Morph Shape

#!/usr/bin/env gmic
# File : morphshape.gmic
# Author : David Tschumperle

# Entrypoint when run from CLI:
go =>[^] "Morph Shape" e[] "" animate 30

# Main function
go :
  v 0

  shape_cupid 500 # Source shape
  shape_dragonfly 500 # Target shape
  ge 50% r 512,512,1,1,0,0,0.5,0.5

  # Extract contour parameterizations of largest components.
  foreach { edgels -1 k[{argmax(${"-lof h"})}] channels. 0,1 f. "I==J[-1]?[-1,-1]:I" discard. -1 r. 1,50%,1,2,-1 }
  r 1,${-max_h},1,2,1 1,32,1,1,y%4 r. 1,{-2,h} a[-3,-2] .,c rm.
  => source,target
  512,512,1,3,"lerp([0,64,0],[0,32,128],y/h)" => background
  (0^0^0^0,255^255^255^255,255^0^0^255,255^128^0^255,255^255^0^255) => colormap

  # Perform curve interpolation.
  repeat 50 {
    k:=cut(lerp(-0.15,1.15,$%),0,1)
    [source] sh. 0,1 b. y,{lerp(0,100,$k)},2 rm.
    [target] sh. 0,1 b. y,{lerp(100,0,$k)},2 rm.
    j.. .,0,0,0,0,$k rm.
    {background,[w,h]} eval.. "pP = J[-1,2]; polygon(#-1,2,pP[0],pP[1],i0,i1,1,i2 + 1)"
    dilate. 3 map. [colormap] +ja[background] .
    rm[-3,-2]
  }
  rm[source,target,background,colormap]
  +rv

# End of file.