rescale_subrect

  RESCALE_SUBRECT - resize a rectangle within a larger rectangle according to a scale and shift

   [NEWRECT] = RESCALE_SUBRECT(SUBRECT, ORIGINAL_RECT, SCALED_RECT, [FORMAT])

   This function rescales a rectangle SUBRECT, whose coordinates are located with
   respect to ORIGINAL_RECT. The same transformation that would be required to scale and
   shift ORIGINAL_RECT to SCALED_RECT is applied to SUBRECT, and returned in NEWRECT.

   FORMAT is an optional argument that specifies the format of the rectangles.
   FORMAT == 1 (default) means [left top right bottom]
   FORMAT == 2 means [left bottom right top]
   FORMAT == 3 means [left bottom width height]
   FORMAT == 4 means [left top width height]

   See also: RESCALE, RECT2RECT