styledtext.java

源码为Eclipse开源开发平台桌面开发工具SWT的源代码,

		// systems that don't support Unicode RTF.
		String cpg = System.getProperty("file.encoding").toLowerCase();
		if (cpg.startsWith("cp") || cpg.startsWith("ms")) {
			cpg = cpg.substring(2, cpg.length());
			header.append("\\ansicpg");
			header.append(cpg);
		}
		header.append("\\uc0\\deff0{\\fonttbl{\\f0\\fnil ");
		header.append(fontData.getName());
		header.append(";}}\n{\\colortbl");
		for (int i = 0; i < colorTable.size(); i++) {
			Color color = (Color) colorTable.elementAt(i);
			header.append("\\red");
			header.append(color.getRed());
			header.append("\\green");
			header.append(color.getGreen());
			header.append("\\blue");
			header.append(color.getBlue());
			header.append(";");
		} 
		// some RTF readers ignore the deff0 font tag. Explicitly 
		// set the font for the whole document to work around this.
		header.append("}\n{\\f0\\fs");
		// font size is specified in half points
		header.append(fontData.getHeight() * 2);
		header.append(" ");
		write(header.toString(), 0);
	}
	/**
	 * Appends the specified line text to the RTF data.  Lines will be formatted 
	 * using the styles queried from the LineStyleListener, if set, or those set 
	 * directly in the widget.
	 * <p>
	 *
	 * @param line line text to write as RTF. Must not contain line breaks
	 * 	Line breaks should be written using writeLineDelimiter()
	 * @param lineOffset offset of the line. 0 based from the start of the 
	 * 	widget document. Any text occurring before the start offset or after the 
	 * 	end offset specified during object creation is ignored.
	 * @exception SWTException <ul>
	 *   <li>ERROR_IO when the writer is closed.</li>
	 * </ul>
	 */
	public void writeLine(String line, int lineOffset) {
		StyleRange[] styles = new StyleRange[0];
		Color lineBackground = null;
		StyledTextEvent event;
		
		if (isClosed()) {
			SWT.error(SWT.ERROR_IO);
		}
		event = renderer.getLineStyleData(lineOffset, line);
		if (event != null) {
			styles = event.styles;
		}
		event = renderer.getLineBackgroundData(lineOffset, line);
		if (event != null) {
			lineBackground = event.lineBackground;
		}
		if (lineBackground == null) {
			lineBackground = getBackground();
		}
		writeStyledLine(line, lineOffset, styles, lineBackground);
	}
	/**
	 * Appends the specified line delmimiter to the RTF data.
	 * <p>
	 *
	 * @param lineDelimiter line delimiter to write as RTF.
	 * @exception SWTException <ul>
	 *   <li>ERROR_IO when the writer is closed.</li>
	 * </ul>
	 */
	public void writeLineDelimiter(String lineDelimiter) {
		if (isClosed()) {
			SWT.error(SWT.ERROR_IO);
		}
		write(lineDelimiter, 0, lineDelimiter.length());
		write("\\par ");
	}
	/**
	 * Appends the specified line text to the RTF data.
	 * Use the colors and font styles specified in "styles" and "lineBackground".
	 * Formatting is written to reflect the text rendering by the text widget.
	 * Style background colors take precedence over the line background color.
	 * Background colors are written using the \highlight tag (vs. the \cb tag).
	 * <p>
	 *
	 * @param line line text to write as RTF. Must not contain line breaks
	 * 	Line breaks should be written using writeLineDelimiter()
	 * @param lineOffset offset of the line. 0 based from the start of the 
	 * 	widget document. Any text occurring before the start offset or after the 
	 * 	end offset specified during object creation is ignored.
	 * @param styles styles to use for formatting. Must not be null.
	 * @param linebackground line background color to use for formatting. 
	 * 	May be null.
	 */
	void writeStyledLine(String line, int lineOffset, StyleRange[] styles, Color lineBackground) {
		int lineLength = line.length();
		int lineIndex;
		int copyEnd;
		int startOffset = getStart();		
		int endOffset = startOffset + super.getCharCount();
		int lineEndOffset = Math.min(lineLength, endOffset - lineOffset);
		int writeOffset = startOffset - lineOffset;
		
		if (writeOffset >= line.length()) {
			return;					// whole line is outside write range
		}
		else
		if (writeOffset > 0) {
			lineIndex = writeOffset;		// line starts before RTF write start
		}
		else {
			lineIndex = 0;
		}
		if (lineBackground != null) {
			write("{\\highlight");
			write(getColorIndex(lineBackground, DEFAULT_BACKGROUND));
			write(" "); 
		}
		for (int i = 0; i < styles.length; i++) {		
			StyleRange style = styles[i];
			int start = style.start - lineOffset;
			int end = start + style.length;
			int colorIndex;
			// skip over partial first line
			if (end < writeOffset) {
				continue;
			}
			// style starts beyond line end or RTF write end
			if (start >= lineEndOffset) {
				break;
			}
			// write any unstyled text
			if (lineIndex < start) { 
				// copy to start of style
				// style starting betond end of write range or end of line 
				// is guarded against above.
				write(line, lineIndex, start);
				lineIndex = start;
			}
			// write styled text
			colorIndex = getColorIndex(style.background, DEFAULT_BACKGROUND);
			write("{\\cf");
			write(getColorIndex(style.foreground, DEFAULT_FOREGROUND));
			if (colorIndex != DEFAULT_BACKGROUND) {
				write("\\highlight");
				write(colorIndex);
			}
			if (style.fontStyle == SWT.BOLD) {
				write("\\b"); 
			}
			write(" "); 
			// copy to end of style or end of write range or end of line
			copyEnd = Math.min(end, lineEndOffset);
			// guard against invalid styles and let style processing continue
			copyEnd = Math.max(copyEnd, lineIndex);
			write(line, lineIndex, copyEnd);
			if (style.fontStyle == SWT.BOLD) {
				write("\\b0"); 
			}
			write("}");
			lineIndex = copyEnd;
		}
		// write unstyled text at the end of the line
		if (lineIndex < lineEndOffset) {
			write(line, lineIndex, lineEndOffset);
		}
		if (lineBackground != null) {
			write("}");
		}
	}
	}
	/**
	 * The <code>TextWriter</code> class is used to write widget content to
	 * a string.  Whole and partial lines and line breaks can be written. To write 
	 * partial lines, specify the start and length of the desired segment 
	 * during object creation.
	 * <p>
	 * </b>NOTE:</b> <code>toString()</code> is guaranteed to return a valid string only after close() 
	 * has been called. 
	 */
	class TextWriter {
		private StringBuffer buffer;
		private int startOffset;	// offset of first character that will be written
		private int endOffset;		// offset of last character that will be written. 
									// 0 based from the beginning of the widget text. 
		private boolean isClosed = false;
	
	/**
	 * Creates a writer that writes content starting at offset "start"
	 * in the document.  <code>start</code> and <code>length</code> can be set to specify partial lines.
	 * <p>
	 *
	 * @param start start offset of content to write, 0 based from beginning of document
	 * @param length length of content to write
	 */
	public TextWriter(int start, int length) {
		buffer = new StringBuffer(length);
		startOffset = start;
		endOffset = start + length;
	}
	/**
	 * Closes the writer. Once closed no more content can be written.
	 * <b>NOTE:</b>  <code>toString()</code> is not guaranteed to return a valid string unless
	 * the writer is closed.
	 */
	public void close() {
		if (isClosed == false) {
			isClosed = true;
		}
	}
	/** 
	 * Returns the number of characters to write.
	 */
	public int getCharCount() {
		return endOffset - startOffset;
	}	
	/** 
	 * Returns the offset where writing starts. 0 based from the start of 
	 * the widget text. Used to write partial lines.
	 */
	public int getStart() {
		return startOffset;
	}
	/**
	 * Returns whether the writer is closed.
	 */
	public boolean isClosed() {
		return isClosed;
	}
	/**
	 * Returns the string.  <code>close()</code> must be called before <code>toString()</code> 
	 * is guaranteed to return a valid string.
	 * <p>
	 *
	 * @return the string
	 */
	public String toString() {
		return buffer.toString();
	}
	/**
	 * Appends the given string to the data.
	 */
	void write(String string) {
		buffer.append(string);
	}	
	/**
	 * Inserts the given string to the data at the specified offset.
	 * Do nothing if "offset" is < 0 or > getCharCount()
	 * <p>
	 *
	 * @param string text to insert
	 * @param offset offset in the existing data to insert "string" at.
	 */
	void write(String string, int offset) {
		if (offset < 0 || offset > buffer.length()) {
			return;
		}
		buffer.insert(offset, string);
	}	
	/**
	 * Appends the given int to the data.
	 */
	void write(int i) {
		buffer.append(i);
	}
	/**
	 * Appends the given character to the data.
	 */
	void write(char i) {
		buffer.append(i);
	}			
	/**
	 * Appends the specified line text to the data.
	 * <p>
	 *
	 * @param line line text to write. Must not contain line breaks
	 * 	Line breaks should be written using writeLineDelimiter()
	 * @param lineOffset offset of the line. 0 based from the start of the 
	 * 	widget document. Any text occurring before the start offset or after the 
	 *	end offset specified during object creation is ignored.
	 * @exception SWTException <ul>
	 *   <li>ERROR_IO when the writer is closed.</li>
	 * </ul>
	 */
	public void writeLine(String line, int lineOffset) {
		int lineLength = line.length();
		int lineIndex;
		int copyEnd;
		int writeOffset = startOffset - lineOffset;
		
		if (isClosed) {
			SWT.error(SWT.ERROR_IO);
		}		
		if (writeOffset >= lineLength) {
			return;							// whole line is outside write range
		}
		else
		if (writeOffset > 0) {
			lineIndex = writeOffset;		// line starts before write start
		}
		else {
			lineIndex = 0;
		}
		copyEnd = Math.min(lineLength, endOffset - lineOffset);
		if (lineIndex < copyEnd) {
			write(line.substring(lineIndex, copyEnd));
		}		
	}
	/**
	 * Appends the specified line delmimiter to the data.
	 * <p>
	 *
	 * @param lineDelimiter line delimiter to write
	 * @exception SWTException <ul>
	 *   <li>ERROR_IO when the writer is closed.</li>
	 * </ul>
	 */
	public void writeLineDelimiter(String lineDelimiter) {
		if (isClosed) {
			SWT.error(SWT.ERROR_IO);
		}
		write(lineDelimiter);
	}
	}
	/**
	 * LineCache provides an interface to calculate and invalidate 
	 * line based data.
	 * Implementors need to return a line width in <code>getWidth</code>.
	 */
	interface LineCache {
	/**
	 * Calculates the lines in the specified range.
	 * <p>
	 * 
	 * @param startLine first line to calculate
	 * @param lineCount number of lines to calculate
	 */
	public void calculate(int startLine, int lineCount);
	/**
	 * Returns a width that will be used by the <code>StyledText</code> 
	 * widget to size a horizontal scroll bar.
	 * <p>
	 *
	 * @return the line width
	 */
	public int getWidth();
	/**
	 * Resets the lines in the specified range.
	 * This method is called in <code>StyledText.redraw()</code>
	 * and allows implementors to call redraw themselves during reset.
	 * <p>
	 *
	 * @param startLine the first line to reset
	 * @param lineCount the number of lines to reset
	 * @param calculateMaxWidth true=implementors should retain a 
	 * 	valid width even if it is affected by the reset operation.
	 * 	false=the width may be set to 0
	 */
	public void redrawReset(int startLine, int lineCount, boolean calculateMaxWidth);
	/**
	 * Resets the lines in the specified range.
	 * <p>
	 *
	 * @param startLine the first line to reset
	 * @param lineCount the number of lines to reset
	 * @param calculateMaxWidth true=implementors should retain a 
	 * 	valid width even if it is affected by the reset operation.
	 * 	false=the width may be set to 0
	 */
	public void reset(int startLine, int lineCount, boolean calculateMaxWidth);
	/** 
	 * Called when a text change occurred.
	 * <p>
	 *
	 * @param startOffset	the start offset of the text change
	 * @param newLineCount the number of inserted lines
	 * @param replaceLineCount the number of deleted lines
	 * @param newCharCount the number of new characters
	 * @param replaceCharCount the number of deleted characters
	 */  
	public void textChanged(int startOffset, int newLineCount, int replaceLineCount, int newCharCount, int replaceCharCount);
	}
	/**
	 * Keeps track of line widths and the longest line in the 
	 * StyledText document.
	 * Line widths are calculated when requested by a call to 
	 * <code>calculate</code> and cached until reset by a call 
	 * to <code>redrawReset</code> or <code>reset</code>.