| 摘要 |
In this invention, an original image is read to be formed as a tour bit map, and the bit map is read out for each plurality of picture elements. Then, in the position to which the aforementioned unit plurality of picture elements corresponds on the original image, a predetermined bit map data is to be written by a logical sum. If the operation is indicated as a shadowing process, a bit map of a predetermined oblique line for a shadow designated by a direction and a length is to be written. The aforementioned operation is carried out for every plurality of picture elements on the contour bit map so as to thicken or shadow the original image at a high speed. When the method of this invention is applied as to a large size region, since the work area for the reservation of the contour data becomes larger to exhibit less effectiveness of the space usage, the processing area is designed to be divided, if required, to be processed. In such a division method, it is required to set up as work areas a reservation area for keeping the contour bit map and a writing-in region for writing in the synthetic unit data in the use of the logical sum. Providing the latter mentioned writing-in region makes it possible to save a clipping treatment, and also give an advantage for effecting the thinning operation.
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