package org.fxmisc.richtext;
import java.text.BreakIterator;
import javafx.scene.control.IndexRange;
/**
* Navigation actions for {@link TextEditingArea}.
*/
public interface NavigationActions<S> extends TextEditingArea<S> {
/**
* Indicates how to treat selection when caret is moved.
*/
static enum SelectionPolicy {
CLEAR,
ADJUST,
EXTEND,
}
/**
* Moves the caret to the given position in the text
* and clears any selection.
*/
default void moveTo(int pos) {
selectRange(pos, pos);
}
/**
* Moves the caret to the position indicated by {@code pos}.
* Based on the selection policy, the selection is either <em>cleared</em>
* (i.e. anchor is set to the same position as caret), <em>adjusted</em>
* (i.e. anchor is not moved at all), or <em>extended</em>
* (i.e. {@code pos} becomes the new caret and, if {@code pos} points
* outside the current selection, the far end of the current selection
* becomes the anchor.
*/
default void moveTo(int pos, SelectionPolicy selectionPolicy) {
switch(selectionPolicy) {
case CLEAR:
selectRange(pos, pos);
break;
case ADJUST:
selectRange(getAnchor(), pos);
break;
case EXTEND:
IndexRange sel = getSelection();
int anchor;
if(pos <= sel.getStart())
anchor = sel.getEnd();
else if(pos >= sel.getEnd())
anchor = sel.getStart();
else
anchor = getAnchor();
selectRange(anchor, pos);
break;
}
}
/**
* Moves the caret backward one char in the text.
* Based on the given selection policy, anchor either moves with
* the caret, stays put, or moves to the former caret position.
*/
default void previousChar(SelectionPolicy selectionPolicy) {
if (getCaretPosition() > 0) {
int newCaretPos = Character.offsetByCodePoints(getText(), getCaretPosition(), -1);
moveTo(newCaretPos, selectionPolicy);
}
}
/**
* Moves the caret forward one char in the text.
* Based on the given selection policy, anchor either moves with
* the caret, stays put, or moves to the former caret position.
*/
default void nextChar(SelectionPolicy selectionPolicy) {
if (getCaretPosition() < getLength()) {
int newCaretPos = Character.offsetByCodePoints(getText(), getCaretPosition(), 1);
moveTo(newCaretPos, selectionPolicy);
}
}
/**
* Skips two word boundaries backwards.
* Based on the given selection policy, anchor either moves with
* the caret, stays put, or moves to the former caret position.
*/
default void previousWord(SelectionPolicy selectionPolicy) {
if(getLength() == 0) {
return;
}
BreakIterator wordBreakIterator = BreakIterator.getWordInstance();
wordBreakIterator.setText(getText());
wordBreakIterator.preceding(getCaretPosition());
wordBreakIterator.previous();
moveTo(wordBreakIterator.current(), selectionPolicy);
}
/**
* Skips two word boundaries forward.
* Based on the given selection policy, anchor either moves with
* the caret, stays put, or moves to the former caret position.
*/
default void nextWord(SelectionPolicy selectionPolicy) {
if(getLength() == 0) {
return;
}
BreakIterator wordBreakIterator = BreakIterator.getWordInstance();
wordBreakIterator.setText(getText());
wordBreakIterator.following(getCaretPosition());
wordBreakIterator.next();
moveTo(wordBreakIterator.current(), selectionPolicy);
}
/**
* Moves the caret to the beginning of the current line.
*/
default void lineStart(SelectionPolicy selectionPolicy) {
moveTo(getCaretPosition() - getCaretColumn(), selectionPolicy);
}
/**
* Moves the caret to the end of the current line.
*/
default void lineEnd(SelectionPolicy selectionPolicy) {
int lineLen = getText(getCurrentParagraph()).length();
int newPos = getCaretPosition() - getCaretColumn() + lineLen;
moveTo(newPos, selectionPolicy);
}
/**
* Moves the caret to the beginning of the text.
*/
default void start(SelectionPolicy selectionPolicy) {
moveTo(0, selectionPolicy);
}
/**
* Moves the caret to the end of the text.
*/
default void end(SelectionPolicy selectionPolicy) {
moveTo(getLength(), selectionPolicy);
}
/**
* Selects the current line.
*/
default void selectLine() {
lineStart(SelectionPolicy.CLEAR);
lineEnd(SelectionPolicy.ADJUST);
}
/**
* Selects all text in the text input.
*/
default void selectAll() {
selectRange(0, getLength());
}
/**
* Clears the selection while keeping the caret position.
*/
default void deselect() {
int p = getCaretPosition();
selectRange(p, p);
}
}