As-Rigid-As-Possible Curve Editing
Demonstration Applet

Pull:      Grab and drag the curve to deform. Click the curve to put a pushpin.
Smooth:    Scrub the curve to smooth. 
Draw:      Drag to draw a stroke.
T. Igarashi, T. Moscovich, J.F. Hughes, "As-Rigid-As-Possible Shape Manipulation",
ACM Transactions on Computer Graphics, Vol.24, No.3, 2005. PDF

Copyright (C) 2005 Takeo Igarashi