libjava/classpath/javax/swing/plaf/basic/BasicLabelUI.java

   1 /* BasicLabelUI.java
   2  Copyright (C) 2002, 2004 Free Software Foundation, Inc.
   3
   4  This file is part of GNU Classpath.
   5
   6  GNU Classpath is free software; you can redistribute it and/or modify
   7  it under the terms of the GNU General Public License as published by
   8  the Free Software Foundation; either version 2, or (at your option)
   9  any later version.
  10
  11  GNU Classpath is distributed in the hope that it will be useful, but
  12  WITHOUT ANY WARRANTY; without even the implied warranty of
  13  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  General Public License for more details.
  15
  16  You should have received a copy of the GNU General Public License
  17  along with GNU Classpath; see the file COPYING.  If not, write to the
  18  Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19  02110-1301 USA.
  20
  21  Linking this library statically or dynamically with other modules is
  22  making a combined work based on this library.  Thus, the terms and
  23  conditions of the GNU General Public License cover the whole
  24  combination.
  25
  26  As a special exception, the copyright holders of this library give you
  27  permission to link this library with independent modules to produce an
  28  executable, regardless of the license terms of these independent
  29  modules, and to copy and distribute the resulting executable under
  30  terms of your choice, provided that you also meet, for each linked
  31  independent module, the terms and conditions of the license of that
  32  module.  An independent module is a module which is not derived from
  33  or based on this library.  If you modify this library, you may extend
  34  this exception to your version of the library, but you are not
  35  obligated to do so.  If you do not wish to do so, delete this
  36  exception statement from your version. */
  37
  38 package javax.swing.plaf.basic;
  39
  40 import java.awt.Color;
  41 import java.awt.Dimension;
  42 import java.awt.FontMetrics;
  43 import java.awt.Graphics;
  44 import java.awt.Insets;
  45 import java.awt.Rectangle;
  46 import java.beans.PropertyChangeEvent;
  47 import java.beans.PropertyChangeListener;
  48
  49 import javax.swing.Icon;
  50 import javax.swing.JComponent;
  51 import javax.swing.JLabel;
  52 import javax.swing.LookAndFeel;
  53 import javax.swing.SwingUtilities;
  54 import javax.swing.plaf.ComponentUI;
  55 import javax.swing.plaf.LabelUI;
  56
  57 /**
  58  * This is the Basic Look and Feel class for the JLabel.  One BasicLabelUI
  59  * object is used to paint all JLabels that utilize the Basic Look and Feel.
  60  */
  61 public class BasicLabelUI extends LabelUI implements PropertyChangeListener
  62 {
  63   /** The labelUI that is shared by all labels. */
  64   protected static BasicLabelUI labelUI;
  65
  66   /**
  67    * Creates a new BasicLabelUI object.
  68    */
  69   public BasicLabelUI()
  70   {
  71     super();
  72   }
  73
  74   /**
  75    * Creates and returns a UI for the label. Since one UI is shared by  all
  76    * labels, this means creating only if necessary and returning the  shared
  77    * UI.
  78    *
  79    * @param c The {@link JComponent} that a UI is being created for.
  80    *
  81    * @return A label UI for the Basic Look and Feel.
  82    */
  83   public static ComponentUI createUI(JComponent c)
  84   {
  85     if (labelUI == null)
  86       labelUI = new BasicLabelUI();
  87     return labelUI;
  88   }
  89
  90   /**
  91    * Returns the preferred size of this component as calculated by the
  92    * {@link #layoutCL(JLabel, FontMetrics, String, Icon, Rectangle, Rectangle,
  93    * Rectangle)} method.
  94    *
  95    * @param c This {@link JComponent} to get a preferred size for.
  96    *
  97    * @return The preferred size.
  98    */
  99   public Dimension getPreferredSize(JComponent c)
 100   {
 101     JLabel lab = (JLabel) c;
 102     Rectangle vr = new Rectangle();
 103     Rectangle ir = new Rectangle();
 104     Rectangle tr = new Rectangle();
 105     Insets insets = lab.getInsets();
 106     FontMetrics fm = lab.getFontMetrics(lab.getFont());
 107     layoutCL(lab, fm, lab.getText(), lab.getIcon(), vr, ir, tr);
 108     Rectangle cr = tr.union(ir);
 109     return new Dimension(insets.left + cr.width + insets.right, insets.top
 110         + cr.height + insets.bottom);
 111
 112   }
 113
 114   /**
 115    * This method returns the minimum size of the {@link JComponent} given. If
 116    * this method returns null, then it is up to the Layout Manager to give
 117    * this component a minimum size.
 118    *
 119    * @param c The {@link JComponent} to get a minimum size for.
 120    *
 121    * @return The minimum size.
 122    */
 123   public Dimension getMinimumSize(JComponent c)
 124   {
 125     return getPreferredSize(c);
 126   }
 127
 128   /**
 129    * This method returns the maximum size of the {@link JComponent} given. If
 130    * this method returns null, then it is up to the Layout Manager to give
 131    * this component a maximum size.
 132    *
 133    * @param c The {@link JComponent} to get a maximum size for.
 134    *
 135    * @return The maximum size.
 136    */
 137   public Dimension getMaximumSize(JComponent c)
 138   {
 139     return getPreferredSize(c);
 140   }
 141
 142   /**
 143    * The method that paints the label according to its current state.
 144    *
 145    * @param g The {@link Graphics} object to paint with.
 146    * @param c The {@link JComponent} to paint.
 147    */
 148   public void paint(Graphics g, JComponent c)
 149   {
 150     JLabel b = (JLabel) c;
 151
 152     Rectangle tr = new Rectangle();
 153     Rectangle ir = new Rectangle();
 154     Rectangle vr = new Rectangle();
 155
 156     FontMetrics fm = g.getFontMetrics();
 157     vr = SwingUtilities.calculateInnerArea(c, vr);
 158
 159     if (vr.width < 0)
 160       vr.width = 0;
 161     if (vr.height < 0)
 162       vr.height = 0;
 163
 164     Icon icon = (b.isEnabled()) ? b.getIcon() : b.getDisabledIcon();
 165
 166     String text = layoutCL(b, fm, b.getText(), icon, vr, ir, tr);
 167
 168     if (icon != null)
 169       icon.paintIcon(b, g, ir.x, ir.y);
 170
 171     if (text != null && !text.equals(""))
 172     {
 173       if (b.isEnabled())
 174         paintEnabledText(b, g, text, tr.x, tr.y + fm.getAscent());
 175       else
 176         paintDisabledText(b, g, text, tr.x, tr.y + fm.getAscent());
 177     }
 178   }
 179
 180   /**
 181    * This method is simply calls SwingUtilities's layoutCompoundLabel.
 182    *
 183    * @param label The label to lay out.
 184    * @param fontMetrics The FontMetrics for the font used.
 185    * @param text The text to paint.
 186    * @param icon The icon to draw.
 187    * @param viewR The entire viewable rectangle.
 188    * @param iconR The icon bounds rectangle.
 189    * @param textR The text bounds rectangle.
 190    *
 191    * @return A possibly clipped version of the text.
 192    */
 193   protected String layoutCL(JLabel label, FontMetrics fontMetrics, String text,
 194       Icon icon, Rectangle viewR, Rectangle iconR, Rectangle textR)
 195   {
 196     return SwingUtilities.layoutCompoundLabel(label, fontMetrics, text, icon,
 197         label.getVerticalAlignment(), label.getHorizontalAlignment(), label
 198             .getVerticalTextPosition(), label.getHorizontalTextPosition(),
 199         viewR, iconR, textR, label.getIconTextGap());
 200   }
 201
 202   /**
 203    * Paints the text if the label is disabled. By default, this paints the
 204    * clipped text returned by layoutCompoundLabel using the
 205    * background.brighter() color. It also paints the same text using the
 206    * background.darker() color one pixel to the right and one pixel down.
 207    *
 208    * @param l The {@link JLabel} being painted.
 209    * @param g The {@link Graphics} object to paint with.
 210    * @param s The String to paint.
 211    * @param textX The x coordinate of the start of the baseline.
 212    * @param textY The y coordinate of the start of the baseline.
 213    */
 214   protected void paintDisabledText(JLabel l, Graphics g, String s, int textX,
 215       int textY)
 216   {
 217     Color saved_color = g.getColor();
 218
 219     g.setColor(l.getBackground().brighter());
 220
 221     int mnemIndex = l.getDisplayedMnemonicIndex();
 222
 223     if (mnemIndex != -1)
 224       BasicGraphicsUtils.drawStringUnderlineCharAt(g, s, mnemIndex, textX,
 225           textY);
 226     else
 227       g.drawString(s, textX, textY);
 228
 229     g.setColor(l.getBackground().darker());
 230     if (mnemIndex != -1)
 231       BasicGraphicsUtils.drawStringUnderlineCharAt(g, s, mnemIndex, textX + 1,
 232           textY + 1);
 233     else
 234       g.drawString(s, textX + 1, textY + 1);
 235
 236     g.setColor(saved_color);
 237   }
 238
 239   /**
 240    * Paints the text if the label is enabled. The text is painted using the
 241    * foreground color.
 242    *
 243    * @param l The {@link JLabel} being painted.
 244    * @param g The {@link Graphics} object to paint with.
 245    * @param s The String to paint.
 246    * @param textX The x coordinate of the start of the baseline.
 247    * @param textY The y coordinate of the start of the baseline.
 248    */
 249   protected void paintEnabledText(JLabel l, Graphics g, String s, int textX,
 250       int textY)
 251   {
 252     Color saved_color = g.getColor();
 253     g.setColor(l.getForeground());
 254
 255     int mnemIndex = l.getDisplayedMnemonicIndex();
 256
 257     if (mnemIndex != -1)
 258       BasicGraphicsUtils.drawStringUnderlineCharAt(g, s, mnemIndex, textX,
 259           textY);
 260     else
 261       g.drawString(s, textX, textY);
 262
 263     g.setColor(saved_color);
 264   }
 265
 266   /**
 267    * This method installs the UI for the given {@link JComponent}.  This
 268    * method will install the component, defaults, listeners,  and keyboard
 269    * actions.
 270    *
 271    * @param c The {@link JComponent} that this UI is being installed on.
 272    */
 273   public void installUI(JComponent c)
 274   {
 275     super.installUI(c);
 276     if (c instanceof JLabel)
 277     {
 278       JLabel l = (JLabel) c;
 279
 280       installComponents(l);
 281       installDefaults(l);
 282       installListeners(l);
 283       installKeyboardActions(l);
 284     }
 285   }
 286
 287   /**
 288    * This method uninstalls the UI for the given {@link JComponent}. This
 289    * method will uninstall the component, defaults, listeners,  and keyboard
 290    * actions.
 291    *
 292    * @param c The {@link JComponent} that this UI is being installed on.
 293    */
 294   public void uninstallUI(JComponent c)
 295   {
 296     super.uninstallUI(c);
 297     if (c instanceof JLabel)
 298     {
 299       JLabel l = (JLabel) c;
 300
 301       uninstallKeyboardActions(l);
 302       uninstallListeners(l);
 303       uninstallDefaults(l);
 304       uninstallComponents(l);
 305     }
 306   }
 307
 308   /**
 309    * This method installs the components for this {@link JLabel}.
 310    *
 311    * @param c The {@link JLabel} to install components for.
 312    */
 313   protected void installComponents(JLabel c)
 314   {
 315     //FIXME: fix javadoc + implement.
 316   }
 317
 318   /**
 319    * This method uninstalls the components for this {@link JLabel}.
 320    *
 321    * @param c The {@link JLabel} to uninstall components for.
 322    */
 323   protected void uninstallComponents(JLabel c)
 324   {
 325     //FIXME: fix javadoc + implement.
 326   }
 327
 328   /**
 329    * This method installs the defaults that are defined in  the Basic look and
 330    * feel for this {@link JLabel}.
 331    *
 332    * @param c The {@link JLabel} to install defaults for.
 333    */
 334   protected void installDefaults(JLabel c)
 335   {
 336     LookAndFeel.installColorsAndFont(c, "Label.background", "Label.foreground",
 337                                      "Label.font");
 338     //XXX: There are properties we don't use called disabledForeground
 339     //and disabledShadow.
 340   }
 341
 342   /**
 343    * This method uninstalls the defaults that are defined in the Basic look
 344    * and feel for this {@link JLabel}.
 345    *
 346    * @param c The {@link JLabel} to uninstall defaults for.
 347    */
 348   protected void uninstallDefaults(JLabel c)
 349   {
 350     c.setForeground(null);
 351     c.setBackground(null);
 352     c.setFont(null);
 353   }
 354
 355   /**
 356    * This method installs the keyboard actions for the given {@link JLabel}.
 357    *
 358    * @param l The {@link JLabel} to install keyboard actions for.
 359    */
 360   protected void installKeyboardActions(JLabel l)
 361   {
 362     //FIXME: implement.
 363   }
 364
 365   /**
 366    * This method uninstalls the keyboard actions for the given {@link JLabel}.
 367    *
 368    * @param l The {@link JLabel} to uninstall keyboard actions for.
 369    */
 370   protected void uninstallKeyboardActions(JLabel l)
 371   {
 372     //FIXME: implement.
 373   }
 374
 375   /**
 376    * This method installs the listeners for the  given {@link JLabel}. The UI
 377    * delegate only listens to  the label.
 378    *
 379    * @param c The {@link JLabel} to install listeners for.
 380    */
 381   protected void installListeners(JLabel c)
 382   {
 383     c.addPropertyChangeListener(this);
 384   }
 385
 386   /**
 387    * This method uninstalls the listeners for the given {@link JLabel}. The UI
 388    * delegate only listens to the label.
 389    *
 390    * @param c The {@link JLabel} to uninstall listeners for.
 391    */
 392   protected void uninstallListeners(JLabel c)
 393   {
 394     c.removePropertyChangeListener(this);
 395   }
 396
 397   /**
 398    * This method is called whenever any JLabel's that use this UI has one of
 399    * their properties change.
 400    *
 401    * @param e The {@link PropertyChangeEvent} that describes the change.
 402    */
 403   public void propertyChange(PropertyChangeEvent e)
 404   {
 405     // What to do here?
 406   }
 407 }