JPS6444758A - Method for compressing character font - Google Patents

Abstract

PURPOSE:To enhance a compressibility with a few amount of stored data and to improve an approximate accuracy to obtain a more shapely reproduced image, by a method wherein, an outline of a character is divided into some blocks by initial division points, spline functions through respective sample points in the respective blocks are obtained as approximate curves, and the respective blocks are approximated by interpolation with the approximate curves. CONSTITUTION:Initial division points are determined on an outline, whereby the outline is divided into some blocks. A point on just the center of two initial division points as the end points of the block is set as a sample point. A spline function through the three points in the appropriate block is obtained as a first approximate curve. Next, a distance l between the approximate curve and the outline at respective points in the block is calculated. A point on the outline with a maximum l is set as a new sample point, and a spline function through four points, i.e. this new point and the previous three points, is obtained as a new second approximate curve. Similarly, a distance l between the new approximate curve and the outline at respective points in the block is calculated. A point on the outline with a maximum l is set as a new sample point, and a spline function through five points, i.e. this new point and the previous four points, is obtained as a new approximate curve. The outline is approximated by obtaining approximate curves for all the blocks by the repeat of the above operation.