Point relocation for digital ink curve moderation

摘要

With some splines, such as cardinal splines, irregularly spaced data points may cause undesired bumps. Bump moderation makes a spline curve more visually appealing by reducing bumps, and by doing so even if the curve happens to be already smooth in a mathematical sense. Data points P1, P2, and P3 are not suitably spaced an outlier is present in a set of linear distances between the points. The bump is moderated by moving a point of the spline along a pathway to a position for which the data points P1, P2, and P3 are suitably spaced. The pathway may be a Bezier segment or a line segment. A point is moved on the pathway to its midpoint, or to a particular portion of the pathway such as its central third or central fifth.

主权项

1. An automated process for visibly moderating a bump in a digital ink curve which is already visually smooth through at least N points, the process utilizing a particular device which has a computer-readable memory, a display, and logic (software interoperating with hardware) to perform the process, the process including the following steps performed by the logic:
getting in the computer-readable memory N data points for the digital ink curve, N being at least three, the N data points including at least a point P1, a point P2, and a point P3 which are positioned in that order relative to each other along a spline of the digital ink curve, the bump being a part of the spline and having a peak; computationally determining that the data points P1, P2, and P3 are not suitably spaced, in that an outlier is present in the linear distances between the data points P1, P2, and P3, namely, a linear distance between a first pair of the points P1, P2, and P3 is larger than R times a linear distance between a second pair of the points P1, P2, and P3, and the factor R is at least 3.0 and no more than 8.0; moderating the bump by altering computer-readable memory content, namely, by moving a control point of the spline to a position for which the data points P1, P2, and P3 are suitably spaced; and displaying at least a portion of the digital ink curve on the display with the bump moderated.