7. The method of claim 3 , wherein annotating of the captured portion of the reference document further comprises: displaying the captured portion of the reference document to be annotated; receiving a first input from a user designating a first point in the captured portion of the reference document defining a corner of an annotation rectangle; receiving a second input from the user designating a second point in the captured portion of the reference document defining an opposite corner of the annotation rectangle; and annotating the captured portion of the reference document from the first point to the second point of the annotation rectangle when the second input is released.
7. The method of claim 3 , wherein annotating of the captured portion of the reference document further comprises: displaying the captured portion of the reference document to be annotated; receiving a first input from a user designating a first point in the captured portion of the reference document defining a corner of an annotation rectangle; receiving a second input from the user designating a second point in the captured portion of the reference document defining an opposite corner of the annotation rectangle; and annotating the captured portion of the reference document from the first point to the second point of the annotation rectangle when the second input is released. 8. The method as recited in claim 7 , further comprising: displaying a shape corresponding to the annotation rectangle of the captured portion of the reference document before annotating the captured portion of the reference document.