org.eclipse.swt.custom.BidiSegmentEvent Maven / Gradle / Ivy
/*******************************************************************************
* Copyright (c) 2000, 2012 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.custom;
import org.eclipse.swt.events.*;
/**
* This event is sent to BidiSegmentListeners when a line is to
* be measured or rendered in a bidi locale.
* 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 in the line
* that should be treated as separate segments for bidi reordering. Each
* segment will be reordered and rendered separately.
*
* The elements in the segments field specify the start offset of
* a segment relative to the start of the line. They must follow
* the following rules:
*
* - elements must be in ascending order and must not have duplicates
*
- elements must not exceed the line 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 line should
* be reordered as is.
*
* A BidiSegmentListener 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 line = "R1R2R3" + "R4R5R6"
* R1 to R6 are right-to-left characters. The quotation marks
* are part of the line text. The line is 13 characters long.
*
* segments = null:
* entire line will be reordered and thus the two R2L segments
* swapped (as per the bidi algorithm).
* visual line (rendered on screen) = "R6R5R4" + "R3R2R1"
*
* segments = [0, 5, 8]
* "R1R2R3" will be reordered, followed by [blank]+[blank] and
* "R4R5R6".
* visual line = "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 line, 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 line length
*
*
*
* @see Sample code and further information
*/
public class BidiSegmentEvent extends SegmentEvent {
static final long serialVersionUID = -3712986188155944253L;
BidiSegmentEvent(StyledTextEvent e) {
super(e);
}
}