set cut_paste_input [stack 0]
push $cut_paste_input
Group {
 name Tonemap_PiecewiseHyperbolic
 label "Piecewise Hyperbolic\n Grey + White Pivoted Toe + Surround"
 addUserKnob {20 Tonemap}
 addUserKnob {78 g l grey t "input -> output grey" n 2}
 g {0.18 0.1}
 addUserKnob {78 w l white t "input -> output white" n 2}
 w {16 1}
 addUserKnob {7 p l contrast R 0.8 2}
 p 1.2
 addUserKnob {7 ps l surround t "surround compensation: un-pivoted power function" R 0.8 1.2}
 ps 1.05
 addUserKnob {7 t0 l toe R 0 0.1}
 t0 0.01
 addUserKnob {78 s l scale n 2}
 s {{(pow(2,-1/p)*pow(g.1+sqrt(g.1)*sqrt(4*t0+g.1),1/p))/g.0} {(s.0*pow(w.0-g.0,2)*pow(s.0*g.0-pow(2,-1/p)*pow(w.1+sqrt(w.1)*sqrt(w.1+4*t0),1/p),2))/pow(s.0*w.0-pow(2,-1/p)*pow(w.1+sqrt(w.1)*sqrt(w.1+4*t0),1/p),2)}}
 addUserKnob {4 direction M {forward inverse}}
 addUserKnob {26 "" +STARTLINE}
 addUserKnob {26 plot_label l " " T "<style>a:link \{color:#ccc\}</style><a href=\"https://www.desmos.com/calculator/zspschwjmr\">desmos plot</a>"}
}
 Input {
  inputs 0
  name Input
  xpos -40
  ypos 20
 }
set N95558f0 [stack 0]
 Expression {
  temp_name0 tr
  temp_expr0 pow(0.5*(pow(r,1/ps)+sqrt(pow(r,1/ps)*(pow(r,1/ps)+4*t0))),1/p)
  temp_name1 tg
  temp_expr1 pow(0.5*(pow(g,1/ps)+sqrt(pow(g,1/ps)*(pow(g,1/ps)+4*t0))),1/p)
  temp_name2 tb
  temp_expr2 pow(0.5*(pow(b,1/ps)+sqrt(pow(b,1/ps)*(pow(b,1/ps)+4*t0))),1/p)
  temp_name3 th
  temp_expr3 pow(g.1,ps)
  expr0 r>th?h.0-s.1/(tr-h.1):tr/s.0
  expr1 g>th?h.0-s.1/(tg-h.1):tg/s.0
  expr2 b>th?h.0-s.1/(tb-h.1):tb/s.0
  name InvCompress
  xpos 70
  ypos 81
  addUserKnob {20 Param_tab l Param}
  addUserKnob {78 h n 2}
  h {{g.0-sqrt(s.1/s.0)} {s.0*g.0+sqrt(s.0*s.1)}}
 }
push $N95558f0
 Expression {
  temp_name0 hr
  temp_expr0 pow(h.1-s.1/(r-h.0),p)
  temp_name1 hg
  temp_expr1 pow(h.1-s.1/(g-h.0),p)
  temp_name2 hb
  temp_expr2 pow(h.1-s.1/(b-h.0),p)
  expr0 r>g.0?pow(pow(hr,2)/(hr+t0),ps):pow(pow(s.0*r,2*p)/(pow(s.0*r,p)+t0),ps)
  expr1 g>g.0?pow(pow(hg,2)/(hg+t0),ps):pow(pow(s.0*g,2*p)/(pow(s.0*g,p)+t0),ps)
  expr2 b>g.0?pow(pow(hb,2)/(hb+t0),ps):pow(pow(s.0*b,2*p)/(pow(s.0*b,p)+t0),ps)
  name Compress
  xpos -150
  ypos 81
  addUserKnob {20 Param_tab l Param}
  addUserKnob {78 h n 2}
  h {{g.0-sqrt(s.1/s.0)} {s.0*g.0+sqrt(s.0*s.1)}}
 }
 Switch {
  inputs 2
  which {{parent.direction}}
  name SwitchDirection
  xpos -40
  ypos 141
 }
 Output {
  name Output
  xpos -40
  ypos 223
 }
end_group