/* The {convex} option for image interpolation. */
/* Last edited on 2017-03-11 19:33:29 by stolfilocal */

/* 
  The {convex} flag is relevant for interpolation order 1 or higher.
  
  If {convex} is true, the result is a convex combination of the
  neighboring image samples, and therefore always lies in the interval
  spanned by their values. However, for {order>=1} it will not be a true
  interpolation: when evaluated at pixel centers it will return a
  slightly smoothed version of the original image.
  
  If the {convex} flag is false, the function performs an exact
  interpolation: when evaluated at a pixel center, it returns the
  original value of that pixel. In this case the values interpolated
  between pixel centers may over- or undershoot the range spanned by the
  neighboring image samples. The amount of over- or undershoot 
  is at most {K} times the width of the 
  
*/

/*    
  If {order} is 2, the result is piecewise cubic C2 B-spline. It is 
  not a true interpolation; if sampled at pixel centers, it gives
  a slightly smoothed version of the original image.
*/