| 摘要 |
PURPOSE:To plot a circle or a circular arc with a good quality by generating no inconvenience in the connecting part of an octant even when the circle is plotted according to a line type pattern having a periodicity such as an alternate long and short dash line by generating and processing the dot of the circle and the circular arc successively in a constant direction. CONSTITUTION:After an initial value for plotting the circular arcs a0, a2 in the range of 0 deg.-45 deg. is set, a processing is started, when the number of the generations of the dots goes (R/2<1/2>-Rsintheta0), an initialization for plotting in the range of next 46 deg.-90 deg. is carried out. Namely, the coordinate axis of a reference is converted from (y) to (x) and the incremental value of the discriminating function of an (x) axis and a (y) axis direction is initialized. Similarly, the number of the generations of the dots is initialized to (R/2<1/2>-Rcostheta1). Then, the (x) address and the (y) address of a dot memory 709 are initialized to the coordinate (xs, ys) of an a0 point. Then, the number of processing dots (ym-ys) of the circular arcs a0a2 is obtained. Then, adiscriminating expression in a first point of the circular arcs a0a2 is calculated. |
