/**
* Moves this piece to a new position on the board.
*
* @param newRow The destination row.
* @param newColumn The destination column.
* @return <code>false</code> if the destination is not a legal board position, or if the piece is
* already moving.
*/
public boolean moveTo(int newRow, int newColumn) {
if (!board.isLegalPosition(newRow, newColumn)) return false;
if (moving) return false;
int startX = board.columnToX(column);
int startY = board.rowToY(row);
int finishX = board.columnToX(newColumn);
int finishY = board.rowToY(newRow);
int changeInX = finishX - startX;
int changeInY = finishY - startY;
Rectangle oldRect = getRectangle();
Rectangle newRect = new Rectangle(oldRect);
// compensate for squares being slightly different sizes
oldRect.width += 2;
newRect.width += 2;
oldRect.height += 2;
newRect.height += 2;
// Move smoothly towards new position
moving = true;
board.moveToTop(this);
int deltaRow = Math.abs(row - newRow);
int deltaColumn = Math.abs(column - newColumn);
int distance = Math.max(deltaRow, deltaColumn) + Math.min(deltaRow, deltaColumn) / 2;
int numberOfSteps = distance * FRAME_RATE / getSpeed();
for (int i = 1; i <= numberOfSteps; i++) {
oldRect.x = x;
oldRect.y = y;
x = startX + (i * changeInX) / numberOfSteps;
y = startY + (i * changeInY) / numberOfSteps;
newRect.x = x;
newRect.y = y;
board.getJPanel().paintImmediately(oldRect.union(newRect));
// redraw(oldRect.union(newRect));
try {
Thread.sleep(PAUSE_MS);
} catch (InterruptedException e) {
/* Deliberately empty */
}
}
moving = false;
if (canMoveTo(newRow, newColumn)) {
changePosition(newRow, newColumn);
}
redraw(oldRect.union(newRect));
return true;
}
/**
* Continues dragging a piece.
*
* @see java.awt.event.MouseMotionListener#mouseDragged(java.awt.event.MouseEvent)
*/
@Override
public void mouseDragged(MouseEvent e) {
int x;
int y;
if (pieceBeingDragged == null) return;
// Don't allow drag outside board boundaries
int maxX = board.columnToX(board.getColumns() - 1);
int maxY = board.rowToY(board.getRows() - 1);
x = e.getX() - board.getCellWidth() / 2;
if (x < 0) {
x = 0;
} else {
if (x > maxX) x = maxX;
}
y = e.getY() - board.getCellHeight() / 2;
if (y < 0) {
y = 0;
} else {
if (y > maxY) y = maxY;
}
pieceBeingDragged.x = x;
pieceBeingDragged.y = y;
// Track mouse movement
pieceBeingDragged.setChanged();
pieceBeingDragged.notifyObservers();
}
/**
* Change the position of this piece on the board.
*
* @param newRow The new row for this piece.
* @param newColumn The new column for this piece.
*/
private void changePosition(int newRow, int newColumn) {
if (!atLegalPosition()) return;
int oldRow = row;
int oldColumn = column;
board.changePositionOnBoard(this, oldRow, oldColumn, newRow, newColumn);
row = newRow;
column = newColumn;
x = board.columnToX(column);
y = board.rowToY(row);
redraw();
}
/**
* For internal use only!
*
* @param board The board on which to place this piece.
* @param row The row number.
* @param column The column number.
*/
final void placeHelper(Board board, int row, int column) {
// When a piece is placed on a board, both the piece and
// the board must be updated. This method is called from
// Board.place to update the piece.
this.board = board;
this.row = row;
this.column = column;
x = board.columnToX(column);
y = board.rowToY(row);
addObserver(board);
redraw(getRectangle());
}
/**
* Returns the rectangle in which this piece should be painted.
*
* @return The rectangle in which to paint this piece.
*/
protected Rectangle getRectangle() {
int leftEdge = getX() + 1;
int topEdge = getY() + 1;
int width;
int height;
if (moving) {
width = board.getCellWidth() - 1;
height = board.getCellHeight() - 1;
} else {
width = board.columnToX(column + 1) - leftEdge;
height = board.rowToY(row + 1) - topEdge;
}
return new Rectangle(leftEdge, topEdge, width, height);
}
/**
* Returns the x-coordinate at which this piece will be painted.
*
* @return The x-coordinate.
*/
protected int getX() {
return moving ? x : board.columnToX(column);
}
