/**
* Provides a way to determine the next visually represented model location that one might place a
* caret. Some views may not be visible, they might not be in the same order found in the model,
* or they just might not allow access to some of the locations in the model.
*
* @param v the view to use
* @param pos the position to convert >= 0
* @param a the allocated region to render into
* @param direction the direction from the current position that can be thought of as the arrow
* keys typically found on a keyboard. This may be SwingConstants.WEST, SwingConstants.EAST,
* SwingConstants.NORTH, or SwingConstants.SOUTH.
* @return the location within the model that best represents the next location visual position.
* @exception BadLocationException
* @exception IllegalArgumentException for an invalid direction
*/
public int getNextVisualPositionFrom(
GlyphView v, int pos, Position.Bias b, Shape a, int direction, Position.Bias[] biasRet)
throws BadLocationException {
int startOffset = v.getStartOffset();
int endOffset = v.getEndOffset();
Segment text;
AbstractDocument doc;
boolean viewIsLeftToRight;
TextHitInfo currentHit, nextHit;
switch (direction) {
case View.NORTH:
break;
case View.SOUTH:
break;
case View.EAST:
doc = (AbstractDocument) v.getDocument();
viewIsLeftToRight = doc.isLeftToRight(startOffset, endOffset);
if (startOffset == doc.getLength()) {
if (pos == -1) {
biasRet[0] = Position.Bias.Forward;
return startOffset;
}
// End case for bidi text where newline is at beginning
// of line.
return -1;
}
if (pos == -1) {
// Entering view from the left.
if (viewIsLeftToRight) {
biasRet[0] = Position.Bias.Forward;
return startOffset;
} else {
text = v.getText(endOffset - 1, endOffset);
char c = text.array[text.offset];
SegmentCache.releaseSharedSegment(text);
if (c == '\n') {
biasRet[0] = Position.Bias.Forward;
return endOffset - 1;
}
biasRet[0] = Position.Bias.Backward;
return endOffset;
}
}
if (b == Position.Bias.Forward) currentHit = TextHitInfo.afterOffset(pos - startOffset);
else currentHit = TextHitInfo.beforeOffset(pos - startOffset);
nextHit = layout.getNextRightHit(currentHit);
if (nextHit == null) {
return -1;
}
if (viewIsLeftToRight != layout.isLeftToRight()) {
// If the layout's base direction is different from
// this view's run direction, we need to use the weak
// carrat.
nextHit = layout.getVisualOtherHit(nextHit);
}
pos = nextHit.getInsertionIndex() + startOffset;
if (pos == endOffset) {
// A move to the right from an internal position will
// only take us to the endOffset in a left to right run.
text = v.getText(endOffset - 1, endOffset);
char c = text.array[text.offset];
SegmentCache.releaseSharedSegment(text);
if (c == '\n') {
return -1;
}
biasRet[0] = Position.Bias.Backward;
} else {
biasRet[0] = Position.Bias.Forward;
}
return pos;
case View.WEST:
doc = (AbstractDocument) v.getDocument();
viewIsLeftToRight = doc.isLeftToRight(startOffset, endOffset);
if (startOffset == doc.getLength()) {
if (pos == -1) {
biasRet[0] = Position.Bias.Forward;
return startOffset;
}
// End case for bidi text where newline is at beginning
// of line.
return -1;
}
if (pos == -1) {
// Entering view from the right
if (viewIsLeftToRight) {
text = v.getText(endOffset - 1, endOffset);
char c = text.array[text.offset];
SegmentCache.releaseSharedSegment(text);
if ((c == '\n') || Character.isSpaceChar(c)) {
biasRet[0] = Position.Bias.Forward;
return endOffset - 1;
}
biasRet[0] = Position.Bias.Backward;
return endOffset;
} else {
biasRet[0] = Position.Bias.Forward;
return startOffset;
}
}
if (b == Position.Bias.Forward) currentHit = TextHitInfo.afterOffset(pos - startOffset);
else currentHit = TextHitInfo.beforeOffset(pos - startOffset);
nextHit = layout.getNextLeftHit(currentHit);
if (nextHit == null) {
return -1;
}
if (viewIsLeftToRight != layout.isLeftToRight()) {
// If the layout's base direction is different from
// this view's run direction, we need to use the weak
// carrat.
nextHit = layout.getVisualOtherHit(nextHit);
}
pos = nextHit.getInsertionIndex() + startOffset;
if (pos == endOffset) {
// A move to the left from an internal position will
// only take us to the endOffset in a right to left run.
text = v.getText(endOffset - 1, endOffset);
char c = text.array[text.offset];
SegmentCache.releaseSharedSegment(text);
if (c == '\n') {
return -1;
}
biasRet[0] = Position.Bias.Backward;
} else {
biasRet[0] = Position.Bias.Forward;
}
return pos;
default:
throw new IllegalArgumentException("Bad direction: " + direction);
}
return pos;
}
