Drawing coordinate system and scale setting method

Claim 1

A drawing coordinate system and scale setting method for automatically setting in a tablet device a drawing coordinate system and a scale S of a figure drawn on a drawing placed on a tablet surface having a tablet coordinate system comprising the steps of: (a) obtaining coordinates (x t1 , y t1 ), (x t2 ,y t2 ) in the tablet coordinate system by touching two points P 1 and P 2 on the figure; (b) calculating a distance between said two points in the tablet coordinate system; (c) inputting coordinates (x f1 ,y f1 ), (x f2 ,y f2 ) of said two points P 1 ,P 2 from the drawing coordinate system; (d) calculating a distance between said two points in the drawing coordinate system using the coordinates of said two points P 1 , P 2 in the drawing coordinate system; (e) obtaining the scale S of the figure by using the distance between said two points in the drawing coordinate system and the distance between said two points in the tablet coordinate system; (f) obtaining in the table coordinate system a line segment P 1 ,O 1 being parallel to an X axis of the drawing coordinate system, where O 1 represents a point of intersection between a circle whose center is the point P 1 and whose radius is S * |x f2 -x f1 |, and a circle whose center is the point P 2 and whose radius is S * |y f2 -y f1 |; (g) setting in the tablet device coordinates defining a straight line as a Y axis of the drawing coordinate system, which is perpendicular to the line segment P 1 O 1 passing through a point P 0 that is on an extension of line segment P 1 O 1 and located at a distance of S * x f1 from the point P 1 ; and (h) setting in the tablet device coordinates defining a point as an origin of the drawing coordinate system which is on the Y axis at a distance of S * y f1 from the point P 0 (i) displaying the drawing coordinate system.