PxFck_IErode, A little hack based on PxF_IDefocus to make selective eroding possible.

copypasta.tcl

set cut_paste_input [stack 0]
version 9.0 v3
push 0
push $cut_paste_input
Group {
 inputs 2
 name PxFck_IErode
 help "Variable erode based on a control channel."
 knobChanged "\nm = nuke.thisNode() # grabs current node\nkc = nuke.thisKnob() #node that is being changed\n\nif kc.name() in \[\"filter\", \"slices\"]: #if changed knob is filer or slices\n    i = nuke.toNode('img') \n    i2 = nuke.toNode('Shuffle1')\n    o = nuke.toNode('Output1')\n    \n    for n in nuke.allNodes():\n      if \"static\" not in n\['label'].getValue():\n        nuke.delete(n)\n    \n    slices = int(m\['slices'].value())\n    step = 1\n    ii = i\n    for x in range(1,slices+step,step):\n      \n      k = nuke.nodes.Keyer()\n      k.setInput(0, i2)\n      k\['operation'].setValue(\"red keyer\")\n      k\['range'].setExpression(\"(1/parent.slices*\" + str(x) +\")-1/parent.slices\", 0)\n      k\['range'].setExpression(\"(1/parent.slices*\" + str(x-1) + \") + (1/parent.slices*parent.overlap)\", 1)\n      k\['range'].setValue(1.0, 2)\n      k\['range'].setValue(1.0, 3)\n     \n      f = m\['filter'].value()\n      if f in \[\"box\", \"triangle\", \"quadratic\", \"gaussian\"]:\n        d = nuke.nodes.FilterErode()\n        d.setInput(0, i)\n        d\['channels'].setValue(\"alpha\")\n        d\['size'].setSingleValue(False)\n        d\['size'].setExpression('parent.size/parent.slices*' + str(x) + \"*parent.aspect\", 0 )\n        d\['size'].setExpression('parent.size/parent.slices*' + str(x), 1)\n        d\['filter'].setValue(m\['filter'].value())\n\n      km = nuke.nodes.Keymix()\n      km.setInput(0, ii)\n      km.setInput(1, d)\n      km.setInput(2, k)\n      km\['bbox'].setValue(\"A side\")\n    \n      ii = km\n    \n    o.setInput(0, ii)\n\n"
 tile_color 0xd6a000ff
 selected true
 xpos -21856
 ypos 3470
 mapsize {0.3694810225 1}
 addUserKnob {20 IDefocus}
 addUserKnob {4 filter t "box, triangle, quadratic, gaussian = Erode filter type" M {box triangle quadratic gaussian "" "" "" ""}}
 addUserKnob {7 size t "Maximum amount of defocus (when the control channel is white)." R 0 100}
 size -4
 addUserKnob {7 aspect t "Aspect ratio of the kernel. Use this to simulate 'oval' bokeh from an anamorphic lens." R 0 4}
 aspect 1
 addUserKnob {4 controlChannel t "Which channel of the 'map' input used to drive the defocus." M {red green blue alpha "" ""}}
 controlChannel alpha
 addUserKnob {3 slices t "How many slices are generated from the 'map' image. More slices are more precise, but slower."}
 slices 10
 addUserKnob {7 overlap t "Normalized overlap between slices. An overlap of 0 means hard slices with no soft transition. "}
 overlap 0.5
 addUserKnob {7 min t "Minimum value of the control channel. Values lower than this will be clamped to 0." R 0 10}
 addUserKnob {7 max t "Maximum value of the control channel. Values above this will be clamped to 1." R 0 10}
 max 1
 addUserKnob {26 ""}
 addUserKnob {26 t l "" +STARTLINE T "PxFck_IErode--- A friendly mod of PxF_IDefocus 1.0.2"}
}
 Input {
  inputs 0
  name map
  label static
  xpos 3093
  ypos -899
  number 1
 }
 Grade {
  channels rgba
  blackpoint {{parent.min i}}
  whitepoint {{parent.max i}}
  white_clamp true
  name Grade1
  label static
  xpos 3093
  ypos -802
 }
 Shuffle {
  red {{parent.controlChannel+1 i}}
  green black
  blue black
  alpha black
  name Shuffle1
  label static
  xpos 3093
  ypos -738
 }
set N15b8f040 [stack 0]
 Keyer {
  operation "red keyer"
  range {{(1/parent.slices*10)-1/parent.slices} {"(1/parent.slices*9) + (1/parent.slices*parent.overlap)"} 1 1}
  name Keyer10
  xpos 3861
  ypos -700
 }
 Input {
  inputs 0
  name img
  label static
  xpos 3416
  ypos -1096
 }
set N3ad0e4e0 [stack 0]
 FilterErode {
  channels alpha
  size {{parent.size/parent.slices*10*parent.aspect} {parent.size/parent.slices*10}}
  name FilterErode10
  xpos 3848
  ypos -1058
 }
push $N15b8f040
 Keyer {
  operation "red keyer"
  range {{(1/parent.slices*9)-1/parent.slices} {"(1/parent.slices*8) + (1/parent.slices*parent.overlap)"} 1 1}
  name Keyer9
  xpos 3813
  ypos -700
 }
push $N3ad0e4e0
 FilterErode {
  channels alpha
  size {{parent.size/parent.slices*9*parent.aspect} {parent.size/parent.slices*9}}
  name FilterErode9
  xpos 3800
  ypos -1058
 }
push $N15b8f040
 Keyer {
  operation "red keyer"
  range {{(1/parent.slices*8)-1/parent.slices} {"(1/parent.slices*7) + (1/parent.slices*parent.overlap)"} 1 1}
  name Keyer8
  xpos 3765
  ypos -700
 }
push $N3ad0e4e0
 FilterErode {
  channels alpha
  size {{parent.size/parent.slices*8*parent.aspect} {parent.size/parent.slices*8}}
  name FilterErode8
  xpos 3752
  ypos -1058
 }
push $N15b8f040
 Keyer {
  operation "red keyer"
  range {{(1/parent.slices*7)-1/parent.slices} {"(1/parent.slices*6) + (1/parent.slices*parent.overlap)"} 1 1}
  name Keyer7
  xpos 3717
  ypos -700
 }
push $N3ad0e4e0
 FilterErode {
  channels alpha
  size {{parent.size/parent.slices*7*parent.aspect} {parent.size/parent.slices*7}}
  name FilterErode7
  xpos 3704
  ypos -1058
 }
push $N15b8f040
 Keyer {
  operation "red keyer"
  range {{(1/parent.slices*6)-1/parent.slices} {"(1/parent.slices*5) + (1/parent.slices*parent.overlap)"} 1 1}
  name Keyer6
  xpos 3333
  ypos -700
 }
push $N3ad0e4e0
 FilterErode {
  channels alpha
  size {{parent.size/parent.slices*6*parent.aspect} {parent.size/parent.slices*6}}
  name FilterErode6
  xpos 3656
  ypos -1058
 }
push $N15b8f040
 Keyer {
  operation "red keyer"
  range {{(1/parent.slices*5)-1/parent.slices} {"(1/parent.slices*4) + (1/parent.slices*parent.overlap)"} 1 1}
  name Keyer5
  xpos 3285
  ypos -700
 }
push $N3ad0e4e0
 FilterErode {
  channels alpha
  size {{parent.size/parent.slices*5*parent.aspect} {parent.size/parent.slices*5}}
  name FilterErode5
  xpos 3608
  ypos -1058
 }
push $N15b8f040
 Keyer {
  operation "red keyer"
  range {{(1/parent.slices*4)-1/parent.slices} {"(1/parent.slices*3) + (1/parent.slices*parent.overlap)"} 1 1}
  name Keyer4
  xpos 3237
  ypos -700
 }
push $N3ad0e4e0
 FilterErode {
  channels alpha
  size {{parent.size/parent.slices*4*parent.aspect} {parent.size/parent.slices*4}}
  name FilterErode4
  xpos 3560
  ypos -1058
 }
push $N15b8f040
 Keyer {
  operation "red keyer"
  range {{(1/parent.slices*3)-1/parent.slices} {"(1/parent.slices*2) + (1/parent.slices*parent.overlap)"} 1 1}
  name Keyer3
  xpos 3189
  ypos -700
 }
push $N3ad0e4e0
 FilterErode {
  channels alpha
  size {{parent.size/parent.slices*3*parent.aspect} {parent.size/parent.slices*3}}
  name FilterErode3
  xpos 3512
  ypos -1058
 }
push $N15b8f040
 Keyer {
  operation "red keyer"
  range {{(1/parent.slices*2)-1/parent.slices} {"(1/parent.slices*1) + (1/parent.slices*parent.overlap)"} 1 1}
  name Keyer2
  xpos 3141
  ypos -700
 }
push $N3ad0e4e0
 FilterErode {
  channels alpha
  size {{parent.size/parent.slices*2*parent.aspect} {parent.size/parent.slices*2}}
  name FilterErode2
  xpos 3464
  ypos -1058
 }
push $N15b8f040
 Keyer {
  operation "red keyer"
  range {{(1/parent.slices*1)-1/parent.slices} {"(1/parent.slices*0) + (1/parent.slices*parent.overlap)"} 1 1}
  name Keyer1
  xpos 3093
  ypos -694
 }
push $N3ad0e4e0
 FilterErode {
  channels alpha
  size {{parent.size/parent.slices*1*parent.aspect} {parent.size/parent.slices*1}}
  name FilterErode1
  xpos 3416
  ypos -1058
 }
push $N3ad0e4e0
 Keymix {
  inputs 3
  bbox A
  name Keymix1
  xpos 3416
  ypos -694
 }
 Keymix {
  inputs 3
  bbox A
  name Keymix2
  xpos 3464
  ypos -694
 }
 Keymix {
  inputs 3
  bbox A
  name Keymix3
  xpos 3512
  ypos -694
 }
 Keymix {
  inputs 3
  bbox A
  name Keymix4
  xpos 3560
  ypos -694
 }
 Keymix {
  inputs 3
  bbox A
  name Keymix5
  xpos 3608
  ypos -694
 }
 Keymix {
  inputs 3
  bbox A
  name Keymix6
  xpos 3656
  ypos -694
 }
 Keymix {
  inputs 3
  bbox A
  name Keymix7
  xpos 3717
  ypos -674
 }
 Keymix {
  inputs 3
  bbox A
  name Keymix8
  xpos 3765
  ypos -674
 }
 Keymix {
  inputs 3
  bbox A
  name Keymix9
  xpos 3813
  ypos -674
 }
 Keymix {
  inputs 3
  bbox A
  name Keymix10
  xpos 3861
  ypos -674
 }
 Output {
  name Output1
  label static
  xpos 3871
  ypos 87
 }
end_group

script.py

    string="""
    
    m = nuke.thisNode() # grabs current node
    kc = nuke.thisKnob() #node that is being changed
    
    if kc.name() in ["filter", "slices"]: #if changed knob is filer or slices
        i = nuke.toNode('img') 
        i2 = nuke.toNode('Shuffle1')
        o = nuke.toNode('Output1')
        
        for n in nuke.allNodes():
          if "static" not in n['label'].getValue():
            nuke.delete(n)
        
        slices = m['slices'].value()
        step = 1
        ii = i
        for x in range(1,slices+step,step):
          
          k = nuke.nodes.Keyer()
          k.setInput(0, i2)
          k['operation'].setValue("red keyer")
          k['range'].setExpression("(1/parent.slices*" + str(x) +")-1/parent.slices", 0)
          k['range'].setExpression("(1/parent.slices*" + str(x-1) + ") + (1/parent.slices*parent.overlap)", 1)
          k['range'].setValue(1.0, 2)
          k['range'].setValue(1.0, 3)
         
          f = m['filter'].value()
          if f in ["box", "triangle", "quadratic", "gaussian"]:
            d = nuke.nodes.FilterErode()
            d.setInput(0, i)
            d['channels'].setValue("alpha")
            d['size'].setSingleValue(False)
            d['size'].setExpression('parent.size/parent.slices*' + str(x) + "*parent.aspect", 0 )
            d['size'].setExpression('parent.size/parent.slices*' + str(x), 1)
            d['filter'].setValue(m['filter'].value())
    
          km = nuke.nodes.Keymix()
          km.setInput(0, ii)
          km.setInput(1, d)
          km.setInput(2, k)
          km['bbox'].setValue("A side")
        
          ii = km
        
        o.setInput(0, ii)
    
    """
    node["knobChanged"].setValue(string)