old-autovect-branch/libjava/classpath/javax/swing/border/EtchedBorder.java

   1 /* EtchedBorder.java --
   2    Copyright (C) 2003 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
  39 package javax.swing.border;
  40
  41 import java.awt.Color;
  42 import java.awt.Component;
  43 import java.awt.Graphics;
  44 import java.awt.Insets;
  45
  46
  47 /**
  48  * A border that looks like an engraving etched into the background
  49  * surface, or (in its raised variant) coming out of the surface
  50  * plane. Using different constructors, it is possible to either
  51  * explicitly specify the border colors, or to let the colors derive
  52  * from the background color of the enclosed Component.
  53  *
  54  * <p><img src="doc-files/EtchedBorder-1.png" width="500" height="200"
  55  * alt="[An illustration of the two EtchedBorder variants]" />
  56  *
  57  * @author Sascha Brawer (brawer@dandelis.ch)
  58  */
  59 public class EtchedBorder extends AbstractBorder
  60 {
  61   /**
  62    * Determined using the <code>serialver</code> tool
  63    * of Apple/Sun JDK 1.3.1 on MacOS X 10.1.5.
  64    */
  65   static final long serialVersionUID = 4001244046866360638L;
  66
  67
  68   /**
  69    * Indicates that the border appears as coming out of the
  70    * background.
  71    */
  72   public static final int RAISED = 0;
  73
  74
  75   /**
  76    * Indicates that the border appears as engraved into the
  77    * background.
  78    */
  79   public static final int LOWERED = 1;
  80
  81
  82   /**
  83    * The type of this EtchedBorder, which is either {@link #RAISED}
  84    * or {@link #LOWERED}.
  85    */
  86   protected int etchType;
  87
  88
  89   /**
  90    * The highlight color, or <code>null</code> to indicate that the
  91    * color shall be derived from the background of the enclosed
  92    * component.
  93    */
  94   protected Color highlight;
  95
  96
  97   /**
  98    * The shadow color, or <code>null</code> to indicate that the
  99    * color shall be derived from the background of the enclosed
 100    * component.
 101    */
 102   protected Color shadow;
 103
 104
 105   /**
 106    * Constructs a lowered EtchedBorder. The colors will be derived
 107    * from the background color of the enclosed Component when the
 108    * border gets painted.
 109    */
 110   public EtchedBorder()
 111   {
 112     this(LOWERED);
 113   }
 114
 115
 116   /**
 117    * Constructs an EtchedBorder with the specified appearance. The
 118    * colors will be derived from the background color of the enclosed
 119    * Component when the border gets painted.
 120    *
 121    * <p><img src="doc-files/EtchedBorder-1.png" width="500" height="200"
 122    * alt="[An illustration of the two EtchedBorder variants]" />
 123    *
 124    * @param etchType the desired appearance of the border. The value
 125    *        must be either {@link #RAISED} or {@link #LOWERED}.
 126    *
 127    * @throws IllegalArgumentException if <code>etchType</code> has
 128    *         an unsupported value.
 129    */
 130   public EtchedBorder(int etchType)
 131   {
 132     if ((etchType != RAISED) && (etchType != LOWERED))
 133       throw new IllegalArgumentException();
 134
 135     this.etchType = etchType;
 136
 137     /* The highlight and shadow fields already have a null value
 138      * when the constructor gets called, so there is no need to
 139      * assign a value here.
 140      */
 141   }
 142
 143
 144   /**
 145    * Constructs a lowered EtchedBorder, explicitly selecting the
 146    * colors that will be used for highlight and shadow.
 147    *
 148    * @param highlight the color that will be used for painting
 149    *        the highlight part of the border.
 150    *
 151    * @param shadow the color that will be used for painting
 152    *        the shadow part of the border.
 153    *
 154    * @see #EtchedBorder(int, Color, Color)
 155    */
 156   public EtchedBorder(Color highlight, Color shadow)
 157   {
 158     this(LOWERED, highlight, shadow);
 159   }
 160
 161
 162   /**
 163    * Constructs an EtchedBorder with the specified appearance,
 164    * explicitly selecting the colors that will be used for
 165    * highlight and shadow.
 166    *
 167    * <p><img src="doc-files/EtchedBorder-2.png" width="500" height="200"
 168    * alt="[An illustration that shows which pixels get painted
 169    * in what color]" />
 170    *
 171    * @param etchType the desired appearance of the border. The value
 172    *        must be either {@link #RAISED} or {@link #LOWERED}.
 173    *
 174    * @param highlight the color that will be used for painting
 175    *        the highlight part of the border.
 176    *
 177    * @param shadow the color that will be used for painting
 178    *        the shadow part of the border.
 179    *
 180    * @throws IllegalArgumentException if <code>etchType</code> has
 181    *         an unsupported value.
 182    */
 183   public EtchedBorder(int etchType, Color highlight, Color shadow)
 184   {
 185     this(etchType);  // Checks the validity of the value.
 186     this.highlight = highlight;
 187     this.shadow = shadow;
 188   }
 189
 190
 191   /**
 192    * Paints the border for a given component.
 193    *
 194    * @param c the component whose border is to be painted.
 195    * @param g the graphics for painting.
 196    * @param x the horizontal position for painting the border.
 197    * @param y the vertical position for painting the border.
 198    * @param width the width of the available area for painting the border.
 199    * @param height the height of the available area for painting the border.
 200    */
 201   public void paintBorder(Component c, Graphics  g, int x, int y, int width,
 202                           int height)
 203   {
 204     switch (etchType)
 205     {
 206     case RAISED:
 207       paintEtchedBorder(g, x, y, width, height,
 208                         getHighlightColor(c), getShadowColor(c));
 209       break;
 210
 211     case LOWERED:
 212       paintEtchedBorder(g, x, y, width, height,
 213                         getShadowColor(c), getHighlightColor(c));
 214       break;
 215     }
 216   }
 217
 218
 219   /**
 220    * Measures the width of this border.
 221    *
 222    * @param c the component whose border is to be measured.
 223    *
 224    * @return an Insets object whose <code>left</code>, <code>right</code>,
 225    *         <code>top</code> and <code>bottom</code> fields indicate the
 226    *         width of the border at the respective edge.
 227    *
 228    * @see #getBorderInsets(java.awt.Component, java.awt.Insets)
 229    */
 230   public Insets getBorderInsets(Component c)
 231   {
 232     return new Insets(2, 2, 2, 2);
 233   }
 234
 235
 236   /**
 237    * Measures the width of this border, storing the results into a
 238    * pre-existing Insets object.
 239    *
 240    * @param insets an Insets object for holding the result values.
 241    *        After invoking this method, the <code>left</code>,
 242    *        <code>right</code>, <code>top</code> and
 243    *        <code>bottom</code> fields indicate the width of the
 244    *        border at the respective edge.
 245    *
 246    * @return the same object that was passed for <code>insets</code>.
 247    *
 248    * @see #getBorderInsets(Component)
 249    */
 250   public Insets getBorderInsets(Component c, Insets insets)
 251   {
 252     insets.left = insets.right = insets.top = insets.bottom = 2;
 253     return insets;
 254   }
 255
 256
 257   /**
 258    * Determines whether this border fills every pixel in its area
 259    * when painting.
 260    *
 261    * <p>If the border colors are derived from the background color of
 262    * the enclosed component, the result is <code>true</code> because
 263    * the derivation method always returns opaque colors. Otherwise,
 264    * the result depends on the opacity of the individual colors.
 265    *
 266    * @return <code>true</code> if the border is fully opaque, or
 267    *         <code>false</code> if some pixels of the background
 268    *         can shine through the border.
 269    */
 270   public boolean isBorderOpaque()
 271   {
 272     // If the colors are to be derived from the enclosed Component's
 273     // background color, the border is guaranteed to be fully opaque
 274     // because Color.brighten() and Color.darken() always return an
 275     // opaque color.
 276     return
 277       ((highlight == null) || (highlight.getAlpha() == 255))
 278       && ((shadow == null) || (shadow.getAlpha() == 255));
 279   }
 280
 281   /**
 282    * Returns the appearance of this EtchedBorder, which is either
 283    * {@link #RAISED} or {@link #LOWERED}.
 284    */
 285   public int getEtchType()
 286   {
 287     return etchType;
 288   }
 289
 290
 291   /**
 292    * Determines the color that will be used for highlighted parts when
 293    * painting the border around a given component. If a highlight
 294    * color has been specified upon constructing the border, that color
 295    * is returned. Otherwise, the background color of the enclosed
 296    * component is brightened.
 297    *
 298    * @param c the component enclosed by this border.
 299    *
 300    * @see java.awt.Component#getBackground()
 301    * @see java.awt.Color#brighter()
 302    */
 303   public Color getHighlightColor(Component c)
 304   {
 305     if (highlight != null)
 306       return highlight;
 307     else
 308       return c.getBackground().brighter();
 309   }
 310
 311   /**
 312    * Returns the color that will be used for highlighted parts when
 313    * painting the border, or <code>null</code> if that color will be
 314    * derived from the background of the enclosed Component.
 315    */
 316   public Color getHighlightColor()
 317   {
 318     return highlight;
 319   }
 320
 321
 322   /**
 323    * Determines the color that will be used for shadowed parts when
 324    * painting the border around a given component. If a shadow color
 325    * has been specified upon constructing the border, that color is
 326    * returned. Otherwise, the background color of the enclosed
 327    * component is darkened.
 328    *
 329    * @param c the component enclosed by this border.
 330    *
 331    * @see java.awt.Component#getBackground()
 332    * @see java.awt.Color#darker()
 333    */
 334   public Color getShadowColor(Component c)
 335   {
 336     if (shadow != null)
 337       return shadow;
 338     else
 339       return c.getBackground().darker();
 340   }
 341
 342
 343   /**
 344    * Returns the color that will be used for shadowed parts when
 345    * painting the border, or <code>null</code> if that color will be
 346    * derived from the background of the enclosed Component.
 347    */
 348   public Color getShadowColor()
 349   {
 350     return shadow;
 351   }
 352
 353
 354   /**
 355    * Paints a two-pixel etching in two colors.
 356    *
 357    * <pre>
 358    * +++++++++++.
 359    * +.........+.    + = color a
 360    * +.        +.    . = color b
 361    * +.        +.
 362    * +++++++++++.
 363    * ............</pre>
 364    *
 365    * @param g the graphics for painting.
 366    * @param x the horizontal position for painting the border.
 367    * @param y the vertical position for painting the border.
 368    * @param width the width of the available area for painting the border.
 369    * @param height the height of the available area for painting the border.
 370    * @param a one of the two colors.
 371    * @param b the second of the two colors.
 372    */
 373   private static void paintEtchedBorder(Graphics g, int x, int y, int width,
 374                                         int height, Color a, Color b)
 375   {
 376     Color oldColor;
 377
 378     oldColor = g.getColor();
 379     g.translate(x, y);
 380     width = width - 1;
 381     height = height - 1;
 382
 383     try
 384     {
 385       // To understand this code, it might be helpful to look at the
 386       // images that are included with the JavaDoc. They are located
 387       // in the "doc-files" subdirectory. EtchedBorder-2.png might
 388       // be especially informative.
 389       g.setColor(a);
 390       g.drawRect(0, 0, width - 1, height - 1);
 391
 392       g.setColor(b);
 393       g.drawLine(1, 1, width - 2, 1);            // top edge
 394       g.drawLine(1, 2, 1, height - 2);           // left edge
 395       g.drawLine(0, height, width, height);      // bottom edge
 396       g.drawLine(width, 0, width, height - 1);   // right edge
 397     }
 398     finally
 399     {
 400       g.translate(-x, -y);
 401       g.setColor(oldColor);
 402     }
 403   }
 404 }