| 摘要 |
PURPOSE:To generate an optionally rotated elliptic pattern by calculating the coordinate values for each of eight divided areas where X and Y coordinates are increased or reduced by one. CONSTITUTION:A coordinate rotation angle theta is made larger than 0 deg. and smaller than 45 deg., and an ellipse is described clockwise, and the ellipse is described while increasing or reducing an (x) coordinate value X and a (y) coordinate value Y by one. The ellipse is divided into 8 areas such as an area A where the value X is certainly increased by one and the value Y is left as it is or is increased by one and the value Y is left as it is or is reduced by one. A constant AX=b<2> cos<2>theta+sin<2>theta or the like in each area is calculated. X0=-bsintheta and Y0=bcostheta are calculated as initial values. Coordinate values X and Y are calculated in accordance with initial values and the constant, and coordinate values of areas B-H are obtained from those of the area A, thus describing the elliptic pattern. |
