egroupware/phpgwapi/js/dynapi/fx/bezier.js

76 lines
1.6 KiB
JavaScript

/*
DynAPI Distribution
Bezier Class
Bezier Algorithm Reference: http://astronomy.swin.edu.au/~pbourke/curves/bezier/
The DynAPI Distribution is distributed under the terms of the GNU LGPL license.
requires: dynapi.fx.Thread
*/
function Bezier(cp, n) {
var l = cp.length;
var p = [];
for (var i=0; i<n; i++) p = p.concat(Bezier._plot(cp,i/n));
return p.concat([cp[l-2],cp[l-1]]);
}
Bezier._plot = function (cp, mu) {
var n = (cp.length/2)-1;
var k,kn,nn,nkn;
var blend;
var b = [0,0];
var muk = 1;
var munk = Math.pow(1-mu, n);
for (k=0;k<=n;k++) {
nn = n;
kn = k;
nkn = n - k;
blend = muk * munk;
muk *= mu;
munk /= (1-mu);
while (nn >= 1) {
blend *= nn;
nn--;
if (kn > 1) {
blend /= kn;
kn--;
}
if (nkn > 1) {
blend /= nkn;
nkn--;
}
}
b[0] += cp[k*2] * blend;
b[1] += cp[k*2+1] * blend;
}
b[0] = Math.round(b[0]);
b[1] = Math.round(b[1]);
return b;
}
/*function Bezier3(cp,mu) {
var x1=cp[0],y1=cp[1],x2=cp[2],y2=cp[3],x3=cp[4],y3=cp[5];
var mu2 = mu * mu;
var mum1 = 1 - mu;
var mum12 = mum1 * mum1;
var x = Math.round(x1 * mum12 + 2 * x2 * mum1 * mu + x3 * mu2);
var y = Math.round(y1 * mum12 + 2 * y2 * mum1 * mu + y3 * mu2);
return [x,y];
}
function Bezier4(cp,mu) {
var x1=cp[0],y1=cp[1],x2=cp[2],y2=cp[3],x3=cp[4],y3=cp[5],x4=cp[6],y4=cp[7];
var mum1 = 1 - mu;
var mum13 = mum1 * mum1 * mum1;
var mu3 = mu * mu * mu;
var x = Math.round(mum13*x1 + 3*mu*mum1*mum1*x2 + 3*mu*mu*mum1*x3 + mu3*x4);
var y = Math.round(mum13*y1 + 3*mu*mum1*mum1*y2 + 3*mu*mu*mum1*y3 + mu3*y4);
return [x,y];
}*/