textlayout.java

源码为Eclipse开源开发平台桌面开发工具SWT的源代码,

			return untranslateOffset(lastRun.start);
		} else {
			if (trailing != null) trailing[0] = 1;
			return untranslateOffset(lastRun.start + lastRun.length - 1);
		}
	}	
	int width = 0;
	for (int i = 0; i < lineRuns.length; i++) {
		StyleItem run = lineRuns[i];
		if (run.lineBreak && !run.softBreak) return untranslateOffset(run.start);
		if (width + run.width > x) {
			if (run.tab) {
				if (trailing != null) trailing[0] = x < (width + run.width / 2) ? 0 : 1;
				return untranslateOffset(run.start);
			}
			int cChars = run.length;
			int cGlyphs = run.glyphCount;
			int xRun = x - width;
			int[] piCP = new int[1];
			int[] piTrailing = new int[1];
			if ((orientation & SWT.RIGHT_TO_LEFT) != 0) {
				xRun = run.width - xRun;
			}
			OS.ScriptXtoCP(xRun, cChars, cGlyphs, run.clusters, run.visAttrs, run.advances, run.analysis, piCP, piTrailing);
			if (trailing != null) trailing[0] = piTrailing[0];
			return untranslateOffset(run.start + piCP[0]);
		}
		width += run.width;
	}
	if (trailing != null) trailing[0] = 0;
	return untranslateOffset(lineOffset[line + 1]);
}

/**
 * Returns the orientation of the receiver.
 *
 * @return the orientation style
 * 
 * @exception SWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public int getOrientation () {
	checkLayout();
	return orientation;
}

/**
 * Returns the previous offset for the specified offset and movement
 * type.  The movement is one of <code>SWT.MOVEMENT_CHAR</code>, 
 * <code>SWT.MOVEMENT_CLUSTER</code> or <code>SWT.MOVEMENT_WORD</code>.
 * 
 * @param offset the start offset
 * @param movement the movement type 
 * @return the previous offset
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT - if the offset is out of range</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 * 
 * @see #getNextOffset(int, int)
 */
public int getPreviousOffset (int offset, int movement) {
	checkLayout();
	return _getOffset (offset, movement, false);
}

/**
 * Returns the text segments offsets of the receiver.
 *
 * @return the text segments offsets
 *
 * @exception SWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public int[] getSegments () {
	checkLayout();
	return segments;
}

String getSegmentsText() {
	if (segments == null) return text;
	int nSegments = segments.length;
	if (nSegments <= 1) return text;
	int length = text.length();
	if (length == 0) return text;
	if (nSegments == 2) {
		if (segments[0] == 0 && segments[1] == length) return text;
	}
	char[] oldChars = new char[length];
	text.getChars(0, length, oldChars, 0);
	char[] newChars = new char[length + nSegments];
	int charCount = 0, segmentCount = 0;
	char separator = orientation == SWT.RIGHT_TO_LEFT ? RTL_MARK : LTR_MARK;
	while (charCount < length) {
		if (segmentCount < nSegments && charCount == segments[segmentCount]) {
			newChars[charCount + segmentCount++] = separator;
		} else {
			newChars[charCount + segmentCount] = oldChars[charCount++];
		}
	}
	if (segmentCount < nSegments) {
		segments[segmentCount] = charCount;
		newChars[charCount + segmentCount++] = separator;
	}
	return new String(newChars, 0, Math.min(charCount + segmentCount, newChars.length));
}

/**
 * Returns the line spacing of the receiver.
 *
 * @return the line spacing
 *
 * @exception SWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public int getSpacing () {
	checkLayout();	
	return lineSpacing;
}

/**
 * Gets the style of the receiver at the specified character offset.
 *
 * @param offset the text offset
 * @return the style or <code>null</code> if not set
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT - if the character offset is out of range</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public TextStyle getStyle (int offset) {
	checkLayout();
	int length = text.length();
	if (!(0 <= offset && offset < length)) SWT.error(SWT.ERROR_INVALID_RANGE);
	for (int i=1; i<styles.length; i++) {
		if (styles[i].start > offset) {
			return styles[i - 1].style;
		}
	}
	return null;
}

/**
 * Returns the tab list of the receiver.
 *
 * @return the tab list
 *
 * @exception SWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public int[] getTabs () {
	checkLayout();
	return tabs;
}

/**
 * Gets the receiver's text, which will be an empty
 * string if it has never been set.
 *
 * @return the receiver's text
 *
 * @exception SWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public String getText () {
	checkLayout();
	return text;
}

/**
 * Returns the width of the receiver.
 *
 * @return the width
 *
 * @exception SWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public int getWidth () {
	checkLayout();
	return wrapWidth;
}

/**
 * Returns <code>true</code> if the text layout has been disposed,
 * and <code>false</code> otherwise.
 * <p>
 * This method gets the dispose state for the text layout.
 * When a text layout has been disposed, it is an error to
 * invoke any other method using the text layout.
 *
 * @return <code>true</code> when the text layout is disposed and <code>false</code> otherwise
 */
public boolean isDisposed () {
	return device == null;
}

/*
 *  Itemize the receiver text
 */
StyleItem[] itemize () {
	segmentsText = getSegmentsText();
	int length = segmentsText.length();
	SCRIPT_CONTROL scriptControl = new SCRIPT_CONTROL();
	SCRIPT_STATE scriptState = new SCRIPT_STATE();
	final int MAX_ITEM = length + 1;
	
	if ((orientation & SWT.RIGHT_TO_LEFT) != 0) {
		scriptState.uBidiLevel = 1;
		scriptState.fArabicNumContext = true;
	}
	
	int hHeap = OS.GetProcessHeap();
	int pItems = OS.HeapAlloc(hHeap, OS.HEAP_ZERO_MEMORY, MAX_ITEM * SCRIPT_ITEM.sizeof);
	int[] pcItems = new int[1];	
	char[] chars = new char[length];
	segmentsText.getChars(0, length, chars, 0); 
	OS.ScriptItemize(chars, length, MAX_ITEM, scriptControl, scriptState, pItems, pcItems);
//	if (hr == E_OUTOFMEMORY) //TODO handle it
	
	StyleItem[] runs = merge(pItems, pcItems[0]);
	OS.HeapFree(hHeap, 0, pItems);
	return runs;
}

/* 
 *  Merge styles ranges and script items 
 */
StyleItem[] merge (int items, int itemCount) {
	int count = 0, start = 0, end = segmentsText.length(), itemIndex = 0, styleIndex = 0;
	StyleItem[] runs = new StyleItem[itemCount + styles.length];
	SCRIPT_ITEM scriptItem = new SCRIPT_ITEM();
	while (start < end) {
		StyleItem item = new StyleItem();
		item.start = start;
		item.style = styles[styleIndex].style;
		runs[count++] = item;
		OS.MoveMemory(scriptItem, items + itemIndex * SCRIPT_ITEM.sizeof, SCRIPT_ITEM.sizeof);
		item.analysis = scriptItem.a;
		scriptItem.a = new SCRIPT_ANALYSIS();
		OS.MoveMemory(scriptItem, items + (itemIndex + 1) * SCRIPT_ITEM.sizeof, SCRIPT_ITEM.sizeof);
		int itemLimit = scriptItem.iCharPos;
		int styleLimit = translateOffset(styles[styleIndex + 1].start);
		if (styleLimit <= itemLimit) {
			styleIndex++;
			start = styleLimit;
		}
		if (itemLimit <= styleLimit) {
			itemIndex++;
			start = itemLimit;
		}
		item.length = start - item.start;
	}
	StyleItem item = new StyleItem();
	item.start = end;
	OS.MoveMemory(scriptItem, items + itemCount * SCRIPT_ITEM.sizeof, SCRIPT_ITEM.sizeof);
	item.analysis = scriptItem.a;
	runs[count++] = item;
	if (runs.length != count) {
		StyleItem[] result = new StyleItem[count];
		System.arraycopy(runs, 0, result, 0, count);
		return result;
	}
	return runs;
}

/* 
 *  Reorder the run 
 */
StyleItem[] reorder (StyleItem[] runs) {
	byte[] bidiLevels = new byte[runs.length];
	for (int i=0; i<runs.length; i++) {
		bidiLevels[i] = (byte)(runs[i].analysis.s.uBidiLevel & 0x1F);
	}
	int[] log2vis = new int[runs.length];
	OS.ScriptLayout(runs.length, bidiLevels, null, log2vis);
	StyleItem[] result = new StyleItem[runs.length];
	for (int i=0; i<runs.length; i++) {
		result[log2vis[i]] = runs[i];
	}	
	if ((orientation & SWT.RIGHT_TO_LEFT) != 0) {
		for (int i = 0; i < (result.length - 1) / 2 ; i++) {
			StyleItem tmp = result[i];
			result[i] = result[result.length - i - 2];
			result[result.length - i - 2] = tmp;
		}
	}
	return result;
}

/**
 * Sets the text alignment for the receiver. The alignment controls
 * how a line of text is positioned horizontally. The argument should
 * be one of <code>SWT.LEFT</code>, <code>SWT.RIGHT</code> or <code>SWT.CENTER</code>.
 * <p>
 * The default alignment is <code>SWT.LEFT</code>.  Note that the receiver's
 * width must be set in order to use <code>SWT.RIGHT</code> or <code>SWT.CENTER</code>
 * alignment.
 *</p>
 *
 * @param alignment the new alignment 
 *
 * @exception SWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 * 
 * @see #setWidth(int)
 */
public void setAlignment (int alignment) {
	checkLayout();
	int mask = SWT.LEFT | SWT.CENTER | SWT.RIGHT;
	alignment &= mask;
	if (alignment == 0) return;
	if ((alignment & SWT.LEFT) != 0) alignment = SWT.LEFT;
	if ((alignment & SWT.RIGHT) != 0) alignment = SWT.RIGHT;
	this.alignment = alignment;
}

/**
 * Sets the ascent of the receiver. The ascent is distance in pixels
 * from the baseline to the top of the line and it is applied to all
 * lines. The default value is <code>-1</code> which means that the
 * ascent is calculated from the line fonts.
 *
 * @param ascent the new ascent
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT - if the ascent is less than <code>-1</code></li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 * 
 * @see #setDescent(int)
 * @see #getLineMetrics()
 */
public void setAscent(int ascent) {
	checkLayout();
	if (ascent < -1) SWT.error(SWT.ERROR_INVALID_ARGUMENT);
	if (this.ascent == ascent) return;
	freeRuns();
	this.ascent = ascent;
}

/**
 * Sets the descent of the receiver. The descent is distance in pixels
 * from the baseline to the bottom of the line and it is applied to all
 * lines. The default value is <code>-1</code> which means that the
 * descent is calculated from the line fonts.
 *
 * @param descent the new descent
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT - if the descent is less than <code>-1</code></li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 * 
 * @see #setAscent(int)
 * @see #getLineMetrics()
 */
public void setDescent(int descent) {
	checkLayout();
	if (descent < -1) SWT.error(SWT.ERROR_INVALID_ARGUMENT);
	if (this.descent == descent) return;
	freeRuns();
	this.descent = descent;
}

/** 
 * Sets the default font which will be used by the receiver
 * to draw and measure text. If the
 * argument is null, then a default font appropriate
 * for the platform will be used instead. Note that a text
 * style can override the default font.
 *
 * @param font the new font for the receiver, or null to indicate a default font
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT - if the font has been disposed</li>
 * </ul>
 * @exception SWTException <ul>