Source for javax.swing.text.PasswordView

   1: /* PasswordView.java -- 
   2:  Copyright (C) 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: 
  39: package javax.swing.text;
  40: 
  41: import java.awt.Color;
  42: import java.awt.FontMetrics;
  43: import java.awt.Graphics;
  44: import java.awt.Rectangle;
  45: import java.awt.Shape;
  46: 
  47: import javax.swing.JPasswordField;
  48: 
  49: public class PasswordView
  50:   extends FieldView
  51: {
  52:   /**
  53:    * Buffer for putting the echo char into it and
  54:    * then using it to draw it into the view.
  55:    */
  56:   private char[] oneCharBuffer = new char[1];
  57: 
  58:   public PasswordView(Element elem)
  59:   {
  60:     super(elem);
  61:   }
  62: 
  63:   /**
  64:    * Draws one echo character at a given position.
  65:    *
  66:    * @param g the <code>Graphics</code> object to draw to
  67:    * @param x the x-position
  68:    * @param y the y-position
  69:    * @param ch the echo character
  70:    *
  71:    * @return the next x position right of the drawn character
  72:    */
  73:   protected int drawEchoCharacter(Graphics g, int x, int y, char ch)
  74:   {
  75:     // Update font metrics.
  76:     updateMetrics();
  77: 
  78:     // Draw character.
  79:     oneCharBuffer[0] = ch;
  80:     g.drawChars(oneCharBuffer, 0, 1, x, y);
  81: 
  82:     // Return new x position right of drawn character.
  83:     return x + metrics.charWidth(ch);
  84:   }
  85: 
  86:   private char getEchoChar()
  87:   {
  88:     char ch = ((JPasswordField) getContainer()).getEchoChar();
  89: 
  90:     if (ch == 0)
  91:       ch = '*';
  92: 
  93:     return ch;
  94:   }
  95: 
  96:   /**
  97:    * Draws selected text at a given position.
  98:    *
  99:    * @param g the <code>Graphics</code> object to draw to
 100:    * @param x the x-position
 101:    * @param y the y-position
 102:    * @param p0 the position of the first character to draw
 103:    * @param p1 the position of the first character not to draw
 104:    *
 105:    * @return the next x position right of the drawn character
 106:    */
 107:   protected int drawSelectedText(Graphics g, int x, int y, int p0, int p1)
 108:     throws BadLocationException
 109:   {
 110:     // Update font metrics.
 111:     updateMetrics();
 112: 
 113:     // Get echo character.
 114:     char ch = getEchoChar();
 115: 
 116:     // Set color for selected text.
 117:     g.setColor(selectedColor);
 118:     g.setColor(Color.BLACK);
 119: 
 120:     // Draw echo character using drawEchoCharacter() method.
 121:     for (int index = p0; index < p1; ++index)
 122:       x = drawEchoCharacter(g, x, y, ch);
 123:     return x;
 124:   }
 125: 
 126:   /**
 127:    * Draws unselected text at a given position.
 128:    *
 129:    * @param g the <code>Graphics</code> object to draw to
 130:    * @param x the x-position of the start of the baseline
 131:    * @param y the y-position of the start of the baseline
 132:    * @param p0 the position of the first character to draw
 133:    * @param p1 the position of the first character not to draw
 134:    *
 135:    * @return the next x position right of the drawn character
 136:    */
 137:   protected int drawUnselectedText(Graphics g, int x, int y, int p0, int p1)
 138:     throws BadLocationException
 139:   {
 140:     // Update font metrics.
 141:     updateMetrics();
 142: 
 143:     // Get echo character.
 144:     char ch = getEchoChar();
 145: 
 146:     // Set color for unselected text.
 147:     g.setColor(unselectedColor);
 148:     g.setColor(Color.BLACK);
 149: 
 150:     // Draw echo character using drawEchoCharacter() method.
 151:     for (int index = p0; index < p1; ++index)
 152:       x = drawEchoCharacter(g, x, y, ch);
 153:     return x;
 154:   }
 155: 
 156:   /**
 157:    * Determines the preferred span for this view along an axis.
 158:    * 
 159:    * @param axis to get the preferred span of
 160:    * @return the preferred span of the axis
 161:    */
 162:   public float getPreferredSpan(int axis)
 163:   {
 164:     if (axis != X_AXIS && axis != Y_AXIS)
 165:       throw new IllegalArgumentException();
 166: 
 167:     FontMetrics fm = getFontMetrics();
 168: 
 169:     if (axis == Y_AXIS)
 170:         return fm.getHeight();
 171: 
 172:     String text;
 173:     Element elem = getElement();
 174: 
 175:     try
 176:       {
 177:         text = elem.getDocument().getText(elem.getStartOffset(),
 178:                                           elem.getEndOffset());
 179:       }
 180:     catch (BadLocationException e)
 181:       {
 182:         // This should never happen.
 183:         text = "";
 184:       }
 185:     return fm.stringWidth(text);
 186:   }
 187: 
 188:   /**
 189:    * Provides a mapping from the document model coordinate space to the
 190:    * coordinate space of the view mapped to it.
 191:    *
 192:    * This method is overridden to provide a correct mapping with respect to the
 193:    * echo char and not to the real content.
 194:    *
 195:    * @param pos - the position to convert >= 0
 196:    * @param a - the allocated region to render into
 197:    * @param b - typesafe enumeration to indicate bias to a position in the model.
 198:    * @return the bounding box of the given position
 199:    * @throws BadLocationException if the given position does not 
 200:    * represent a valid location in the associated document
 201:    */
 202:   public Shape modelToView(int pos, Shape a, Position.Bias b)
 203:     throws BadLocationException
 204:   {
 205:     Shape newAlloc = adjustAllocation(a);
 206: 
 207:     // Ensure metrics are up-to-date.
 208:     updateMetrics();
 209:     
 210:     // Get rectangle of the line containing position.
 211:     int lineIndex = getElement().getElementIndex(pos);
 212:     Rectangle rect = lineToRect(newAlloc, lineIndex);
 213: 
 214:     // Get the rectangle for position.
 215:     Element line = getElement().getElement(lineIndex);
 216:     int lineStart = line.getStartOffset();
 217:     Segment segment = getLineBuffer();
 218:     segment.array = new char[pos - lineStart];
 219:     char echoChar = getEchoChar();
 220:     for (int i = 0; i < segment.array.length; ++i)
 221:       segment.array[i] = echoChar;
 222:     segment.offset = 0;
 223:     segment.count = segment.array.length;
 224: 
 225:     int xoffset = Utilities.getTabbedTextWidth(segment, metrics, rect.x,
 226:                            this, lineStart);
 227: 
 228:     // Calc the real rectangle.
 229:     rect.x += xoffset;
 230:     rect.width = 1;
 231:     rect.height = metrics.getHeight();
 232: 
 233:     return rect;
 234:   }
 235: 
 236:   /**
 237:    * Provides a mapping from the view coordinate space to the logical 
 238:    * coordinate space of the model.
 239:    * 
 240:    * @param fx - the X coordinate >= 0.0f
 241:    * @param fy - the Y coordinate >= 0.0f
 242:    * @param a - the allocated region to render into 
 243:    * @param bias - typesafe enumeration to indicate bias to a position in the model.
 244:    * @return the location within the model that best represents 
 245:    * the given point in the view
 246:    * 
 247:    */
 248:   public int viewToModel(float fx, float fy, Shape a, Position.Bias[] bias)
 249:   {
 250:     // FIXME: This only provides a view->model mapping for the real text
 251:     // content and does not respect the echo char.
 252:     return super.viewToModel(fx, fy, a, bias);
 253:   }
 254: }