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Diffstat (limited to 'libjava/classpath/javax/swing/text/Utilities.java')
| -rw-r--r-- | libjava/classpath/javax/swing/text/Utilities.java | 198 |
1 files changed, 198 insertions, 0 deletions
diff --git a/libjava/classpath/javax/swing/text/Utilities.java b/libjava/classpath/javax/swing/text/Utilities.java new file mode 100644 index 00000000000..d40408ddc3f --- /dev/null +++ b/libjava/classpath/javax/swing/text/Utilities.java @@ -0,0 +1,198 @@ +/* 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., 51 Franklin Street, Fifth Floor, Boston, MA +02110-1301 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 = s.offset; + 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; + } +} |