org.eclipse.jface.text/src/org/eclipse/jface/text/source/ChangeRulerColumn.java - platform/eclipse.platform.text - Git at Google

 /*******************************************************************************
  * Copyright (c) 2000, 2016 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  *     IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.jface.text.source;

 import org.eclipse.swt.SWT;
 import org.eclipse.swt.custom.StyledText;
 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.events.PaintListener;
 import org.eclipse.swt.graphics.Color;
 import org.eclipse.swt.graphics.Font;
 import org.eclipse.swt.graphics.GC;
 import org.eclipse.swt.graphics.Image;
 import org.eclipse.swt.graphics.Point;
 import org.eclipse.swt.graphics.Rectangle;
 import org.eclipse.swt.widgets.Canvas;
 import org.eclipse.swt.widgets.Composite;
 import org.eclipse.swt.widgets.Control;
 import org.eclipse.swt.widgets.Display;

 import org.eclipse.core.runtime.Assert;

 import org.eclipse.jface.internal.text.revisions.RevisionPainter;
 import org.eclipse.jface.internal.text.source.DiffPainter;
 import org.eclipse.jface.viewers.ISelectionProvider;

 import org.eclipse.jface.text.BadLocationException;
 import org.eclipse.jface.text.IDocument;
 import org.eclipse.jface.text.IRegion;
 import org.eclipse.jface.text.ITextListener;
 import org.eclipse.jface.text.ITextViewer;
 import org.eclipse.jface.text.ITextViewerExtension5;
 import org.eclipse.jface.text.IViewportListener;
 import org.eclipse.jface.text.JFaceTextUtil;
 import org.eclipse.jface.text.TextEvent;
 import org.eclipse.jface.text.revisions.IRevisionRulerColumn;
 import org.eclipse.jface.text.revisions.RevisionInformation;

 /**
  * A vertical ruler column displaying line numbers and serving as a UI for quick diff.
  * Clients instantiate and configure object of this class.
  *
  * @since 3.0
  */
 public final class ChangeRulerColumn implements IChangeRulerColumn, IRevisionRulerColumn {
 	/**
 	 * Handles all the mouse interaction in this line number ruler column.
 	 */
 	private class MouseHandler implements MouseListener, MouseMoveListener {

 		@Override
 		public void mouseUp(MouseEvent event) {
 		}

 		@Override
 		public void mouseDown(MouseEvent event) {
 			fParentRuler.setLocationOfLastMouseButtonActivity(event.x, event.y);
 		}

 		@Override
 		public void mouseDoubleClick(MouseEvent event) {
 			fParentRuler.setLocationOfLastMouseButtonActivity(event.x, event.y);
 		}

 		@Override
 		public void mouseMove(MouseEvent event) {
 			fParentRuler.setLocationOfLastMouseButtonActivity(event.x, event.y);
 		}
 	}

 	/**
 	 * Internal listener class.
 	 */
 	private class InternalListener implements IViewportListener, ITextListener {

 		@Override
 		public void viewportChanged(int verticalPosition) {
 			if (verticalPosition != fScrollPos)
 				redraw();
 		}

 		@Override
 		public void textChanged(TextEvent event) {

 			if (!event.getViewerRedrawState())
 				return;

 			if (fSensitiveToTextChanges || event.getDocumentEvent() == null)
 				postRedraw();

 		}
 	}

 	/**
 	 * The view(port) listener.
 	 */
 	private final InternalListener fInternalListener= new InternalListener();
 	/**
 	 * The mouse handler.
 	 * @since 3.2
 	 */
 	private final MouseHandler fMouseHandler= new MouseHandler();
 	/**
 	 * The revision painter.
 	 * @since 3.2
 	 */
 	private final RevisionPainter fRevisionPainter;
 	/**
 	 * The diff info painter.
 	 * @since 3.2
 	 */
 	private final DiffPainter fDiffPainter;

 	/** This column's parent ruler */
 	private CompositeRuler fParentRuler;
 	/** Cached text viewer */
 	private ITextViewer fCachedTextViewer;
 	/** Cached text widget */
 	private StyledText fCachedTextWidget;
 	/** The columns canvas */
 	private Canvas fCanvas;
 	/** The background color */
 	private Color fBackground;
 	/** The ruler's annotation model. */
 	private IAnnotationModel fAnnotationModel;
 	/** The width of the change ruler column. */
 	private final int fWidth= 5;

 	/** Cache for the actual scroll position in pixels */
 	private int fScrollPos;
 	/** The buffer for double buffering */
 	private Image fBuffer;
 	/** Indicates whether this column reacts on text change events */
 	private boolean fSensitiveToTextChanges= false;

 	/**
 	 * Creates a new ruler column.
 	 *
 	 * @deprecated since 3.2 use {@link #ChangeRulerColumn(ISharedTextColors)} instead
 	 */
 	@Deprecated
 	public ChangeRulerColumn() {
 		fRevisionPainter= null;
 		fDiffPainter= new DiffPainter(this, null);
 	}

 	/**
 	 * Creates a new revision ruler column.
 	 *
 	 * @param sharedColors the colors to look up RGBs
 	 * @since 3.2
 	 */
 	public ChangeRulerColumn(ISharedTextColors sharedColors) {
 		Assert.isNotNull(sharedColors);
 		fRevisionPainter= new RevisionPainter(this, sharedColors);
 		fDiffPainter= new DiffPainter(this, null); // no shading
 	}

 	/**
 	 * Returns the System background color for list widgets.
 	 *
 	 * @return the System background color for list widgets
 	 */
 	private Color getBackground() {
 		if (fBackground == null)
 			return fCachedTextWidget.getDisplay().getSystemColor(SWT.COLOR_LIST_BACKGROUND);
 		return fBackground;
 	}

 	@Override
 	public Control createControl(CompositeRuler parentRuler, Composite parentControl) {

 		fParentRuler= parentRuler;
 		fCachedTextViewer= parentRuler.getTextViewer();
 		fCachedTextWidget= fCachedTextViewer.getTextWidget();

 		fCanvas= new Canvas(parentControl, SWT.NONE);
 		fCanvas.setBackground(getBackground());

 		fCanvas.addPaintListener(new PaintListener() {
 			@Override
 			public void paintControl(PaintEvent event) {
 				if (fCachedTextViewer != null)
 					doubleBufferPaint(event.gc);
 			}
 		});

 		fCanvas.addDisposeListener(new DisposeListener() {
 			@Override
 			public void widgetDisposed(DisposeEvent e) {
 				handleDispose();
 				fCachedTextViewer= null;
 				fCachedTextWidget= null;
 			}
 		});

 		fCanvas.addMouseListener(fMouseHandler);
 		fCanvas.addMouseMoveListener(fMouseHandler);

 		if (fCachedTextViewer != null) {

 			fCachedTextViewer.addViewportListener(fInternalListener);
 			fCachedTextViewer.addTextListener(fInternalListener);
 		}

 		fRevisionPainter.setParentRuler(parentRuler);
 		fDiffPainter.setParentRuler(parentRuler);

 		return fCanvas;
 	}

 	/**
 	 * Disposes the column's resources.
 	 */
 	protected void handleDispose() {

 		if (fCachedTextViewer != null) {
 			fCachedTextViewer.removeViewportListener(fInternalListener);
 			fCachedTextViewer.removeTextListener(fInternalListener);
 		}

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

 	/**
 	 * Double buffer drawing.
 	 *
 	 * @param dest the GC to draw into
 	 */
 	private void doubleBufferPaint(GC dest) {

 		Point size= fCanvas.getSize();

 		if (size.x <= 0 || size.y <= 0)
 			return;

 		if (fBuffer != null) {
 			Rectangle r= fBuffer.getBounds();
 			if (r.width != size.x || r.height != size.y) {
 				fBuffer.dispose();
 				fBuffer= null;
 			}
 		}
 		if (fBuffer == null)
 			fBuffer= new Image(fCanvas.getDisplay(), size.x, size.y);

 		GC gc= new GC(fBuffer);
 		gc.setFont(fCanvas.getFont());

 		try {
 			gc.setBackground(getBackground());
 			gc.fillRectangle(0, 0, size.x, size.y);

 			doPaint(gc);
 		} finally {
 			gc.dispose();
 		}

 		dest.drawImage(fBuffer, 0, 0);
 	}

 	/**
 	 * Returns the view port height in lines.
 	 *
 	 * @return the view port height in lines
 	 * @deprecated as of 3.2 the number of lines in the viewport cannot be computed because
 	 *             StyledText supports variable line heights
 	 */
 	@Deprecated
 	protected int getVisibleLinesInViewport() {
 		// Hack to reduce amount of copied code.
 		return LineNumberRulerColumn.getVisibleLinesInViewport(fCachedTextWidget);
 	}

 	/**
 	 * Returns <code>true</code> if the viewport displays the entire viewer contents, i.e. the
 	 * viewer is not vertically scrollable.
 	 *
 	 * @return <code>true</code> if the viewport displays the entire contents, <code>false</code> otherwise
 	 * @since 3.2
 	 */
 	protected final boolean isViewerCompletelyShown() {
 		return JFaceTextUtil.isShowingEntireContents(fCachedTextWidget);
 	}

 	/**
 	 * Draws the ruler column.
 	 *
 	 * @param gc the GC to draw into
 	 */
 	private void doPaint(GC gc) {
 		ILineRange visibleModelLines= computeVisibleModelLines();
 		if (visibleModelLines == null)
 			return;

 		fSensitiveToTextChanges= isViewerCompletelyShown();

 		fScrollPos= fCachedTextWidget.getTopPixel();

 		fRevisionPainter.paint(gc, visibleModelLines);
 		if (!fRevisionPainter.hasInformation()) // don't paint quick diff colors if revisions are painted
 			fDiffPainter.paint(gc, visibleModelLines);
 	}

 	@Override
 	public void redraw() {

 		if (fCachedTextViewer != null && fCanvas != null && !fCanvas.isDisposed()) {
 			if (VerticalRuler.AVOID_NEW_GC) {
 				fCanvas.redraw();
 			} else {
 				GC gc= new GC(fCanvas);
 				doubleBufferPaint(gc);
 				gc.dispose();
 			}
 		}
 	}

 	@Override
 	public void setFont(Font font) {
 	}

 	/**
 	 * Returns the parent (composite) ruler of this ruler column.
 	 *
 	 * @return the parent ruler
 	 * @since 3.0
 	 */
 	private CompositeRuler getParentRuler() {
 		return fParentRuler;
 	}

 	@Override
 	public int getLineOfLastMouseButtonActivity() {
 		return getParentRuler().getLineOfLastMouseButtonActivity();
 	}

 	@Override
 	public int toDocumentLineNumber(int y_coordinate) {
 		return getParentRuler().toDocumentLineNumber(y_coordinate);
 	}

 	@Override
 	public IAnnotationHover getHover() {
 		int activeLine= getParentRuler().getLineOfLastMouseButtonActivity();
 		if (fRevisionPainter.hasHover(activeLine))
 			return fRevisionPainter.getHover();
 		if (fDiffPainter.hasHover(activeLine))
 			return fDiffPainter.getHover();
 		return null;
 	}

 	@Override
 	public void setHover(IAnnotationHover hover) {
 		fRevisionPainter.setHover(hover);
 		fDiffPainter.setHover(hover);
 	}

 	@Override
 	public void setModel(IAnnotationModel model) {
 		setAnnotationModel(model);
 		fRevisionPainter.setModel(model);
 		fDiffPainter.setModel(model);
 	}

 	private void setAnnotationModel(IAnnotationModel model) {
 		if (fAnnotationModel != model)
 			fAnnotationModel= model;
 	}

 	@Override
 	public void setBackground(Color background) {
 		fBackground= background;
 		if (fCanvas != null && !fCanvas.isDisposed())
 			fCanvas.setBackground(getBackground());
 		fRevisionPainter.setBackground(background);
 		fDiffPainter.setBackground(background);
 	}

 	@Override
 	public void setAddedColor(Color addedColor) {
 		fDiffPainter.setAddedColor(addedColor);
 	}

 	@Override
 	public void setChangedColor(Color changedColor) {
 		fDiffPainter.setChangedColor(changedColor);
 	}

 	@Override
 	public void setDeletedColor(Color deletedColor) {
 		fDiffPainter.setDeletedColor(deletedColor);
 	}

 	@Override
 	public IAnnotationModel getModel() {
 		return fAnnotationModel;
 	}

 	@Override
 	public Control getControl() {
 		return fCanvas;
 	}

 	@Override
 	public int getWidth() {
 		return fWidth;
 	}

 	/**
 	 * Triggers a redraw in the display thread.
 	 */
 	protected final void postRedraw() {
 		if (fCanvas != null && !fCanvas.isDisposed()) {
 			Display d= fCanvas.getDisplay();
 			if (d != null) {
 				d.asyncExec(new Runnable() {
 					@Override
 					public void run() {
 						redraw();
 					}
 				});
 			}
 		}
 	}

 	@Override
 	public void addVerticalRulerListener(IVerticalRulerListener listener) {
 		throw new UnsupportedOperationException();
 	}

 	@Override
 	public void removeVerticalRulerListener(IVerticalRulerListener listener) {
 		throw new UnsupportedOperationException();
 	}

 	/**
 	 * Computes the document based line range visible in the text widget.
 	 *
 	 * @return the document based line range visible in the text widget
 	 * @since 3.2
 	 */
 	private final ILineRange computeVisibleModelLines() {
 		IDocument doc= fCachedTextViewer.getDocument();
 		if (doc == null)
 			return null;

 		int topLine;
 		IRegion coverage;

 		if (fCachedTextViewer instanceof ITextViewerExtension5) {
 			ITextViewerExtension5 extension= (ITextViewerExtension5) fCachedTextViewer;

 			// ITextViewer.getTopIndex returns the fully visible line, but we want the partially
 			// visible one
 			int widgetTopLine= JFaceTextUtil.getPartialTopIndex(fCachedTextWidget);
 			topLine= extension.widgetLine2ModelLine(widgetTopLine);

 			coverage= extension.getModelCoverage();

 		} else {
 			topLine= JFaceTextUtil.getPartialTopIndex(fCachedTextViewer);
 			coverage= fCachedTextViewer.getVisibleRegion();
 		}

 		int bottomLine= fCachedTextViewer.getBottomIndex();
 		if (bottomLine != -1)
 			++ bottomLine;

 		// clip by coverage window
 		try {
 			int firstLine= doc.getLineOfOffset(coverage.getOffset());
 			if (firstLine > topLine)
 				topLine= firstLine;

 			int lastLine= doc.getLineOfOffset(coverage.getOffset() + coverage.getLength());
 			if (lastLine < bottomLine || bottomLine == -1)
 				bottomLine= lastLine;
 		} catch (BadLocationException x) {
 			return null;
 		}

 		ILineRange visibleModelLines= new LineRange(topLine, bottomLine - topLine + 1);
 		return visibleModelLines;
 	}

 	@Override
 	public void setRevisionInformation(RevisionInformation info) {
 		fRevisionPainter.setRevisionInformation(info);
 		fRevisionPainter.setBackground(getBackground());
 	}

 	/**
      * Returns the revision selection provider.
      *
      * @return the revision selection provider
      * @since 3.2
      */
     public ISelectionProvider getRevisionSelectionProvider() {
     	return fRevisionPainter.getRevisionSelectionProvider();
     }
 }
	/*******************************************************************************
	* Copyright (c) 2000, 2016 IBM Corporation and others.
	* All rights reserved. This program and the accompanying materials
	* are made available under the terms of the Eclipse Public License v1.0
	* which accompanies this distribution, and is available at
	* http://www.eclipse.org/legal/epl-v10.html
	*
	* Contributors:
	* IBM Corporation - initial API and implementation
	*******************************************************************************/
	package org.eclipse.jface.text.source;

	import org.eclipse.swt.SWT;
	import org.eclipse.swt.custom.StyledText;
	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.events.PaintListener;
	import org.eclipse.swt.graphics.Color;
	import org.eclipse.swt.graphics.Font;
	import org.eclipse.swt.graphics.GC;
	import org.eclipse.swt.graphics.Image;
	import org.eclipse.swt.graphics.Point;
	import org.eclipse.swt.graphics.Rectangle;
	import org.eclipse.swt.widgets.Canvas;
	import org.eclipse.swt.widgets.Composite;
	import org.eclipse.swt.widgets.Control;
	import org.eclipse.swt.widgets.Display;

	import org.eclipse.core.runtime.Assert;

	import org.eclipse.jface.internal.text.revisions.RevisionPainter;
	import org.eclipse.jface.internal.text.source.DiffPainter;
	import org.eclipse.jface.viewers.ISelectionProvider;

	import org.eclipse.jface.text.BadLocationException;
	import org.eclipse.jface.text.IDocument;
	import org.eclipse.jface.text.IRegion;
	import org.eclipse.jface.text.ITextListener;
	import org.eclipse.jface.text.ITextViewer;
	import org.eclipse.jface.text.ITextViewerExtension5;
	import org.eclipse.jface.text.IViewportListener;
	import org.eclipse.jface.text.JFaceTextUtil;
	import org.eclipse.jface.text.TextEvent;
	import org.eclipse.jface.text.revisions.IRevisionRulerColumn;
	import org.eclipse.jface.text.revisions.RevisionInformation;

	/**
	* A vertical ruler column displaying line numbers and serving as a UI for quick diff.
	* Clients instantiate and configure object of this class.
	*
	* @since 3.0
	*/
	public final class ChangeRulerColumn implements IChangeRulerColumn, IRevisionRulerColumn {
	/**
	* Handles all the mouse interaction in this line number ruler column.
	*/
	private class MouseHandler implements MouseListener, MouseMoveListener {

	@Override
	public void mouseUp(MouseEvent event) {
	}

	@Override
	public void mouseDown(MouseEvent event) {
	fParentRuler.setLocationOfLastMouseButtonActivity(event.x, event.y);
	}

	@Override
	public void mouseDoubleClick(MouseEvent event) {
	fParentRuler.setLocationOfLastMouseButtonActivity(event.x, event.y);
	}

	@Override
	public void mouseMove(MouseEvent event) {
	fParentRuler.setLocationOfLastMouseButtonActivity(event.x, event.y);
	}
	}

	/**
	* Internal listener class.
	*/
	private class InternalListener implements IViewportListener, ITextListener {

	@Override
	public void viewportChanged(int verticalPosition) {
	if (verticalPosition != fScrollPos)
	redraw();
	}

	@Override
	public void textChanged(TextEvent event) {

	if (!event.getViewerRedrawState())
	return;

	if (fSensitiveToTextChanges \|\| event.getDocumentEvent() == null)
	postRedraw();

	}
	}

	/**
	* The view(port) listener.
	*/
	private final InternalListener fInternalListener= new InternalListener();
	/**
	* The mouse handler.
	* @since 3.2
	*/
	private final MouseHandler fMouseHandler= new MouseHandler();
	/**
	* The revision painter.
	* @since 3.2
	*/
	private final RevisionPainter fRevisionPainter;
	/**
	* The diff info painter.
	* @since 3.2
	*/
	private final DiffPainter fDiffPainter;

	/** This column's parent ruler */
	private CompositeRuler fParentRuler;
	/** Cached text viewer */
	private ITextViewer fCachedTextViewer;
	/** Cached text widget */
	private StyledText fCachedTextWidget;
	/** The columns canvas */
	private Canvas fCanvas;
	/** The background color */
	private Color fBackground;
	/** The ruler's annotation model. */
	private IAnnotationModel fAnnotationModel;
	/** The width of the change ruler column. */
	private final int fWidth= 5;

	/** Cache for the actual scroll position in pixels */
	private int fScrollPos;
	/** The buffer for double buffering */
	private Image fBuffer;
	/** Indicates whether this column reacts on text change events */
	private boolean fSensitiveToTextChanges= false;

	/**
	* Creates a new ruler column.
	*
	* @deprecated since 3.2 use {@link #ChangeRulerColumn(ISharedTextColors)} instead
	*/
	@Deprecated
	public ChangeRulerColumn() {
	fRevisionPainter= null;
	fDiffPainter= new DiffPainter(this, null);
	}

	/**
	* Creates a new revision ruler column.
	*
	* @param sharedColors the colors to look up RGBs
	* @since 3.2
	*/
	public ChangeRulerColumn(ISharedTextColors sharedColors) {
	Assert.isNotNull(sharedColors);
	fRevisionPainter= new RevisionPainter(this, sharedColors);
	fDiffPainter= new DiffPainter(this, null); // no shading
	}

	/**
	* Returns the System background color for list widgets.
	*
	* @return the System background color for list widgets
	*/
	private Color getBackground() {
	if (fBackground == null)
	return fCachedTextWidget.getDisplay().getSystemColor(SWT.COLOR_LIST_BACKGROUND);
	return fBackground;
	}

	@Override
	public Control createControl(CompositeRuler parentRuler, Composite parentControl) {

	fParentRuler= parentRuler;
	fCachedTextViewer= parentRuler.getTextViewer();
	fCachedTextWidget= fCachedTextViewer.getTextWidget();

	fCanvas= new Canvas(parentControl, SWT.NONE);
	fCanvas.setBackground(getBackground());

	fCanvas.addPaintListener(new PaintListener() {
	@Override
	public void paintControl(PaintEvent event) {
	if (fCachedTextViewer != null)
	doubleBufferPaint(event.gc);
	}
	});

	fCanvas.addDisposeListener(new DisposeListener() {
	@Override
	public void widgetDisposed(DisposeEvent e) {
	handleDispose();
	fCachedTextViewer= null;
	fCachedTextWidget= null;
	}
	});

	fCanvas.addMouseListener(fMouseHandler);
	fCanvas.addMouseMoveListener(fMouseHandler);

	if (fCachedTextViewer != null) {

	fCachedTextViewer.addViewportListener(fInternalListener);
	fCachedTextViewer.addTextListener(fInternalListener);
	}

	fRevisionPainter.setParentRuler(parentRuler);
	fDiffPainter.setParentRuler(parentRuler);

	return fCanvas;
	}

	/**
	* Disposes the column's resources.
	*/
	protected void handleDispose() {

	if (fCachedTextViewer != null) {
	fCachedTextViewer.removeViewportListener(fInternalListener);
	fCachedTextViewer.removeTextListener(fInternalListener);
	}

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

	/**
	* Double buffer drawing.
	*
	* @param dest the GC to draw into
	*/
	private void doubleBufferPaint(GC dest) {

	Point size= fCanvas.getSize();

	if (size.x <= 0 \|\| size.y <= 0)
	return;

	if (fBuffer != null) {
	Rectangle r= fBuffer.getBounds();
	if (r.width != size.x \|\| r.height != size.y) {
	fBuffer.dispose();
	fBuffer= null;
	}
	}
	if (fBuffer == null)
	fBuffer= new Image(fCanvas.getDisplay(), size.x, size.y);

	GC gc= new GC(fBuffer);
	gc.setFont(fCanvas.getFont());

	try {
	gc.setBackground(getBackground());
	gc.fillRectangle(0, 0, size.x, size.y);

	doPaint(gc);
	} finally {
	gc.dispose();
	}

	dest.drawImage(fBuffer, 0, 0);
	}

	/**
	* Returns the view port height in lines.
	*
	* @return the view port height in lines
	* @deprecated as of 3.2 the number of lines in the viewport cannot be computed because
	* StyledText supports variable line heights
	*/
	@Deprecated
	protected int getVisibleLinesInViewport() {
	// Hack to reduce amount of copied code.
	return LineNumberRulerColumn.getVisibleLinesInViewport(fCachedTextWidget);
	}

	/**
	* Returns <code>true</code> if the viewport displays the entire viewer contents, i.e. the
	* viewer is not vertically scrollable.
	*
	* @return <code>true</code> if the viewport displays the entire contents, <code>false</code> otherwise
	* @since 3.2
	*/
	protected final boolean isViewerCompletelyShown() {
	return JFaceTextUtil.isShowingEntireContents(fCachedTextWidget);
	}

	/**
	* Draws the ruler column.
	*
	* @param gc the GC to draw into
	*/
	private void doPaint(GC gc) {
	ILineRange visibleModelLines= computeVisibleModelLines();
	if (visibleModelLines == null)
	return;

	fSensitiveToTextChanges= isViewerCompletelyShown();

	fScrollPos= fCachedTextWidget.getTopPixel();

	fRevisionPainter.paint(gc, visibleModelLines);
	if (!fRevisionPainter.hasInformation()) // don't paint quick diff colors if revisions are painted
	fDiffPainter.paint(gc, visibleModelLines);
	}

	@Override
	public void redraw() {

	if (fCachedTextViewer != null && fCanvas != null && !fCanvas.isDisposed()) {
	if (VerticalRuler.AVOID_NEW_GC) {
	fCanvas.redraw();
	} else {
	GC gc= new GC(fCanvas);
	doubleBufferPaint(gc);
	gc.dispose();
	}
	}
	}

	@Override
	public void setFont(Font font) {
	}

	/**
	* Returns the parent (composite) ruler of this ruler column.
	*
	* @return the parent ruler
	* @since 3.0
	*/
	private CompositeRuler getParentRuler() {
	return fParentRuler;
	}

	@Override
	public int getLineOfLastMouseButtonActivity() {
	return getParentRuler().getLineOfLastMouseButtonActivity();
	}

	@Override
	public int toDocumentLineNumber(int y_coordinate) {
	return getParentRuler().toDocumentLineNumber(y_coordinate);
	}

	@Override
	public IAnnotationHover getHover() {
	int activeLine= getParentRuler().getLineOfLastMouseButtonActivity();
	if (fRevisionPainter.hasHover(activeLine))
	return fRevisionPainter.getHover();
	if (fDiffPainter.hasHover(activeLine))
	return fDiffPainter.getHover();
	return null;
	}

	@Override
	public void setHover(IAnnotationHover hover) {
	fRevisionPainter.setHover(hover);
	fDiffPainter.setHover(hover);
	}

	@Override
	public void setModel(IAnnotationModel model) {
	setAnnotationModel(model);
	fRevisionPainter.setModel(model);
	fDiffPainter.setModel(model);
	}

	private void setAnnotationModel(IAnnotationModel model) {
	if (fAnnotationModel != model)
	fAnnotationModel= model;
	}

	@Override
	public void setBackground(Color background) {
	fBackground= background;
	if (fCanvas != null && !fCanvas.isDisposed())
	fCanvas.setBackground(getBackground());
	fRevisionPainter.setBackground(background);
	fDiffPainter.setBackground(background);
	}

	@Override
	public void setAddedColor(Color addedColor) {
	fDiffPainter.setAddedColor(addedColor);
	}

	@Override
	public void setChangedColor(Color changedColor) {
	fDiffPainter.setChangedColor(changedColor);
	}

	@Override
	public void setDeletedColor(Color deletedColor) {
	fDiffPainter.setDeletedColor(deletedColor);
	}

	@Override
	public IAnnotationModel getModel() {
	return fAnnotationModel;
	}

	@Override
	public Control getControl() {
	return fCanvas;
	}

	@Override
	public int getWidth() {
	return fWidth;
	}

	/**
	* Triggers a redraw in the display thread.
	*/
	protected final void postRedraw() {
	if (fCanvas != null && !fCanvas.isDisposed()) {
	Display d= fCanvas.getDisplay();
	if (d != null) {
	d.asyncExec(new Runnable() {
	@Override
	public void run() {
	redraw();
	}
	});
	}
	}
	}

	@Override
	public void addVerticalRulerListener(IVerticalRulerListener listener) {
	throw new UnsupportedOperationException();
	}

	@Override
	public void removeVerticalRulerListener(IVerticalRulerListener listener) {
	throw new UnsupportedOperationException();
	}

	/**
	* Computes the document based line range visible in the text widget.
	*
	* @return the document based line range visible in the text widget
	* @since 3.2
	*/
	private final ILineRange computeVisibleModelLines() {
	IDocument doc= fCachedTextViewer.getDocument();
	if (doc == null)
	return null;

	int topLine;
	IRegion coverage;

	if (fCachedTextViewer instanceof ITextViewerExtension5) {
	ITextViewerExtension5 extension= (ITextViewerExtension5) fCachedTextViewer;

	// ITextViewer.getTopIndex returns the fully visible line, but we want the partially
	// visible one
	int widgetTopLine= JFaceTextUtil.getPartialTopIndex(fCachedTextWidget);
	topLine= extension.widgetLine2ModelLine(widgetTopLine);

	coverage= extension.getModelCoverage();

	} else {
	topLine= JFaceTextUtil.getPartialTopIndex(fCachedTextViewer);
	coverage= fCachedTextViewer.getVisibleRegion();
	}

	int bottomLine= fCachedTextViewer.getBottomIndex();
	if (bottomLine != -1)
	++ bottomLine;

	// clip by coverage window
	try {
	int firstLine= doc.getLineOfOffset(coverage.getOffset());
	if (firstLine > topLine)
	topLine= firstLine;

	int lastLine= doc.getLineOfOffset(coverage.getOffset() + coverage.getLength());
	if (lastLine < bottomLine \|\| bottomLine == -1)
	bottomLine= lastLine;
	} catch (BadLocationException x) {
	return null;
	}

	ILineRange visibleModelLines= new LineRange(topLine, bottomLine - topLine + 1);
	return visibleModelLines;
	}

	@Override
	public void setRevisionInformation(RevisionInformation info) {
	fRevisionPainter.setRevisionInformation(info);
	fRevisionPainter.setBackground(getBackground());
	}

	/**
	* Returns the revision selection provider.
	*
	* @return the revision selection provider
	* @since 3.2
	*/
	public ISelectionProvider getRevisionSelectionProvider() {
	return fRevisionPainter.getRevisionSelectionProvider();
	}
	}