| 摘要 |
A wipe pattern generating apparatus includes a first memory for storing polar coordinate data of the contour of a wipe pattern, a polar coordinate data forming unit for forming polar coordinate data indicating the position of the pixels on a display screen of a display unit, and a comparator for comparing distance data of the contour of the wipe pattern read out from the first memory on the basis of angle data outputted from the polar coordinate data forming unit and distance data outputted from the polar coordinate data forming unit, for forming switching data. The apparatus also includes a second memory for storing polar coordinate data of a portion of the wipe pattern contour within the range of 0 DEG to 360 DEG . The polar coordinate data of the entire wipe pattern contour formed on the basis of the polar coordinate data of the portion of the wipe pattern contour stored in the second memory are written in the first memory to allow to produce a wipe pattern of a desired shape with a lesser memory capacity. The apparatus also includes a modulating unit for modulating the angle data outputted from the polar coordinate data forming unit with the distance data. The polar coordinate data of the contour of the wipe pattern stored in the memory are read out with the aid of the modulated angle data to generate a spiral wipe pattern.
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