Method for generating a two-dimensional distance field within a cell associated with a corner of a two-dimensional object

Claim 1

A computer implemented method for generating a two-dimensional distance field within a cell associated with a corner of a two-dimensional graphical object to represent a shape of the corner of the two-dimensional graphical object, comprising: determining a set of boundary descriptors for the two-dimensional graphical object; identifying a corner point enclosed in the cell from the set of boundary descriptors, the corner point partitioning the set of boundary descriptors into a first subset of boundary descriptors and a second subset of boundary descriptors, the corner point representing the corner of the graphical object; partitioning the cell into a first region closest to the corner point and a second region closest to the set of boundary descriptors, the partitioning further comprising: determining two lines passing through the corner point, each line corresponding to one of the first and second subsets of boundary descriptors and an outward facing normal direction of the corresponding subset of boundary descriptors at the corner point; and delimiting the first and second regions with the lines, wherein the first region is between exterior sides of both lines and the second region is on an interior side of either line; specifying a set of values, the set of values comprising a first set of sampled distance values determined from an extended curve corresponding to the first subset of boundary descriptors and a second set of sampled distance values determined from an extended curve corresponding to the second subset of boundary descriptors, and a reconstruction method using the first region and the second region for reconstructing the distance field within the cell, wherein the specifying the reconstruction method further comprises: reconstructing the distance field within the first region by determining a sample distance at a sample point in the first region as a distance from the sample point to the corner point; and reconstructing the distance field within the second region by determining a sample distance at a sample point in the second region, the determining for the second region further comprising: determining a first distance from the first set of sampled distance values; determining a second distance from the second set of sampled distance values; and selecting a minimum of the first and second distances to reconstruct the sample distance; and storing for the cell, the corner point, the lines delimiting the first and second regions, the reconstruction method, and the set of values in a memory to enable reconstruction of the distance field within the cell by applying the reconstruction method to represent a shape of the corner of the two-dimensional graphical object.