Smooth shading of an object

A computer program, tangibly stored on a computer-readable medium, for rendering a two dimensional (2D) patch associated with an object to achieve a smooth shading across the object where the 2D patch defines a complex gradient including at least one foldover edge, the computer program comprising instructions for causing a computer to:

• convert the object to a mesh;
• divide the mesh to create a series of patches defining a gradient where patch boundaries correspond to segment vertices in the multisegment edges of a boundary of the object;
• render the mesh;
• display the object having a shading defined by the mesh;
• and
• edit the mesh until a desired result is achieved in the displayed object.

A method for defining a smooth shading across an object for display on a raster output device, the object including a boundary comprising edges at least one of which is a multisegment curve, the method comprising:

• converting the object to a mesh including creating a mesh boundary that includes edges that include a same number of segments as a corresponding edge in the boundary of the object;
• rendering the mesh;
• displaying the object having a shading defined by the mesh;
• and
• editing the mesh until a desired result is achieved in the displayed object.

A method for defining a gradient across an object for display on a raster output device, the object including a boundary comprising multisegment edges, the method comprising:

• selecting the object;
• finding the boundary for the object;
• creating a bounding box including four corners that encloses the object boundary;
• identify four points on the boundary of the object that are closest to the four corners of the boundary box;
• constructing a single patch mesh from the four points and segments connecting pairs of the four points;
• and
• dividing the single patch mesh to create a series of patches defining the gradient where patch boundaries correspond to segment vertices in the multisegment edges of the boundary of the object.