Function pack 

pub fn pack<T, I>(
    into_rect: Rect,
    items: I,
) -> Result<Vec<PackedItem<T>>, Vec<PackedItem<T>>>
where
    T: Clone,
    I: IntoIterator<Item = Item<T>>,

Attempts to tightly pack the supplied items into into_rect.

Returns a collection of Vec<(Rect, T)> on success, or all items that were packed before failure.

Shorthand for:

let mut packer = Packer::with_items(items);
packer.pack(into_rect);

Example usage:

let rect = Rect::of_size(15, 15);
let items = vec![
    Item::new('A', 2, 9, Rotation::Allowed),
    Item::new('B', 3, 8, Rotation::Allowed),
    Item::new('C', 4, 7, Rotation::Allowed),
    Item::new('D', 5, 6, Rotation::Allowed),
    Item::new('E', 6, 5, Rotation::Allowed),
    Item::new('F', 7, 4, Rotation::Allowed),
    Item::new('G', 8, 3, Rotation::Allowed),
    Item::new('H', 9, 2, Rotation::Allowed),
];

let packed = match pack(rect, items) {
    Ok(all_packed) => all_packed,
    Err(some_packed) => some_packed,
};

// Every item fits inside rect without overlapping any others.
for a in &packed {
    assert!(rect.contains(&a.rect));
    for b in &packed {
        assert!(a.data == b.data || !a.rect.overlaps(&b.rect));
    }
}