| 摘要 |
PURPOSE:To shorten a processing time by processing a hidden line in such a manner that a form element having information which is not displayed is not plotted on a display screen. CONSTITUTION:A processor 11a obtains the respective form elements constituting a subform FG2 according to a program control, for instance, an intersection Pc intersecting the form element of a main form FG1 with respect to a linear element EL1, divides the form element EL1 at the intersection Pc to turn on the hidden bit of the internal sub-form element EL12 of the main form FG1 and thereafter apply a hidden line processing to all the form elements of the sub-form FG2. At the time of intersecting no all the form element of the main form FG1, for instance, when the start point Ps of the form element EL2 is present internally of the main form FG1, the hidden bit is turned on. Then, it is not plotted on the display screen 12. Thereby, the hidden processing can be automatically decided to shorten the processing time. |
