| 摘要 |
PURPOSE:To perform shadowing of a drawing as stereoscopical shadowing and further to realize shadow processing at high speed. CONSTITUTION:Offset values x and y of an image expressing the direction and size of shadowing are previously set, first of all, read data are read as the run length data of an n-th line (X line in the figure) and a drawing part G (the part of hatching expressed by a real line in the figure) included in the read data is extracted. Next, the processing of (n+1)th line is started and a shadow area S1 corresponding to a head picture element G0 at the drawing part G is calculated based on inclination (k) calculated from x and y. Then, the shadow area of the (n+1)th line corresponding to the drawing part G is calculated from the shadow area S1 and a length L of the drawing part G. Similarly, the shadow areas of (n+2)th and (n+3)th lines are calculated, and the total sum of these shadow areas is decided as a shadow area S corresponding to a drawing part G2. Therefore, it is enough to perform operation processing based on a shadowing parameter just for only the head picture element G0. |
