Abstract: Methods and apparatus, including computer program products, implementing and using techniques for performing computer graphics operations on an image represented by digital data. A representation of a digital image is received. The image includes vector objects, each specified by control points. An editing brush is provided for interactive editing of the image by a user. The editing brush has a region of influence and applies a displacement function to control points in the region of influence, whereby when the editing brush is applied by the user to the image, a local distortion of the image is generated.

Abstract: Methods and apparatus, including computer program products, implementing techniques for performing envelope-based computer graphics operations on vector objects in an image. An envelope in an image generally contains an original drawing object. The envelope is a manipulable graphic object defining a coordinate remapping that is applied to generate a resulting drawing object for any original drawing object in the envelope. In one embodiment, the envelope has an interior control point that is an anchor point. User manipulation of the interior control point redefines the coordinate remapping. In another embodiment, a precision variable determines how closely an object in the envelope will follow the envelope when the corresponding resulting object is generated. Additional control points can be added to the original contained object if necessary to achieve the required precision before applying the coordinate remapping.

Abstract: Methods and apparatus, including computer program products, implementing techniques for performing colorization of the control points of vector objects in an image represented by digital data. A representation of a digital image is received. The image includes vector objects, and each of the objects is specified by an assemblage of control points each possessing a color. An image sampling utility, a gradient sampling utility, and a mesh painting utility are provided for interactive editing of the image by the user. The image sampling utility, gradient sampling utility, and mesh painting utility have graphical extents and apply a colorization function to control points within that extent, whereby when the control points have been colorized the graphical representation of the vector object is generated.

Abstract: A technique of stroke substitution and digital halftoning uses prioritized textures to produce digital halftones which appear to be hand drawn in the traditional pen and ink fashion. A user may control geometric attributes of the halftone strokes and sampling parameters of the image, which allows for the creation of a wide variety of halftones.