Systems and methods for efficiently generating table layouts using moveable items

An API is provided for positioning items in a table. The API allows a number of columns or a number of rows, or both, to be specified for a table. Any items to be placed in the table may be identified for the API. Items may be "moveable," or not associated with fixed positions in the table. The moveable items may be placed adjacently in the table to fill a first row. New rows or columns may be generated to accommodate additional items. Items may also be "fixed," or associated with fixed positions in the table. Moveable items may fill in around the fixed items. A novel algorithm is provided to efficiently place both moveable and fixed items in a table. An on-demand reservation grid may be used in conjunction with the algorithm, thereby accommodating items that span multiple columns and/or rows.