| /* Utilities.java -- |
| Copyright (C) 2004, 2005 Free Software Foundation, Inc. |
| |
| This file is part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| GNU Classpath is distributed in the hope that it will be useful, but |
| WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
| 02111-1307 USA. |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| |
| package javax.swing.text; |
| |
| import java.awt.FontMetrics; |
| import java.awt.Graphics; |
| |
| /** |
| * A set of utilities to deal with text. This is used by several other classes |
| * inside this package. |
| * |
| * @author Roman Kennke (roman@ontographics.com) |
| */ |
| public class Utilities |
| { |
| /** |
| * The length of the char buffer that holds the characters to be drawn. |
| */ |
| private static final int BUF_LENGTH = 64; |
| |
| /** |
| * Creates a new <code>Utilities</code> object. |
| */ |
| public Utilities() |
| { |
| // Nothing to be done here. |
| } |
| |
| /** |
| * Draws the given text segment. Contained tabs and newline characters |
| * are taken into account. Tabs are expanded using the |
| * specified {@link TabExpander}. |
| * |
| * @param s the text fragment to be drawn. |
| * @param x the x position for drawing. |
| * @param y the y position for drawing. |
| * @param g the {@link Graphics} context for drawing. |
| * @param e the {@link TabExpander} which specifies the Tab-expanding |
| * technique. |
| * @param startOffset starting offset in the text. |
| * @return the x coordinate at the end of the drawn text. |
| */ |
| public static final int drawTabbedText(Segment s, int x, int y, Graphics g, |
| TabExpander e, int startOffset) |
| { |
| // This buffers the chars to be drawn. |
| char[] buffer = s.array; |
| |
| |
| // The current x and y pixel coordinates. |
| int pixelX = x; |
| int pixelY = y; |
| |
| // The font metrics of the current selected font. |
| FontMetrics metrics = g.getFontMetrics(); |
| int ascent = metrics.getAscent(); |
| |
| int pixelWidth = 0; |
| int pos = 0; |
| int len = 0; |
| |
| for (int offset = s.offset; offset < (s.offset + s.count); ++offset) |
| { |
| char c = buffer[offset]; |
| if (c == '\t' || c == '\n') |
| { |
| if (len > 0) { |
| g.drawChars(buffer, pos, len, pixelX, pixelY + ascent); |
| pixelX += pixelWidth; |
| pixelWidth = 0; |
| } |
| pos = offset+1; |
| len = 0; |
| } |
| |
| switch (c) |
| { |
| case '\t': |
| // In case we have a tab, we just 'jump' over the tab. |
| // When we have no tab expander we just use the width of ' '. |
| if (e != null) |
| pixelX = (int) e.nextTabStop((float) pixelX, |
| startOffset + offset - s.offset); |
| else |
| pixelX += metrics.charWidth(' '); |
| break; |
| case '\n': |
| // In case we have a newline, we must jump to the next line. |
| pixelY += metrics.getHeight(); |
| pixelX = x; |
| break; |
| default: |
| ++len; |
| pixelWidth += metrics.charWidth(buffer[offset]); |
| break; |
| } |
| } |
| |
| if (len > 0) |
| g.drawChars(buffer, pos, len, pixelX, pixelY + ascent); |
| |
| return pixelX; |
| } |
| |
| /** |
| * Determines the width, that the given text <code>s</code> would take |
| * if it was printed with the given {@link java.awt.FontMetrics} on the |
| * specified screen position. |
| * @param s the text fragment |
| * @param metrics the font metrics of the font to be used |
| * @param x the x coordinate of the point at which drawing should be done |
| * @param e the {@link TabExpander} to be used |
| * @param startOffset the index in <code>s</code> where to start |
| * @returns the width of the given text s. This takes tabs and newlines |
| * into account. |
| */ |
| public static final int getTabbedTextWidth(Segment s, FontMetrics metrics, |
| int x, TabExpander e, |
| int startOffset) |
| { |
| // This buffers the chars to be drawn. |
| char[] buffer = s.array; |
| |
| // The current x coordinate. |
| int pixelX = x; |
| |
| // The current maximum width. |
| int maxWidth = 0; |
| |
| for (int offset = s.offset; offset < (s.offset + s.count); ++offset) |
| { |
| switch (buffer[offset]) |
| { |
| case '\t': |
| // In case we have a tab, we just 'jump' over the tab. |
| // When we have no tab expander we just use the width of 'm'. |
| if (e != null) |
| pixelX = (int) e.nextTabStop((float) pixelX, |
| startOffset + offset - s.offset); |
| else |
| pixelX += metrics.charWidth(' '); |
| break; |
| case '\n': |
| // In case we have a newline, we must 'draw' |
| // the buffer and jump on the next line. |
| pixelX += metrics.charWidth(buffer[offset]); |
| maxWidth = Math.max(maxWidth, pixelX - x); |
| pixelX = x; |
| break; |
| default: |
| // Here we draw the char. |
| pixelX += metrics.charWidth(buffer[offset]); |
| break; |
| } |
| } |
| |
| // Take the last line into account. |
| maxWidth = Math.max(maxWidth, pixelX - x); |
| |
| return maxWidth; |
| } |
| } |