The maximum deviation used when automatically clipping traced points to fit order tracing polynomials.
It is expressed in units of pixels and will usually be a fraction of a pixel.
Any traced point which is further than this limit from the fitted polynomial (for that X-coordinate) is liable to be clipped. Automatic clipping only stops when either all points have deviations of less than TUNE_CLPMXDEV from the polynomial; or when so many points have been clipped that a meaningful fit can no longer be attempted. In this latter case, the order will be automatically disabled. The user may re-fit manually if the order is still to be processed.
The default value is 0.5.
Martin Clayton