001/* LabelView.java -- A view to render styled text
002   Copyright (C) 2005  Free Software Foundation, Inc.
003
004This file is part of GNU Classpath.
005
006GNU Classpath is free software; you can redistribute it and/or modify
007it under the terms of the GNU General Public License as published by
008the Free Software Foundation; either version 2, or (at your option)
009any later version.
010
011GNU Classpath is distributed in the hope that it will be useful, but
012WITHOUT ANY WARRANTY; without even the implied warranty of
013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014General Public License for more details.
015
016You should have received a copy of the GNU General Public License
017along with GNU Classpath; see the file COPYING.  If not, write to the
018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
01902110-1301 USA.
020
021Linking this library statically or dynamically with other modules is
022making a combined work based on this library.  Thus, the terms and
023conditions of the GNU General Public License cover the whole
024combination.
025
026As a special exception, the copyright holders of this library give you
027permission to link this library with independent modules to produce an
028executable, regardless of the license terms of these independent
029modules, and to copy and distribute the resulting executable under
030terms of your choice, provided that you also meet, for each linked
031independent module, the terms and conditions of the license of that
032module.  An independent module is a module which is not derived from
033or based on this library.  If you modify this library, you may extend
034this exception to your version of the library, but you are not
035obligated to do so.  If you do not wish to do so, delete this
036exception statement from your version. */
037
038
039package javax.swing.text;
040
041import java.awt.Color;
042import java.awt.Container;
043import java.awt.Font;
044import java.awt.FontMetrics;
045import java.awt.Shape;
046import java.awt.Toolkit;
047
048import javax.swing.event.DocumentEvent;
049
050/**
051 * A {@link GlyphView} that caches the textattributes for most effective
052 * rendering.
053 *
054 * @author Roman Kennke (kennke@aicas.com)
055 */
056public class LabelView extends GlyphView
057{
058
059  /**
060   * The background color.
061   */
062  Color background;
063
064  /**
065   * The foreground color.
066   */
067  Color foreground;
068
069  /**
070   * The background color.
071   */
072  Font font;
073
074  /**
075   * The strikethrough flag.
076   */
077  boolean strikeThrough;
078
079  /**
080   * The underline flag.
081   */
082  boolean underline;
083
084  /**
085   * The subscript flag.
086   */
087  boolean subscript;
088
089  /**
090   * The superscript flag.
091   */
092  boolean superscript;
093
094  /**
095   * Indicates if the attributes must be refetched.
096   */
097  private boolean valid;
098
099  /**
100   * Creates a new <code>GlyphView</code> for the given <code>Element</code>.
101   *
102   * @param element the element that is rendered by this GlyphView
103   */
104  public LabelView(Element element)
105  {
106    super(element);
107    valid = false;
108  }
109
110  /**
111   * Loads the properties of this label view from the element's text
112   * attributes. This method is called from the constructor and the
113   * {@link #changedUpdate} method
114   */
115  protected void setPropertiesFromAttributes()
116  {
117    AttributeSet atts = getAttributes();
118    setStrikeThrough(StyleConstants.isStrikeThrough(atts));
119    setSubscript(StyleConstants.isSubscript(atts));
120    setSuperscript(StyleConstants.isSuperscript(atts));
121    setUnderline(StyleConstants.isUnderline(atts));
122
123    // Determine the font and colors.
124    Document d = getDocument();
125    if (d instanceof StyledDocument)
126      {
127        StyledDocument doc = (StyledDocument) d;
128        font = doc.getFont(atts);
129        if (atts.isDefined(StyleConstants.Background))
130          background = doc.getBackground(atts);
131        else
132          background = null;
133        foreground = doc.getForeground(atts);
134      }
135    valid = true;
136  }
137
138  /**
139   * Receives notification when text attributes change in the chunk of
140   * text that this view is responsible for. This simply calls
141   * {@link #setPropertiesFromAttributes()}.
142   *
143   * @param e the document event
144   * @param a the allocation of this view
145   * @param vf the view factory to use for creating new views
146   */
147  public void changedUpdate(DocumentEvent e, Shape a, ViewFactory vf)
148  {
149    valid = false;
150    super.changedUpdate(e, a, vf);
151  }
152
153  /**
154   * Returns the background color for the glyphs.
155   *
156   * @return the background color for the glyphs
157   */
158  public Color getBackground()
159  {
160    if (! valid)
161      setPropertiesFromAttributes();
162    return background;
163  }
164
165  /**
166   * Sets the background color for the glyphs. A value of <code>null</code>
167   * means the background of the parent view should shine through.
168   *
169   * @param bg the background to set or <code>null</code>
170   *
171   * @since 1.5
172   */
173  protected void setBackground(Color bg)
174  {
175    background = bg;
176  }
177
178  /**
179   * Returns the foreground color for the glyphs.
180   *
181   * @return the foreground color for the glyphs
182   */
183  public Color getForeground()
184  {
185    if (! valid)
186      setPropertiesFromAttributes();
187    return foreground;
188  }
189
190  /**
191   * Returns the font for the glyphs.
192   *
193   * @return the font for the glyphs
194   */
195  public Font getFont()
196  {
197    if (! valid)
198      setPropertiesFromAttributes();
199    return font;
200  }
201
202  /**
203   * Returns the font metrics of the current font.
204   *
205   * @return the font metrics of the current font
206   *
207   * @deprecated this is not used anymore
208   */
209  protected FontMetrics getFontMetrics()
210  {
211    if (! valid)
212      setPropertiesFromAttributes();
213
214    Container c = getContainer();
215    FontMetrics fm;
216    if (c != null)
217      fm = c.getFontMetrics(font);
218    else
219      fm = Toolkit.getDefaultToolkit().getFontMetrics(font);
220    return fm;
221  }
222
223  /**
224   * Returns <code>true</code> if the glyphs are rendered underlined,
225   * <code>false</code> otherwise.
226   *
227   * @return <code>true</code> if the glyphs are rendered underlined,
228   *         <code>false</code> otherwise
229   */
230  public boolean isUnderline()
231  {
232    if (! valid)
233      setPropertiesFromAttributes();
234    return underline;
235  }
236
237  /**
238   * Sets the underline flag.
239   *
240   * @param flag <code>true</code> if the glyphs are rendered underlined,
241   *             <code>false</code> otherwise
242   */
243  protected void setUnderline(boolean flag)
244  {
245    underline = flag;
246  }
247
248  /**
249   * Returns <code>true</code> if the glyphs are rendered as subscript,
250   * <code>false</code> otherwise.
251   *
252   * @return <code>true</code> if the glyphs are rendered as subscript,
253   *         <code>false</code> otherwise
254   */
255  public boolean isSubscript()
256  {
257    if (! valid)
258      setPropertiesFromAttributes();
259    return subscript;
260  }
261
262  /**
263   * Sets the subscript flag.
264   *
265   * @param flag <code>true</code> if the glyphs are rendered as subscript,
266   *             <code>false</code> otherwise
267   */
268  protected void setSubscript(boolean flag)
269  {
270    subscript = flag;
271  }
272
273  /**
274   * Returns <code>true</code> if the glyphs are rendered as superscript,
275   * <code>false</code> otherwise.
276   *
277   * @return <code>true</code> if the glyphs are rendered as superscript,
278   *         <code>false</code> otherwise
279   */
280  public boolean isSuperscript()
281  {
282    if (! valid)
283      setPropertiesFromAttributes();
284    return superscript;
285  }
286
287  /**
288   * Sets the superscript flag.
289   *
290   * @param flag <code>true</code> if the glyphs are rendered as superscript,
291   *             <code>false</code> otherwise
292   */
293  protected void setSuperscript(boolean flag)
294  {
295    superscript = flag;
296  }
297
298  /**
299   * Returns <code>true</code> if the glyphs are rendered strike-through,
300   * <code>false</code> otherwise.
301   *
302   * @return <code>true</code> if the glyphs are rendered strike-through,
303   *         <code>false</code> otherwise
304   */
305  public boolean isStrikeThrough()
306  {
307    if (! valid)
308      setPropertiesFromAttributes();
309    return strikeThrough;
310  }
311
312  /**
313   * Sets the strike-through flag.
314   *
315   * @param flag <code>true</code> if the glyphs are rendered strike-through,
316   *             <code>false</code> otherwise
317   */
318  protected void setStrikeThrough(boolean flag)
319  {
320    strikeThrough = flag;
321  }
322}