Tizen Native API 5.5
Objects may carry hints, so that another object that acts as a manager (see Smart Object Functions) may know how to properly position and resize its subordinate objects. The Size Hints provide a common interface that is recommended as the protocol for such information.
For example, box objects use alignment hints to align its lines/columns inside its container, padding hints to set the padding between each individual child, etc.
Examples on their usage: