CompressionFunctions.nk

set cut_paste_input [stack 0]
push $cut_paste_input
Group {
 name CompressionFunctions
 addUserKnob {20 CompressionFunctions_tab l CompressionFunctions}
 addUserKnob {4 method t "The type of compression function to use. " M {log reinhard power exp arctan tanh}}
 method power
 addUserKnob {7 threshold t "The minimum threshold. Values below this number will not be affected." R 0 6}
 threshold 1
 addUserKnob {7 limit t "The asymptotic maximum value. For example, the value that inf becomes." R 1 10}
 limit 5
 addUserKnob {7 power t "adjust slope of power function (power method only)" R 0 4}
 power 1.2
 addUserKnob {4 direction M {forward inverse}}
}
 Input {
  inputs 0
  name Input
  xpos -40
  ypos -610
 }
 Dot {
  name Dot6
  xpos -6
  ypos -510
 }
set Nb798f200 [stack 0]
 Dot {
  name Dot5
  xpos 654
  ypos -510
 }
set Nb798eb00 [stack 0]
 Expression {
  expr0 "r < t ? r : t+(l-t)*log((1+(r/(l-t)-t/(l-t)))/(1-(r/(l-t)-t/(l-t))))/2"
  expr1 "g < t ? g : t+(l-t)*log((1+(g/(l-t)-t/(l-t)))/(1-(g/(l-t)-t/(l-t))))/2"
  expr2 "b < t ? b : t+(l-t)*log((1+(b/(l-t)-t/(l-t)))/(1-(b/(l-t)-t/(l-t))))/2"
  name uncompress_tanh
  xpos 1170
  ypos -442
  addUserKnob {20 Params_tab l Params}
  addUserKnob {7 t}
  t {{"min(parent.threshold, parent.limit)"}}
  addUserKnob {7 l R 1 2}
  l {{max(th,parent.limit)}}
 }
push $Nb798eb00
 Expression {
  temp_name0 pi
  temp_expr0 3.14159265359
  expr0 "r < t ? r : t+(l-t)*2/pi*tan(pi/2*(r-t)/(l-t))"
  expr1 "g < t ? g : t+(l-t)*2/pi*tan(pi/2*(g-t)/(l-t))"
  expr2 "b < t ? b : t+(l-t)*2/pi*tan(pi/2*(b-t)/(l-t))"
  name uncompress_atan
  xpos 1060
  ypos -442
  addUserKnob {20 Params_tab l Params}
  addUserKnob {7 t}
  t {{"min(parent.threshold, parent.limit)"}}
  addUserKnob {7 l R 1 2}
  l {{max(th,parent.limit)}}
 }
push $Nb798eb00
 Expression {
  expr0 r<th?r:-log((r-lm)/(th-lm))*(-th+lm)/sc+th
  expr1 g<th?g:-log((g-lm)/(th-lm))*(-th+lm)/sc+th
  expr2 b<th?b:-log((b-lm)/(th-lm))*(-th+lm)/sc+th
  name uncompress_exp
  xpos 950
  ypos -442
  addUserKnob {20 Params_tab l Params}
  addUserKnob {7 th}
  th {{"min(parent.threshold, parent.limit)"}}
  addUserKnob {7 lm R 1 2}
  lm {{max(th,parent.limit)}}
  addUserKnob {7 sc}
  sc 1
 }
push $Nb798eb00
 Expression {
  expr0 r<th?r:th+(lm-th)*pow(-pow((r-th)/(lm-th),p)/(pow((r-th)/(lm-th),p)-1),1/p)
  expr1 g<th?g:th+(lm-th)*pow(-pow((g-th)/(lm-th),p)/(pow((g-th)/(lm-th),p)-1),1/p)
  expr2 b<th?b:th+(lm-th)*pow(-pow((b-th)/(lm-th),p)/(pow((b-th)/(lm-th),p)-1),1/p)
  name uncompress_power
  xpos 840
  ypos -442
  addUserKnob {20 Params_tab l Params}
  addUserKnob {7 th}
  th {{parent.threshold}}
  addUserKnob {7 lm}
  lm {{parent.limit}}
  addUserKnob {7 p R 1 5}
  p {{parent.power}}
 }
push $Nb798eb00
 Expression {
  expr0 r<th?r:th+1/(1/(r-th)-1/(lm-th))
  expr1 g<th?g:th+1/(1/(g-th)-1/(lm-th))
  expr2 b<th?b:th+1/(1/(b-th)-1/(lm-th))
  name uncompress_hyperbolic
  xpos 730
  ypos -442
  addUserKnob {20 Params_tab l Params}
  addUserKnob {7 th}
  th {{"min(parent.threshold, parent.limit)"}}
  addUserKnob {7 lm R 1 2}
  lm {{parent.limit}}
 }
push $Nb798eb00
 Expression {
  expr0 r<th?r:exp((r-th+th*log(1-lm)-lm*th*log(1-lm))/(th*(1-lm)))*th+lm*th
  expr1 g<th?g:exp((g-th+th*log(1-lm)-lm*th*log(1-lm))/(th*(1-lm)))*th+lm*th
  expr2 b<th?b:exp((b-th+th*log(1-lm)-lm*th*log(1-lm))/(th*(1-lm)))*th+lm*th
  name uncompress_log
  xpos 620
  ypos -441
  addUserKnob {20 Params_tab l Params}
  addUserKnob {7 th}
  th {{parent.threshold}}
  addUserKnob {7 lm}
  lm {{min(0.999999,(1-parent.limit)+1)}}
 }
 Switch {
  inputs 6
  which {{parent.method}}
  name switch_method1
  xpos 620
  ypos -345
 }
 Dot {
  name Dot2
  xpos 654
  ypos -198
 }
push $Nb798f200
 Expression {
  expr0 "r < t ? r : t+(l-t)*tanh( ( (r-t)/( l-t)))"
  expr1 "g < t ? g : t+(l-t)*tanh( ( (g-t)/( l-t)))"
  expr2 "b < t ? b : t+(l-t)*tanh( ( (b-t)/( l-t)))"
  name compress_tanh
  xpos 510
  ypos -442
  addUserKnob {20 Params_tab l Params}
  addUserKnob {7 t}
  t {{"min(parent.threshold, parent.limit)"}}
  addUserKnob {7 l R 1 2}
  l {{max(th,parent.limit)}}
 }
push $Nb798f200
 Expression {
  temp_name0 pi
  temp_expr0 3.14159265359
  expr0 "r < t ? r : t+(l-t)*2/pi*atan(pi/2*(r-t)/(l-t))"
  expr1 "g < t ? g : t+(l-t)*2/pi*atan(pi/2*(g-t)/(l-t))"
  expr2 "b < t ? b : t+(l-t)*2/pi*atan(pi/2*(b-t)/(l-t))"
  name compress_atan
  xpos 400
  ypos -442
  addUserKnob {20 Params_tab l Params}
  addUserKnob {7 t}
  t {{"min(parent.threshold, parent.limit)"}}
  addUserKnob {7 l R 1 2}
  l {{max(th,parent.limit)}}
 }
push $Nb798f200
 Expression {
  expr0 r<th?r:lm-(lm-th)*exp(-(((r-th)*((sc*lm)/(lm-th))/lm)))
  expr1 g<th?g:lm-(lm-th)*exp(-(((g-th)*((sc*lm)/(lm-th))/lm)))
  expr2 b<th?b:lm-(lm-th)*exp(-(((b-th)*((sc*lm)/(lm-th))/lm)))
  name compress_exp
  xpos 290
  ypos -442
  addUserKnob {20 Params_tab l Params}
  addUserKnob {7 th}
  th {{"min(parent.threshold, parent.limit)"}}
  addUserKnob {7 lm R 1 2}
  lm {{max(th,parent.limit)}}
  addUserKnob {7 sc}
  sc 1
 }
push $Nb798f200
 Expression {
  expr0 r<th?r:th+((r-th)*(lm-th))/pow(pow((lm-th),p)+pow((r-th),p),1/p)
  expr1 g<th?g:th+((g-th)*(lm-th))/pow(pow((lm-th),p)+pow((g-th),p),1/p)
  expr2 b<th?b:th+((b-th)*(lm-th))/pow(pow((lm-th),p)+pow((b-th),p),1/p)
  name compress_power
  xpos 180
  ypos -443
  addUserKnob {20 Params_tab l Params}
  addUserKnob {7 th}
  th {{parent.threshold}}
  addUserKnob {7 lm}
  lm {{parent.limit}}
  addUserKnob {7 p R 1 5}
  p {{parent.power}}
 }
push $Nb798f200
 Expression {
  expr0 r<th?r:th+1/(1/(r-th)+1/(lm-th))
  expr1 g<th?g:th+1/(1/(g-th)+1/(lm-th))
  expr2 b<th?b:th+1/(1/(b-th)+1/(lm-th))
  name compress_hyperbolic
  xpos 70
  ypos -442
  addUserKnob {20 Params_tab l Params}
  addUserKnob {7 th}
  th {{min(parent.threshold,parent.limit)}}
  addUserKnob {7 lm R 1 2}
  lm {{parent.limit}}
 }
push $Nb798f200
 Expression {
  expr0 r<th?r:th*log(r/th-lm)-lm*th*log(r/th-lm)+th-th*log(1-lm)+lm*th*log(1-lm)
  expr1 g<th?g:th*log(g/th-lm)-lm*th*log(g/th-lm)+th-th*log(1-lm)+lm*th*log(1-lm)
  expr2 b<th?b:th*log(b/th-lm)-lm*th*log(b/th-lm)+th-th*log(1-lm)+lm*th*log(1-lm)
  name compress_log
  xpos -40
  ypos -441
  addUserKnob {20 Params_tab l Params}
  addUserKnob {7 th}
  th {{parent.threshold}}
  addUserKnob {7 lm}
  lm {{min(0.999999,(1-parent.limit)+1)}}
 }
 Switch {
  inputs 6
  which {{parent.method}}
  name switch_method
  xpos -40
  ypos -345
 }
 Switch {
  inputs 2
  which {{parent.direction}}
  name switch_reverse
  xpos -40
  ypos -202
 }
 Output {
  name Output
  xpos -40
  ypos -106
 }
 Expression {
  inputs 0
  expr0 r<th?r:sc*((r-th)/sc)/pow(1+pow((r-th)/sc,p),1/p)+th
  expr1 g<th?g:sc*((g-th)/sc)/pow(1+pow((g-th)/sc,p),1/p)+th
  expr2 b<th?b:sc*((b-th)/sc)/pow(1+pow((b-th)/sc,p),1/p)+th
  name compress_hyperbolic_power
  xpos 1390
  ypos -442
  addUserKnob {20 Params_tab l Params}
  addUserKnob {7 th t "threshold to start compression" R 0 2}
  th 0.5
  addUserKnob {7 x0 t "x coordinate to compress to" R 0 2}
  x0 2
  addUserKnob {7 y0 t "y coordinate to compress to" R 0 2}
  y0 0.825
  addUserKnob {7 p R 1 2}
  p 1.2
  addUserKnob {7 sc}
  sc {{(x0-th)/pow(pow((y0-th)/(x0-th),-p)-1,1/p)}}
 }
 Expression {
  inputs 0
  expr0 r<th?r:sc*pow(-pow((r-th)/sc,p)/(pow((r-th)/sc,p)-1),1/p)+th
  expr1 g<th?g:sc*pow(-pow((g-th)/sc,p)/(pow((g-th)/sc,p)-1),1/p)+th
  expr2 b<th?b:sc*pow(-pow((b-th)/sc,p)/(pow((b-th)/sc,p)-1),1/p)+th
  name uncompress_hyperbolic_power
  xpos 1500
  ypos -442
  addUserKnob {20 Params_tab l Params}
  addUserKnob {7 th t "threshold to start compression" R 0 2}
  th 0.5
  addUserKnob {7 x0 t "x coordinate to compress to" R 0 2}
  x0 2
  addUserKnob {7 y0 t "y coordinate to compress to" R 0 2}
  y0 0.825
  addUserKnob {7 p R 1 2}
  p 1.2
  addUserKnob {7 sc}
  sc {{(x0-th)/pow(pow((y0-th)/(x0-th),-p)-1,1/p)}}
 }
 StickyNote {
  inputs 0
  name StickyNote1
  tile_color 0x272727ff
  label "<left>Hyperbolic Power Compression Function with (x0, y0) intersection constraint\nhttps://www.desmos.com/calculator/ht27poixiw"
  note_font_size 8
  note_font_color 0xa8a8a8ff
  xpos 1387
  ypos -496
 }
 Expression {
  inputs 0
  expr0 r<t0?r:sc*sqrt(r-ox)+oy
  expr1 g<t0?g:sc*sqrt(g-ox)+oy
  expr2 b<t0?b:sc*sqrt(b-ox)+oy
  name compress_parabolic
  xpos 1718
  ypos -442
  addUserKnob {20 Params_tab l Params}
  addUserKnob {7 t0 t "threshold to start compression" R 0 2}
  t0 0.3
  addUserKnob {7 x0 t "x coordinate to compress to" R 0 2}
  x0 1
  addUserKnob {7 y0 t "y coordinate to compress to" R 0 2}
  y0 0.5
  addUserKnob {7 sc}
  sc {{(y0-t0)/sqrt(x0-y0)}}
  addUserKnob {7 ox R -2 2}
  ox {{t0-sc*sc/4}}
  addUserKnob {7 oy R -2 2}
  oy {{t0-sc*sqrt(sc*sc/4)}}
 }
 Expression {
  inputs 0
  expr0 r<t0?r:pow((oy-r)/sc,2)+ox
  expr1 g<t0?g:pow((oy-g)/sc,2)+ox
  expr2 b<t0?b:pow((oy-b)/sc,2)+ox
  name uncompress_parabolic
  xpos 1833
  ypos -442
  addUserKnob {20 Params_tab l Params}
  addUserKnob {7 t0 t "threshold to start compression" R 0 2}
  t0 0.3
  addUserKnob {7 x0 t "x coordinate to compress to" R 0 2}
  x0 1
  addUserKnob {7 y0 t "y coordinate to compress to" R 0 2}
  y0 0.5
  addUserKnob {7 sc}
  sc {{(y0-t0)/sqrt(x0-y0)}}
  addUserKnob {7 ox R -2 2}
  ox {{t0-sc*sc/4}}
  addUserKnob {7 oy R -2 2}
  oy {{t0-sc*sqrt(sc*sc/4)}}
 }
 StickyNote {
  inputs 0
  name StickyNote2
  tile_color 0x272727ff
  label "<left>Parabolic Compression Function with (x0, y0) intersection constraint\nhttps://www.desmos.com/calculator/khowxlu6xh"
  note_font_size 8
  note_font_color 0xa8a8a8ff
  xpos 1711
  ypos -496
 }
 Expression {
  inputs 0
  expr0 !x0?r:r>t0?r:sc*sqrt(-r-ox)+oy
  expr1 !x0?g:g>t0?g:sc*sqrt(-g-ox)+oy
  expr2 !x0?b:b>t0?b:sc*sqrt(-b-ox)+oy
  name compress_toe_parabolic
  xpos 2050
  ypos -442
  addUserKnob {20 Params_tab l Params}
  addUserKnob {7 t0 t "threshold to start compression" R 0 2}
  t0 0.3
  addUserKnob {7 x0 t "x coordinate to compress to" R 0 2}
  x0 1
  addUserKnob {7 sc}
  sc {{-t0/sqrt(x0)}}
  addUserKnob {7 ox R -2 2}
  ox {{-sc*sc/4-t0}}
  addUserKnob {7 oy R -2 2}
  oy {{t0-sc*sqrt(sc*sc/4)}}
 }
 Expression {
  inputs 0
  expr0 r>t0?r:-pow((oy-r)/sc,2)-ox
  expr1 g>t0?g:-pow((oy-g)/sc,2)-ox
  expr2 b>t0?b:-pow((oy-b)/sc,2)-ox
  name uncompress_toe_parabolic
  xpos 2160
  ypos -442
  addUserKnob {20 Params_tab l Params}
  addUserKnob {7 t0 t "threshold to start compression" R 0 2}
  t0 0.3
  addUserKnob {7 x0 t "x coordinate to compress to" R 0 2}
  x0 1
  addUserKnob {7 sc}
  sc {{-t0/sqrt(x0)}}
  addUserKnob {7 ox R -2 2}
  ox {{-sc*sc/4-t0}}
  addUserKnob {7 oy R -2 2}
  oy {{t0-sc*sqrt(sc*sc/4)}}
 }
 Expression {
  inputs 0
  temp_name0 n
  temp_expr0 max(r,g,b)
  temp_name1 s
  temp_expr1 n<t0?1:invert?(_b-_a/(n-s1))/n:(_a/(_b-n)+s1)/n
  expr0 r*s
  expr1 g*s
  expr2 b*s
  expr3 a*s
  name HyperbolicCompression
  xpos 2490
  ypos -442
  addUserKnob {20 Params}
  addUserKnob {7 t0}
  t0 0.18
  addUserKnob {7 w0 t "input x" R 0 20}
  w0 4
  addUserKnob {7 w1 t "output y" R 0 4}
  w1 1
  addUserKnob {7 s1 R 0 4}
  s1 {{(w0*w1-t0*(2*w1-t0))/(w0-w1)}}
  addUserKnob {7 _a R 0 4}
  _a {{(t0-s1)**2}}
  addUserKnob {7 _b R 0 4}
  _b {{2*t0-s1}}
  addUserKnob {6 invert +STARTLINE}
 }
 StickyNote {
  inputs 0
  name StickyNote3
  tile_color 0x272727ff
  label "<left>Parabolic Toe Compression Function with (x0, 0) intersection constraint\nhttps://www.desmos.com/calculator/wfw5rzrv5x"
  note_font_size 8
  note_font_color 0xa8a8a8ff
  xpos 2033
  ypos -502
 }
 StickyNote {
  inputs 0
  name StickyNote4
  tile_color 0x272727ff
  label "<left>Simpler hyperbolic compression function\nhttps://www.desmos.com/calculator/e4ik6xh0tz"
  note_font_size 8
  note_font_color 0xa8a8a8ff
  xpos 2440
  ypos -509
 }
end_group