The above definitions highlight the difference between the GOF domain and GUI do main; GOF domain can address the implementation of objects while GUI domain addr ess only the interfaces of GUI objects. This is not of much concern for pattern s dealing with interface but does play an advantage for patterns dealing with en capsulation.
In patterns where the main concern is encapsulation the corresponding GUI patter n brings out a secondary aspect of the pattern. It is asserted that although th ese patterns do not directly address usability they are orthogonal to other tech niques for user interface design.
Interface consistency is an explicit force in GUI design. Secondly screen real estate is often discussed and is an important and scarce re source. Finally object identity in GUI's means that GUI's don't have pointers.
The GOF patterns have been translated to GUI design from Object Oriented software desig n. Objects used to express the objects are as follows: An object is a manipulable GUI component such as a windows or dialogue boxes for example. A single object may appear in more than one way and have different attributes and behaviors. A class is described as a group of objects with similar attributes and behaviors. Further classes can be g rouped using inheritance in order capture subtle differences between objects.
Three forces are discussed for all the patterns: Interface consistency is an explicit force in GUI design. Secondly screen real estate is often discussed and is an important and scarce resource. Finally object identity in GUI's means that GUI's don't have pointers.
screen real estate presenting one strategy object at a time ensures preservation of screen real estate.