System and method for specifying elliptical parameters

A method for generating an elliptical arc in response to user input comprising:

• receiving movement of at least one of a center control point, a first foci control point, and a second foci control point associated with the elliptical arc;
• if the at least one center control point is moved, determining a value for at least one of the first foci control point and the second foci control point associated with the elliptical arc;
• determining a value for a focal radius associated with the elliptical arc based on the value for at least one of the foci control points;
• determining a value for a first radius of the elliptical arc based on the value for the focal radius, the first radius defined with respect to a first geometric axis associated with the elliptical arc;
• determining a value for a second radius of the elliptical arc, the second radius defined with respect to a second geometric axis associated with the elliptical arc;
• and
• determining, based on the values for the first radius and the second radius, a new value for the at least one center control point, and the at least one of the first foci control point and the second foci control point associated with the elliptical arc.

A system for rendering an elliptical arc in response to user input, comprising:

• a graphical user interface;
• and
• a pointing device coupled to the graphical user interface, the graphical user interface operable to:
• receive, via the pointing device, a first end point and a second end point for an elliptical arc;
• receive, via the pointing device, a center point for the elliptical arc;
• receive, via the pointing device, a foci point for the elliptical arc;
• and
• render the elliptical arc passing through the first and second end points, and having a center at the center point and a semi-major axis along a line joining the center point and the foci point.

A system for generating an elliptical arc, comprising:

• a processor unit;
• a display unit, the display unit coupled to the processor unit;
• and
• an input device, the input device coupled to the processor unit, responsive to the input device, the processor unit operable to:
• move at least one of a center control point, a first foci control point, and a second foci control point associated with the elliptical arc on the display;
• if the at least one center control point is moved, determine a value for at least one of the first foci control point and the second foci control point associated with the elliptical arc;
• determine a value for a focal radius associated with the elliptical arc based on the value for at least one of the foci control points;
• determine a value for a first radius of the elliptical arc based on the value for the focal radius, the first radius defined with respect to a first geometric axis associated with the elliptical arc;
• determine a value for a second radius of the elliptical arc, the second radius defined with respect to a second geometric axis associated with the elliptical arc;
• and
• determine, based on the values of the first radius and the second radius, a new value for the at least one center control point, and the at least one of the first foci control point and the second foci control point associated with the elliptical arc.

Software for rendering an elliptical arc in response to user input, the software being embodied in logic encoded in media and when executed operable to:

• receive, via a pointing device of a GUI, a first end point and a second end point for an elliptical arc;
• receive, via the pointing device of the GUI, a center point for the elliptical arc;
• receive, via the pointing device of the GUI, a foci point for the elliptical arc;
• render the elliptical arc passing through the first and second endpoints, and having a center at the center point and a semi-major axis along a line joining the center point and the foci point;
• and
• determine a radius of the ellipse along the semi-major axis, a radius of the ellipse along a semi-minor axis and an angle from an x-axis of a coordinate system of the GUI to an x-axis of the ellipse based on the received user input.

A system for rendering an elliptical arc in response to user input, comprising:

• means for receiving from a user a first end point and a second end point for an elliptical arc;
• means for receiving from a user a center point for the elliptical arc;
• means for receiving a foci point for the elliptical arc;
• means for rendering the elliptical arc passing through the first and second endpoints, and having a center at the center point and a semi-major axis along a line joining the center point and the foci point;
• and
• means for determining a radius of the ellipse along a semi-major axis, a radius of the ellipse along a semi-minor axis, an angle from an x-axis of a coordinate system of the GUI to the x-axis of the ellipse based on the received user input.