bundles/org.eclipse.swt/Eclipse SWT Custom Widgets/common/org/eclipse/swt/custom/StyledTextRenderer.java - platform/eclipse.platform.swt - Git at Google

 /*******************************************************************************
  * Copyright (c) 2000, 2004 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Common Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/cpl-v10.html
  *
  * Contributors:
  *     IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.swt.custom;


 import org.eclipse.swt.SWT;
 import org.eclipse.swt.graphics.*;

 /**
  * A StyledTextRenderer renders the content of a StyledText widget.
  * Subclasses can provide a different device (e.g., Display, Printer)
  * to render on and implement abstract methods to return resources
  * created on that device.
  */
 abstract class StyledTextRenderer {
 	private Device device;					// device to render on
 	protected Font regularFont, boldFont, italicFont, boldItalicFont;
 	private int tabWidth;					// width in pixels of a tab character
 	private int ascent, descent;
 	private int lineEndSpaceWidth;			// width in pixels of the space used to represent line delimiters

 /**
  * Creates an instance of <class>StyledTextRenderer</class>.
  * </p>
  * @param device Device to render on
  * @param regularFont Font to use for regular (non-bold) text
  * @param leftMargin margin to the left of the text
  */
 StyledTextRenderer(Device device, Font regularFont) {
 	this.device = device;
 	this.regularFont = regularFont;
 }
 /**
  * Calculates the line height and space width.
  */
 void calculateLineHeight() {
 	GC gc = getGC();
 	lineEndSpaceWidth = gc.stringExtent(" ").x;

 	// don't assume that bold and normal fonts have the same height
 	// fixes bug 41773
 	Font originalFont = gc.getFont();
 	FontMetrics metrics = gc.getFontMetrics();
 	ascent = Math.max(ascent, metrics.getAscent() + metrics.getLeading());
 	descent = Math.max(descent, metrics.getDescent());
 	gc.setFont(getFont(SWT.BOLD));
 	metrics = gc.getFontMetrics();
 	ascent = Math.max(ascent, metrics.getAscent() + metrics.getLeading());
 	descent = Math.max(descent, metrics.getDescent());
 	gc.setFont(getFont(SWT.ITALIC));
 	metrics = gc.getFontMetrics();
 	ascent = Math.max(ascent, metrics.getAscent() + metrics.getLeading());
 	descent = Math.max(descent, metrics.getDescent());
 	gc.setFont(getFont(SWT.BOLD | SWT.ITALIC));
 	metrics = gc.getFontMetrics();
 	ascent = Math.max(ascent, metrics.getAscent() + metrics.getLeading());
 	descent = Math.max(descent, metrics.getDescent());
 	gc.setFont(originalFont);
 	disposeGC(gc);

 	// clear the font cache
 	if (boldFont != null) boldFont.dispose();
 	if (italicFont != null) italicFont.dispose();
 	if (boldItalicFont != null) boldItalicFont.dispose();
 	boldFont = italicFont = boldItalicFont = null;
 }
 /**
  * Disposes the resource created by the receiver.
  */
 void dispose() {
 	if (boldFont != null) boldFont.dispose();
 	if (italicFont != null) italicFont.dispose();
 	if (boldItalicFont != null) boldItalicFont.dispose();
 	boldFont = italicFont = boldItalicFont = null;
 }
 /**
  * Dispose the specified GC.
  * Allows subclasses to reuse GCs.
  * </p>
  * @param gc GC to dispose.
  */
 protected abstract void disposeGC(GC gc);
 /**
  * Draws a line of text at the specified location.
  * </p>
  *
  * @param line the line to draw
  * @param lineIndex	index of the line to draw
  * @param paintY y location to draw at
  * @param gc GC to draw on
  * @param widgetBackground the widget background color.
  * 	Used as the default rendering color.
  * @param widgetForeground the widget foreground color.
  * 	Used as the default rendering color.
  * @param clearBackground true if the line background should be drawn
  * explicitly.
  */
 void drawLine(String line, int lineIndex, int paintY, GC gc, Color widgetBackground, Color widgetForeground, boolean clearBackground) {
 	int lineOffset = getContent().getOffsetAtLine(lineIndex);
 	int lineLength = line.length();
 	Point selection = getSelection();
 	int selectionStart = selection.x;
 	int selectionEnd = selection.y;
 	int leftMargin = getLeftMargin();
 	Color lineBackground = null;
 	TextLayout layout = getTextLayout(line, lineOffset);
 	Rectangle client = getClientArea();
 	StyledTextEvent event = getLineBackgroundData(lineOffset, line);
 	if (event != null) {
 		lineBackground = event.lineBackground;
 	}
 	if (lineBackground == null) {
 		lineBackground = widgetBackground;
 	}

 	if (clearBackground &&
 		(isFullLineSelection() == false ||
 		 selectionStart > lineOffset ||
 		 selectionEnd <= lineOffset + lineLength)) {
 		// draw background if full selection is off or if line is not
 		// completely selected
 		gc.setBackground(lineBackground);
 		gc.setForeground(lineBackground);
 		gc.fillRectangle(client.x + leftMargin, paintY, client.width, ascent + descent);
 	}
 	int paintX = client.x + leftMargin - getHorizontalPixel();
 	if (selectionStart != selectionEnd) {
 		Rectangle rect = layout.getLineBounds(0);
 		drawLineBreakSelection(line, lineOffset, paintX + rect.x + rect.width, paintY, gc);
 	}
 	gc.setForeground(widgetForeground);
 	gc.setBackground(lineBackground);

 	if (selectionStart == selectionEnd || (selectionEnd <= lineOffset && selectionStart > lineOffset + lineLength - 1)) {
 		layout.draw(gc, paintX, paintY);
 	} else {
 		int start = Math.max(0, selectionStart - lineOffset);
 		int end = Math.min(lineLength, selectionEnd - lineOffset);
 		layout.draw(gc, paintX, paintY, start, end - 1, getSelectionForeground(), getSelectionBackground());
 	}
 	disposeTextLayout(layout);
 }
 /**
  * Draws the background of the line selection.
  * Implemented by subclasses for optional selection rendering.
  * </p>
  *
  * @param line the line to draw
  * @param lineOffset offset of the first character in the line.
  * 	Relative to the start of the document.
  * @param styles line styles
  * @param paintY y location to draw at
  * @param gc GC to draw on
  * @param bidi the bidi object to use for measuring and rendering 	text in bidi
  * locales. null when not in bidi mode.
  */
 protected abstract void drawLineBreakSelection(String line, int lineOffset, int paintX, int paintY, GC gc);

 /**
  * Returns the visible client area that can be used for rendering.
  * </p>
  * @return the visible client area that can be used for rendering.
  */
 protected abstract Rectangle getClientArea();
 /**
  * Returns the <class>StyledTextContent</class> to use for line offset
  * calculations.
  * </p>
  * @return the <class>StyledTextContent</class> to use for line offset
  * calculations.
  */
 protected abstract StyledTextContent getContent();
 /**
  * Returns the Device that is being rendered on.
  * </p>
  * @return the Device that is being rendered on.
  */
 Device getDevice() {
 	return device;
 }
 int getBaseline() {
 	return ascent;
 }
 /**
  * Returns the text segments that should be treated as if they
  * had a different direction than the surrounding text.
  * </p>
  *
  * @param lineOffset offset of the first character in the line.
  * 	0 based from the beginning of the document.
  * @param line text of the line to specify bidi segments for
  * @return text segments that should be treated as if they had a
  * 	different direction than the surrounding text. Only the start
  * 	index of a segment is specified, relative to the start of the
  * 	line. Always starts with 0 and ends with the line length.
  * @exception IllegalArgumentException <ul>
  *    <li>ERROR_INVALID_ARGUMENT - if the segment indices returned
  * 		by the listener do not start with 0, are not in ascending order,
  * 		exceed the line length or have duplicates</li>
  * </ul>
  */
 protected abstract int[] getBidiSegments(int lineOffset, String lineText);
 /**
  *  Returns the Font according with the given style
  */
 Font getFont(int style) {
 	switch (style) {
 		case SWT.BOLD:
 			if (boldFont != null) return boldFont;
 			return boldFont = new Font(device, getFontData(style));
 		case SWT.ITALIC:
 			if (italicFont != null) return italicFont;
 			return italicFont = new Font(device, getFontData(style));
 		case SWT.BOLD | SWT.ITALIC:
 			if (boldItalicFont != null) return boldItalicFont;
 			return boldItalicFont = new Font(device, getFontData(style));
 		default:
 			return regularFont;
 	}
 }
 FontData[] getFontData(int style) {
 	FontData[] fontDatas = regularFont.getFontData();
 	for (int i = 0; i < fontDatas.length; i++) {
 		fontDatas[i].setStyle(style);
 	}
 	return fontDatas;
 }
 /**
  * Returns the GC to use for rendering and measuring.
  * Allows subclasses to reuse GCs.
  * </p>
  * @return the GC to use for rendering and measuring.
  */
 protected abstract GC getGC();
 /**
  * Returns the horizontal scroll position.
  * </p>
  * @return the horizontal scroll position.
  */
 protected abstract int getHorizontalPixel();
 protected int getLeftMargin() {
 	return 0;
 }
 /**
  * Returns the width in pixels of the space used to represent line delimiters.
  * @return the width in pixels of the space used to represent line delimiters.
  */
 int getLineEndSpaceWidth() {
 	return lineEndSpaceWidth;
 }
 /**
  * Returns the line background data for the given line or null if
  * there is none.
  * </p>
  * @param lineOffset offset of the line start relative to the start
  * 	of the content.
  * @param line line to get line background data for
  * @return line background data for the given line. may return null
  */
 protected abstract StyledTextEvent getLineBackgroundData(int lineOffset, String line);
 /**
  * Returns the height in pixels of a line.
  * </p>
  * @return the height in pixels of a line.
  */
 int getLineHeight() {
 	return ascent + descent;
 }
 /**
  * Returns the line style data for the specified line.
  * The lineOffset and line may specify a segment of a logical line stored
  * in the <class>StyledTextContent</class> of the widget.
  * The returned styles are guaranteed to be at least partially on the
  * segment.
  * </p>
  * @param event the styles for the logical line
  * @param lineOffset offset of the line start relative to the start of
  * 	the content.
  * @param line line to get line styles for
  * @return line style data for the given line segment. Styles may start
  * 	before line start and end after line end but are guaranteed to be at
  * 	least partially on the line.
  */
 StyledTextEvent getLineStyleData(StyledTextEvent event, int lineOffset, String line) {
 	int lineLength = line.length();

 	if (event.styles != null && getWordWrap()) {
 		event.styles = getVisualLineStyleData(event.styles, lineOffset, lineLength);
 	}
 	if (event.styles == null) {
 		event.styles = new StyleRange[0];
 	}
 	return event;
 }
 /**
  * Returns the line style data for the given line or null if there is
  * none. If there is a LineStyleListener but it does not set any styles,
  * the StyledTextEvent.styles field will be initialized to an empty
  * array.
  * </p>
  *
  * @param lineOffset offset of the line start relative to the start of
  * 	the content.
  * @param line line to get line styles for
  * @return line style data for the given line. Styles may start before
  * 	line start and end after line end
  */
 protected abstract StyledTextEvent getLineStyleData(int lineOffset, String line);
 /**
  *
  */
 protected abstract int getOrientation ();
 /**
 *
 */
 protected int getRightMargin() {
 	return 0;
 }
 /**
  *
  */
 protected abstract Color getSelectionForeground();
 /**
  *
  */
 protected abstract Color getSelectionBackground();
 /**
  * Returns the widget selection.
  * Implemented by subclasses for optional selection rendering.
  * </p>
  * @return the widget selection.
  */
 protected abstract Point getSelection();
 /**
  * Returns styles for the specified visual (wrapped) line.
  * </p>
  *
  * @param logicalStyles the styles for a logical (unwrapped) line
  * @param lineOffset offset of the visual line
  * @param lineLength length of the visual line
  * @return styles in the logicalStyles array that are at least
  * 	partially on the specified visual line.
  */
 StyleRange[] getVisualLineStyleData(StyleRange[] logicalStyles, int lineOffset, int lineLength) {
 	int lineEnd = lineOffset + lineLength;
 	int oldStyleCount = logicalStyles.length;
 	int newStyleCount = 0;

 	for (int i = 0; i < oldStyleCount; i++) {
 		StyleRange style = logicalStyles[i];
 		if (style.start < lineEnd && style.start + style.length > lineOffset) {
 			newStyleCount++;
 		}
 	}
 	if (newStyleCount != oldStyleCount) {
 		StyleRange[] newStyles = new StyleRange[newStyleCount];
 		for (int i = 0, j = 0; i < oldStyleCount; i++) {
 			StyleRange style = logicalStyles[i];
 			if (style.start < lineEnd && style.start + style.length > lineOffset) {
 				newStyles[j++] = logicalStyles[i];
 			}
 		}
 		logicalStyles = newStyles;
 	}
 	return logicalStyles;
 }
 /**
  * Returns the word wrap state.
  * </p>
  * @return true=word wrap is on. false=no word wrap, lines may extend
  * 	beyond the right side of the client area.
  */
 protected abstract boolean getWordWrap();
 /**
  * Returns whether the widget was created with the SWT.FULL_SELECTION style.
  * Implemented by subclasses for optional selection rendering.
  * </p>
  * @return true=the widget is running in full line selection mode,
  * 	false=otherwise
  */
 protected abstract boolean isFullLineSelection();
 /**
  * Calculates the width in pixel of a tab character
  * </p>
  * @param tabLength number of space characters represented by a tab character.
  */
 void setTabLength(int tabLength) {
 	GC gc = getGC();
 	StringBuffer tabBuffer = new StringBuffer(tabLength);

 	for (int i = 0; i < tabLength; i++) {
 		tabBuffer.append(' ');
 	}
 	tabWidth = gc.stringExtent(tabBuffer.toString()).x;
 	disposeGC(gc);
 }
 /**
  *  Returns TextLayout given a line index and an array of styles
  */
 TextLayout getTextLayout(String line, int lineOffset) {
 	TextLayout layout = createTextLayout(lineOffset);
 	layout.setFont(regularFont);
 	layout.setAscent(ascent);
 	layout.setDescent(descent);
 	layout.setText(line);
 	layout.setOrientation(getOrientation());
 	layout.setSegments(getBidiSegments(lineOffset, line));
 	layout.setTabs(new int[]{tabWidth});
 	int length = line.length();
 	StyledTextEvent event = getLineStyleData(lineOffset, line);
 	StyleRange[] styles = event != null ? event.styles : null;
 	int lastOffset = 0;
 	if (styles != null) {
 		for (int styleIndex = 0; styleIndex < styles.length; styleIndex++) {
 			StyleRange style = styles[styleIndex];
 			if (style.isUnstyled()) continue;
 			int start, end;
 			if (lineOffset > style.start) {
 				start = 0;
 				end = Math.min (length, style.length - lineOffset + style.start);
 			} else {
 				start = style.start - lineOffset;
 				end = Math.min(length, start + style.length);
 			}
 			if (start >= length) break;
 			if (lastOffset != start) {
 				layout.setStyle(null, lastOffset, start - 1);
 			}
 			TextStyle textStyle = new TextStyle(getFont(style.fontStyle), style.foreground, style.background);
 			layout.setStyle(textStyle, start, end - 1);
 			lastOffset = end;
 		}
 	}
 	if (lastOffset != length) layout.setStyle(null, lastOffset, length);
 	return layout;
 }
 TextLayout createTextLayout(int lineOffset) {
 	return new TextLayout(device);
 }
 void disposeTextLayout (TextLayout layout) {
 	layout.dispose();
 }
 }
	/*******************************************************************************
	* Copyright (c) 2000, 2004 IBM Corporation and others.
	* All rights reserved. This program and the accompanying materials
	* are made available under the terms of the Common Public License v1.0
	* which accompanies this distribution, and is available at
	* http://www.eclipse.org/legal/cpl-v10.html
	*
	* Contributors:
	* IBM Corporation - initial API and implementation
	*******************************************************************************/
	package org.eclipse.swt.custom;


	import org.eclipse.swt.SWT;
	import org.eclipse.swt.graphics.*;

	/**
	* A StyledTextRenderer renders the content of a StyledText widget.
	* Subclasses can provide a different device (e.g., Display, Printer)
	* to render on and implement abstract methods to return resources
	* created on that device.
	*/
	abstract class StyledTextRenderer {
	private Device device; // device to render on
	protected Font regularFont, boldFont, italicFont, boldItalicFont;
	private int tabWidth; // width in pixels of a tab character
	private int ascent, descent;
	private int lineEndSpaceWidth; // width in pixels of the space used to represent line delimiters

	/**
	* Creates an instance of <class>StyledTextRenderer</class>.
	* </p>
	* @param device Device to render on
	* @param regularFont Font to use for regular (non-bold) text
	* @param leftMargin margin to the left of the text
	*/
	StyledTextRenderer(Device device, Font regularFont) {
	this.device = device;
	this.regularFont = regularFont;
	}
	/**
	* Calculates the line height and space width.
	*/
	void calculateLineHeight() {
	GC gc = getGC();
	lineEndSpaceWidth = gc.stringExtent(" ").x;

	// don't assume that bold and normal fonts have the same height
	// fixes bug 41773
	Font originalFont = gc.getFont();
	FontMetrics metrics = gc.getFontMetrics();
	ascent = Math.max(ascent, metrics.getAscent() + metrics.getLeading());
	descent = Math.max(descent, metrics.getDescent());
	gc.setFont(getFont(SWT.BOLD));
	metrics = gc.getFontMetrics();
	ascent = Math.max(ascent, metrics.getAscent() + metrics.getLeading());
	descent = Math.max(descent, metrics.getDescent());
	gc.setFont(getFont(SWT.ITALIC));
	metrics = gc.getFontMetrics();
	ascent = Math.max(ascent, metrics.getAscent() + metrics.getLeading());
	descent = Math.max(descent, metrics.getDescent());
	gc.setFont(getFont(SWT.BOLD \| SWT.ITALIC));
	metrics = gc.getFontMetrics();
	ascent = Math.max(ascent, metrics.getAscent() + metrics.getLeading());
	descent = Math.max(descent, metrics.getDescent());
	gc.setFont(originalFont);
	disposeGC(gc);

	// clear the font cache
	if (boldFont != null) boldFont.dispose();
	if (italicFont != null) italicFont.dispose();
	if (boldItalicFont != null) boldItalicFont.dispose();
	boldFont = italicFont = boldItalicFont = null;
	}
	/**
	* Disposes the resource created by the receiver.
	*/
	void dispose() {
	if (boldFont != null) boldFont.dispose();
	if (italicFont != null) italicFont.dispose();
	if (boldItalicFont != null) boldItalicFont.dispose();
	boldFont = italicFont = boldItalicFont = null;
	}
	/**
	* Dispose the specified GC.
	* Allows subclasses to reuse GCs.
	* </p>
	* @param gc GC to dispose.
	*/
	protected abstract void disposeGC(GC gc);
	/**
	* Draws a line of text at the specified location.
	* </p>
	*
	* @param line the line to draw
	* @param lineIndex index of the line to draw
	* @param paintY y location to draw at
	* @param gc GC to draw on
	* @param widgetBackground the widget background color.
	* Used as the default rendering color.
	* @param widgetForeground the widget foreground color.
	* Used as the default rendering color.
	* @param clearBackground true if the line background should be drawn
	* explicitly.
	*/
	void drawLine(String line, int lineIndex, int paintY, GC gc, Color widgetBackground, Color widgetForeground, boolean clearBackground) {
	int lineOffset = getContent().getOffsetAtLine(lineIndex);
	int lineLength = line.length();
	Point selection = getSelection();
	int selectionStart = selection.x;
	int selectionEnd = selection.y;
	int leftMargin = getLeftMargin();
	Color lineBackground = null;
	TextLayout layout = getTextLayout(line, lineOffset);
	Rectangle client = getClientArea();
	StyledTextEvent event = getLineBackgroundData(lineOffset, line);
	if (event != null) {
	lineBackground = event.lineBackground;
	}
	if (lineBackground == null) {
	lineBackground = widgetBackground;
	}

	if (clearBackground &&
	(isFullLineSelection() == false \|\|
	selectionStart > lineOffset \|\|
	selectionEnd <= lineOffset + lineLength)) {
	// draw background if full selection is off or if line is not
	// completely selected
	gc.setBackground(lineBackground);
	gc.setForeground(lineBackground);
	gc.fillRectangle(client.x + leftMargin, paintY, client.width, ascent + descent);
	}
	int paintX = client.x + leftMargin - getHorizontalPixel();
	if (selectionStart != selectionEnd) {
	Rectangle rect = layout.getLineBounds(0);
	drawLineBreakSelection(line, lineOffset, paintX + rect.x + rect.width, paintY, gc);
	}
	gc.setForeground(widgetForeground);
	gc.setBackground(lineBackground);

	if (selectionStart == selectionEnd \|\| (selectionEnd <= lineOffset && selectionStart > lineOffset + lineLength - 1)) {
	layout.draw(gc, paintX, paintY);
	} else {
	int start = Math.max(0, selectionStart - lineOffset);
	int end = Math.min(lineLength, selectionEnd - lineOffset);
	layout.draw(gc, paintX, paintY, start, end - 1, getSelectionForeground(), getSelectionBackground());
	}
	disposeTextLayout(layout);
	}
	/**
	* Draws the background of the line selection.
	* Implemented by subclasses for optional selection rendering.
	* </p>
	*
	* @param line the line to draw
	* @param lineOffset offset of the first character in the line.
	* Relative to the start of the document.
	* @param styles line styles
	* @param paintY y location to draw at
	* @param gc GC to draw on
	* @param bidi the bidi object to use for measuring and rendering text in bidi
	* locales. null when not in bidi mode.
	*/
	protected abstract void drawLineBreakSelection(String line, int lineOffset, int paintX, int paintY, GC gc);

	/**
	* Returns the visible client area that can be used for rendering.
	* </p>
	* @return the visible client area that can be used for rendering.
	*/
	protected abstract Rectangle getClientArea();
	/**
	* Returns the <class>StyledTextContent</class> to use for line offset
	* calculations.
	* </p>
	* @return the <class>StyledTextContent</class> to use for line offset
	* calculations.
	*/
	protected abstract StyledTextContent getContent();
	/**
	* Returns the Device that is being rendered on.
	* </p>
	* @return the Device that is being rendered on.
	*/
	Device getDevice() {
	return device;
	}
	int getBaseline() {
	return ascent;
	}
	/**
	* Returns the text segments that should be treated as if they
	* had a different direction than the surrounding text.
	* </p>
	*
	* @param lineOffset offset of the first character in the line.
	* 0 based from the beginning of the document.
	* @param line text of the line to specify bidi segments for
	* @return text segments that should be treated as if they had a
	* different direction than the surrounding text. Only the start
	* index of a segment is specified, relative to the start of the
	* line. Always starts with 0 and ends with the line length.
	* @exception IllegalArgumentException <ul>
	* <li>ERROR_INVALID_ARGUMENT - if the segment indices returned
	* by the listener do not start with 0, are not in ascending order,
	* exceed the line length or have duplicates</li>
	* </ul>
	*/
	protected abstract int[] getBidiSegments(int lineOffset, String lineText);
	/**
	* Returns the Font according with the given style
	*/
	Font getFont(int style) {
	switch (style) {
	case SWT.BOLD:
	if (boldFont != null) return boldFont;
	return boldFont = new Font(device, getFontData(style));
	case SWT.ITALIC:
	if (italicFont != null) return italicFont;
	return italicFont = new Font(device, getFontData(style));
	case SWT.BOLD \| SWT.ITALIC:
	if (boldItalicFont != null) return boldItalicFont;
	return boldItalicFont = new Font(device, getFontData(style));
	default:
	return regularFont;
	}
	}
	FontData[] getFontData(int style) {
	FontData[] fontDatas = regularFont.getFontData();
	for (int i = 0; i < fontDatas.length; i++) {
	fontDatas[i].setStyle(style);
	}
	return fontDatas;
	}
	/**
	* Returns the GC to use for rendering and measuring.
	* Allows subclasses to reuse GCs.
	* </p>
	* @return the GC to use for rendering and measuring.
	*/
	protected abstract GC getGC();
	/**
	* Returns the horizontal scroll position.
	* </p>
	* @return the horizontal scroll position.
	*/
	protected abstract int getHorizontalPixel();
	protected int getLeftMargin() {
	return 0;
	}
	/**
	* Returns the width in pixels of the space used to represent line delimiters.
	* @return the width in pixels of the space used to represent line delimiters.
	*/
	int getLineEndSpaceWidth() {
	return lineEndSpaceWidth;
	}
	/**
	* Returns the line background data for the given line or null if
	* there is none.
	* </p>
	* @param lineOffset offset of the line start relative to the start
	* of the content.
	* @param line line to get line background data for
	* @return line background data for the given line. may return null
	*/
	protected abstract StyledTextEvent getLineBackgroundData(int lineOffset, String line);
	/**
	* Returns the height in pixels of a line.
	* </p>
	* @return the height in pixels of a line.
	*/
	int getLineHeight() {
	return ascent + descent;
	}
	/**
	* Returns the line style data for the specified line.
	* The lineOffset and line may specify a segment of a logical line stored
	* in the <class>StyledTextContent</class> of the widget.
	* The returned styles are guaranteed to be at least partially on the
	* segment.
	* </p>
	* @param event the styles for the logical line
	* @param lineOffset offset of the line start relative to the start of
	* the content.
	* @param line line to get line styles for
	* @return line style data for the given line segment. Styles may start
	* before line start and end after line end but are guaranteed to be at
	* least partially on the line.
	*/
	StyledTextEvent getLineStyleData(StyledTextEvent event, int lineOffset, String line) {
	int lineLength = line.length();

	if (event.styles != null && getWordWrap()) {
	event.styles = getVisualLineStyleData(event.styles, lineOffset, lineLength);
	}
	if (event.styles == null) {
	event.styles = new StyleRange[0];
	}
	return event;
	}
	/**
	* Returns the line style data for the given line or null if there is
	* none. If there is a LineStyleListener but it does not set any styles,
	* the StyledTextEvent.styles field will be initialized to an empty
	* array.
	* </p>
	*
	* @param lineOffset offset of the line start relative to the start of
	* the content.
	* @param line line to get line styles for
	* @return line style data for the given line. Styles may start before
	* line start and end after line end
	*/
	protected abstract StyledTextEvent getLineStyleData(int lineOffset, String line);
	/**
	*
	*/
	protected abstract int getOrientation ();
	/**
	*
	*/
	protected int getRightMargin() {
	return 0;
	}
	/**
	*
	*/
	protected abstract Color getSelectionForeground();
	/**
	*
	*/
	protected abstract Color getSelectionBackground();
	/**
	* Returns the widget selection.
	* Implemented by subclasses for optional selection rendering.
	* </p>
	* @return the widget selection.
	*/
	protected abstract Point getSelection();
	/**
	* Returns styles for the specified visual (wrapped) line.
	* </p>
	*
	* @param logicalStyles the styles for a logical (unwrapped) line
	* @param lineOffset offset of the visual line
	* @param lineLength length of the visual line
	* @return styles in the logicalStyles array that are at least
	* partially on the specified visual line.
	*/
	StyleRange[] getVisualLineStyleData(StyleRange[] logicalStyles, int lineOffset, int lineLength) {
	int lineEnd = lineOffset + lineLength;
	int oldStyleCount = logicalStyles.length;
	int newStyleCount = 0;

	for (int i = 0; i < oldStyleCount; i++) {
	StyleRange style = logicalStyles[i];
	if (style.start < lineEnd && style.start + style.length > lineOffset) {
	newStyleCount++;
	}
	}
	if (newStyleCount != oldStyleCount) {
	StyleRange[] newStyles = new StyleRange[newStyleCount];
	for (int i = 0, j = 0; i < oldStyleCount; i++) {
	StyleRange style = logicalStyles[i];
	if (style.start < lineEnd && style.start + style.length > lineOffset) {
	newStyles[j++] = logicalStyles[i];
	}
	}
	logicalStyles = newStyles;
	}
	return logicalStyles;
	}
	/**
	* Returns the word wrap state.
	* </p>
	* @return true=word wrap is on. false=no word wrap, lines may extend
	* beyond the right side of the client area.
	*/
	protected abstract boolean getWordWrap();
	/**
	* Returns whether the widget was created with the SWT.FULL_SELECTION style.
	* Implemented by subclasses for optional selection rendering.
	* </p>
	* @return true=the widget is running in full line selection mode,
	* false=otherwise
	*/
	protected abstract boolean isFullLineSelection();
	/**
	* Calculates the width in pixel of a tab character
	* </p>
	* @param tabLength number of space characters represented by a tab character.
	*/
	void setTabLength(int tabLength) {
	GC gc = getGC();
	StringBuffer tabBuffer = new StringBuffer(tabLength);

	for (int i = 0; i < tabLength; i++) {
	tabBuffer.append(' ');
	}
	tabWidth = gc.stringExtent(tabBuffer.toString()).x;
	disposeGC(gc);
	}
	/**
	* Returns TextLayout given a line index and an array of styles
	*/
	TextLayout getTextLayout(String line, int lineOffset) {
	TextLayout layout = createTextLayout(lineOffset);
	layout.setFont(regularFont);
	layout.setAscent(ascent);
	layout.setDescent(descent);
	layout.setText(line);
	layout.setOrientation(getOrientation());
	layout.setSegments(getBidiSegments(lineOffset, line));
	layout.setTabs(new int[]{tabWidth});
	int length = line.length();
	StyledTextEvent event = getLineStyleData(lineOffset, line);
	StyleRange[] styles = event != null ? event.styles : null;
	int lastOffset = 0;
	if (styles != null) {
	for (int styleIndex = 0; styleIndex < styles.length; styleIndex++) {
	StyleRange style = styles[styleIndex];
	if (style.isUnstyled()) continue;
	int start, end;
	if (lineOffset > style.start) {
	start = 0;
	end = Math.min (length, style.length - lineOffset + style.start);
	} else {
	start = style.start - lineOffset;
	end = Math.min(length, start + style.length);
	}
	if (start >= length) break;
	if (lastOffset != start) {
	layout.setStyle(null, lastOffset, start - 1);
	}
	TextStyle textStyle = new TextStyle(getFont(style.fontStyle), style.foreground, style.background);
	layout.setStyle(textStyle, start, end - 1);
	lastOffset = end;
	}
	}
	if (lastOffset != length) layout.setStyle(null, lastOffset, length);
	return layout;
	}
	TextLayout createTextLayout(int lineOffset) {
	return new TextLayout(device);
	}
	void disposeTextLayout (TextLayout layout) {
	layout.dispose();
	}
	}