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

 /*******************************************************************************
  * Copyright (c) 2000, 2015 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
  *     Tom Eicher (Avaloq Evolution AG) - block selection mode
  *     Holger Voormann - Word Wrap - https://bugs.eclipse.org/bugs/show_bug.cgi?id=35779
  *     Florian Weßling <flo@cdhq.de> - Word Wrap - https://bugs.eclipse.org/bugs/show_bug.cgi?id=35779
  *******************************************************************************/

 package org.eclipse.jface.text;


 import org.eclipse.swt.custom.LineBackgroundEvent;
 import org.eclipse.swt.custom.LineBackgroundListener;
 import org.eclipse.swt.custom.StyledText;
 import org.eclipse.swt.graphics.Color;
 import org.eclipse.swt.graphics.Point;


 /**
  * A painter the draws the background of the caret line in a configured color.
  * <p>
  * Clients usually instantiate and configure object of this class.</p>
  * <p>
  * This class is not intended to be subclassed.</p>
  *
  * @since 2.1
  * @noextend This class is not intended to be subclassed by clients.
  */
 public class CursorLinePainter implements IPainter, LineBackgroundListener {

 	/** The viewer the painter works on */
 	private final ITextViewer fViewer;
 	/** The cursor line back ground color */
 	private Color fHighlightColor;
 	/** The paint position manager for managing the line coordinates */
 	private IPaintPositionManager fPositionManager;

 	/** Keeps track of the line to be painted */
 	private Position fCurrentLine= new Position(0, 0);
 	/** Keeps track of the line to be cleared */
 	private Position fLastLine= new Position(0, 0);
 	/** Keeps track of the line number of the last painted line */
 	private int fLastLineNumber= -1;
 	/** Indicates whether this painter is active */
 	private boolean fIsActive;

 	/**
 	 * Creates a new painter for the given source viewer.
 	 *
 	 * @param textViewer the source viewer for which to create a painter
 	 */
 	public CursorLinePainter(ITextViewer textViewer) {
 		fViewer= textViewer;
 	}

 	/**
 	 * Sets the color in which to draw the background of the cursor line.
 	 *
 	 * @param highlightColor the color in which to draw the background of the cursor line
 	 */
 	public void setHighlightColor(Color highlightColor) {
 		fHighlightColor= highlightColor;
 	}

 	@Override
 	public void lineGetBackground(LineBackgroundEvent event) {
 		// don't use cached line information because of asynchronous painting

 		StyledText textWidget= fViewer.getTextWidget();
 		if (textWidget != null) {

 			int caret= textWidget.getCaretOffset();
 			int length= event.lineText.length();

 			if (event.lineOffset <= caret && caret <= event.lineOffset + length && !hasMultiLineSelection(textWidget))
 				event.lineBackground= fHighlightColor;
 		}
 	}

 	/**
 	 * Updates all the cached information about the lines to be painted and to be cleared. Returns <code>true</code>
 	 * if the line number of the cursor line has changed.
 	 *
 	 * @return <code>true</code> if cursor line changed
 	 */
 	private boolean updateHighlightLine() {
 		try {

 			IDocument document= fViewer.getDocument();
 			int modelCaret= getModelCaret();
 			int lineNumber= document.getLineOfOffset(modelCaret);

 			// redraw if the current line number is different from the last line number we painted
 			// initially fLastLineNumber is -1
 			if (lineNumber != fLastLineNumber || !fCurrentLine.overlapsWith(modelCaret, 0)) {

 				fLastLine.offset= fCurrentLine.offset;
 				fLastLine.length= fCurrentLine.length;
 				fLastLine.isDeleted= fCurrentLine.isDeleted;

 				if (fCurrentLine.isDeleted) {
 					fCurrentLine.isDeleted= false;
 					fPositionManager.managePosition(fCurrentLine);
 				}

 				fCurrentLine.offset= document.getLineOffset(lineNumber);
 				if (lineNumber == document.getNumberOfLines() - 1)
 					fCurrentLine.length= document.getLength() - fCurrentLine.offset;
 				else
 					fCurrentLine.length= document.getLineOffset(lineNumber + 1) - fCurrentLine.offset;

 				fLastLineNumber= lineNumber;
 				return true;

 			}

 		} catch (BadLocationException e) {
 		}

 		return false;
 	}

 	/**
 	 * Returns the location of the caret as offset in the source viewer's
 	 * input document.
 	 *
 	 * @return the caret location
 	 */
 	private int getModelCaret() {
 		int widgetCaret= fViewer.getTextWidget().getCaretOffset();
 		if (fViewer instanceof ITextViewerExtension5) {
 			ITextViewerExtension5 extension= (ITextViewerExtension5) fViewer;
 			return extension.widgetOffset2ModelOffset(widgetCaret);
 		}
 		IRegion visible= fViewer.getVisibleRegion();
 		return widgetCaret + visible.getOffset();
 	}

 	/**
 	 * Assumes the given position to specify offset and length of a line to be painted.
 	 *
 	 * @param position the specification of the line  to be painted
 	 */
 	private void drawHighlightLine(Position position) {

 		// if the position that is about to be drawn was deleted then we can't
 		if (position.isDeleted())
 			return;

 		int widgetOffset= 0;
 		if (fViewer instanceof ITextViewerExtension5) {

 			ITextViewerExtension5 extension= (ITextViewerExtension5) fViewer;
 			widgetOffset= extension.modelOffset2WidgetOffset(position.getOffset());
 			if (widgetOffset == -1)
 				return;

 		} else {

 			IRegion visible= fViewer.getVisibleRegion();
 			widgetOffset= position.getOffset() - visible.getOffset();
 			if (widgetOffset < 0 || visible.getLength() < widgetOffset )
 				return;
 		}

 		StyledText textWidget= fViewer.getTextWidget();
 		// check for https://bugs.eclipse.org/bugs/show_bug.cgi?id=64898
 		// this is a guard against the symptoms but not the actual solution
 		int charCount= textWidget.getCharCount();
 		if (widgetOffset > charCount) {
 			return;
 		}
 		Point upperLeft= textWidget.getLocationAtOffset(widgetOffset);
 		int width= textWidget.getClientArea().width + textWidget.getHorizontalPixel();

 		// different height if word wrap is activated and line is not empty
 		int height;
 		if (position.length == 0 || !textWidget.getWordWrap()) {
 			height= textWidget.getLineHeight(widgetOffset);
 		} else {
 			int offsetEnd= widgetOffset + position.length - 1;
 			if (offsetEnd >= charCount) {
 				offsetEnd= charCount - 1;
 			}
 			height= textWidget.getTextBounds(widgetOffset, offsetEnd).height;
 		}
 		textWidget.redraw(0, upperLeft.y, width, height, false);
 	}

 	@Override
 	public void deactivate(boolean redraw) {
 		if (fIsActive) {
 			fIsActive= false;

 			/* on turning off the feature one has to paint the currently
 			 * highlighted line with the standard background color
 			 */
 			if (redraw)
 				drawHighlightLine(fCurrentLine);

 			fViewer.getTextWidget().removeLineBackgroundListener(this);

 			if (fPositionManager != null)
 				fPositionManager.unmanagePosition(fCurrentLine);

 			fLastLineNumber= -1;
 			fCurrentLine.offset= 0;
 			fCurrentLine.length= 0;
 		}
 	}

 	@Override
 	public void dispose() {
 	}

 	@Override
 	public void paint(int reason) {
 		if (fViewer.getDocument() == null) {
 			deactivate(false);
 			return;
 		}

 		StyledText textWidget= fViewer.getTextWidget();

 		// check selection
 		if (hasMultiLineSelection(textWidget)) {
 			deactivate(true);
 			return;
 		}

 		// initialization
 		if (!fIsActive) {
 			textWidget.addLineBackgroundListener(this);
 			fPositionManager.managePosition(fCurrentLine);
 			fIsActive= true;
 		}

 		//redraw line highlight only if it hasn't been drawn yet on the respective line
 		if (updateHighlightLine()) {
 			// clear last line
 			drawHighlightLine(fLastLine);
 			// draw new line
 			drawHighlightLine(fCurrentLine);
 		}
 	}

 	/**
 	 * Returns <code>true</code> if the widget has a selection spanning multiple lines,
 	 * <code>false</code> otherwise.
 	 *
 	 * @param textWidget the text widget to check
 	 * @return <code>true</code> if <code>textWidget</code> has a multiline selection,
 	 *         <code>false</code> otherwise
 	 * @since 3.5
 	 */
 	private boolean hasMultiLineSelection(StyledText textWidget) {
 		Point selection= textWidget.getSelection();
 		try {
 			int startLine= textWidget.getLineAtOffset(selection.x);
 			int endLine= textWidget.getLineAtOffset(selection.y);
 			return startLine != endLine;
 		} catch (IllegalArgumentException e) {
 			// ignore - apparently, the widget has a stale selection
 			// see https://bugs.eclipse.org/bugs/show_bug.cgi?id=273721
 			return false;
 		}
 	}

 	@Override
 	public void setPositionManager(IPaintPositionManager manager) {
 		fPositionManager = manager;
 	}
 }
	/*******************************************************************************
	* Copyright (c) 2000, 2015 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
	* Tom Eicher (Avaloq Evolution AG) - block selection mode
	* Holger Voormann - Word Wrap - https://bugs.eclipse.org/bugs/show_bug.cgi?id=35779
	* Florian Weßling <flo@cdhq.de> - Word Wrap - https://bugs.eclipse.org/bugs/show_bug.cgi?id=35779
	*******************************************************************************/

	package org.eclipse.jface.text;


	import org.eclipse.swt.custom.LineBackgroundEvent;
	import org.eclipse.swt.custom.LineBackgroundListener;
	import org.eclipse.swt.custom.StyledText;
	import org.eclipse.swt.graphics.Color;
	import org.eclipse.swt.graphics.Point;


	/**
	* A painter the draws the background of the caret line in a configured color.
	* <p>
	* Clients usually instantiate and configure object of this class.</p>
	* <p>
	* This class is not intended to be subclassed.</p>
	*
	* @since 2.1
	* @noextend This class is not intended to be subclassed by clients.
	*/
	public class CursorLinePainter implements IPainter, LineBackgroundListener {

	/** The viewer the painter works on */
	private final ITextViewer fViewer;
	/** The cursor line back ground color */
	private Color fHighlightColor;
	/** The paint position manager for managing the line coordinates */
	private IPaintPositionManager fPositionManager;

	/** Keeps track of the line to be painted */
	private Position fCurrentLine= new Position(0, 0);
	/** Keeps track of the line to be cleared */
	private Position fLastLine= new Position(0, 0);
	/** Keeps track of the line number of the last painted line */
	private int fLastLineNumber= -1;
	/** Indicates whether this painter is active */
	private boolean fIsActive;

	/**
	* Creates a new painter for the given source viewer.
	*
	* @param textViewer the source viewer for which to create a painter
	*/
	public CursorLinePainter(ITextViewer textViewer) {
	fViewer= textViewer;
	}

	/**
	* Sets the color in which to draw the background of the cursor line.
	*
	* @param highlightColor the color in which to draw the background of the cursor line
	*/
	public void setHighlightColor(Color highlightColor) {
	fHighlightColor= highlightColor;
	}

	@Override
	public void lineGetBackground(LineBackgroundEvent event) {
	// don't use cached line information because of asynchronous painting

	StyledText textWidget= fViewer.getTextWidget();
	if (textWidget != null) {

	int caret= textWidget.getCaretOffset();
	int length= event.lineText.length();

	if (event.lineOffset <= caret && caret <= event.lineOffset + length && !hasMultiLineSelection(textWidget))
	event.lineBackground= fHighlightColor;
	}
	}

	/**
	* Updates all the cached information about the lines to be painted and to be cleared. Returns <code>true</code>
	* if the line number of the cursor line has changed.
	*
	* @return <code>true</code> if cursor line changed
	*/
	private boolean updateHighlightLine() {
	try {

	IDocument document= fViewer.getDocument();
	int modelCaret= getModelCaret();
	int lineNumber= document.getLineOfOffset(modelCaret);

	// redraw if the current line number is different from the last line number we painted
	// initially fLastLineNumber is -1
	if (lineNumber != fLastLineNumber \|\| !fCurrentLine.overlapsWith(modelCaret, 0)) {

	fLastLine.offset= fCurrentLine.offset;
	fLastLine.length= fCurrentLine.length;
	fLastLine.isDeleted= fCurrentLine.isDeleted;

	if (fCurrentLine.isDeleted) {
	fCurrentLine.isDeleted= false;
	fPositionManager.managePosition(fCurrentLine);
	}

	fCurrentLine.offset= document.getLineOffset(lineNumber);
	if (lineNumber == document.getNumberOfLines() - 1)
	fCurrentLine.length= document.getLength() - fCurrentLine.offset;
	else
	fCurrentLine.length= document.getLineOffset(lineNumber + 1) - fCurrentLine.offset;

	fLastLineNumber= lineNumber;
	return true;

	}

	} catch (BadLocationException e) {
	}

	return false;
	}

	/**
	* Returns the location of the caret as offset in the source viewer's
	* input document.
	*
	* @return the caret location
	*/
	private int getModelCaret() {
	int widgetCaret= fViewer.getTextWidget().getCaretOffset();
	if (fViewer instanceof ITextViewerExtension5) {
	ITextViewerExtension5 extension= (ITextViewerExtension5) fViewer;
	return extension.widgetOffset2ModelOffset(widgetCaret);
	}
	IRegion visible= fViewer.getVisibleRegion();
	return widgetCaret + visible.getOffset();
	}

	/**
	* Assumes the given position to specify offset and length of a line to be painted.
	*
	* @param position the specification of the line to be painted
	*/
	private void drawHighlightLine(Position position) {

	// if the position that is about to be drawn was deleted then we can't
	if (position.isDeleted())
	return;

	int widgetOffset= 0;
	if (fViewer instanceof ITextViewerExtension5) {

	ITextViewerExtension5 extension= (ITextViewerExtension5) fViewer;
	widgetOffset= extension.modelOffset2WidgetOffset(position.getOffset());
	if (widgetOffset == -1)
	return;

	} else {

	IRegion visible= fViewer.getVisibleRegion();
	widgetOffset= position.getOffset() - visible.getOffset();
	if (widgetOffset < 0 \|\| visible.getLength() < widgetOffset )
	return;
	}

	StyledText textWidget= fViewer.getTextWidget();
	// check for https://bugs.eclipse.org/bugs/show_bug.cgi?id=64898
	// this is a guard against the symptoms but not the actual solution
	int charCount= textWidget.getCharCount();
	if (widgetOffset > charCount) {
	return;
	}
	Point upperLeft= textWidget.getLocationAtOffset(widgetOffset);
	int width= textWidget.getClientArea().width + textWidget.getHorizontalPixel();

	// different height if word wrap is activated and line is not empty
	int height;
	if (position.length == 0 \|\| !textWidget.getWordWrap()) {
	height= textWidget.getLineHeight(widgetOffset);
	} else {
	int offsetEnd= widgetOffset + position.length - 1;
	if (offsetEnd >= charCount) {
	offsetEnd= charCount - 1;
	}
	height= textWidget.getTextBounds(widgetOffset, offsetEnd).height;
	}
	textWidget.redraw(0, upperLeft.y, width, height, false);
	}

	@Override
	public void deactivate(boolean redraw) {
	if (fIsActive) {
	fIsActive= false;

	/* on turning off the feature one has to paint the currently
	* highlighted line with the standard background color
	*/
	if (redraw)
	drawHighlightLine(fCurrentLine);

	fViewer.getTextWidget().removeLineBackgroundListener(this);

	if (fPositionManager != null)
	fPositionManager.unmanagePosition(fCurrentLine);

	fLastLineNumber= -1;
	fCurrentLine.offset= 0;
	fCurrentLine.length= 0;
	}
	}

	@Override
	public void dispose() {
	}

	@Override
	public void paint(int reason) {
	if (fViewer.getDocument() == null) {
	deactivate(false);
	return;
	}

	StyledText textWidget= fViewer.getTextWidget();

	// check selection
	if (hasMultiLineSelection(textWidget)) {
	deactivate(true);
	return;
	}

	// initialization
	if (!fIsActive) {
	textWidget.addLineBackgroundListener(this);
	fPositionManager.managePosition(fCurrentLine);
	fIsActive= true;
	}

	//redraw line highlight only if it hasn't been drawn yet on the respective line
	if (updateHighlightLine()) {
	// clear last line
	drawHighlightLine(fLastLine);
	// draw new line
	drawHighlightLine(fCurrentLine);
	}
	}

	/**
	* Returns <code>true</code> if the widget has a selection spanning multiple lines,
	* <code>false</code> otherwise.
	*
	* @param textWidget the text widget to check
	* @return <code>true</code> if <code>textWidget</code> has a multiline selection,
	* <code>false</code> otherwise
	* @since 3.5
	*/
	private boolean hasMultiLineSelection(StyledText textWidget) {
	Point selection= textWidget.getSelection();
	try {
	int startLine= textWidget.getLineAtOffset(selection.x);
	int endLine= textWidget.getLineAtOffset(selection.y);
	return startLine != endLine;
	} catch (IllegalArgumentException e) {
	// ignore - apparently, the widget has a stale selection
	// see https://bugs.eclipse.org/bugs/show_bug.cgi?id=273721
	return false;
	}
	}

	@Override
	public void setPositionManager(IPaintPositionManager manager) {
	fPositionManager = manager;
	}
	}