1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
import flash.geom.Point;
import com.senocular.drawing.PathSegment;
import com.senocular.drawing.PathLineSegment;
class com.senocular.drawing.PathCurveSegment extends PathLineSegment {
private var _control:Point;
// Constructor
public function PathCurveSegment(startPt:Point, controlPt:Point, endPt:Point) {
super(startPt, endPt);
_control = controlPt.clone();
_command = "curveTo";
}
// Public Properties
public function get length():Number {
if (isNaN(_length)){
_length = curveLength();
}
return _length;
}
public function get control():Point {
return _control.clone();
}
// Public Methods
public function draw(target:Object):Void {
target[command](_control.x, _control.y, _end.x, _end.y);
}
public function pointAt(t:Number):Point {
var p1:Point = Point.interpolate(_control, _start, t);
var p2:Point = Point.interpolate(_end, _control, t);
return Point.interpolate(p2, p1, t);
}
public function angleAt(t:Number):Number {
var startPt:Point = super.pointAt(t, _start, _control);
var endPt:Point = super.pointAt(t, _control, _end);
return super.angleAt(t, startPt, endPt);
}
// Private Methods
private function trim(t:Number, fromStart:Boolean):PathSegment {
var startPt:Point;
var endPt:Point;
if (fromStart){
endPt = _start;
startPt = _end;
t = 1 - t;
}else{
startPt = _start;
endPt = _end;
}
var newstart:Point = startPt;
var newcontrol:Point;
var newend:Point = startPt;
var dscx:Number = _control.x - startPt.x;
var dscy:Number = _control.y - startPt.y;
var dcex:Number = endPt.x - _control.x;
var dcey:Number = endPt.y - _control.y;
var dx:Number;
var dy:Number;
newcontrol = new Point(startPt.x + dscx*t, startPt.y + dscy*t);
dx = _control.x + dcex*t - newcontrol.x;
dy = _control.y + dcey*t - newcontrol.y;
if (fromStart){
newstart = new Point(newcontrol.x + dx*t, newcontrol.y + dy*t);
}else{
newend = new Point(newcontrol.x + dx*t, newcontrol.y + dy*t);
}
return new __constructor__(newstart, newcontrol, newend);
}
private function curveLength(startPt:Point, controlPt:Point, endPt:Point):Number {
if (!startPt) startPt = _start;
if (!controlPt) controlPt = _control;
if (!endPt) endPt = _end;
var dx:Number = endPt.x - startPt.x;
var dy:Number = endPt.y - startPt.y;
var cx:Number = (controlPt.x - startPt.x)/dx;
var cy:Number = (controlPt.y - startPt.y)/dy;
var f1:Number;
var f2:Number;
var t:Number;
var d:Number = 0;
var p:Point = startPt;
var np:Point;
var i:Number;
for (i=1; i<curveAccuracy; i++){
t = i/curveAccuracy;
f1 = 2*t*(1 - t);
f2 = t*t;
np = new Point(startPt.x + dx*(f1*cx + f2), startPt.y + dy*(f1*cy + f2));
d += lineLength(p, np);
p = np;
}
return d + lineLength(p, endPt);
}
}
