expandBy method
Expands this envelope by a given distance in all directions. Both positive and negative distances are supported.
@param deltaX the distance to expand the envelope along the the X axis @param deltaY the distance to expand the envelope along the the Y axis
Implementation
void expandBy(double deltaX, double deltaY) {
if (isNull()) return;
_minx -= deltaX;
_maxx += deltaX;
_miny -= deltaY;
_maxy += deltaY;
// check for envelope disappearing
if (_minx > _maxx || _miny > _maxy) {
setToNull();
}
}