Method and apparatus for rendering a stroked curve for display in a graphics processing system

摘要

An input stroked curve that is received by a graphics processing system can be rendering using at least two, and preferably more, rendering processes that are available for use by the system. The process or processes that are used for rendering the received stroked curve are selected based on whether the input stroked curve comprises one or more regions having a particular characteristic or characteristics, e.g. whether the input stroked curve comprises one or more self-overlapping regions. Preferably, the at least two rendering processes are each capable of correctly rendering different sets of stroked curves. Furthermore, the least two rendering process preferably differ in the processing burden that they place on the graphics processing system.

主权项

1. A method of rendering a stroked curve for display in a graphics processing system, the graphics processing system being capable of using a plurality of rendering processes for the purpose of rendering stroked curves, the method comprising:
receiving, by one or more data processors, an input stroked curve defined in a defined space by a centre curve and an associated stroke width; determining, by the one or more data processors, whether the input stroked curve comprises at least one self-overlapping region; determining whether the input stroked curve should be sub-divided into at least two portions for purposes of rendering based on said step of determining whether the input stroked curve comprises at least one self-overlapping region; if it is determined that the input stroked curve comprises at least one self-overlapping region, then sub-dividing the input stroked curve into at least two portions based on said determination, wherein at least one of the portions includes the at least one self-overlapping region and another of the portions does not include the at least one self-overlapping region; and for each of the at least two portions:
selecting, by the one or more data processors, one of the plurality of rendering processes of the graphics processing system to be used for rendering the portion of the input stroked curve based on whether the portion includes the at least one self-overlapping region, the one of the plurality of rendering processes being selected between:
a first rendering process to be used for rendering portions of the input stroked curve that do not include at least one self-overlapping region, anda second rendering process to be used for rendering portions of the input stroked curve that do include at least one self-overlapping region,wherein the second rendering process requires more onerous processing than the first rendering process; andthe graphics processing system rendering the portion of the input stroked curve using the selected one of the plurality of rendering processes; wherein the step of determining whether the input stroked curve comprises at least one self-overlapping region comprises determining the radius of curvature at at least one point on the centre curve of the input stroked curve, and comparing the determined radius of curvature to half the associated stroke width of the input stroked curve.