org.eclipse.swt.events.SegmentEvent Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of org.eclipse.swt.gtk.linux.aarch64 Show documentation
Standard Widget Toolkit for GTK on aarch64
The newest version!
/*******************************************************************************
 * Copyright (c) 2000, 2012 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.swt.events;

import org.eclipse.swt.widgets.*;

/**
 * This event is sent to SegmentListeners when a text content is to be modified.
 * The segments field can be used in conjunction with the segmentsChars field or
 * by itself. Setting only the segmentsChars field has no effect. When used by
 * itself, the segments field specify text ranges that should be treated as
 * separate segments.
 * 
 * The elements in the segments field specify the start offset of a segment
 * relative to the start of the text. They must follow the following rules:
 * 
 * elements must be in ascending order and must not have duplicates
 * 
elements must not exceed the text length
 * 
 * In addition, the first element may be set to zero and the last element may
 * be set to the end of the line but this is not required.
 * 
 * The segments field may be left null if the entire text content doesn't
 * require segmentation.
 * 
 * A SegmentListener may be used when adjacent segments of right-to-left text
 * should not be reordered relative to each other. For example, within a Java
 * editor, you may wish multiple right-to-left string literals to be reordered
 * differently than the bidi algorithm specifies.
 *
 * Example:
 *  * 	stored text = "R1R2R3" + "R4R5R6"
 *		R1 to R6 are right-to-left characters. The quotation marks
 * 		are part of the text. The text is 13 characters long.
 *
 * 	segments = null:
 * 		entire text content will be reordered and thus the two R2L segments
 * 		swapped (as per the bidi algorithm).
 *		visual display (rendered on screen) = "R6R5R4" + "R3R2R1"
 *
 * 	segments = [0, 5, 8]
 * 		"R1R2R3" will be reordered, followed by [blank]+[blank] and
 * 		"R4R5R6".
 *		visual display = "R3R2R1" + "R6R5R4"
 * 
 *
 * 
 * The segments and segmentsChars fields can be used together to obtain different
 * types of bidi reordering and text display. The application can use these two fields
 * to insert Unicode Control Characters in specific offsets in the text, the character
 * at segmentsChars[i] is inserted at the offset specified by segments[i]. When both fields
 * are set, the rules for the segments field are less restrictive:
 * 
 * 
 * elements must be in ascending order, duplicates are allowed
 * 
elements must not exceed the text length
 * 
 *
 * @since 3.8
 */

public class SegmentEvent extends TypedEvent {

	/**
	 * The start offset of the lineText relative to text (always zero for single line widget)
	 */
	public int lineOffset;

	/**
	 * Text used to calculate the segments
	 */
	public String lineText;

	/**
	 * Text ranges that should be treated as separate segments (e.g. for bidi reordering)
	 */
	public int[] segments;

	/**
	 * Characters to be used in the segment boundaries (optional)
	 */
	public char[] segmentsChars;

	static final long serialVersionUID = -2414889726745247762L;

	public SegmentEvent(Event e) {
		super(e);
		lineText = e.text;
		lineOffset = e.detail;
	}
}