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

 package org.eclipse.swt.custom;

 /*
  * Copyright (c) 2002 IBM Corp.  All rights reserved.
  * This file is 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
  */

 import java.util.*;

 import org.eclipse.swt.*;
 import org.eclipse.swt.custom.StyledText.*;
 import org.eclipse.swt.graphics.*;

 /**
  * A DisplayRenderer renders the content of a StyledText widget on
  * a display device.
  */
 class DisplayRenderer extends StyledTextRenderer {
 	private StyledText parent;			// used to get content and styles during rendering

 /**
  * Creates an instance of <class>DisplayRenderer</class>.
  * </p>
  * @param device Device to render on
  * @param regularFont Font to use for regular (non-bold) text
  * @param isBidi true=bidi platform, false=no bidi platform
  * @param leftMargin margin to the left of the text
  * @param parent <class>StyledText</class> widget to render
  * @param tabLength length in characters of a tab character
  */
 DisplayRenderer(Device device, Font regularFont, boolean isBidi, int leftMargin, StyledText parent, int tabLength) {
 	super(device, regularFont, isBidi, leftMargin);
 	this.parent = parent;
 	calculateLineHeight();
 	setTabLength(tabLength);
 }
 /**
  * Dispose the specified GC.
  * </p>
  * @param gc GC to dispose.
  */
 protected void disposeGC(GC gc) {
 	gc.dispose();
 }
 /**
  * Draws the background of the line selection.
  * </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 currentFont the font currently set in gc. Cached for
  * 	better performance.
  * @param bidi the bidi object to use for measuring and rendering
  * 	text in bidi locales. null when not in bidi mode.
  */
 protected void drawLineSelectionBackground(String line, int lineOffset, StyleRange[] styles, int paintY, GC gc, FontData currentFont, StyledTextBidi bidi) {
 	Point selection = parent.internalGetSelection();
 	LineCache lineCache = parent.internalGetLineCache();
 	StyledTextContent content = getContent();
 	int lineLength = line.length();
 	int paintX;
 	int selectionBackgroundWidth = -1;
 	int selectionStart = Math.max(0, selection.x - lineOffset);
 	int selectionEnd = selection.y - lineOffset;
 	int selectionLength = selectionEnd - selectionStart;
 	int horizontalScrollOffset = parent.internalGetHorizontalPixel();
 	int leftMargin = getLeftMargin();
 	int lineEndSpaceWidth = getLineEndSpaceWidth();
 	int lineHeight = getLineHeight();
 	boolean wordWrap = parent.internalGetWordWrap();

 	if (selectionEnd == selectionStart || selectionEnd < 0 || selectionStart > lineLength) {
 		return;
 	}
 	if (bidi != null) {
 		paintX = bidiTextWidth(line, 0, selectionStart, 0, bidi);
 	}
 	else {
 		paintX = textWidth(line, lineOffset, 0, selectionStart, filterLineStyles(styles), 0, gc, currentFont);
 	}
 	// selection extends past end of line?
 	if (selectionEnd > lineLength) {
 		if ((parent.getStyle() & SWT.FULL_SELECTION) != 0) {
 			// use the greater of the client area width and the content
 			// width. fixes 1G8IYRD
 			selectionBackgroundWidth = Math.max(getClientArea().width, lineCache.getWidth());
 		}
 		else {
 			selectionLength = lineLength - selectionStart;
 		}
 	}
 	gc.setBackground(getSelectionBackground());
 	gc.setForeground(getSelectionForeground());
 	if (selectionBackgroundWidth == -1) {
 		boolean isWrappedLine = false;

 		if (wordWrap) {
 			int lineEnd = lineOffset + lineLength;
 			int lineIndex = content.getLineAtOffset(lineEnd);

 			// is the start offset of the next line the same as the end
 			// offset of this line?
 			if (lineIndex < content.getLineCount() - 1 &&
 				content.getOffsetAtLine(lineIndex + 1) == lineEnd) {
 				isWrappedLine = true;
 			}
 		}
 		if (bidi != null) {
 			selectionBackgroundWidth = bidiTextWidth(line, selectionStart, selectionLength, paintX, bidi);
 		}
 		else {
 			selectionBackgroundWidth = textWidth(line, lineOffset, selectionStart, selectionLength, styles, paintX, gc, currentFont);
 		}
 		if (selectionBackgroundWidth < 0) {
 			// width can be negative when in R2L bidi segment
 			paintX += selectionBackgroundWidth;
 			selectionBackgroundWidth *= -1;
 		}
 		if (selectionEnd > lineLength && isWrappedLine == false) {
 			selectionEnd = selectionStart + selectionLength;
 			// if the selection extends past this line, render an additional
 			// whitespace background at the end of the line to represent the
 			// selected line break
 			if (bidi != null && selectionEnd > 0 && bidi.isRightToLeft(selectionEnd - 1)) {
 				int lineEndX = bidi.getTextWidth();
 				gc.fillRectangle(lineEndX - horizontalScrollOffset + leftMargin, paintY, lineEndSpaceWidth, lineHeight);
 			}
 			else {
 				selectionBackgroundWidth += lineEndSpaceWidth;
 			}
 		}
 	}
 	// handle empty line case
 	if (bidi != null && paintX == 0) {
 		paintX = StyledText.XINSET;
 	}
 	// fill the background first since expanded tabs are not
 	// drawn as spaces. tabs just move the draw position.
 	gc.fillRectangle(paintX - horizontalScrollOffset + leftMargin, paintY, selectionBackgroundWidth, lineHeight);
 }
 /**
  * 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 int[] getBidiSegments(int lineOffset, String lineText) {
 	return parent.getBidiSegments(lineOffset, lineText);
 }
 /**
  * Returns the visible client area that can be used for rendering.
  * </p>
  * @return the visible client area that can be used for rendering.
  */
 protected Rectangle getClientArea() {
 	return parent.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 StyledTextContent getContent() {
 	return parent.internalGetContent();
 }
 /**
  * Returns a new GC to use for rendering and measuring.
  * When the GC is no longer used it needs to be disposed by
  * calling disposeGC.
  * </p>
  * @return the GC to use for rendering and measuring.
  * @see disposeGC
  */
 protected GC getGC() {
 	return new GC(parent);
 }
 /**
  * Returns the horizontal scroll position.
  * </p>
  * @return the horizontal scroll position.
  */
 protected int getHorizontalPixel() {
 	return parent.internalGetHorizontalPixel();
 }
 /**
  * Returns the most recent caret direction.
  * Used for measuring caret positions.
  * </p>
  * @return the most recent caret direction.
  */
 protected int getLastCaretDirection() {
 	return parent.internalGetLastCaretDirection();
 }
 /**
  * @see StyledTextRenderer#getLineBackgroundData
  */
 protected StyledTextEvent getLineBackgroundData(int lineOffset, String line) {
 	return parent.getLineBackgroundData(lineOffset, line);
 }
 /**
  * @see StyledTextRenderer#getLineStyleData
  */
 protected StyledTextEvent getLineStyleData(int lineOffset, String line) {
 	StyledTextEvent logicalLineEvent = parent.getLineStyleData(lineOffset, line);

 	if (logicalLineEvent != null) {
 		logicalLineEvent = getLineStyleData(logicalLineEvent, lineOffset, line);
 	}
 	return logicalLineEvent;
 }
 /**
  * @see StyledTextRenderer#getSelection
  */
 protected Point getSelection() {
 	return parent.internalGetSelection();
 }
 /**
  * Returns the background color to be used for rendering selected text.
  * <p>
  * @return background color to be used for rendering selected text
  */
 private Color getSelectionBackground() {
 	return getDevice().getSystemColor(SWT.COLOR_LIST_SELECTION);
 }
 /**
  * Returns the foreground color to be used for rendering selected text.
  * <p>
  * @return foreground color to be used for rendering selected text
  */
 private Color getSelectionForeground() {
 	return getDevice().getSystemColor(SWT.COLOR_LIST_SELECTION_TEXT);
 }
 /**
  * @see StyledTextRenderer#getSelectionLineStyles
  */
 /*
 Pseudo code for getSelectionLineStyles
 	for each style {
 		if (style ends before selection start) {
 			add style to list
 		}
 		else
 		if (style overlaps selection start (i.e., starts before selection start, ends after selection start) {
 			change style end
 			create new selection style with same font style starting at selection start ending at style end
 			add selection style
 			// does style extend beyond selection?
 			if (selection style end > selection end) {
 				selection style end = selection end
 				// preserve rest (unselected part) of old style
 				style start = selection end
 				style length = old style end - selection end
 				add style
 			}
 		}
 		else
 		if (style starts within selection) {
 			if (no selection style created) {
 				create selection style with regular font style, starting at selection start, ending at style start
 				add selection style
 				if (style start == selection start) {
 					set selection style font to style font
 				}
 			}
 			// gap between current selection style end and new style start?
 			if (style start > selection styke end && selection style font style != NORMAL) {
 				create selection style with regular font style, starting at selection style end, ending at style start
 				add selection style
 			}
 			if (selection style font != style font) {
 				selection style end = style start
 				add selection style
 				create selection style with style font style, starting at style start, ending at style end
 			}
 			else {
 				selection style end = style end
 			}
 			// does style extend beyond selection?
 			if (selection style end > selection end) {
 				selection style end = selection end
 				// preserve rest (unselected part) of old style
 				style start = selection end
 				style length = old style end - selection end
 				style start = selection end
 				add style
 			}
 		}
 		else {
 			if (no selection style created) {
 				create selection style with regular font style, starting at selection start, ending at selection end
 				add selection style
 			}
 			else
 			if (selection style end < selection end) {
 				if (selection style font style != NORMAL) {
 					create selection style with regular font style, starting at selection style end, ending at selection end
 					add selection style
 				}
 				else {
 					selection style end = selection end
 				}
 			}
 			add style
 		}
 	}
 	if (no selection style created) {
 		create selection style with regular font style, starting at selection start, ending at selection end
 		add selection style to list
 	}
 	else
 	if (selection style end < selection end) {
 		if (selection style font style != NORMAL) {
 			create selection style with regular font style, starting at selection style end, ending at selection end
 			add selection style
 		}
 		else {
 			selection style end = selection end
 		}
 	}
 */
 protected StyleRange[] mergeSelectionLineStyles(StyleRange[] styles) {
 	Point selection = parent.internalGetSelection();
 	int selectionStart = selection.x;
 	int selectionEnd = selection.y;
 	Vector newStyles = new Vector(styles.length);
 	StyleRange selectionStyle = null;
 	Color foreground = getSelectionForeground();
 	Color background = getSelectionBackground();

 	// potential optimization: ignore styles if there is no bold style and the entire line is selected
 	for (int i = 0; i < styles.length; i++) {
 		StyleRange style = styles[i];
 		int styleEnd = style.start + style.length;

 		if (styleEnd <= selectionStart) {
 			newStyles.addElement(style);
 		}
 		else // style overlaps selection start? (i.e., starts before selection start, ends after selection start
 		if (style.start < selectionStart && styleEnd > selectionStart) {
 			StyleRange newStyle = (StyleRange) style.clone();
 			newStyle.length -= styleEnd - selectionStart;
 			newStyles.addElement(newStyle);
 			// create new selection style with same font style starting at selection start ending at style end
 			selectionStyle = new StyleRange(selectionStart, styleEnd - selectionStart, foreground, background, newStyle.fontStyle);
 			newStyles.addElement(selectionStyle);
 			// if style extends beyond selection a new style is returned for the unselected part of the style
 			newStyle = setSelectionStyleEnd(selectionStyle, style);
 			if (newStyle != null) {
 				newStyles.addElement(newStyle);
 			}
 		}
 		else // style starts within selection?
 		if (style.start >= selectionStart && style.start < selectionEnd) {
 			StyleRange newStyle;
 			int selectionStyleEnd;
 			// no selection style created yet?
 			if (selectionStyle == null) {
 				// create selection style with regular font style, starting at selection start, ending at style start
 				selectionStyle = new StyleRange(selectionStart, style.start - selectionStart, foreground, background);
 				newStyles.addElement(selectionStyle);
 				if (style.start == selectionStart) {
 					selectionStyle.fontStyle = style.fontStyle;
 				}
 			}
 			selectionStyleEnd = selectionStyle.start + selectionStyle.length;
 			// gap between current selection style end and style start?
 			if (style.start > selectionStyleEnd && selectionStyle.fontStyle != SWT.NORMAL) {
 				// create selection style with regular font style, starting at selection style end, ending at style start
 				selectionStyle = new StyleRange(selectionStyleEnd, style.start - selectionStyleEnd, foreground, background);
 				newStyles.addElement(selectionStyle);
 			}
 			if (selectionStyle.fontStyle != style.fontStyle) {
 				// selection style end = style start
 				selectionStyle.length = style.start - selectionStyle.start;
 				// create selection style with style font style, starting at style start, ending at style end
 				selectionStyle = new StyleRange(style.start, style.length, foreground, background, style.fontStyle);
 				newStyles.addElement(selectionStyle);
 			}
 			else {
 				// selection style end = style end
 				selectionStyle.length = styleEnd - selectionStyle.start;
 			}
 			// if style extends beyond selection a new style is returned for the unselected part of the style
 			newStyle = setSelectionStyleEnd(selectionStyle, style);
 			if (newStyle != null) {
 				newStyles.addElement(newStyle);
 			}
 		}
 		else {
 			// no selection style created yet?
 			if (selectionStyle == null) {
 				// create selection style with regular font style, starting at selection start, ending at selection end
 				selectionStyle = new StyleRange(selectionStart, selectionEnd - selectionStart, foreground, background);
 				newStyles.addElement(selectionStyle);
 			}
 			else // does the current selection style end before the selection end?
 			if (selectionStyle.start + selectionStyle.length < selectionEnd) {
 				if (selectionStyle.fontStyle != SWT.NORMAL) {
 					int selectionStyleEnd = selectionStyle.start + selectionStyle.length;
 					// create selection style with regular font style, starting at selection style end, ending at selection end
 					selectionStyle = new StyleRange(selectionStyleEnd, selectionEnd - selectionStyleEnd, foreground, background);
 					newStyles.addElement(selectionStyle);
 				}
 				else {
 					selectionStyle.length = selectionEnd - selectionStyle.start;
 				}
 			}
 			newStyles.addElement(style);
 		}
 	}
 	if (selectionStyle == null) {
 		// create selection style with regular font style, starting at selection start, ending at selection end
 		selectionStyle = new StyleRange(selectionStart, selectionEnd - selectionStart, foreground, background);
 		newStyles.addElement(selectionStyle);
 	}
 	else // does the current selection style end before the selection end?
 	if (selectionStyle.start + selectionStyle.length < selectionEnd) {
 		if (selectionStyle.fontStyle != SWT.NORMAL) {
 			int selectionStyleEnd = selectionStyle.start + selectionStyle.length;
 			// create selection style with regular font style, starting at selection style end, ending at selection end
 			selectionStyle = new StyleRange(selectionStyleEnd, selectionEnd - selectionStyleEnd, foreground, background);
 			newStyles.addElement(selectionStyle);
 		}
 		else {
 			selectionStyle.length = selectionEnd - selectionStyle.start;
 		}
 	}
 	styles = new StyleRange[newStyles.size()];
 	newStyles.copyInto(styles);
 	return styles;
 }
 /**
  * @see StyledTextRenderer#getWordWrap
  */
 protected boolean getWordWrap() {
 	return parent.getWordWrap();
 }
 /**
  * @see StyledTextRenderer#isFullLineSelection
  */
 protected boolean isFullLineSelection() {
 	return (parent.getStyle() & SWT.FULL_SELECTION) != 0;
 }
 /**
  * Ensures that the selection style ends at the selection end.
  * <code>selectionStyle</code> is assumed to be created based on the style
  * range of <code>style</code>. If <code>selectionStyle</code> does extend
  * beyond the selection range a new style is returned to preserve the style
  * passed in with <code>style</code>.
  * <p>
  * @param selectionStyle the selection style based on the style range in
  * 	<code>style</code>
  * @param style the existing style that is to be merged with the selection
  * @return a new style that preserves the style passed in with <code>style</code>
  * 	if the selection does not fully extend over the existing style range.
  *  null otherwise.
  */
 private StyleRange setSelectionStyleEnd(StyleRange selectionStyle, StyleRange style) {
 	int selectionEnd = parent.internalGetSelection().y;
 	StyleRange newStyle = null;

 	// does style extend beyond selection?
 	if (selectionStyle.start + selectionStyle.length > selectionEnd) {
 		int styleEnd = style.start + style.length;
 		selectionStyle.length = selectionEnd - selectionStyle.start;
 		// preserve rest (unselected part) of old style
 		newStyle = (StyleRange) style.clone();
 		newStyle.start = selectionEnd;
 		newStyle.length = styleEnd - selectionEnd;
 	}
 	return newStyle;
 }
 }
	package org.eclipse.swt.custom;

	/*
	* Copyright (c) 2002 IBM Corp. All rights reserved.
	* This file is 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
	*/

	import java.util.*;

	import org.eclipse.swt.*;
	import org.eclipse.swt.custom.StyledText.*;
	import org.eclipse.swt.graphics.*;

	/**
	* A DisplayRenderer renders the content of a StyledText widget on
	* a display device.
	*/
	class DisplayRenderer extends StyledTextRenderer {
	private StyledText parent; // used to get content and styles during rendering

	/**
	* Creates an instance of <class>DisplayRenderer</class>.
	* </p>
	* @param device Device to render on
	* @param regularFont Font to use for regular (non-bold) text
	* @param isBidi true=bidi platform, false=no bidi platform
	* @param leftMargin margin to the left of the text
	* @param parent <class>StyledText</class> widget to render
	* @param tabLength length in characters of a tab character
	*/
	DisplayRenderer(Device device, Font regularFont, boolean isBidi, int leftMargin, StyledText parent, int tabLength) {
	super(device, regularFont, isBidi, leftMargin);
	this.parent = parent;
	calculateLineHeight();
	setTabLength(tabLength);
	}
	/**
	* Dispose the specified GC.
	* </p>
	* @param gc GC to dispose.
	*/
	protected void disposeGC(GC gc) {
	gc.dispose();
	}
	/**
	* Draws the background of the line selection.
	* </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 currentFont the font currently set in gc. Cached for
	* better performance.
	* @param bidi the bidi object to use for measuring and rendering
	* text in bidi locales. null when not in bidi mode.
	*/
	protected void drawLineSelectionBackground(String line, int lineOffset, StyleRange[] styles, int paintY, GC gc, FontData currentFont, StyledTextBidi bidi) {
	Point selection = parent.internalGetSelection();
	LineCache lineCache = parent.internalGetLineCache();
	StyledTextContent content = getContent();
	int lineLength = line.length();
	int paintX;
	int selectionBackgroundWidth = -1;
	int selectionStart = Math.max(0, selection.x - lineOffset);
	int selectionEnd = selection.y - lineOffset;
	int selectionLength = selectionEnd - selectionStart;
	int horizontalScrollOffset = parent.internalGetHorizontalPixel();
	int leftMargin = getLeftMargin();
	int lineEndSpaceWidth = getLineEndSpaceWidth();
	int lineHeight = getLineHeight();
	boolean wordWrap = parent.internalGetWordWrap();

	if (selectionEnd == selectionStart \|\| selectionEnd < 0 \|\| selectionStart > lineLength) {
	return;
	}
	if (bidi != null) {
	paintX = bidiTextWidth(line, 0, selectionStart, 0, bidi);
	}
	else {
	paintX = textWidth(line, lineOffset, 0, selectionStart, filterLineStyles(styles), 0, gc, currentFont);
	}
	// selection extends past end of line?
	if (selectionEnd > lineLength) {
	if ((parent.getStyle() & SWT.FULL_SELECTION) != 0) {
	// use the greater of the client area width and the content
	// width. fixes 1G8IYRD
	selectionBackgroundWidth = Math.max(getClientArea().width, lineCache.getWidth());
	}
	else {
	selectionLength = lineLength - selectionStart;
	}
	}
	gc.setBackground(getSelectionBackground());
	gc.setForeground(getSelectionForeground());
	if (selectionBackgroundWidth == -1) {
	boolean isWrappedLine = false;

	if (wordWrap) {
	int lineEnd = lineOffset + lineLength;
	int lineIndex = content.getLineAtOffset(lineEnd);

	// is the start offset of the next line the same as the end
	// offset of this line?
	if (lineIndex < content.getLineCount() - 1 &&
	content.getOffsetAtLine(lineIndex + 1) == lineEnd) {
	isWrappedLine = true;
	}
	}
	if (bidi != null) {
	selectionBackgroundWidth = bidiTextWidth(line, selectionStart, selectionLength, paintX, bidi);
	}
	else {
	selectionBackgroundWidth = textWidth(line, lineOffset, selectionStart, selectionLength, styles, paintX, gc, currentFont);
	}
	if (selectionBackgroundWidth < 0) {
	// width can be negative when in R2L bidi segment
	paintX += selectionBackgroundWidth;
	selectionBackgroundWidth *= -1;
	}
	if (selectionEnd > lineLength && isWrappedLine == false) {
	selectionEnd = selectionStart + selectionLength;
	// if the selection extends past this line, render an additional
	// whitespace background at the end of the line to represent the
	// selected line break
	if (bidi != null && selectionEnd > 0 && bidi.isRightToLeft(selectionEnd - 1)) {
	int lineEndX = bidi.getTextWidth();
	gc.fillRectangle(lineEndX - horizontalScrollOffset + leftMargin, paintY, lineEndSpaceWidth, lineHeight);
	}
	else {
	selectionBackgroundWidth += lineEndSpaceWidth;
	}
	}
	}
	// handle empty line case
	if (bidi != null && paintX == 0) {
	paintX = StyledText.XINSET;
	}
	// fill the background first since expanded tabs are not
	// drawn as spaces. tabs just move the draw position.
	gc.fillRectangle(paintX - horizontalScrollOffset + leftMargin, paintY, selectionBackgroundWidth, lineHeight);
	}
	/**
	* 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 int[] getBidiSegments(int lineOffset, String lineText) {
	return parent.getBidiSegments(lineOffset, lineText);
	}
	/**
	* Returns the visible client area that can be used for rendering.
	* </p>
	* @return the visible client area that can be used for rendering.
	*/
	protected Rectangle getClientArea() {
	return parent.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 StyledTextContent getContent() {
	return parent.internalGetContent();
	}
	/**
	* Returns a new GC to use for rendering and measuring.
	* When the GC is no longer used it needs to be disposed by
	* calling disposeGC.
	* </p>
	* @return the GC to use for rendering and measuring.
	* @see disposeGC
	*/
	protected GC getGC() {
	return new GC(parent);
	}
	/**
	* Returns the horizontal scroll position.
	* </p>
	* @return the horizontal scroll position.
	*/
	protected int getHorizontalPixel() {
	return parent.internalGetHorizontalPixel();
	}
	/**
	* Returns the most recent caret direction.
	* Used for measuring caret positions.
	* </p>
	* @return the most recent caret direction.
	*/
	protected int getLastCaretDirection() {
	return parent.internalGetLastCaretDirection();
	}
	/**
	* @see StyledTextRenderer#getLineBackgroundData
	*/
	protected StyledTextEvent getLineBackgroundData(int lineOffset, String line) {
	return parent.getLineBackgroundData(lineOffset, line);
	}
	/**
	* @see StyledTextRenderer#getLineStyleData
	*/
	protected StyledTextEvent getLineStyleData(int lineOffset, String line) {
	StyledTextEvent logicalLineEvent = parent.getLineStyleData(lineOffset, line);

	if (logicalLineEvent != null) {
	logicalLineEvent = getLineStyleData(logicalLineEvent, lineOffset, line);
	}
	return logicalLineEvent;
	}
	/**
	* @see StyledTextRenderer#getSelection
	*/
	protected Point getSelection() {
	return parent.internalGetSelection();
	}
	/**
	* Returns the background color to be used for rendering selected text.
	* <p>
	* @return background color to be used for rendering selected text
	*/
	private Color getSelectionBackground() {
	return getDevice().getSystemColor(SWT.COLOR_LIST_SELECTION);
	}
	/**
	* Returns the foreground color to be used for rendering selected text.
	* <p>
	* @return foreground color to be used for rendering selected text
	*/
	private Color getSelectionForeground() {
	return getDevice().getSystemColor(SWT.COLOR_LIST_SELECTION_TEXT);
	}
	/**
	* @see StyledTextRenderer#getSelectionLineStyles
	*/
	/*
	Pseudo code for getSelectionLineStyles
	for each style {
	if (style ends before selection start) {
	add style to list
	}
	else
	if (style overlaps selection start (i.e., starts before selection start, ends after selection start) {
	change style end
	create new selection style with same font style starting at selection start ending at style end
	add selection style
	// does style extend beyond selection?
	if (selection style end > selection end) {
	selection style end = selection end
	// preserve rest (unselected part) of old style
	style start = selection end
	style length = old style end - selection end
	add style
	}
	}
	else
	if (style starts within selection) {
	if (no selection style created) {
	create selection style with regular font style, starting at selection start, ending at style start
	add selection style
	if (style start == selection start) {
	set selection style font to style font
	}
	}
	// gap between current selection style end and new style start?
	if (style start > selection styke end && selection style font style != NORMAL) {
	create selection style with regular font style, starting at selection style end, ending at style start
	add selection style
	}
	if (selection style font != style font) {
	selection style end = style start
	add selection style
	create selection style with style font style, starting at style start, ending at style end
	}
	else {
	selection style end = style end
	}
	// does style extend beyond selection?
	if (selection style end > selection end) {
	selection style end = selection end
	// preserve rest (unselected part) of old style
	style start = selection end
	style length = old style end - selection end
	style start = selection end
	add style
	}
	}
	else {
	if (no selection style created) {
	create selection style with regular font style, starting at selection start, ending at selection end
	add selection style
	}
	else
	if (selection style end < selection end) {
	if (selection style font style != NORMAL) {
	create selection style with regular font style, starting at selection style end, ending at selection end
	add selection style
	}
	else {
	selection style end = selection end
	}
	}
	add style
	}
	}
	if (no selection style created) {
	create selection style with regular font style, starting at selection start, ending at selection end
	add selection style to list
	}
	else
	if (selection style end < selection end) {
	if (selection style font style != NORMAL) {
	create selection style with regular font style, starting at selection style end, ending at selection end
	add selection style
	}
	else {
	selection style end = selection end
	}
	}
	*/
	protected StyleRange[] mergeSelectionLineStyles(StyleRange[] styles) {
	Point selection = parent.internalGetSelection();
	int selectionStart = selection.x;
	int selectionEnd = selection.y;
	Vector newStyles = new Vector(styles.length);
	StyleRange selectionStyle = null;
	Color foreground = getSelectionForeground();
	Color background = getSelectionBackground();

	// potential optimization: ignore styles if there is no bold style and the entire line is selected
	for (int i = 0; i < styles.length; i++) {
	StyleRange style = styles[i];
	int styleEnd = style.start + style.length;

	if (styleEnd <= selectionStart) {
	newStyles.addElement(style);
	}
	else // style overlaps selection start? (i.e., starts before selection start, ends after selection start
	if (style.start < selectionStart && styleEnd > selectionStart) {
	StyleRange newStyle = (StyleRange) style.clone();
	newStyle.length -= styleEnd - selectionStart;
	newStyles.addElement(newStyle);
	// create new selection style with same font style starting at selection start ending at style end
	selectionStyle = new StyleRange(selectionStart, styleEnd - selectionStart, foreground, background, newStyle.fontStyle);
	newStyles.addElement(selectionStyle);
	// if style extends beyond selection a new style is returned for the unselected part of the style
	newStyle = setSelectionStyleEnd(selectionStyle, style);
	if (newStyle != null) {
	newStyles.addElement(newStyle);
	}
	}
	else // style starts within selection?
	if (style.start >= selectionStart && style.start < selectionEnd) {
	StyleRange newStyle;
	int selectionStyleEnd;
	// no selection style created yet?
	if (selectionStyle == null) {
	// create selection style with regular font style, starting at selection start, ending at style start
	selectionStyle = new StyleRange(selectionStart, style.start - selectionStart, foreground, background);
	newStyles.addElement(selectionStyle);
	if (style.start == selectionStart) {
	selectionStyle.fontStyle = style.fontStyle;
	}
	}
	selectionStyleEnd = selectionStyle.start + selectionStyle.length;
	// gap between current selection style end and style start?
	if (style.start > selectionStyleEnd && selectionStyle.fontStyle != SWT.NORMAL) {
	// create selection style with regular font style, starting at selection style end, ending at style start
	selectionStyle = new StyleRange(selectionStyleEnd, style.start - selectionStyleEnd, foreground, background);
	newStyles.addElement(selectionStyle);
	}
	if (selectionStyle.fontStyle != style.fontStyle) {
	// selection style end = style start
	selectionStyle.length = style.start - selectionStyle.start;
	// create selection style with style font style, starting at style start, ending at style end
	selectionStyle = new StyleRange(style.start, style.length, foreground, background, style.fontStyle);
	newStyles.addElement(selectionStyle);
	}
	else {
	// selection style end = style end
	selectionStyle.length = styleEnd - selectionStyle.start;
	}
	// if style extends beyond selection a new style is returned for the unselected part of the style
	newStyle = setSelectionStyleEnd(selectionStyle, style);
	if (newStyle != null) {
	newStyles.addElement(newStyle);
	}
	}
	else {
	// no selection style created yet?
	if (selectionStyle == null) {
	// create selection style with regular font style, starting at selection start, ending at selection end
	selectionStyle = new StyleRange(selectionStart, selectionEnd - selectionStart, foreground, background);
	newStyles.addElement(selectionStyle);
	}
	else // does the current selection style end before the selection end?
	if (selectionStyle.start + selectionStyle.length < selectionEnd) {
	if (selectionStyle.fontStyle != SWT.NORMAL) {
	int selectionStyleEnd = selectionStyle.start + selectionStyle.length;
	// create selection style with regular font style, starting at selection style end, ending at selection end
	selectionStyle = new StyleRange(selectionStyleEnd, selectionEnd - selectionStyleEnd, foreground, background);
	newStyles.addElement(selectionStyle);
	}
	else {
	selectionStyle.length = selectionEnd - selectionStyle.start;
	}
	}
	newStyles.addElement(style);
	}
	}
	if (selectionStyle == null) {
	// create selection style with regular font style, starting at selection start, ending at selection end
	selectionStyle = new StyleRange(selectionStart, selectionEnd - selectionStart, foreground, background);
	newStyles.addElement(selectionStyle);
	}
	else // does the current selection style end before the selection end?
	if (selectionStyle.start + selectionStyle.length < selectionEnd) {
	if (selectionStyle.fontStyle != SWT.NORMAL) {
	int selectionStyleEnd = selectionStyle.start + selectionStyle.length;
	// create selection style with regular font style, starting at selection style end, ending at selection end
	selectionStyle = new StyleRange(selectionStyleEnd, selectionEnd - selectionStyleEnd, foreground, background);
	newStyles.addElement(selectionStyle);
	}
	else {
	selectionStyle.length = selectionEnd - selectionStyle.start;
	}
	}
	styles = new StyleRange[newStyles.size()];
	newStyles.copyInto(styles);
	return styles;
	}
	/**
	* @see StyledTextRenderer#getWordWrap
	*/
	protected boolean getWordWrap() {
	return parent.getWordWrap();
	}
	/**
	* @see StyledTextRenderer#isFullLineSelection
	*/
	protected boolean isFullLineSelection() {
	return (parent.getStyle() & SWT.FULL_SELECTION) != 0;
	}
	/**
	* Ensures that the selection style ends at the selection end.
	* <code>selectionStyle</code> is assumed to be created based on the style
	* range of <code>style</code>. If <code>selectionStyle</code> does extend
	* beyond the selection range a new style is returned to preserve the style
	* passed in with <code>style</code>.
	* <p>
	* @param selectionStyle the selection style based on the style range in
	* <code>style</code>
	* @param style the existing style that is to be merged with the selection
	* @return a new style that preserves the style passed in with <code>style</code>
	* if the selection does not fully extend over the existing style range.
	* null otherwise.
	*/
	private StyleRange setSelectionStyleEnd(StyleRange selectionStyle, StyleRange style) {
	int selectionEnd = parent.internalGetSelection().y;
	StyleRange newStyle = null;

	// does style extend beyond selection?
	if (selectionStyle.start + selectionStyle.length > selectionEnd) {
	int styleEnd = style.start + style.length;
	selectionStyle.length = selectionEnd - selectionStyle.start;
	// preserve rest (unselected part) of old style
	newStyle = (StyleRange) style.clone();
	newStyle.start = selectionEnd;
	newStyle.length = styleEnd - selectionEnd;
	}
	return newStyle;
	}
	}