栅格注记的几何变换

Geometric Transformation of Raster-Mode Lettering

对点阵汉字实施几何变换,若以象元(栅格点)为单位,简单地按矢量变换(即一一对应)方式处理,会破坏汉字图形的连续性。要保持原图形的连续性,栅格点间的变换就不是一一对应的,而且对应关系也不是固定不变的,这种映射除与具体的变换有关外,还依赖于栅格点的坐标和此点的邻接关系。据此,本文介绍一种基于动态确定栅格点的对应关系和汉字几何关系的方法,其中包括对点阵汉字进行比例变换和对地图注记进行仿射变换。

In geometric transformation of a matrix Chinese character, the continuity of its graph would be lost if a raster point (pixel) is transferred into a new one just as in vector-mode. To keep the continuity,a mapping between raster point sets is not one-to-one and not constant. The mapping depends on coordinates and neighborhood of pixels in addition to transformation. So a method of geometric transformation of a raster chatacter is introduced in this paper based on dynamic determining the mapping between pixel sets. An algorithm of scaling transformation is outlined and that of affine transformation is then given.