Function _stackblur

pattern/canvas.js:3640–3646

(img, buffer, radius)

var _stackblur_shg=[9,11,12,13,13,14,14,15,15,15,15,16,16,16,16,17,17,17,17,17,17,17,18,18,18,18,18,18,18,18,18,19,19,19,19,19,19,19,19,19,19,19,19,19,19,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24];

function _stackblur(img, buffer, radius) {

function BlurStack(){this.r=0;this.g=0;this.b=0;this.a=0;this.next=null}function stackBlurCanvasRGBA(a,b,c,d,e,f){if(isNaN(f)||f<1)return;f|=0;var g=a.element;var h=g.getContext("2d");var i;i=h.getImageData(b,c,d,e);var k=i.data;var l,m,n,o,p,q,r,s,t,u,v,w,x,y,z,A,B,C,D,E,F,G,H,I;var J=f+f+1;var K=d<<2;var L=d-1;var M=e-1;var N=f+1;var O=N*(N+1)/2;var P=new BlurStack;var Q=P;for(n=1;n<J;n++){Q=Q.next=new BlurStack;if(n==N)var R=Q}Q.next=P;var S=null;var T=null;r=q=0;var U=_stackblur_mul[f];var V=_stackblur_shg[f];for(m=0;m<e;m++){A=B=C=D=s=t=u=v=0;w=N*(E=k[q]);x=N*(F=k[q+1]);y=N*(G=k[q+2]);z=N*(H=k[q+3]);s+=O*E;t+=O*F;u+=O*G;v+=O*H;Q=P;for(n=0;n<N;n++){Q.r=E;Q.g=F;Q.b=G;Q.a=H;Q=Q.next}for(n=1;n<N;n++){o=q+((L<n?L:n)<<2);s+=(Q.r=E=k[o])*(I=N-n);t+=(Q.g=F=k[o+1])*I;u+=(Q.b=G=k[o+2])*I;v+=(Q.a=H=k[o+3])*I;A+=E;B+=F;C+=G;D+=H;Q=Q.next}S=P;T=R;for(l=0;l<d;l++){k[q+3]=H=v*U>>V;if(H!=0){H=255/H;k[q]=(s*U>>V)*H;k[q+1]=(t*U>>V)*H;k[q+2]=(u*U>>V)*H}else{k[q]=k[q+1]=k[q+2]=0}s-=w;t-=x;u-=y;v-=z;w-=S.r;x-=S.g;y-=S.b;z-=S.a;o=r+((o=l+f+1)<L?o:L)<<2;A+=S.r=k[o];B+=S.g=k[o+1];C+=S.b=k[o+2];D+=S.a=k[o+3];s+=A;t+=B;u+=C;v+=D;S=S.next;w+=E=T.r;x+=F=T.g;y+=G=T.b;z+=H=T.a;A-=E;B-=F;C-=G;D-=H;T=T.next;q+=4}r+=d}for(l=0;l<d;l++){B=C=D=A=t=u=v=s=0;q=l<<2;w=N*(E=k[q]);x=N*(F=k[q+1]);y=N*(G=k[q+2]);z=N*(H=k[q+3]);s+=O*E;t+=O*F;u+=O*G;v+=O*H;Q=P;for(n=0;n<N;n++){Q.r=E;Q.g=F;Q.b=G;Q.a=H;Q=Q.next}p=d;for(n=1;n<=f;n++){q=p+l<<2;s+=(Q.r=E=k[q])*(I=N-n);t+=(Q.g=F=k[q+1])*I;u+=(Q.b=G=k[q+2])*I;v+=(Q.a=H=k[q+3])*I;A+=E;B+=F;C+=G;D+=H;Q=Q.next;if(n<M){p+=d}}q=l;S=P;T=R;for(m=0;m<e;m++){o=q<<2;k[o+3]=H=v*U>>V;if(H>0){H=255/H;k[o]=(s*U>>V)*H;k[o+1]=(t*U>>V)*H;k[o+2]=(u*U>>V)*H}else{k[o]=k[o+1]=k[o+2]=0}s-=w;t-=x;u-=y;v-=z;w-=S.r;x-=S.g;y-=S.b;z-=S.a;o=l+((o=m+N)<M?o:M)*d<<2;s+=A+=S.r=k[o];t+=B+=S.g=k[o+1];u+=C+=S.b=k[o+2];v+=D+=S.a=k[o+3];S=S.next;w+=E=T.r;x+=F=T.g;y+=G=T.b;z+=H=T.a;A-=E;B-=F;C-=G;D-=H;T=T.next;q+=d}}h.putImageData(i,b,c)}function stackBlurImage(a,b,c,d){var e=a._img;var f=e.width;var g=e.height;var h=b.element;h.style.width=f+"px";h.style.height=g+"px";h.width=f;h.height=g;var i=h.getContext("2d");i.clearRect(0,0,f,g);i.drawImage(e,0,0);if(isNaN(c)||c<1)return;if(d)stackBlurCanvasRGBA(b,0,0,f,g,c);else stackBlurCanvasRGB(b,0,0,f,g,c)}

stackBlurImage(img, buffer, radius, true);
return buffer.image();
};

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