com.google.eclipse.tm.terminal/src/org/eclipse/tm/internal/terminal/textcanvas/AbstractTextCanvasModel.java - elt - Git at Google

 /*******************************************************************************
  * Copyright (c) 2007, 2010 Wind River Systems, Inc. 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:
  * Michael Scharf (Wind River) - initial API and implementation
  * Martin Oberhuber (Wind River) - [168197] Fix Terminal for CDC-1.1/Foundation-1.1
  * Anton Leherbauer (Wind River) - [219589] Copy an entire line selection
  *******************************************************************************/
 package org.eclipse.tm.internal.terminal.textcanvas;

 import java.util.ArrayList;
 import java.util.Iterator;
 import java.util.List;

 import org.eclipse.swt.graphics.Point;
 import org.eclipse.tm.terminal.model.ITerminalTextDataReadOnly;
 import org.eclipse.tm.terminal.model.ITerminalTextDataSnapshot;

 abstract public class AbstractTextCanvasModel implements ITextCanvasModel {
 	protected List fListeners = new ArrayList();
 	private int fCursorLine;
 	private int fCursorColumn;
 	private boolean fShowCursor;
 	private long fCursorTime;
 	private boolean fCursorIsEnabled;
 	private final ITerminalTextDataSnapshot fSnapshot;
 	private int fLines;

 	private int fSelectionStartLine=-1;
 	private int fSeletionEndLine;
 	private int fSelectionStartCoumn;
 	private int fSelectionEndColumn;
 	private ITerminalTextDataSnapshot fSelectionSnapshot;
 	private String fCurrentSelection=""; //$NON-NLS-1$
 	private final Point fSelectionAnchor=new Point(0,0);
 	/**
 	 * do not update while update is running
 	 */
 	boolean fInUpdate;
 	private int fCols;

 	public AbstractTextCanvasModel(ITerminalTextDataSnapshot snapshot) {
 		fSnapshot=snapshot;
 		fLines=fSnapshot.getHeight();
 	}
 	public void addCellCanvasModelListener(ITextCanvasModelListener listener) {
 		fListeners.add(listener);
 	}

 	public void removeCellCanvasModelListener(ITextCanvasModelListener listener) {
 		fListeners.remove(listener);
 	}

 	protected void fireCellRangeChanged(int x, int y, int width, int height) {
 		for (Iterator iter = fListeners.iterator(); iter.hasNext();) {
 			ITextCanvasModelListener listener = (ITextCanvasModelListener) iter.next();
 			listener.rangeChanged(x, y, width, height);
 		}
 	}
 	protected void fireDimensionsChanged( int width,int height) {
 		for (Iterator iter = fListeners.iterator(); iter.hasNext();) {
 			ITextCanvasModelListener listener = (ITextCanvasModelListener) iter.next();
 			listener.dimensionsChanged(width,height);
 		}

 	}
 	protected void fireTerminalDataChanged() {
 		for (Iterator iter = fListeners.iterator(); iter.hasNext();) {
 			ITextCanvasModelListener listener = (ITextCanvasModelListener) iter.next();
 			listener.terminalDataChanged();
 		}

 	}

 	public ITerminalTextDataReadOnly getTerminalText() {
 		return fSnapshot;
 	}
 	protected ITerminalTextDataSnapshot getSnapshot() {
 		return fSnapshot;
 	}
 	protected void updateSnapshot() {
 		if(!fInUpdate && fSnapshot.isOutOfDate()) {
 			fInUpdate=true;
 			try {
 				fSnapshot.updateSnapshot(false);
 				if(fSnapshot.hasTerminalChanged())
 					fireTerminalDataChanged();
 				// TODO why does hasDimensionsChanged not work??????
 				//			if(fSnapshot.hasDimensionsChanged())
 				//				fireDimensionsChanged();
 				if(fLines!=fSnapshot.getHeight() || fCols!=fSnapshot.getWidth()) {
 					fireDimensionsChanged(fSnapshot.getWidth(),fSnapshot.getHeight());
 					fLines=fSnapshot.getHeight();
 					fCols=fSnapshot.getWidth();
 				}
 				int y=fSnapshot.getFirstChangedLine();
 				// has any line changed?
 				if(y<Integer.MAX_VALUE) {
 					int height=fSnapshot.getLastChangedLine()-y+1;
 					fireCellRangeChanged(0, y, fSnapshot.getWidth(), height);
 				}

 			} finally {
 				fInUpdate=false;
 			}
 		}
 	}
 	/**
 	 * must be called from the UI thread
 	 */
 	public void update() {
 		// do the poll....
 		updateSnapshot();
 		updateSelection();
 		updateCursor();
 	}


 	public int getCursorColumn() {
 		return fCursorColumn;
 	}

 	public int getCursorLine() {
 		return fCursorLine;
 	}

 	public boolean isCursorOn() {
 		return fShowCursor && fCursorIsEnabled;
 	}
 	/**
 	 * should be called regularly to draw an update of the
 	 * blinking cursor
 	 */
 	protected void updateCursor() {
 		if(!fCursorIsEnabled)
 			return;
 		int cursorLine=getSnapshot().getCursorLine();
 		int cursorColumn=getSnapshot().getCursorColumn();
 		// if cursor at the end put it to the end of the
 		// last line...
 		if(cursorLine>=getSnapshot().getHeight()) {
 			cursorLine=getSnapshot().getHeight()-1;
 			cursorColumn=getSnapshot().getWidth()-1;
 		}
 		// has the cursor moved?
 		if(fCursorLine!=cursorLine || fCursorColumn!=cursorColumn) {
 			// hide the old cursor!
 			fShowCursor=false;
 			// clean the previous cursor
 			// bug 206363: paint also the char to the left and right of the cursor - see also below
 			int col=fCursorColumn;
 			int width=2;
 			if(col>0) {
 				col--;
 				width++;
 			}
 			fireCellRangeChanged(col, fCursorLine, width, 1);
 			// the cursor is shown when it moves!
 			fShowCursor=true;
 			fCursorTime=System.currentTimeMillis();
 			fCursorLine=cursorLine;
 			fCursorColumn=cursorColumn;
 			// and draw the new cursor
 			fireCellRangeChanged(fCursorColumn, fCursorLine, 1, 1);
 		} else {
 			long t=System.currentTimeMillis();
 			// TODO make the cursor blink time customisable
 			if(t-fCursorTime>500) {
 				fShowCursor=!fShowCursor;
 				fCursorTime=t;
 				// on some windows machines, there is some left
 				// over when updating the cursor .
 				// https://bugs.eclipse.org/bugs/show_bug.cgi?id=206363
 				int col=fCursorColumn;
 				int width=2;
 				if(col>0) {
 					col--;
 					width++;
 				}
 				fireCellRangeChanged(col, fCursorLine, width, 1);
 			}
 		}
 	}
 	public void setVisibleRectangle(int startLine, int startCol, int height, int width) {
 		fSnapshot.setInterestWindow(Math.max(0,startLine), Math.max(1,height));
 		update();
 	}
 	protected void showCursor(boolean show) {
 		fShowCursor=true;
 	}
 	public void setCursorEnabled(boolean visible) {
 		fCursorTime=System.currentTimeMillis();
 		fShowCursor=visible;
 		fCursorIsEnabled=visible;
 		fireCellRangeChanged(fCursorColumn, fCursorLine, 1, 1);
 	}
 	public boolean isCursorEnabled() {
 		return fCursorIsEnabled;
 	}

 	public Point getSelectionEnd() {
 		if(fSelectionStartLine<0)
 			return null;
 		else
 			return new Point(fSelectionEndColumn, fSeletionEndLine);
 	}

 	public Point getSelectionStart() {
 		if (fSelectionStartLine < 0)
 			return null;
 		else
 			return new Point(fSelectionStartCoumn,fSelectionStartLine);
 	}
 	public Point getSelectionAnchor() {
 		if(fSelectionStartLine<0)
 			return null;
 		return new Point(fSelectionAnchor.x,fSelectionAnchor.y);
 	}
 	public void setSelectionAnchor(Point anchor) {
 		fSelectionAnchor.x=anchor.x;
 		fSelectionAnchor.y=anchor.y;
 	}

 	public void setSelection(int startLine, int endLine, int startColumn, int endColumn) {
 //		System.err.println(startLine+","+endLine+","+startColumn+","+endColumn);
 		doSetSelection(startLine, endLine, startColumn, endColumn);
 		fCurrentSelection=extractSelectedText();
 	}
 	private void doSetSelection(int startLine, int endLine, int startColumn, int endColumn) {
 		assert(startLine<0 || startLine<=endLine);
 		if(startLine>=0) {
 			if(fSelectionSnapshot==null) {
 				fSelectionSnapshot=fSnapshot.getTerminalTextData().makeSnapshot();
 				fSelectionSnapshot.updateSnapshot(true);
 			}
 		} else if(fSelectionSnapshot!=null) {
 			fSelectionSnapshot.detach();
 			fSelectionSnapshot=null;
 		}
 		int oldStart=fSelectionStartLine;
 		int oldEnd=fSeletionEndLine;
 		fSelectionStartLine = startLine;
 		fSeletionEndLine = endLine;
 		fSelectionStartCoumn = startColumn;
 		fSelectionEndColumn = endColumn;
 		if(fSelectionSnapshot!=null) {
 			fSelectionSnapshot.setInterestWindow(0, fSelectionSnapshot.getHeight());
 		}
 		int changedStart;
 		int changedEnd;
 		if(oldStart<0) {
 			changedStart=fSelectionStartLine;
 			changedEnd=fSeletionEndLine;
 		} else if(fSelectionStartLine<0) {
 			changedStart=oldStart;
 			changedEnd=oldEnd;
 		} else {
 			changedStart=Math.min(oldStart, fSelectionStartLine);
 			changedEnd=Math.max(oldEnd, fSeletionEndLine);
 		}
 		if(changedStart>=0) {
 			fireCellRangeChanged(0, changedStart, fSnapshot.getWidth(), changedEnd-changedStart+1);
 		}
 	}

 	public boolean hasLineSelection(int line) {
 		if (fSelectionStartLine < 0)
 			return false;
 		else
 			return line >= fSelectionStartLine && line <= fSeletionEndLine;
 	}

 	public String getSelectedText() {
 		return fCurrentSelection;
 	}
 	/**
 	 * Calculates the currently selected text
 	 * @return the currently selected text
 	 */
 	private String extractSelectedText() {
 		if(fSelectionStartLine<0 || fSelectionStartCoumn<0 || fSelectionSnapshot==null)
 			return ""; //$NON-NLS-1$
 		StringBuffer buffer=new StringBuffer();
 		for (int line = fSelectionStartLine; line <= fSeletionEndLine; line++) {
 			String text;
 			char[] chars=fSelectionSnapshot.getChars(line);
 			if(chars!=null) {
 				text=new String(chars);
 				if(line==fSeletionEndLine && fSelectionEndColumn >= 0)
 					text=text.substring(0, Math.min(fSelectionEndColumn+1,text.length()));
 				if(line==fSelectionStartLine)
 					text=text.substring(Math.min(fSelectionStartCoumn,text.length()));
 				// get rid of the empty space at the end of the lines
 				// text=text.replaceAll("\000+$","");  //$NON-NLS-1$//$NON-NLS-2$
 				// <J2ME-CDC-1.1 version>
 				int i = text.length() - 1;
 				while (i >= 0 && text.charAt(i) == '\000') {
 					i--;
 				}
 				text = text.substring(0, i + 1);
 				// </J2ME-CDC-1.1 version>
 				// null means space
 				text=text.replace('\000', ' ');
 			} else {
 				text=""; //$NON-NLS-1$
 			}
 			buffer.append(text);
 			if(line < fSeletionEndLine)
 				buffer.append('\n');
 		}
 		return buffer.toString();
 	}
 	private void updateSelection() {
 		if (fSelectionSnapshot != null && fSelectionSnapshot.isOutOfDate()) {
 			fSelectionSnapshot.updateSnapshot(true);
 			// has the selection moved?
 			if (fSelectionSnapshot != null && fSelectionStartLine >= 0 && fSelectionSnapshot.getScrollWindowSize() > 0) {
 				int start = fSelectionStartLine + fSelectionSnapshot.getScrollWindowShift();
 				int end = fSeletionEndLine + fSelectionSnapshot.getScrollWindowShift();
 				if (start < 0)
 					if (end >= 0)
 						start = 0;
 					else
 						start = -1;
 				doSetSelection(start, end, fSelectionStartCoumn, fSelectionEndColumn);
 			}
 			// check if the content of the selection has changed. If the content has
 			// changed, clear the selection
 			if (fCurrentSelection.length()>0 && fSelectionSnapshot != null
 					&& fSelectionSnapshot.getFirstChangedLine() <= fSeletionEndLine
 					&& fSelectionSnapshot.getLastChangedLine() >= fSelectionStartLine) {
 				// has the selected text changed?
 				if (!fCurrentSelection.equals(extractSelectedText())) {
 					setSelection(-1, -1, -1, -1);
 				}
 			}
 			// update the observed window...
 			if (fSelectionSnapshot != null)
 				// todo make -1 to work!
 				fSelectionSnapshot.setInterestWindow(0, fSelectionSnapshot.getHeight());
 		}
 	}

 }
	/*******************************************************************************
	* Copyright (c) 2007, 2010 Wind River Systems, Inc. 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:
	* Michael Scharf (Wind River) - initial API and implementation
	* Martin Oberhuber (Wind River) - [168197] Fix Terminal for CDC-1.1/Foundation-1.1
	* Anton Leherbauer (Wind River) - [219589] Copy an entire line selection
	*******************************************************************************/
	package org.eclipse.tm.internal.terminal.textcanvas;

	import java.util.ArrayList;
	import java.util.Iterator;
	import java.util.List;

	import org.eclipse.swt.graphics.Point;
	import org.eclipse.tm.terminal.model.ITerminalTextDataReadOnly;
	import org.eclipse.tm.terminal.model.ITerminalTextDataSnapshot;

	abstract public class AbstractTextCanvasModel implements ITextCanvasModel {
	protected List fListeners = new ArrayList();
	private int fCursorLine;
	private int fCursorColumn;
	private boolean fShowCursor;
	private long fCursorTime;
	private boolean fCursorIsEnabled;
	private final ITerminalTextDataSnapshot fSnapshot;
	private int fLines;

	private int fSelectionStartLine=-1;
	private int fSeletionEndLine;
	private int fSelectionStartCoumn;
	private int fSelectionEndColumn;
	private ITerminalTextDataSnapshot fSelectionSnapshot;
	private String fCurrentSelection=""; //$NON-NLS-1$
	private final Point fSelectionAnchor=new Point(0,0);
	/**
	* do not update while update is running
	*/
	boolean fInUpdate;
	private int fCols;

	public AbstractTextCanvasModel(ITerminalTextDataSnapshot snapshot) {
	fSnapshot=snapshot;
	fLines=fSnapshot.getHeight();
	}
	public void addCellCanvasModelListener(ITextCanvasModelListener listener) {
	fListeners.add(listener);
	}

	public void removeCellCanvasModelListener(ITextCanvasModelListener listener) {
	fListeners.remove(listener);
	}

	protected void fireCellRangeChanged(int x, int y, int width, int height) {
	for (Iterator iter = fListeners.iterator(); iter.hasNext();) {
	ITextCanvasModelListener listener = (ITextCanvasModelListener) iter.next();
	listener.rangeChanged(x, y, width, height);
	}
	}
	protected void fireDimensionsChanged( int width,int height) {
	for (Iterator iter = fListeners.iterator(); iter.hasNext();) {
	ITextCanvasModelListener listener = (ITextCanvasModelListener) iter.next();
	listener.dimensionsChanged(width,height);
	}

	}
	protected void fireTerminalDataChanged() {
	for (Iterator iter = fListeners.iterator(); iter.hasNext();) {
	ITextCanvasModelListener listener = (ITextCanvasModelListener) iter.next();
	listener.terminalDataChanged();
	}

	}

	public ITerminalTextDataReadOnly getTerminalText() {
	return fSnapshot;
	}
	protected ITerminalTextDataSnapshot getSnapshot() {
	return fSnapshot;
	}
	protected void updateSnapshot() {
	if(!fInUpdate && fSnapshot.isOutOfDate()) {
	fInUpdate=true;
	try {
	fSnapshot.updateSnapshot(false);
	if(fSnapshot.hasTerminalChanged())
	fireTerminalDataChanged();
	// TODO why does hasDimensionsChanged not work??????
	// if(fSnapshot.hasDimensionsChanged())
	// fireDimensionsChanged();
	if(fLines!=fSnapshot.getHeight() \|\| fCols!=fSnapshot.getWidth()) {
	fireDimensionsChanged(fSnapshot.getWidth(),fSnapshot.getHeight());
	fLines=fSnapshot.getHeight();
	fCols=fSnapshot.getWidth();
	}
	int y=fSnapshot.getFirstChangedLine();
	// has any line changed?
	if(y<Integer.MAX_VALUE) {
	int height=fSnapshot.getLastChangedLine()-y+1;
	fireCellRangeChanged(0, y, fSnapshot.getWidth(), height);
	}

	} finally {
	fInUpdate=false;
	}
	}
	}
	/**
	* must be called from the UI thread
	*/
	public void update() {
	// do the poll....
	updateSnapshot();
	updateSelection();
	updateCursor();
	}


	public int getCursorColumn() {
	return fCursorColumn;
	}

	public int getCursorLine() {
	return fCursorLine;
	}

	public boolean isCursorOn() {
	return fShowCursor && fCursorIsEnabled;
	}
	/**
	* should be called regularly to draw an update of the
	* blinking cursor
	*/
	protected void updateCursor() {
	if(!fCursorIsEnabled)
	return;
	int cursorLine=getSnapshot().getCursorLine();
	int cursorColumn=getSnapshot().getCursorColumn();
	// if cursor at the end put it to the end of the
	// last line...
	if(cursorLine>=getSnapshot().getHeight()) {
	cursorLine=getSnapshot().getHeight()-1;
	cursorColumn=getSnapshot().getWidth()-1;
	}
	// has the cursor moved?
	if(fCursorLine!=cursorLine \|\| fCursorColumn!=cursorColumn) {
	// hide the old cursor!
	fShowCursor=false;
	// clean the previous cursor
	// bug 206363: paint also the char to the left and right of the cursor - see also below
	int col=fCursorColumn;
	int width=2;
	if(col>0) {
	col--;
	width++;
	}
	fireCellRangeChanged(col, fCursorLine, width, 1);
	// the cursor is shown when it moves!
	fShowCursor=true;
	fCursorTime=System.currentTimeMillis();
	fCursorLine=cursorLine;
	fCursorColumn=cursorColumn;
	// and draw the new cursor
	fireCellRangeChanged(fCursorColumn, fCursorLine, 1, 1);
	} else {
	long t=System.currentTimeMillis();
	// TODO make the cursor blink time customisable
	if(t-fCursorTime>500) {
	fShowCursor=!fShowCursor;
	fCursorTime=t;
	// on some windows machines, there is some left
	// over when updating the cursor .
	// https://bugs.eclipse.org/bugs/show_bug.cgi?id=206363
	int col=fCursorColumn;
	int width=2;
	if(col>0) {
	col--;
	width++;
	}
	fireCellRangeChanged(col, fCursorLine, width, 1);
	}
	}
	}
	public void setVisibleRectangle(int startLine, int startCol, int height, int width) {
	fSnapshot.setInterestWindow(Math.max(0,startLine), Math.max(1,height));
	update();
	}
	protected void showCursor(boolean show) {
	fShowCursor=true;
	}
	public void setCursorEnabled(boolean visible) {
	fCursorTime=System.currentTimeMillis();
	fShowCursor=visible;
	fCursorIsEnabled=visible;
	fireCellRangeChanged(fCursorColumn, fCursorLine, 1, 1);
	}
	public boolean isCursorEnabled() {
	return fCursorIsEnabled;
	}

	public Point getSelectionEnd() {
	if(fSelectionStartLine<0)
	return null;
	else
	return new Point(fSelectionEndColumn, fSeletionEndLine);
	}

	public Point getSelectionStart() {
	if (fSelectionStartLine < 0)
	return null;
	else
	return new Point(fSelectionStartCoumn,fSelectionStartLine);
	}
	public Point getSelectionAnchor() {
	if(fSelectionStartLine<0)
	return null;
	return new Point(fSelectionAnchor.x,fSelectionAnchor.y);
	}
	public void setSelectionAnchor(Point anchor) {
	fSelectionAnchor.x=anchor.x;
	fSelectionAnchor.y=anchor.y;
	}

	public void setSelection(int startLine, int endLine, int startColumn, int endColumn) {
	// System.err.println(startLine+","+endLine+","+startColumn+","+endColumn);
	doSetSelection(startLine, endLine, startColumn, endColumn);
	fCurrentSelection=extractSelectedText();
	}
	private void doSetSelection(int startLine, int endLine, int startColumn, int endColumn) {
	assert(startLine<0 \|\| startLine<=endLine);
	if(startLine>=0) {
	if(fSelectionSnapshot==null) {
	fSelectionSnapshot=fSnapshot.getTerminalTextData().makeSnapshot();
	fSelectionSnapshot.updateSnapshot(true);
	}
	} else if(fSelectionSnapshot!=null) {
	fSelectionSnapshot.detach();
	fSelectionSnapshot=null;
	}
	int oldStart=fSelectionStartLine;
	int oldEnd=fSeletionEndLine;
	fSelectionStartLine = startLine;
	fSeletionEndLine = endLine;
	fSelectionStartCoumn = startColumn;
	fSelectionEndColumn = endColumn;
	if(fSelectionSnapshot!=null) {
	fSelectionSnapshot.setInterestWindow(0, fSelectionSnapshot.getHeight());
	}
	int changedStart;
	int changedEnd;
	if(oldStart<0) {
	changedStart=fSelectionStartLine;
	changedEnd=fSeletionEndLine;
	} else if(fSelectionStartLine<0) {
	changedStart=oldStart;
	changedEnd=oldEnd;
	} else {
	changedStart=Math.min(oldStart, fSelectionStartLine);
	changedEnd=Math.max(oldEnd, fSeletionEndLine);
	}
	if(changedStart>=0) {
	fireCellRangeChanged(0, changedStart, fSnapshot.getWidth(), changedEnd-changedStart+1);
	}
	}

	public boolean hasLineSelection(int line) {
	if (fSelectionStartLine < 0)
	return false;
	else
	return line >= fSelectionStartLine && line <= fSeletionEndLine;
	}

	public String getSelectedText() {
	return fCurrentSelection;
	}
	/**
	* Calculates the currently selected text
	* @return the currently selected text
	*/
	private String extractSelectedText() {
	if(fSelectionStartLine<0 \|\| fSelectionStartCoumn<0 \|\| fSelectionSnapshot==null)
	return ""; //$NON-NLS-1$
	StringBuffer buffer=new StringBuffer();
	for (int line = fSelectionStartLine; line <= fSeletionEndLine; line++) {
	String text;
	char[] chars=fSelectionSnapshot.getChars(line);
	if(chars!=null) {
	text=new String(chars);
	if(line==fSeletionEndLine && fSelectionEndColumn >= 0)
	text=text.substring(0, Math.min(fSelectionEndColumn+1,text.length()));
	if(line==fSelectionStartLine)
	text=text.substring(Math.min(fSelectionStartCoumn,text.length()));
	// get rid of the empty space at the end of the lines
	// text=text.replaceAll("\000+$",""); //$NON-NLS-1$//$NON-NLS-2$
	// <J2ME-CDC-1.1 version>
	int i = text.length() - 1;
	while (i >= 0 && text.charAt(i) == '\000') {
	i--;
	}
	text = text.substring(0, i + 1);
	// </J2ME-CDC-1.1 version>
	// null means space
	text=text.replace('\000', ' ');
	} else {
	text=""; //$NON-NLS-1$
	}
	buffer.append(text);
	if(line < fSeletionEndLine)
	buffer.append('\n');
	}
	return buffer.toString();
	}
	private void updateSelection() {
	if (fSelectionSnapshot != null && fSelectionSnapshot.isOutOfDate()) {
	fSelectionSnapshot.updateSnapshot(true);
	// has the selection moved?
	if (fSelectionSnapshot != null && fSelectionStartLine >= 0 && fSelectionSnapshot.getScrollWindowSize() > 0) {
	int start = fSelectionStartLine + fSelectionSnapshot.getScrollWindowShift();
	int end = fSeletionEndLine + fSelectionSnapshot.getScrollWindowShift();
	if (start < 0)
	if (end >= 0)
	start = 0;
	else
	start = -1;
	doSetSelection(start, end, fSelectionStartCoumn, fSelectionEndColumn);
	}
	// check if the content of the selection has changed. If the content has
	// changed, clear the selection
	if (fCurrentSelection.length()>0 && fSelectionSnapshot != null
	&& fSelectionSnapshot.getFirstChangedLine() <= fSeletionEndLine
	&& fSelectionSnapshot.getLastChangedLine() >= fSelectionStartLine) {
	// has the selected text changed?
	if (!fCurrentSelection.equals(extractSelectedText())) {
	setSelection(-1, -1, -1, -1);
	}
	}
	// update the observed window...
	if (fSelectionSnapshot != null)
	// todo make -1 to work!
	fSelectionSnapshot.setInterestWindow(0, fSelectionSnapshot.getHeight());
	}
	}

	}