Source for javax.swing.text.FieldView

   1: /* FieldView.java -- 
   2:    Copyright (C) 2004, 2006 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.text;
  40: 
  41: import java.awt.Component;
  42: import java.awt.Container;
  43: import java.awt.FontMetrics;
  44: import java.awt.Graphics;
  45: import java.awt.Insets;
  46: import java.awt.Rectangle;
  47: import java.awt.Shape;
  48: 
  49: import javax.swing.BoundedRangeModel;
  50: import javax.swing.JTextField;
  51: import javax.swing.SwingUtilities;
  52: import javax.swing.event.ChangeEvent;
  53: import javax.swing.event.ChangeListener;
  54: import javax.swing.event.DocumentEvent;
  55: 
  56: public class FieldView extends PlainView
  57: {
  58:   BoundedRangeModel horizontalVisibility;
  59:   
  60:   /** Caches the preferred span of the X axis. It is invalidated by
  61:    * setting it to -1f. This is done when text in the document
  62:    * is inserted, removed or changed. The value is corrected as
  63:    * soon as calculateHorizontalSpan() is called. 
  64:    */
  65:   float cachedSpan = -1f;
  66: 
  67:   public FieldView(Element elem)
  68:   {
  69:     super(elem);
  70:     
  71:   }
  72:   
  73:   /** Checks whether the given container is a JTextField. If so
  74:    * it retrieves the textfield's horizontalVisibility instance.
  75:    * 
  76:    * <p>This method should be only called when the view's container
  77:    * is valid. Naturally that would be the setParent() method however
  78:    * that method is not overridden in the RI and that is why we chose
  79:    * paint() instead.</p>
  80:    */ 
  81:   private void checkContainer()
  82:   {
  83:     Container c = getContainer();
  84:     
  85:     if (c instanceof JTextField)
  86:       {
  87:         horizontalVisibility = ((JTextField) c).getHorizontalVisibility();
  88:         
  89:         // Provokes a repaint when the BoundedRangeModel's values change
  90:         // (which is what the RI does).
  91:         horizontalVisibility.addChangeListener(new ChangeListener(){
  92:           public void stateChanged(ChangeEvent event) {
  93:             getContainer().repaint();
  94:           }
  95:         });
  96: 
  97:         // It turned out that the span calculated at this point is wrong
  98:         // and needs to be recalculated (e.g. a different font setting is
  99:         // not taken into account).
 100:         calculateHorizontalSpan();
 101:         
 102:         // Initializes the BoundedRangeModel properly.
 103:         updateVisibility();
 104:       }
 105:     
 106:   }
 107:   
 108:   private void updateVisibility()
 109:   {
 110:     JTextField tf = (JTextField) getContainer();
 111:     Insets insets = tf.getInsets();
 112: 
 113:     int width = tf.getWidth() - insets.left - insets.right;
 114:         
 115:     horizontalVisibility.setMaximum(Math.max((int) ((cachedSpan != -1f)
 116:                                                  ? cachedSpan
 117:                                                  : calculateHorizontalSpan()),
 118:                                              width));
 119:         
 120:     horizontalVisibility.setExtent(width - 1);
 121:   }
 122: 
 123:   protected FontMetrics getFontMetrics()
 124:   {
 125:     Component container = getContainer();
 126:     return container.getFontMetrics(container.getFont());
 127:   }
 128: 
 129:   /**
 130:    * Vertically centers the single line of text within the
 131:    * bounds of the input shape. The returned Rectangle is centered
 132:    * vertically within <code>shape</code> and has a height of the
 133:    * preferred span along the Y axis. Horizontal adjustment is done according
 134:    * to the horizontalAligment property of the component that is rendered.
 135:    *
 136:    * @param shape the shape within which the line is beeing centered
 137:    */
 138:   protected Shape adjustAllocation(Shape shape)
 139:   {
 140:     // Return null when the original allocation is null (like the RI).
 141:     if (shape == null)
 142:       return null;
 143:     
 144:     Rectangle rectIn = shape.getBounds();
 145:     // vertical adjustment
 146:     int height = (int) getPreferredSpan(Y_AXIS);
 147:     int y = rectIn.y + (rectIn.height - height) / 2;
 148:     // horizontal adjustment
 149:     JTextField textField = (JTextField) getContainer();
 150:     int width = (int) ((cachedSpan != -1f) ? cachedSpan : calculateHorizontalSpan());
 151:     int x;
 152:     if (horizontalVisibility != null && horizontalVisibility.getExtent() < width)
 153:         x = rectIn.x - horizontalVisibility.getValue();
 154:     else
 155:       switch (textField.getHorizontalAlignment())
 156:         {
 157:         case JTextField.CENTER:
 158:           x = rectIn.x + (rectIn.width - width) / 2;
 159:           break;
 160:         case JTextField.RIGHT:
 161:           x = rectIn.x + (rectIn.width - width - 1);
 162:           break;
 163:         case JTextField.TRAILING:
 164:           if (textField.getComponentOrientation().isLeftToRight())
 165:             x = rectIn.x + (rectIn.width - width - 1);
 166:           else
 167:             x = rectIn.x;
 168:           break;
 169:         case JTextField.LEADING:
 170:           if (textField.getComponentOrientation().isLeftToRight())
 171:             x = rectIn.x;
 172:           else
 173:             x = rectIn.x + (rectIn.width - width - 1);
 174:           break;
 175:         case JTextField.LEFT:
 176:         default:
 177:           x = rectIn.x;
 178:           break;
 179:         }
 180:     
 181:     return new Rectangle(x, y, width, height);
 182:   }
 183: 
 184:   public float getPreferredSpan(int axis)
 185:   {
 186:     if (axis != X_AXIS && axis != Y_AXIS)
 187:       throw new IllegalArgumentException();
 188: 
 189: 
 190:     if (axis == Y_AXIS)
 191:       return super.getPreferredSpan(axis);
 192: 
 193:     if (cachedSpan != -1f)
 194:       return cachedSpan;
 195:     
 196:     return calculateHorizontalSpan();
 197:   }
 198:   
 199:   /** Calculates and sets the horizontal span and stores the value
 200:    * in cachedSpan.
 201:    */ 
 202:   private float calculateHorizontalSpan()
 203:   {
 204:     Segment s = getLineBuffer();
 205:     Element elem = getElement();
 206: 
 207:     try
 208:       {
 209:         elem.getDocument().getText(elem.getStartOffset(),
 210:                                           elem.getEndOffset() - 1,
 211:                                           s);
 212:         
 213:         return cachedSpan = Utilities.getTabbedTextWidth(s, getFontMetrics(), 0, this, s.offset);
 214:       }
 215:     catch (BadLocationException e)
 216:       {
 217:     // Should never happen
 218:     AssertionError ae = new AssertionError();
 219:     ae.initCause(e);
 220:     throw ae;
 221:       }
 222:   }
 223: 
 224:   public int getResizeWeight(int axis)
 225:   {
 226:     return axis == X_AXIS ? 1 : 0;
 227:   }
 228:   
 229:   public Shape modelToView(int pos, Shape a, Position.Bias bias)
 230:     throws BadLocationException
 231:   {
 232:     Shape newAlloc = adjustAllocation(a);
 233:     return super.modelToView(pos, newAlloc, bias);
 234:   }
 235:   
 236:   public void paint(Graphics g, Shape s)
 237:   {
 238:     if (horizontalVisibility == null)
 239:       checkContainer();
 240: 
 241:     Shape newAlloc = adjustAllocation(s);
 242:     
 243:     Shape clip = g.getClip();
 244:     if (clip != null)
 245:       {
 246:         // Reason for this: The allocation area is always determined by the
 247:         // size of the component (and its insets) regardless of whether
 248:         // parts of the component are invisible or not (e.g. when the
 249:         // component is part of a JScrollPane and partly moved out of
 250:         // the user-visible range). However the clip of the Graphics
 251:         // instance may be adjusted properly to that condition but
 252:         // does not handle insets. By calculating the intersection
 253:         // we get the correct clip to paint the text in all cases.
 254:         Rectangle r = s.getBounds();
 255:         Rectangle cb = clip.getBounds();
 256:         SwingUtilities.computeIntersection(r.x, r.y, r.width, r.height, cb);
 257: 
 258:         g.setClip(cb);
 259:       }
 260:     else
 261:       g.setClip(s);
 262: 
 263:     super.paint(g, newAlloc);
 264:     g.setClip(clip);
 265:     
 266:   }
 267: 
 268:   public void insertUpdate(DocumentEvent ev, Shape shape, ViewFactory vf)
 269:   {
 270:     cachedSpan = -1f;
 271:     
 272:     if (horizontalVisibility != null)
 273:       updateVisibility();
 274:     
 275:     Shape newAlloc = adjustAllocation(shape);
 276:     
 277:     super.insertUpdate(ev, newAlloc, vf);
 278:     getContainer().repaint();
 279:   }
 280: 
 281:   public void removeUpdate(DocumentEvent ev, Shape shape, ViewFactory vf)
 282:   {
 283:     cachedSpan = -1f;
 284:     
 285:     if (horizontalVisibility != null)
 286:       updateVisibility();
 287: 
 288:     Shape newAlloc = adjustAllocation(shape);
 289:     super.removeUpdate(ev, newAlloc, vf);
 290:     getContainer().repaint();
 291:   }
 292: 
 293:   public void changedUpdate(DocumentEvent ev, Shape shape, ViewFactory vf)
 294:   {
 295:     cachedSpan = -1f;
 296:     
 297:     if (horizontalVisibility != null)
 298:       updateVisibility();
 299: 
 300:     Shape newAlloc = adjustAllocation(shape);
 301:     super.changedUpdate(ev, newAlloc, vf);
 302:     getContainer().repaint();
 303:   }
 304: 
 305:   public int viewToModel(float fx, float fy, Shape a, Position.Bias[] bias)
 306:   {
 307:     return super.viewToModel(fx, fy, adjustAllocation(a), bias);
 308:   }
 309:   
 310: }