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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 20 | reyssat | 1 | /* |
| 2 | DynAPI Distribution |
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| 3 | Bezier Class |
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| 4 | |||
| 5 | Bezier Algorithm Reference: http://astronomy.swin.edu.au/~pbourke/curves/bezier/ |
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| 6 | |||
| 7 | The DynAPI Distribution is distributed under the terms of the GNU LGPL license. |
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| 8 | |||
| 9 | requires: dynapi.fx.Thread |
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| 10 | */ |
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| 11 | |||
| 12 | |||
| 13 | function Bezier(cp, n) { |
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| 14 | var l = cp.length; |
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| 15 | var p = []; |
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| 16 | for (var i=0; i<n; i++) p = p.concat(Bezier._plot(cp,i/n)); |
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| 17 | return p.concat([cp[l-2],cp[l-1]]); |
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| 18 | } |
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| 19 | |||
| 20 | Bezier._plot = function (cp, mu) { |
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| 21 | var n = (cp.length/2)-1; |
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| 22 | var k,kn,nn,nkn; |
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| 23 | var blend; |
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| 24 | var b = [0,0]; |
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| 25 | |||
| 26 | var muk = 1; |
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| 27 | var munk = Math.pow(1-mu, n); |
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| 28 | |||
| 29 | for (k=0;k<=n;k++) { |
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| 30 | nn = n; |
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| 31 | kn = k; |
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| 32 | nkn = n - k; |
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| 33 | blend = muk * munk; |
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| 34 | muk *= mu; |
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| 35 | munk /= (1-mu); |
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| 36 | while (nn >= 1) { |
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| 37 | blend *= nn; |
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| 38 | nn--; |
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| 39 | if (kn > 1) { |
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| 40 | blend /= kn; |
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| 41 | kn--; |
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| 42 | } |
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| 43 | if (nkn > 1) { |
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| 44 | blend /= nkn; |
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| 45 | nkn--; |
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| 46 | } |
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| 47 | } |
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| 48 | |||
| 49 | b[0] += cp[k*2] * blend; |
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| 50 | b[1] += cp[k*2+1] * blend; |
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| 51 | } |
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| 52 | b[0] = Math.round(b[0]); |
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| 53 | b[1] = Math.round(b[1]); |
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| 54 | return b; |
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| 55 | } |
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| 56 | |||
| 57 | /*function Bezier3(cp,mu) { |
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| 58 | var x1=cp[0],y1=cp[1],x2=cp[2],y2=cp[3],x3=cp[4],y3=cp[5]; |
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| 59 | var mu2 = mu * mu; |
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| 60 | var mum1 = 1 - mu; |
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| 61 | var mum12 = mum1 * mum1; |
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| 62 | var x = Math.round(x1 * mum12 + 2 * x2 * mum1 * mu + x3 * mu2); |
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| 63 | var y = Math.round(y1 * mum12 + 2 * y2 * mum1 * mu + y3 * mu2); |
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| 64 | return [x,y]; |
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| 65 | } |
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| 66 | |||
| 67 | function Bezier4(cp,mu) { |
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| 68 | 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]; |
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| 69 | var mum1 = 1 - mu; |
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| 70 | var mum13 = mum1 * mum1 * mum1; |
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| 71 | var mu3 = mu * mu * mu; |
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| 72 | var x = Math.round(mum13*x1 + 3*mu*mum1*mum1*x2 + 3*mu*mu*mum1*x3 + mu3*x4); |
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| 73 | var y = Math.round(mum13*y1 + 3*mu*mum1*mum1*y2 + 3*mu*mu*mum1*y3 + mu3*y4); |
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| 74 | return [x,y]; |
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| 75 | }*/ |