/*******************************************************************************
* Copyright (c) 2007, 2009 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.swt.widgets;
import org.eclipse.swt.graphics.*;
/**
* Instances of this class represent input method editors.
* These are typically in-line pre-edit text areas that allow
* the user to compose characters from Far Eastern languages
* such as Japanese, Chinese or Korean.
*
* <dl>
* <dt><b>Styles:</b></dt>
* <dd>(none)</dd>
* <dt><b>Events:</b></dt>
* <dd>ImeComposition</dd>
* </dl>
* <p>
* IMPORTANT: This class is <em>not</em> intended to be subclassed.
* </p>
*
* @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>
*
* @since 3.4
* @noextend This class is not intended to be subclassed by clients.
*/
public class IME extends Widget {
Canvas parent;
int caretOffset;
int startOffset;
int commitCount;
String text;
int [] ranges;
TextStyle [] styles;
/**
* Prevents uninitialized instances from being created outside the package.
*/
IME () {
}
/**
* Constructs a new instance of this class given its parent
* and a style value describing its behavior and appearance.
* <p>
* The style value is either one of the style constants defined in
* class <code>SWT</code> which is applicable to instances of this
* class, or must be built by <em>bitwise OR</em>'ing together
* (that is, using the <code>int</code> "|" operator) two or more
* of those <code>SWT</code> style constants. The class description
* lists the style constants that are applicable to the class.
* Style bits are also inherited from superclasses.
* </p>
*
* @param parent a canvas control which will be the parent of the new instance (cannot be null)
* @param style the style of control to construct
*
* @exception IllegalArgumentException <ul>
* <li>ERROR_NULL_ARGUMENT - if the parent is null</li>
* </ul>
* @exception SWTException <ul>
* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent</li>
* <li>ERROR_INVALID_SUBCLASS - if this class is not an allowed subclass</li>
* </ul>
*
* @see Widget#checkSubclass
* @see Widget#getStyle
*/
public IME (Canvas parent, int style) {
super (parent, style);
this.parent = parent;
createWidget ();
}
void createWidget () {
text = "";
startOffset = -1;
if (parent.getIME () == null) {
parent.setIME (this);
}
}
/**
* Returns the offset of the caret from the start of the document.
* The caret is within the current composition.
*
* @return the caret offset
*
* @exception SWTException <ul>
* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
* </ul>
*/
public int getCaretOffset () {
checkWidget ();
return startOffset + caretOffset;
}
/**
* Returns the commit count of the composition. This is the
* number of characters that have been composed. When the
* commit count is equal to the length of the composition
* text, then the in-line edit operation is complete.
*
* @return the commit count
*
* @exception SWTException <ul>
* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
* </ul>
*
* @see IME#getText
*/
public int getCommitCount () {
checkWidget ();
return commitCount;
}
/**
* Returns the offset of the composition from the start of the document.
* This is the start offset of the composition within the document and
* in not changed by the input method editor itself during the in-line edit
* session.
*
* @return the offset of the composition
*
* @exception SWTException <ul>
* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
* </ul>
*/
public int getCompositionOffset () {
checkWidget ();
return startOffset;
}
/**
* Returns the ranges for the style that should be applied during the
* in-line edit session.
* <p>
* The ranges array contains start and end pairs. Each pair refers to
* the corresponding style in the styles array. For example, the pair
* that starts at ranges[n] and ends at ranges[n+1] uses the style
* at styles[n/2] returned by <code>getStyles()</code>.
* </p>
* @return the ranges for the styles
*
* @exception SWTException <ul>
* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
* </ul>
*
* @see IME#getStyles
*/
public int [] getRanges () {
checkWidget ();
return ranges != null ? ranges : new int [0];
}
/**
* Returns the styles for the ranges.
* <p>
* The ranges array contains start and end pairs. Each pair refers to
* the corresponding style in the styles array. For example, the pair
* that starts at ranges[n] and ends at ranges[n+1] uses the style
* at styles[n/2].
* </p>
*
* @return the ranges for the styles
*
* @exception SWTException <ul>
* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
* </ul>
*
* @see IME#getRanges
*/
public TextStyle [] getStyles () {
checkWidget ();
return styles != null ? styles : new TextStyle [0];
}
/**
* Returns the composition text.
* <p>
* The text for an IME is the characters in the widget that
* are in the current composition. When the commit count is
* equal to the length of the composition text, then the
* in-line edit operation is complete.
* </p>
*
* @return the widget text
*
* @exception SWTException <ul>
* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
* </ul>
*/
public String getText () {
checkWidget ();
return text;
}
/**
* Returns <code>true</code> if the caret should be wide, and
* <code>false</code> otherwise. In some languages, for example
* Korean, the caret is typically widened to the width of the
* current character in the in-line edit session.
*
* @return the wide caret state
*
* @exception SWTException <ul>
* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
* </ul>
*/
public boolean getWideCaret() {
return false;
}
void releaseParent () {
super.releaseParent ();
if (this == parent.getIME ()) parent.setIME (null);
}
void releaseWidget () {
super.releaseWidget ();
parent = null;
text = null;
styles = null;
ranges = null;
}
/**
* Sets the offset of the composition from the start of the document.
* This is the start offset of the composition within the document and
* in not changed by the input method editor itself during the in-line edit
* session but may need to be changed by clients of the IME. For example,
* if during an in-line edit operation, a text editor inserts characters
* above the IME, then the IME must be informed that the composition
* offset has changed.
*
* @param offset the offset of the composition
*
* @exception SWTException <ul>
* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
* </ul>
*/
public void setCompositionOffset (int offset) {
checkWidget ();
if (offset < 0) return;
if (startOffset != -1) {
startOffset = offset;
}
}
}