The majority of the new code is contained within new modules that are simply linked with the base driver. The areas of the base driver code that must be modified include the following:

• The Dispatch Table, which contains the new Entry Points

• All drawing functions, which contain extra tests to determine whether they should accumulate clipped screen bounds and, if necessary, code to calculate the clipped bounding rectangle

• Seamless Windows cursor exclusion code, which is modified to call the new bounds accumulation routine.