 		int max = text.getCharCount();
 		Rectangle bounds = text.getBounds();
 		Point minLocation = new Point(bounds.width, bounds.height);
 		for (int i = 0; i <= length; i++) {
 			int k = offset + i;
 			if (k < 0 || k > max)
 				break;

 			Point location = text.getLocationAtOffset(k);
 			if (location.x < minLocation.x)
 				minLocation.x = location.x;
 			if (location.y < minLocation.y)
 				minLocation.y = location.y;
 		}

 		return minLocation;
 	}

 	private Point getMaximumLocation(StyledText text, int offset, int length) {
 		Point maxLocation = new Point(0, 0);

 		for (int i = 0; i <= length; i++) {
 			int k = offset + i;
 			if (k < 0 || k > text.getCharCount())
 				break;

 			Point location = text.getLocationAtOffset(k);
 			if (location.x > maxLocation.x)
 				maxLocation.x = location.x;
 			if (location.y > maxLocation.y)
 				maxLocation.y = location.y;
 		}

 		return maxLocation;
 	}

 	private boolean includes(IRegion region, IRegion position) {
 		return position.getOffset() >= region.getOffset() && position.getOffset() + position.getLength() <= region.getOffset() + region.getLength();
 	}

 	/*
 	 * @see org.eclipse.jface.text.IDocumentListener#documentAboutToBeChanged(org.eclipse.jface.text.DocumentEvent)
 	 */
 	public void documentAboutToBeChanged(DocumentEvent event) {
 		if (fActiveRegion != null) {
 			fRememberedPosition = new Position(fActiveRegion.getOffset(), fActiveRegion.getLength());
 			try {
 				event.getDocument().addPosition(fRememberedPosition);
 			}
 			catch (BadLocationException x) {
 				fRememberedPosition = null;
 			}
 		}
 	}

 	/*
 	 * @see org.eclipse.jface.text.IDocumentListener#documentChanged(org.eclipse.jface.text.DocumentEvent)
 	 */
 	public void documentChanged(DocumentEvent event) {
 		if (fRememberedPosition != null) {
 			if (!fRememberedPosition.isDeleted()) {

 				event.getDocument().removePosition(fRememberedPosition);
 				fActiveRegion = new Region(fRememberedPosition.getOffset(), fRememberedPosition.getLength());
 				fRememberedPosition = null;

 				StyledText widget = fTextViewer.getTextWidget();
 				if (widget != null && !widget.isDisposed()) {
 					widget.getDisplay().asyncExec(new Runnable() {
 						public void run() {
 							hideHyperlinks();
 						}
 					});
 				}

 			}
 			else {
 				fActiveRegion = null;
 				fRememberedPosition = null;
 				hideHyperlinks();
 			}
 		}
 	}

 	/*
 	 * @see org.eclipse.jface.text.ITextInputListener#inputDocumentAboutToBeChanged(org.eclipse.jface.text.IDocument,
 	 *      org.eclipse.jface.text.IDocument)
 	 */
 	public void inputDocumentAboutToBeChanged(IDocument oldInput, IDocument newInput) {
 		if (oldInput == null)
 			return;
 		hideHyperlinks();
 		oldInput.removeDocumentListener(this);
 	}

 	/*
 	 * @see org.eclipse.jface.text.ITextInputListener#inputDocumentChanged(org.eclipse.jface.text.IDocument,
 	 *      org.eclipse.jface.text.IDocument)
 	 */
 	public void inputDocumentChanged(IDocument oldInput, IDocument newInput) {
 		if (newInput == null)
 			return;
 		newInput.addDocumentListener(this);
 	}

 	/**
 	 * Creates a color from the information stored in the given preference
 	 * store.
 	 *
 	 * @param store
 	 *            the preference store
 	 * @param key
 	 *            the key
 	 * @param display
 	 *            the display
 	 * @return the color or <code>null</code> if there is no such
 	 *         information available
 	 */
 	private Color createColor(IPreferenceStore store, String key, Display display) {

 		RGB rgb = null;

 		if (store.contains(key)) {

 			if (store.isDefault(key))
 				rgb = PreferenceConverter.getDefaultColor(store, key);
 			else
 				rgb = PreferenceConverter.getColor(store, key);

 			if (rgb != null)
 				return new Color(display, rgb);
 		}

 		return null;
 	}

 	/*
 	 * @see org.eclipse.jface.util.IPropertyChangeListener#propertyChange(org.eclipse.jface.util.PropertyChangeEvent)
 	 */
 	public void propertyChange(PropertyChangeEvent event) {
 		if (!HYPERLINK_COLOR.equals(event.getProperty()))
 			return;

 		if (fDisposeColor && fColor != null && !fColor.isDisposed())
 			fColor.dispose();
 		fColor = null;

 		StyledText textWidget = fTextViewer.getTextWidget();
 		if (textWidget != null && !textWidget.isDisposed())
 			fColor = createColor(fPreferenceStore, HYPERLINK_COLOR, textWidget.getDisplay());
 	}
 }
	package org.eclipse.wst.sse.ui.internal.hyperlink;

	import org.eclipse.jface.preference.IPreferenceStore;
	import org.eclipse.jface.preference.PreferenceConverter;
	import org.eclipse.jface.text.Assert;
	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.IRegion;
	import org.eclipse.jface.text.ITextInputListener;
	import org.eclipse.jface.text.ITextViewer;
	import org.eclipse.jface.text.ITextViewerExtension2;
	import org.eclipse.jface.text.ITextViewerExtension5;
	import org.eclipse.jface.text.Position;
	import org.eclipse.jface.text.Region;
	import org.eclipse.jface.text.hyperlink.IHyperlink;
	import org.eclipse.jface.text.hyperlink.IHyperlinkPresenter;
	import org.eclipse.jface.util.IPropertyChangeListener;
	import org.eclipse.jface.util.PropertyChangeEvent;
	import org.eclipse.swt.SWT;
	import org.eclipse.swt.custom.StyleRange;
	import org.eclipse.swt.custom.StyledText;
	import org.eclipse.swt.events.PaintEvent;
	import org.eclipse.swt.events.PaintListener;
	import org.eclipse.swt.graphics.Color;
	import org.eclipse.swt.graphics.Cursor;
	import org.eclipse.swt.graphics.GC;
	import org.eclipse.swt.graphics.Point;
	import org.eclipse.swt.graphics.RGB;
	import org.eclipse.swt.graphics.Rectangle;
	import org.eclipse.swt.widgets.Display;


	/**
	* The is almost an exact copy of DefaultHyperlinkPresenter. However this
	* hyperlink presenter works with the StructuredTextEditor's Highlighter
	* instead of TextPresentation.
	*
	* The main difference is <code>text.redrawRange(offset, length, true);</code>
	* is called instead of passing false for clearBackground. Also all mention of
	* TextPresentation was removed since it does not really apply.
	*
	* @see org.eclipse.jface.text.hyperlink.DefaultHyperlinkPresenter
	*/
	public class HighlighterHyperlinkPresenter implements IHyperlinkPresenter, PaintListener, ITextInputListener, IDocumentListener, IPropertyChangeListener {

	/**
	* A named preference that holds the color used for hyperlinks.
	* <p>
	* Value is of type <code>String</code>. A RGB color value encoded as a
	* string using class <code>PreferenceConverter</code>
	* </p>
	*
	* @see org.eclipse.jface.resource.StringConverter
	* @see org.eclipse.jface.preference.PreferenceConverter
	*/
	public final static String HYPERLINK_COLOR = "hyperlinkColor"; //$NON-NLS-1$


	/** The text viewer. */
	private ITextViewer fTextViewer;
	/** The hand cursor. */
	private Cursor fCursor;
	/** The link color. */
	private Color fColor;
	/** Tells whether to dispose the color on uninstall. */
	private boolean fDisposeColor;
	/** The currently active region. */
	private IRegion fActiveRegion;
	/** The currently active style range as position. */
	private Position fRememberedPosition;
	/** The optional preference store */
	private IPreferenceStore fPreferenceStore;


	/**
	* Creates a new default hyperlink presenter which uses
	* {@link #HYPERLINK_COLOR}to read the color from the given preference
	* store.
	*
	* @param store
	* the preference store
	*/
	public HighlighterHyperlinkPresenter(IPreferenceStore store) {
	fPreferenceStore = store;
	fDisposeColor = true;
	}

	/**
	* Creates a new default hyperlink presenter.
	*
	* @param color
	* the hyperlink color, to be disposed by the caller
	*/
	public HighlighterHyperlinkPresenter(Color color) {
	fDisposeColor = false;
	fColor = color;
	}

	public boolean canShowMultipleHyperlinks() {
	return false;
	}

	public void showHyperlinks(IHyperlink[] hyperlinks) {
	Assert.isLegal(hyperlinks != null && hyperlinks.length == 1);
	highlightRegion(hyperlinks[0].getHyperlinkRegion());
	activateCursor();
	}

	public void hideHyperlinks() {
	repairRepresentation();
	fRememberedPosition = null;
	}

	public void install(ITextViewer textViewer) {
	Assert.isNotNull(textViewer);
	fTextViewer = textViewer;
	fTextViewer.addTextInputListener(this);

	StyledText text = fTextViewer.getTextWidget();
	if (text != null && !text.isDisposed()) {
	text.addPaintListener(this);
	if (fPreferenceStore != null)
	fColor = createColor(fPreferenceStore, HYPERLINK_COLOR, text.getDisplay());
	}

	if (fPreferenceStore != null)
	fPreferenceStore.addPropertyChangeListener(this);
	}

	public void uninstall() {
	fTextViewer.removeTextInputListener(this);

	if (fColor != null) {
	if (fDisposeColor)
	fColor.dispose();
	fColor = null;
	}

	if (fCursor != null) {
	fCursor.dispose();
	fCursor = null;
	}

	StyledText text = fTextViewer.getTextWidget();
	if (text != null && !text.isDisposed())
	text.removePaintListener(this);

	fTextViewer = null;

	if (fPreferenceStore != null)
	fPreferenceStore.removePropertyChangeListener(this);
	}

	public void setColor(Color color) {
	Assert.isNotNull(fTextViewer);
	fColor = color;
	}

	private void highlightRegion(IRegion region) {

	if (region.equals(fActiveRegion))
	return;

	repairRepresentation();

	StyledText text = fTextViewer.getTextWidget();
	if (text == null \|\| text.isDisposed())
	return;


	// Underline
	int offset = 0;
	int length = 0;
	if (fTextViewer instanceof ITextViewerExtension5) {
	ITextViewerExtension5 extension = (ITextViewerExtension5) fTextViewer;
	IRegion widgetRange = extension.modelRange2WidgetRange(region);
	if (widgetRange == null)
	return;

	offset = widgetRange.getOffset();
	length = widgetRange.getLength();

	}
	else {
	offset = region.getOffset() - fTextViewer.getVisibleRegion().getOffset();
	length = region.getLength();
	}

	// needs to clean background due to StructuredTextEditor's highlighter
	text.redrawRange(offset, length, true);

	// Invalidate region ==> apply text presentation
	fActiveRegion = region;

	if (fTextViewer instanceof ITextViewerExtension2)
	((ITextViewerExtension2) fTextViewer).invalidateTextPresentation(region.getOffset(), region.getLength());
	else
	fTextViewer.invalidateTextPresentation();
	}

	private void activateCursor() {
	StyledText text = fTextViewer.getTextWidget();
	if (text == null \|\| text.isDisposed())
	return;
	Display display = text.getDisplay();
	if (fCursor == null)
	fCursor = new Cursor(display, SWT.CURSOR_HAND);
	text.setCursor(fCursor);
	}

	private void resetCursor() {
	StyledText text = fTextViewer.getTextWidget();
	if (text != null && !text.isDisposed())
	text.setCursor(null);

	if (fCursor != null) {
	fCursor.dispose();
	fCursor = null;
	}
	}

	private void repairRepresentation() {

	if (fActiveRegion == null)
	return;

	int offset = fActiveRegion.getOffset();
	int length = fActiveRegion.getLength();
	fActiveRegion = null;

	resetCursor();

	// Invalidate ==> remove applied text presentation
	if (fTextViewer instanceof ITextViewerExtension2)
	((ITextViewerExtension2) fTextViewer).invalidateTextPresentation(offset, length);
	else
	fTextViewer.invalidateTextPresentation();

	// Remove underline
	if (fTextViewer instanceof ITextViewerExtension5) {
	ITextViewerExtension5 extension = (ITextViewerExtension5) fTextViewer;
	offset = extension.modelOffset2WidgetOffset(offset);
	}
	else {
	offset -= fTextViewer.getVisibleRegion().getOffset();
	}
	try {
	StyledText text = fTextViewer.getTextWidget();

	// needs to clean background due to StructuredTextEditor's
	// highlighter
	text.redrawRange(offset, length, true);

	}
	catch (IllegalArgumentException x) {
	// ignore - do not log
	}
	}

	/*
	* @see PaintListener#paintControl(PaintEvent)
	*/
	public void paintControl(PaintEvent event) {
	if (fActiveRegion == null)
	return;

	StyledText text = fTextViewer.getTextWidget();
	if (text == null \|\| text.isDisposed())
	return;

	int offset = 0;
	int length = 0;

	if (fTextViewer instanceof ITextViewerExtension5) {

	ITextViewerExtension5 extension = (ITextViewerExtension5) fTextViewer;
	IRegion widgetRange = extension.modelRange2WidgetRange(fActiveRegion);
	if (widgetRange == null)
	return;

	offset = widgetRange.getOffset();
	length = widgetRange.getLength();

	}
	else {

	IRegion region = fTextViewer.getVisibleRegion();
	if (!includes(region, fActiveRegion))
	return;

	offset = fActiveRegion.getOffset() - region.getOffset();
	length = fActiveRegion.getLength();
	}

	// support for BIDI
	Point minLocation = getMinimumLocation(text, offset, length);
	Point maxLocation = getMaximumLocation(text, offset, length);

	int x1 = minLocation.x;
	int x2 = maxLocation.x - 1;
	int y = minLocation.y + text.getLineHeight() - 1;

	GC gc = event.gc;
	if (fColor != null && !fColor.isDisposed())
	gc.setForeground(fColor);
	else if (fColor == null && !(offset < 0 && offset >= text.getCharCount())) {
	StyleRange style = text.getStyleRangeAtOffset(offset);
	if (style != null)
	gc.setForeground(style.foreground);
	}
	gc.drawLine(x1, y, x2, y);
	}

	private Point getMinimumLocation(StyledText text, int offset, int length) {
	int max = text.getCharCount();
	Rectangle bounds = text.getBounds();
	Point minLocation = new Point(bounds.width, bounds.height);
	for (int i = 0; i <= length; i++) {
	int k = offset + i;
	if (k < 0 \|\| k > max)
	break;

	Point location = text.getLocationAtOffset(k);
	if (location.x < minLocation.x)
	minLocation.x = location.x;
	if (location.y < minLocation.y)
	minLocation.y = location.y;
	}

	return minLocation;
	}

	private Point getMaximumLocation(StyledText text, int offset, int length) {
	Point maxLocation = new Point(0, 0);

	for (int i = 0; i <= length; i++) {
	int k = offset + i;
	if (k < 0 \|\| k > text.getCharCount())
	break;

	Point location = text.getLocationAtOffset(k);
	if (location.x > maxLocation.x)
	maxLocation.x = location.x;
	if (location.y > maxLocation.y)
	maxLocation.y = location.y;
	}

	return maxLocation;
	}

	private boolean includes(IRegion region, IRegion position) {
	return position.getOffset() >= region.getOffset() && position.getOffset() + position.getLength() <= region.getOffset() + region.getLength();
	}

	/*
	* @see org.eclipse.jface.text.IDocumentListener#documentAboutToBeChanged(org.eclipse.jface.text.DocumentEvent)
	*/
	public void documentAboutToBeChanged(DocumentEvent event) {
	if (fActiveRegion != null) {
	fRememberedPosition = new Position(fActiveRegion.getOffset(), fActiveRegion.getLength());
	try {
	event.getDocument().addPosition(fRememberedPosition);
	}
	catch (BadLocationException x) {
	fRememberedPosition = null;
	}
	}
	}

	/*
	* @see org.eclipse.jface.text.IDocumentListener#documentChanged(org.eclipse.jface.text.DocumentEvent)
	*/
	public void documentChanged(DocumentEvent event) {
	if (fRememberedPosition != null) {
	if (!fRememberedPosition.isDeleted()) {

	event.getDocument().removePosition(fRememberedPosition);
	fActiveRegion = new Region(fRememberedPosition.getOffset(), fRememberedPosition.getLength());
	fRememberedPosition = null;

	StyledText widget = fTextViewer.getTextWidget();
	if (widget != null && !widget.isDisposed()) {
	widget.getDisplay().asyncExec(new Runnable() {
	public void run() {
	hideHyperlinks();
	}
	});
	}

	}
	else {
	fActiveRegion = null;
	fRememberedPosition = null;
	hideHyperlinks();
	}
	}
	}

	/*
	* @see org.eclipse.jface.text.ITextInputListener#inputDocumentAboutToBeChanged(org.eclipse.jface.text.IDocument,
	* org.eclipse.jface.text.IDocument)
	*/
	public void inputDocumentAboutToBeChanged(IDocument oldInput, IDocument newInput) {
	if (oldInput == null)
	return;
	hideHyperlinks();
	oldInput.removeDocumentListener(this);
	}

	/*
	* @see org.eclipse.jface.text.ITextInputListener#inputDocumentChanged(org.eclipse.jface.text.IDocument,
	* org.eclipse.jface.text.IDocument)
	*/
	public void inputDocumentChanged(IDocument oldInput, IDocument newInput) {
	if (newInput == null)
	return;
	newInput.addDocumentListener(this);
	}

	/**
	* Creates a color from the information stored in the given preference
	* store.
	*
	* @param store
	* the preference store
	* @param key
	* the key
	* @param display
	* the display
	* @return the color or <code>null</code> if there is no such
	* information available
	*/
	private Color createColor(IPreferenceStore store, String key, Display display) {

	RGB rgb = null;

	if (store.contains(key)) {

	if (store.isDefault(key))
	rgb = PreferenceConverter.getDefaultColor(store, key);
	else
	rgb = PreferenceConverter.getColor(store, key);

	if (rgb != null)
	return new Color(display, rgb);
	}

	return null;
	}

	/*
	* @see org.eclipse.jface.util.IPropertyChangeListener#propertyChange(org.eclipse.jface.util.PropertyChangeEvent)
	*/
	public void propertyChange(PropertyChangeEvent event) {
	if (!HYPERLINK_COLOR.equals(event.getProperty()))
	return;

	if (fDisposeColor && fColor != null && !fColor.isDisposed())
	fColor.dispose();
	fColor = null;

	StyledText textWidget = fTextViewer.getTextWidget();
	if (textWidget != null && !textWidget.isDisposed())
	fColor = createColor(fPreferenceStore, HYPERLINK_COLOR, textWidget.getDisplay());
	}
	}