ellipser

Ellipser is a term used in geometry and computer graphics to describe tools, libraries, or algorithms that create, manipulate, and analyze ellipses in two-dimensional space. While not a single standardized project, Ellipser denotes a family of capabilities found in many math and graphics software packages, including representations, computations, and rendering workflows for ellipses.

Common representations handled by Ellipser-style systems include the parametric form x = x0 + a cos t cos θ − b sin t sin θ, y = y0 + a cos t sin θ + b sin t cos θ, with center (x0,y0), semi-axes a and b, and rotation θ; and the quadratic form Ax^2 + Bxy + Cy^2 + Dx + Ey + F = 0. Implementations typically support conversions between these forms, as well as operations such as point containment, finding intersections with lines or other ellipses, computing tangents, and generating ellipse arcs for rendering.

Ellipse fitting is a common task, where a set of points is used to estimate ellipse parameters. Direct least squares fitting, as described by Fitzgibbon, Pilu, and Fisher, is a widely used method in Ellipser-type libraries due to its robustness for noisy data.

Applications include computer-aided design, geographic information systems, data visualization, and font rendering, where precise and efficient ellipse handling is required. See also ellipse, conic section, ellipse fitting, and parametric curves.