Real-time rub-out erase for an electronic handwriting facility
First Claim
1. In an electronic handwriting facility comprising a central processor unit, an all points addressable display, and an electronic tablet and stylus, said handwriting facility simulating writing with a pen or pencil and paper and generating an electronic document by periodically sending to the central processing unit the absolute location of the stylus in relation to the tablet, mapping each location point to the display coordinate system, and storing the points in a point list, the improvement comprising a real-time rub-out erase feature for the handwriting facility comprising the steps ofestablishing a grid over the write area on the tablet to delineate the write area into a plurality of grid boxes,storing in a grid table the starting and ending points of line segments within each of said grid boxes, said grid table being updated whenever a point is added to said point list,setting the system to erase mode and displaying an erase cursor on said display showing the relative location of said stylus to the electronic tablet,searching only the segments and points in the grid boxes touched by the erase cursor during erasure,updating said point list and said grid table after erasure, andupdating said display to provide a real-time display of the erasure.
1 Assignment
0 Petitions
Accused Products
Abstract
An electronic handwriting facility comprises a central processing unit (10), an all points addressable display (12), and an electronic tablet (14) and stylus (16). The handwriting facility simulates writing with a pen or pencil and paper. An electronic document is generated by periodically sending to the central processing unit (10) the absolute location of the stylus (16) in relation to the tablet (14). Each point is mapped to the display coordinate system, and the points are stored in point list. The handwriting facility is provided with a real-time rub-out erase feature wherein the handwriting facility is first set to the erase mode and then the points in the point list to be erased are identified. Real-time erasure is assured by using a grid overlaying the write area to limit the number of points searched to a small percentage of the total. The grid breaks the write area into a number of grid boxes. Only the grid boxes touched by the erase cursor are searched for erasure. When a point is inside the erase cursor, it is deleted from the point list. The user is provided with a menu from which to select an erase stylus size further adding to the flexibility of the erase feature.
101 Citations
8 Claims
-
1. In an electronic handwriting facility comprising a central processor unit, an all points addressable display, and an electronic tablet and stylus, said handwriting facility simulating writing with a pen or pencil and paper and generating an electronic document by periodically sending to the central processing unit the absolute location of the stylus in relation to the tablet, mapping each location point to the display coordinate system, and storing the points in a point list, the improvement comprising a real-time rub-out erase feature for the handwriting facility comprising the steps of
establishing a grid over the write area on the tablet to delineate the write area into a plurality of grid boxes, storing in a grid table the starting and ending points of line segments within each of said grid boxes, said grid table being updated whenever a point is added to said point list, setting the system to erase mode and displaying an erase cursor on said display showing the relative location of said stylus to the electronic tablet, searching only the segments and points in the grid boxes touched by the erase cursor during erasure, updating said point list and said grid table after erasure, and updating said display to provide a real-time display of the erasure.
Specification