2362N/A * Copyright (c) 1998, 2001, Oracle and/or its affiliates. All rights reserved. 0N/A * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 0N/A * This code is free software; you can redistribute it and/or modify it 0N/A * under the terms of the GNU General Public License version 2 only, as 2362N/A * published by the Free Software Foundation. Oracle designates this 0N/A * particular file as subject to the "Classpath" exception as provided 2362N/A * by Oracle in the LICENSE file that accompanied this code. 0N/A * This code is distributed in the hope that it will be useful, but WITHOUT 0N/A * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 0N/A * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 0N/A * version 2 for more details (a copy is included in the LICENSE file that 0N/A * accompanied this code). 0N/A * You should have received a copy of the GNU General Public License version 0N/A * 2 along with this work; if not, write to the Free Software Foundation, 0N/A * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 2362N/A * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 2362N/A * or visit www.oracle.com if you need additional information or have any 0N/A * (C) Copyright Taligent, Inc. 1996 - 1997, All Rights Reserved 0N/A * (C) Copyright IBM Corp. 1996 - 1998, All Rights Reserved 0N/A * The original version of this source code and documentation is 0N/A * copyrighted and owned by Taligent, Inc., a wholly-owned subsidiary 0N/A * of IBM. These materials are provided under terms of a License 0N/A * Agreement between Taligent and Sun. This technology is protected 0N/A * by multiple US and International patents. 0N/A * This notice and attribution to Taligent may not be removed. 0N/A * Taligent is a registered trademark of Taligent, Inc. 0N/A * The <code>LineBreakMeasurer</code> class allows styled text to be 0N/A * broken into lines (or segments) that fit within a particular visual 0N/A * advance. This is useful for clients who wish to display a paragraph of 0N/A * text that fits within a specific width, called the <b>wrapping 0N/A * <code>LineBreakMeasurer</code> is constructed with an iterator over 0N/A * styled text. The iterator's range should be a single paragraph in the 0N/A * <code>LineBreakMeasurer</code> maintains a position in the text for the 0N/A * start of the next text segment. Initially, this position is the 0N/A * start of text. Paragraphs are assigned an overall direction (either 0N/A * left-to-right or right-to-left) according to the bidirectional 0N/A * formatting rules. All segments obtained from a paragraph have the 0N/A * same direction as the paragraph. 0N/A * Segments of text are obtained by calling the method 0N/A * <code>nextLayout</code>, which returns a {@link TextLayout} 0N/A * representing the text that fits within the wrapping width. 0N/A * The <code>nextLayout</code> method moves the current position 0N/A * to the end of the layout returned from <code>nextLayout</code>. 0N/A * <code>LineBreakMeasurer</code> implements the most commonly used 0N/A * line-breaking policy: Every word that fits within the wrapping 0N/A * width is placed on the line. If the first word does not fit, then all 0N/A * of the characters that fit within the wrapping width are placed on the 0N/A * line. At least one character is placed on each line. 0N/A * The <code>TextLayout</code> instances returned by 0N/A * <code>LineBreakMeasurer</code> treat tabs like 0-width spaces. Clients 0N/A * who wish to obtain tab-delimited segments for positioning should use 0N/A * the overload of <code>nextLayout</code> which takes a limiting offset 0N/A * The limiting offset should be the first character after the tab. 0N/A * The <code>TextLayout</code> objects returned from this method end 0N/A * at the limit provided (or before, if the text between the current 0N/A * position and the limit won't fit entirely within the wrapping 0N/A * Clients who are laying out tab-delimited text need a slightly 0N/A * different line-breaking policy after the first segment has been 0N/A * placed on a line. Instead of fitting partial words in the 0N/A * remaining space, they should place words which don't fit in the 0N/A * remaining space entirely on the next line. This change of policy 0N/A * can be requested in the overload of <code>nextLayout</code> which 0N/A * takes a <code>boolean</code> parameter. If this parameter is 0N/A * <code>true</code>, <code>nextLayout</code> returns 0N/A * <code>null</code> if the first word won't fit in 0N/A * the given space. See the tab sample below. 0N/A * In general, if the text used to construct the 0N/A * <code>LineBreakMeasurer</code> changes, a new 0N/A * <code>LineBreakMeasurer</code> must be constructed to reflect 0N/A * the change. (The old <code>LineBreakMeasurer</code> continues to 0N/A * function properly, but it won't be aware of the text change.) 0N/A * Nevertheless, if the text change is the insertion or deletion of a 0N/A * single character, an existing <code>LineBreakMeasurer</code> can be 0N/A * 'updated' by calling <code>insertChar</code> or 0N/A * <code>deleteChar</code>. Updating an existing 0N/A * <code>LineBreakMeasurer</code> is much faster than creating a new one. 0N/A * Clients who modify text based on user typing should take advantage 0N/A * <strong>Examples</strong>:<p> 0N/A * Rendering a paragraph in a component 0N/A * public void paint(Graphics graphics) { 0N/A * Point2D pen = new Point2D(10, 20); 0N/A * Graphics2D g2d = (Graphics2D)graphics; 0N/A * FontRenderContext frc = g2d.getFontRenderContext(); 0N/A * // let styledText be an AttributedCharacterIterator containing at least 0N/A * LineBreakMeasurer measurer = new LineBreakMeasurer(styledText, frc); 0N/A * float wrappingWidth = getSize().width - 15; 0N/A * while (measurer.getPosition() < fStyledText.length()) { 0N/A * TextLayout layout = measurer.nextLayout(wrappingWidth); 0N/A * pen.y += (layout.getAscent()); 0N/A * float dx = layout.isLeftToRight() ? 0N/A * 0 : (wrappingWidth - layout.getAdvance()); 0N/A * layout.draw(graphics, pen.x + dx, pen.y); 0N/A * pen.y += layout.getDescent() + layout.getLeading(); 0N/A * Rendering text with tabs. For simplicity, the overall text 0N/A * direction is assumed to be left-to-right 0N/A * public void paint(Graphics graphics) { 0N/A * float leftMargin = 10, rightMargin = 310; 0N/A * float[] tabStops = { 100, 250 }; 0N/A * // assume styledText is an AttributedCharacterIterator, and the number 0N/A * // of tabs in styledText is tabCount 0N/A * int[] tabLocations = new int[tabCount+1]; 0N/A * for (char c = styledText.first(); c != styledText.DONE; c = styledText.next()) { 0N/A * tabLocations[i++] = styledText.getIndex(); 0N/A * tabLocations[tabCount] = styledText.getEndIndex() - 1; 0N/A * // Now tabLocations has an entry for every tab's offset in 0N/A * // the text. For convenience, the last entry is tabLocations 0N/A * // is the offset of the last character in the text. 0N/A * LineBreakMeasurer measurer = new LineBreakMeasurer(styledText); 0N/A * int currentTab = 0; 0N/A * float verticalPos = 20; 0N/A * while (measurer.getPosition() < styledText.getEndIndex()) { 0N/A * // Lay out and draw each line. All segments on a line 0N/A * // must be computed before any drawing can occur, since 0N/A * // we must know the largest ascent on the line. 0N/A * // TextLayouts are computed and stored in a Vector; 0N/A * // their horizontal positions are stored in a parallel 0N/A * // lineContainsText is true after first segment is drawn 0N/A * boolean lineContainsText = false; 0N/A * boolean lineComplete = false; 0N/A * float maxAscent = 0, maxDescent = 0; 0N/A * float horizontalPos = leftMargin; 0N/A * Vector layouts = new Vector(1); 0N/A * Vector penPositions = new Vector(1); 0N/A * while (!lineComplete) { 0N/A * float wrappingWidth = rightMargin - horizontalPos; 0N/A * TextLayout layout = 0N/A * measurer.nextLayout(wrappingWidth, 0N/A * tabLocations[currentTab]+1, 0N/A * lineContainsText); 0N/A * // layout can be null if lineContainsText is true 0N/A * if (layout != null) { 0N/A * layouts.addElement(layout); 0N/A * penPositions.addElement(new Float(horizontalPos)); 0N/A * horizontalPos += layout.getAdvance(); 0N/A * maxAscent = Math.max(maxAscent, layout.getAscent()); 0N/A * maxDescent = Math.max(maxDescent, 0N/A * layout.getDescent() + layout.getLeading()); 0N/A * lineComplete = true; 0N/A * lineContainsText = true; 0N/A * if (measurer.getPosition() == tabLocations[currentTab]+1) { 0N/A * if (measurer.getPosition() == styledText.getEndIndex()) 0N/A * lineComplete = true; 0N/A * else if (horizontalPos >= tabStops[tabStops.length-1]) 0N/A * lineComplete = true; 0N/A * if (!lineComplete) { 0N/A * // move to next tab stop 0N/A * for (j=0; horizontalPos >= tabStops[j]; j++) {} 0N/A * horizontalPos = tabStops[j]; 0N/A * verticalPos += maxAscent; 0N/A * Enumeration layoutEnum = layouts.elements(); 0N/A * Enumeration positionEnum = penPositions.elements(); 0N/A * // now iterate through layouts and draw them 0N/A * while (layoutEnum.hasMoreElements()) { 0N/A * TextLayout nextLayout = (TextLayout) layoutEnum.nextElement(); 0N/A * Float nextPosition = (Float) positionEnum.nextElement(); 0N/A * nextLayout.draw(graphics, nextPosition.floatValue(), verticalPos); 0N/A * verticalPos += maxDescent; 0N/A * Constructs a <code>LineBreakMeasurer</code> for the specified text. 0N/A * @param text the text for which this <code>LineBreakMeasurer</code> 0N/A * produces <code>TextLayout</code> objects; the text must contain 0N/A * at least one character; if the text available through 0N/A * <code>iter</code> changes, further calls to this 0N/A * <code>LineBreakMeasurer</code> instance are undefined (except, 0N/A * in some cases, when <code>insertChar</code> or 0N/A * <code>deleteChar</code> are invoked afterward - see below) 0N/A * @param frc contains information about a graphics device which is 0N/A * needed to measure the text correctly; 0N/A * text measurements can vary slightly depending on the 0N/A * device resolution, and attributes such as antialiasing; this 0N/A * parameter does not specify a translation between the 0N/A * <code>LineBreakMeasurer</code> and user space 0N/A * @see LineBreakMeasurer#insertChar 0N/A * @see LineBreakMeasurer#deleteChar 0N/A * Constructs a <code>LineBreakMeasurer</code> for the specified text. 0N/A * @param text the text for which this <code>LineBreakMeasurer</code> 0N/A * produces <code>TextLayout</code> objects; the text must contain 0N/A * at least one character; if the text available through 0N/A * <code>iter</code> changes, further calls to this 0N/A * <code>LineBreakMeasurer</code> instance are undefined (except, 0N/A * in some cases, when <code>insertChar</code> or 0N/A * <code>deleteChar</code> are invoked afterward - see below) 0N/A * @param breakIter the {@link BreakIterator} which defines line 0N/A * @param frc contains information about a graphics device which is 0N/A * needed to measure the text correctly; 0N/A * text measurements can vary slightly depending on the 0N/A * device resolution, and attributes such as antialiasing; this 0N/A * parameter does not specify a translation between the 0N/A * <code>LineBreakMeasurer</code> and user space 0N/A * @throws IllegalArgumentException if the text has less than one character 0N/A * @see LineBreakMeasurer#insertChar 0N/A * @see LineBreakMeasurer#deleteChar 0N/A * Returns the position at the end of the next layout. Does NOT 0N/A * update the current position of this <code>LineBreakMeasurer</code>. 0N/A * @param wrappingWidth the maximum visible advance permitted for 0N/A * the text in the next layout 0N/A * @return an offset in the text representing the limit of the 0N/A * next <code>TextLayout</code>. 0N/A * Returns the position at the end of the next layout. Does NOT 0N/A * update the current position of this <code>LineBreakMeasurer</code>. 0N/A * @param wrappingWidth the maximum visible advance permitted for 0N/A * the text in the next layout 0N/A * @param offsetLimit the first character that can not be included 0N/A * in the next layout, even if the text after the limit would fit 0N/A * within the wrapping width; <code>offsetLimit</code> must be 0N/A * greater than the current position 0N/A * @param requireNextWord if <code>true</code>, the current position 0N/A * that is returned if the entire next word does not fit within 0N/A * <code>wrappingWidth</code>; if <code>false</code>, the offset 0N/A * returned is at least one greater than the current position 0N/A * @return an offset in the text representing the limit of the 0N/A * next <code>TextLayout</code> 0N/A // Break is in a word; back up to previous break. 0N/A // NOTE: I think that breakIter.preceding(limit) should be 0N/A // equivalent to breakIter.last(), breakIter.previous() but 0N/A // the authors of BreakIterator thought otherwise... 0N/A // If they were equivalent then the first branch would be 0N/A // first word doesn't fit on line 0N/A * Returns the next layout, and updates the current position. 0N/A * @param wrappingWidth the maximum visible advance permitted for 0N/A * the text in the next layout 0N/A * @return a <code>TextLayout</code>, beginning at the current 0N/A * position, which represents the next line fitting within 0N/A * <code>wrappingWidth</code> 0N/A * Returns the next layout, and updates the current position. 0N/A * @param wrappingWidth the maximum visible advance permitted 0N/A * for the text in the next layout 0N/A * @param offsetLimit the first character that can not be 0N/A * included in the next layout, even if the text after the limit 0N/A * would fit within the wrapping width; <code>offsetLimit</code> 0N/A * must be greater than the current position 0N/A * @param requireNextWord if <code>true</code>, and if the entire word 0N/A * at the current position does not fit within the wrapping width, 0N/A * <code>null</code> is returned. If <code>false</code>, a valid 0N/A * layout is returned that includes at least the character at the 0N/A * @return a <code>TextLayout</code>, beginning at the current 0N/A * position, that represents the next line fitting within 0N/A * <code>wrappingWidth</code>. If the current position is at the end 0N/A * of the text used by this <code>LineBreakMeasurer</code>, 0N/A * <code>null</code> is returned 0N/A * Returns the current position of this <code>LineBreakMeasurer</code>. 0N/A * @return the current position of this <code>LineBreakMeasurer</code> 0N/A * Sets the current position of this <code>LineBreakMeasurer</code>. 0N/A * @param newPosition the current position of this 0N/A * <code>LineBreakMeasurer</code>; the position should be within the 0N/A * text used to construct this <code>LineBreakMeasurer</code> (or in 0N/A * the text most recently passed to <code>insertChar</code> 0N/A * or <code>deleteChar</code> 0N/A * Updates this <code>LineBreakMeasurer</code> after a single 0N/A * character is inserted into the text, and sets the current 0N/A * position to the beginning of the paragraph. 0N/A * @param newParagraph the text after the insertion 0N/A * @param insertPos the position in the text at which the character 0N/A * @throws IndexOutOfBoundsException if <code>insertPos</code> is less 0N/A * than the start of <code>newParagraph</code> or greater than 0N/A * or equal to the end of <code>newParagraph</code> 0N/A * @throws NullPointerException if <code>newParagraph</code> is 0N/A * Updates this <code>LineBreakMeasurer</code> after a single 0N/A * character is deleted from the text, and sets the current 0N/A * position to the beginning of the paragraph. 0N/A * @param newParagraph the text after the deletion 0N/A * @param deletePos the position in the text at which the character 0N/A * @throws IndexOutOfBoundsException if <code>deletePos</code> is 0N/A * less than the start of <code>newParagraph</code> or greater 0N/A * than the end of <code>newParagraph</code> 0N/A * @throws NullPointerException if <code>newParagraph</code> is