hcirn_colorblind_simulation.js

// Code grabbed from http://web.archive.org/web/20090318054431/http://www.nofunc.com/Color_Blindness_Library
// Added 2 missing } to fix code.
// Used Lookup table for Math.pow(<>/255, gamma)
/*
This function allows you to see what colors look like to those who are color blind.

Use the fBlind[] in order to convert. For instance: fBlind['Tritanomaly'](RGB) would convert RGB[] into Tritanomaly.
*/
/*

    The Color Blind Simulation function is
    copyright (c) 2000-2001 by Matthew Wickline and the
    Human-Computer Interaction Resource Network ( http://hcirn.com/ ).

    It is used with the permission of Matthew Wickline and HCIRN,
    and is freely available for non-commercial use. For commercial use, please
    contact the Human-Computer Interaction Resource Network ( http://hcirn.com/ ).

*/
var rBlind={tetartan:{cpu:1.07401,cpv:1.08197,am:-0.0472546,ayi:0.328447}};var fBlind={Tetartanopia:function(v){return(blindMK(v,'tetartan'))},Tetartanomaly:function(v){return(anomylize(v,blindMK(v,'tetartan')))}};powGammaLookup=Array(256);(function(){var i;for(i=0;i<256;i++){powGammaLookup[i]=Math.pow(i/255,2.2)}})();function blindMK(rgb,t){var gamma=2.2;var wx=0.312713;var wy=0.329016;var wz=0.358271;var b=rgb[2];var g=rgb[1];var r=rgb[0];var cr=powGammaLookup[r];var cg=powGammaLookup[g];var cb=powGammaLookup[b];var cx=(0.430574*cr+0.341550*cg+0.178325*cb);var cy=(0.222015*cr+0.706655*cg+0.071330*cb);var cz=(0.020183*cr+0.129553*cg+0.939180*cb);var sum_xyz=cx+cy+cz;var cu=0;var cv=0;if(sum_xyz!=0){cu=cx/sum_xyz;cv=cy/sum_xyz}var nx=wx*cy/wy;var nz=wz*cy/wy;var clm;var dy=0;if(cu<rBlind[t].cpu){clm=(rBlind[t].cpv-cv)/(rBlind[t].cpu-cu)}else{clm=(cv-rBlind[t].cpv)/(cu-rBlind[t].cpu)}var clyi=cv-cu*clm;var du=(rBlind[t].ayi-clyi)/(clm-rBlind[t].am);var dv=(clm*du)+clyi;var sx=du*cy/dv;var sy=cy;var sz=(1-(du+dv))*cy/dv;var sr=(3.063218*sx-1.393325*sy-0.475802*sz);var sg=(-0.969243*sx+1.875966*sy+0.041555*sz);var sb=(0.067871*sx-0.228834*sy+1.069251*sz);var dx=nx-sx;var dz=nz-sz;dr=(3.063218*dx-1.393325*dy-0.475802*dz);dg=(-0.969243*dx+1.875966*dy+0.041555*dz);db=(0.067871*dx-0.228834*dy+1.069251*dz);var adjr=dr?((sr<0?0:1)-sr)/dr:0;var adjg=dg?((sg<0?0:1)-sg)/dg:0;var adjb=db?((sb<0?0:1)-sb)/db:0;var adjust=Math.max(((adjr>1||adjr<0)?0:adjr),((adjg>1||adjg<0)?0:adjg),((adjb>1||adjb<0)?0:adjb));sr=sr+(adjust*dr);sg=sg+(adjust*dg);sb=sb+(adjust*db);return([inversePow(sr),inversePow(sg),inversePow(sb)])}function inversePow(v){return(255*(v<=0?0:v>=1?1:Math.pow(v,1/2.2)))}function anomylize(a,b){var v=1.75,d=v*1+1;return([(v*b[0]+a[0]*1)/d,(v*b[1]+a[1]*1)/d,(v*b[2]+a[2]*1)/d])}