libjava/java/awt/im/InputMethodRequests.java

   1 /* InputMethodRequests.java -- handles text insertion via input methods
   2    Copyright (C) 2002, 2005  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., 59 Temple Place, Suite 330, Boston, MA
  19 02111-1307 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 java.awt.im;
  39
  40 import java.awt.Rectangle;
  41 import java.awt.font.TextHitInfo;
  42 import java.text.AttributedCharacterIterator;
  43 import java.text.AttributedCharacterIterator.Attribute;
  44
  45 /**
  46  * This interface handles requests made by input methods on text editing
  47  * components. A component must specify a handler for input methods that
  48  * implements this interface, and which supports one of two user interfaces:
  49  * <ul><li><em>on-the-spot</em>: composed text is shown in place</li>
  50  * <li><em>below-the-spot</em>: composed text is in a separate window,
  51  * usually below the main text window, until it is committed into place at
  52  * the insertion point, overwriting any selected text</li></ul>
  53  *
  54  * @author Eric Blake (ebb9@email.byu.edu)
  55  * @see Component#getInputMethodRequests()
  56  * @see InputMethodListener
  57  * @since 1.2
  58  * @status updated to 1.4
  59  */
  60 public interface InputMethodRequests
  61 {
  62   /**
  63    * Gets the location of a given offset of the text. This can be used to
  64    * position a composition window near the location of where the composed
  65    * text will be inserted.
  66    *
  67    * <p>If the component has composed text (from the most recent
  68    * InputMethodEvent), then offset 0 indicates the location of the first
  69    * character of this composed text. Otherwise, the offset is ignored, and
  70    * the location should be the beginning of the final line of selected
  71    * text (in horizontal left-to-right text, like English, this would be the
  72    * lower left corner of the selction; in vertical top-to-bottom text, like
  73    * Chinese, this would be the top right corner of the selection).
  74    *
  75    * <p>The location returned is a 0-thickness caret (either horizontal or
  76    * vertical, depending on text flow), mapped to absolute screen coordinates.
  77    *
  78    * @param offset offset within composed text, or null
  79    * @return the screen location of the caret at the offset
  80    */
  81   Rectangle getTextLocation(TextHitInfo offset);
  82
  83   /**
  84    * Get the text offset for the given screen coordinate. The offset is
  85    * relative to the composed text, and the return is null if it is outside
  86    * the range of composed text. For example, this can be used to find
  87    * where a mouse click should pop up a text composition window.
  88    *
  89    * @param x the x screen coordinate
  90    * @param y the y screen coordinate
  91    * @return a text hit info describing the composed text offset
  92    */
  93   TextHitInfo getLocationOffset(int x, int y);
  94
  95   /**
  96    * Gets the offset where the committed text exists in the text editing
  97    * component. This can be used to examine the text surrounding the insert
  98    * position.
  99    *
 100    * @return the offset of the insert position
 101    */
 102   int getInsertPositionOffset();
 103
 104   /**
 105    * Gets an interator which provides access to the text and its attributes,
 106    * except for the uncommitted text. The input method may provide a list of
 107    * attributes it is interested in; and the iterator need not provide
 108    * information on the remaining attributes. If the attribute list is null,
 109    * the iterator must list all attributes.
 110    *
 111    * @param beginIndex the index of the first character in the iteration
 112    * @param endIndex the index of the last character in the iteration
 113    * @param attributes a list of attributes interested in, or null
 114    * @return an iterator over the region of text with its attributes
 115    */
 116   AttributedCharacterIterator getCommittedText(int beginIndex, int endIndex,
 117                                                Attribute[] attributes);
 118
 119   /**
 120    * Gets the length of committed text.
 121    *
 122    * @return the number of committed characters
 123    */
 124   int getCommittedTextLength();
 125
 126   /**
 127    * Gets the latest committed text, and removes it from the component's text
 128    * body. This allows an input method to provide an "Undo" command. In
 129    * general, this should only be supported immediately after a commit, and
 130    * not when other actions intervene; if not supported, simply return null.
 131    * The input method may provide a list of attributes it is interested in;
 132    * and the iterator need not provide information on the remaining attributes.
 133    * If the attribute list is null, the iterator must list all attributes.
 134    *
 135    * @param attributes a list of attributes interested in, or null
 136    * @return the latest committed text, or null
 137    */
 138   AttributedCharacterIterator cancelLatestCommittedText
 139     (Attribute[] attributes);
 140
 141   /**
 142    * Gets the currently selected text. One use of this is to implement a
 143    * "Reconvert" feature in an input method, which modifies the selection
 144    * based on the text in the composition window. The input method may
 145    * provide a list of attributes it is interested in; and the iterator need
 146    * not provide information on the remaining attributes. If the attribute
 147    * list is null, the iterator must list all attributes.
 148    *
 149    * @param attributes a list of attributes interested in, or null
 150    * @return the current selection
 151    */
 152   AttributedCharacterIterator getSelectedText(Attribute[] attributes);
 153 } // interface InputMethodRequests