RepaintArea.java 文件源码

/**
 * Adds a {@code Rectangle} to this {@code RepaintArea}.
 * PAINT Rectangles are divided into mostly vertical and mostly horizontal.
 * Each group is unioned together.
 * UPDATE Rectangles are unioned.
 *
 * @param   r   the specified {@code Rectangle}
 * @param   id  possible values PaintEvent.UPDATE or PaintEvent.PAINT
 * @since   1.3
 */
public synchronized void add(Rectangle r, int id) {
    // Make sure this new rectangle has positive dimensions
    if (r.isEmpty()) {
        return;
    }
    int addTo = UPDATE;
    if (id == PaintEvent.PAINT) {
        addTo = (r.width > r.height) ? HORIZONTAL : VERTICAL;
    }
    if (paintRects[addTo] != null) {
        paintRects[addTo].add(r);
    } else {
        paintRects[addTo] = new Rectangle(r);
    }
}