- Author:
- David Nickerson <nickerso@users.sourceforge.net>
- Date:
- 2009-07-16 02:00:03+12:00
- Desc:
- the starting point for the HH tutorial example
- Permanent Source URI:
- https://models.fieldml.org/workspace/a1/rawfile/f6a8f90307388eb4b040ee3566b84d88b59247f7/dojo-presentation/js/dojo/dojox/math/curves.js
dojo.provide("dojox.math.curves");
dojo.mixin(dojox.math.curves, {
Line:function (start, end) {
this.start = start;
this.end = end;
this.dimensions = start.length;
for (var i = 0; i < start.length; i++) {
start[i] = Number(start[i]);
}
for (var i = 0; i < end.length; i++) {
end[i] = Number(end[i]);
}
this.getValue = function (n) {
var retVal = new Array(this.dimensions);
for (var i = 0; i < this.dimensions; i++) {
retVal[i] = ((this.end[i] - this.start[i]) * n) + this.start[i];
}
return retVal;
};
return this;
},
Bezier:function(pnts) {
this.getValue = function (step) {
if (step >= 1) {
return this.p[this.p.length - 1];
}
if (step <= 0) {
return this.p[0];
}
var retVal = new Array(this.p[0].length);
for (var k = 0; j < this.p[0].length; k++) {
retVal[k] = 0;
}
for (var j = 0; j < this.p[0].length; j++) {
var C = 0;
var D = 0;
for (var i = 0; i < this.p.length; i++) {
C += this.p[i][j] * this.p[this.p.length - 1][0] * dojox.math.bernstein(step, this.p.length, i);
}
for (var l = 0; l < this.p.length; l++) {
D += this.p[this.p.length - 1][0] * dojox.math.bernstein(step, this.p.length, l);
}
retVal[j] = C / D;
}
return retVal;
};
this.p = pnts;
return this;
},
CatmullRom:function (pnts, c) {
this.getValue = function (step) {
var percent = step * (this.p.length - 1);
var node = Math.floor(percent);
var progress = percent - node;
var i0 = node - 1;
if (i0 < 0) {
i0 = 0;
}
var i = node;
var i1 = node + 1;
if (i1 >= this.p.length) {
i1 = this.p.length - 1;
}
var i2 = node + 2;
if (i2 >= this.p.length) {
i2 = this.p.length - 1;
}
var u = progress;
var u2 = progress * progress;
var u3 = progress * progress * progress;
var retVal = new Array(this.p[0].length);
for (var k = 0; k < this.p[0].length; k++) {
var x1 = (-this.c * this.p[i0][k]) + ((2 - this.c) * this.p[i][k]) + ((this.c - 2) * this.p[i1][k]) + (this.c * this.p[i2][k]);
var x2 = (2 * this.c * this.p[i0][k]) + ((this.c - 3) * this.p[i][k]) + ((3 - 2 * this.c) * this.p[i1][k]) + (-this.c * this.p[i2][k]);
var x3 = (-this.c * this.p[i0][k]) + (this.c * this.p[i1][k]);
var x4 = this.p[i][k];
retVal[k] = x1 * u3 + x2 * u2 + x3 * u + x4;
}
return retVal;
};
if (!c) {
this.c = 0.7;
} else {
this.c = c;
}
this.p = pnts;
return this;
},
Arc:function (start, end, ccw){
function translate(a,b){
var c=new Array(a.length);
for(var i=0; i<a.length; i++){ c[i]=a[i]+b[i]; }
return c;
}
function invert(a){
var b = new Array(a.length);
for(var i=0; i<a.length; i++){ b[i]=-a[i]; }
return b;
}
var center = dojox.math.midpoint(start, end);
var sides = translate(invert(center), start);
var rad = Math.sqrt(Math.pow(sides[0], 2) + Math.pow(sides[1], 2));
var theta = dojox.math.radiansToDegrees(Math.atan(sides[1] / sides[0]));
if (sides[0] < 0){
theta -= 90;
} else {
theta += 90;
}
dojox.math.curves.CenteredArc.call(this, center, rad, theta, theta + (ccw ? -180 : 180));
},
CenteredArc:function (center, radius, start, end) {
this.center = center;
this.radius = radius;
this.start = start || 0;
this.end = end;
this.getValue = function (n) {
var retVal = new Array(2);
var theta = dojox.math.degreesToRadians(this.start + ((this.end - this.start) * n));
retVal[0] = this.center[0] + this.radius * Math.sin(theta);
retVal[1] = this.center[1] - this.radius * Math.cos(theta);
return retVal;
};
return this;
},
Circle:function(center, radius){
dojox.math.curves.CenteredArc.call(this, center, radius, 0, 360);
return this;
},
Path:function () {
var curves = [];
var weights = [];
var ranges = [];
var totalWeight = 0;
this.add = function (curve, weight) {
if (weight < 0) {
console.error("dojox.math.curves.Path.add: weight cannot be less than 0");
}
curves.push(curve);
weights.push(weight);
totalWeight += weight;
computeRanges();
};
this.remove = function (curve) {
for (var i = 0; i < curves.length; i++) {
if (curves[i] == curve) {
curves.splice(i, 1);
totalWeight -= weights.splice(i, 1)[0];
break;
}
}
computeRanges();
};
this.removeAll = function () {
curves = [];
weights = [];
totalWeight = 0;
};
this.getValue = function (n) {
var found = false, value = 0;
for (var i = 0; i < ranges.length; i++) {
var r = ranges[i];
if (n >= r[0] && n < r[1]) {
var subN = (n - r[0]) / r[2];
value = curves[i].getValue(subN);
found = true;
break;
}
}
if (!found) {
value = curves[curves.length - 1].getValue(1);
}
for (var j = 0; j < i; j++) {
value = dojox.math.points.translate(value, curves[j].getValue(1));
}
return value;
};
function computeRanges() {
var start = 0;
for (var i = 0; i < weights.length; i++) {
var end = start + weights[i] / totalWeight;
var len = end - start;
ranges[i] = [start, end, len];
start = end;
}
}
return this;
}
});
