/*
* @(#)InputMethodRequests.java 1.18 03/12/19
*
* Copyright 2004 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
package java.awt.im;
import java.awt.Rectangle;
import java.awt.font.TextHitInfo;
import java.text.AttributedCharacterIterator;
import java.text.AttributedCharacterIterator.Attribute;
/**
* InputMethodRequests defines the requests that a text editing component
* has to handle in order to work with input methods. The component
* can implement this interface itself or use a separate object that
* implements it. The object implementing this interface must be returned
* from the component's getInputMethodRequests method.
*
* <p>
* The text editing component also has to provide an input method event
* listener.
*
* <p>
* The interface is designed to support one of two input user interfaces:
* <ul>
* <li><em>on-the-spot</em> input, where the composed text is displayed as part
* of the text component's text body.
* <li><em>below-the-spot</em> input, where the composed text is displayed in
* a separate composition window just below the insertion point where
* the text will be inserted when it is committed. Note that, if text is
* selected within the component's text body, this text will be replaced by
* the committed text upon commitment; therefore it is not considered part
* of the context that the text is input into.
* </ul>
*
* @see java.awt.Component#getInputMethodRequests
* @see java.awt.event.InputMethodListener
*
* @version 1.18, 12/19/03
* @author JavaSoft Asia/Pacific
* @since 1.2
*/
public interface InputMethodRequests {
/**
* Gets the location of a specified offset in the current composed text,
* or of the selection in committed text.
* This information is, for example, used to position the candidate window
* near the composed text, or a composition window near the location
* where committed text will be inserted.
*
* <p>
* If the component has composed text (because the most recent
* InputMethodEvent sent to it contained composed text), then the offset is
* relative to the composed text - offset 0 indicates the first character
* in the composed text. The location returned should be for this character.
*
* <p>
* If the component doesn't have composed text, the offset should be ignored,
* and the location returned should reflect the beginning (in line
* direction) of the highlight in the last line containing selected text.
* For example, for horizontal left-to-right text (such as English), the
* location to the left of the left-most character on the last line
* containing selected text is returned. For vertical top-to-bottom text,
* with lines proceding from right to left, the location to the top of the
* left-most line containing selected text is returned.
*
* <p>
* The location is represented as a 0-thickness caret, that is, it has 0
* width if the text is drawn horizontally, and 0 height if the text is
* drawn vertically. Other text orientations need to be mapped to
* horizontal or vertical orientation. The rectangle uses absolute screen
* coordinates.
*
* @param offset the offset within the composed text, if there is composed
* text; null otherwise
* @return a rectangle representing the screen location of the offset
*/
Rectangle getTextLocation(TextHitInfo offset);
/**
* Gets the offset within the composed text for the specified absolute x
* and y coordinates on the screen. This information is used, for example
* to handle mouse clicks and the mouse cursor. The offset is relative to
* the composed text, so offset 0 indicates the beginning of the composed
* text.
*
* <p>
* Return null if the location is outside the area occupied by the composed
* text.
*
* @param x the absolute x coordinate on screen
* @param y the absolute y coordinate on screen
* @return a text hit info describing the offset in the composed text.
*/
TextHitInfo getLocationOffset(int x, int y);
/**
* Gets the offset of the insert position in the committed text contained
* in the text editing component. This is the offset at which characters
* entered through an input method are inserted. This information is used
* by an input method, for example, to examine the text surrounding the
* insert position.
*
* @return the offset of the insert position
*/
int getInsertPositionOffset();
/**
* Gets an iterator providing access to the entire text and attributes
* contained in the text editing component except for uncommitted
* text. Uncommitted (composed) text should be ignored for index
* calculations and should not be made accessible through the iterator.
*
* <p>
* The input method may provide a list of attributes that it is
* interested in. In that case, information about other attributes that
* the implementor may have need not be made accessible through the
* iterator. If the list is null, all available attribute information
* should be made accessible.
*
* @param beginIndex the index of the first character
* @param endIndex the index of the character following the last character
* @param attributes a list of attributes that the input method is
* interested in
* @return an iterator providing access to the text and its attributes
*/
AttributedCharacterIterator getCommittedText(int beginIndex, int endIndex,
Attribute[] attributes);
/**
* Gets the length of the entire text contained in the text
* editing component except for uncommitted (composed) text.
*
* @return the length of the text except for uncommitted text
*/
int getCommittedTextLength();
/**
* Gets the latest committed text from the text editing component and
* removes it from the component's text body.
* This is used for the "Undo Commit" feature in some input methods, where
* the committed text reverts to its previous composed state. The composed
* text will be sent to the component using an InputMethodEvent.
*
* <p>
* Generally, this feature should only be supported immediately after the
* text was committed, not after the user performed other operations on the
* text. When the feature is not supported, return null.
*
* <p>
* The input method may provide a list of attributes that it is
* interested in. In that case, information about other attributes that
* the implementor may have need not be made accessible through the
* iterator. If the list is null, all available attribute information
* should be made accessible.
*
* @param attributes a list of attributes that the input method is
* interested in
* @return the latest committed text, or null when the "Undo Commit"
* feature is not supported
*/
AttributedCharacterIterator cancelLatestCommittedText(Attribute[] attributes);
/**
* Gets the currently selected text from the text editing component.
* This may be used for a variety of purposes.
* One of them is the "Reconvert" feature in some input methods.
* In this case, the input method will typically send an input method event
* to replace the selected text with composed text. Depending on the input
* method's capabilities, this may be the original composed text for the
* selected text, the latest composed text entered anywhere in the text, or
* a version of the text that's converted back from the selected text.
*
* <p>
* The input method may provide a list of attributes that it is
* interested in. In that case, information about other attributes that
* the implementor may have need not be made accessible through the
* iterator. If the list is null, all available attribute information
* should be made accessible.
*
* @param attributes a list of attributes that the input method is
* interested in
* @return the currently selected text
*/
AttributedCharacterIterator getSelectedText(Attribute[] attributes);
}
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