var Class = require('./class');
module.exports = Class({
initialize: function(path){
this.reset().push(path);
},
/* parser */
push: function(){
var p = Array.prototype.join.call(arguments, ' ')
.match(/[a-df-z]|[\-+]?(?:[\d\.]e[\-+]?|[^\s\-+,a-z])+/ig);
if (!p) return this;
var last, cmd = p[0], i = 1;
while (cmd){
switch (cmd){
case 'm': this.move(p[i++], p[i++]); break;
case 'l': this.line(p[i++], p[i++]); break;
case 'c': this.curve(p[i++], p[i++], p[i++], p[i++], p[i++], p[i++]); break;
case 's': this.curve(p[i++], p[i++], null, null, p[i++], p[i++]); break;
case 'q': this.curve(p[i++], p[i++], p[i++], p[i++]); break;
case 't': this.curve(p[i++], p[i++]); break;
case 'a': this.arc(p[i+5], p[i+6], p[i], p[i+1], p[i+3], !+p[i+4], p[i+2]); i += 7; break;
case 'h': this.line(p[i++], 0); break;
case 'v': this.line(0, p[i++]); break;
case 'M': this.moveTo(p[i++], p[i++]); break;
case 'L': this.lineTo(p[i++], p[i++]); break;
case 'C': this.curveTo(p[i++], p[i++], p[i++], p[i++], p[i++], p[i++]); break;
case 'S': this.curveTo(p[i++], p[i++], null, null, p[i++], p[i++]); break;
case 'Q': this.curveTo(p[i++], p[i++], p[i++], p[i++]); break;
case 'T': this.curveTo(p[i++], p[i++]); break;
case 'A': this.arcTo(p[i+5], p[i+6], p[i], p[i+1], p[i+3], !+p[i+4], p[i+2]); i += 7; break;
case 'H': this.lineTo(p[i++], this.penY); break;
case 'V': this.lineTo(this.penX, p[i++]); break;
case 'Z': case 'z': this.close(); break;
default: cmd = last; i--; continue;
}
last = cmd;
if (last == 'm') last = 'l';
else if (last == 'M') last = 'L';
cmd = p[i++];
}
return this;
},
/* utility methods */
reset: function(){
this.penX = this.penY = 0;
this.penDownX = this.penDownY = null;
this._pivotX = this._pivotY = 0;
this.onReset();
return this;
},
move: function(x,y){
this.onMove(this.penX, this.penY, this._pivotX = this.penX += (+x), this._pivotY = this.penY += (+y));
return this;
},
moveTo: function(x,y){
this.onMove(this.penX, this.penY, this._pivotX = this.penX = (+x), this._pivotY = this.penY = (+y));
return this;
},
line: function(x,y){
return this.lineTo(this.penX + (+x), this.penY + (+y));
},
lineTo: function(x,y){
if (this.penDownX == null){ this.penDownX = this.penX; this.penDownY = this.penY; }
this.onLine(this.penX, this.penY, this._pivotX = this.penX = (+x), this._pivotY = this.penY = (+y));
return this;
},
curve: function(c1x, c1y, c2x, c2y, ex, ey){
var x = this.penX, y = this.penY;
return this.curveTo(
x + (+c1x), y + (+c1y),
c2x == null ? null : x + (+c2x),
c2y == null ? null : y + (+c2y),
ex == null ? null : x + (+ex),
ey == null ? null : y + (+ey)
);
},
curveTo: function(c1x, c1y, c2x, c2y, ex, ey){
var x = this.penX, y = this.penY;
if (c2x == null){
c2x = +c1x; c2y = +c1y;
c1x = (x * 2) - (this._pivotX || 0); c1y = (y * 2) - (this._pivotY || 0);
}
if (ex == null){
this._pivotX = +c1x; this._pivotY = +c1y;
ex = +c2x; ey = +c2y;
c2x = (ex + (+c1x) * 2) / 3; c2y = (ey + (+c1y) * 2) / 3;
c1x = (x + (+c1x) * 2) / 3; c1y = (y + (+c1y) * 2) / 3;
} else {
this._pivotX = +c2x; this._pivotY = +c2y;
}
if (this.penDownX == null){ this.penDownX = x; this.penDownY = y; }
this.onBezierCurve(x, y, +c1x, +c1y, +c2x, +c2y, this.penX = +ex, this.penY = +ey);
return this;
},
arc: function(x, y, rx, ry, outer, counterClockwise, rotation){
return this.arcTo(this.penX + (+x), this.penY + (+y), rx, ry, outer, counterClockwise, rotation);
},
arcTo: function(x, y, rx, ry, outer, counterClockwise, rotation){
ry = Math.abs(+ry || +rx || (+y - this.penY));
rx = Math.abs(+rx || (+x - this.penX));
if (!rx || !ry || (x == this.penX && y == this.penY)) return this.lineTo(x, y);
var tX = this.penX, tY = this.penY, clockwise = !+counterClockwise, large = !!+outer;
var rad = rotation ? rotation * Math.PI / 180 : 0, cos = Math.cos(rad), sin = Math.sin(rad);
x -= tX; y -= tY;
// Ellipse Center
var cx = cos * x / 2 + sin * y / 2,
cy = -sin * x / 2 + cos * y / 2,
rxry = rx * rx * ry * ry,
rycx = ry * ry * cx * cx,
rxcy = rx * rx * cy * cy,
a = rxry - rxcy - rycx;
if (a < 0){
a = Math.sqrt(1 - a / rxry);
rx *= a; ry *= a;
cx = x / 2; cy = y / 2;
} else {
a = Math.sqrt(a / (rxcy + rycx));
if (large == clockwise) a = -a;
var cxd = -a * cy * rx / ry,
cyd = a * cx * ry / rx;
cx = cos * cxd - sin * cyd + x / 2;
cy = sin * cxd + cos * cyd + y / 2;
}
// Rotation + Scale Transform
var xx = cos / rx, yx = sin / rx,
xy = -sin / ry, yy = cos / ry;
// Start and End Angle
var sa = Math.atan2(xy * -cx + yy * -cy, xx * -cx + yx * -cy),
ea = Math.atan2(xy * (x - cx) + yy * (y - cy), xx * (x - cx) + yx * (y - cy));
cx += tX; cy += tY;
x += tX; y += tY;
// Circular Arc
if (this.penDownX == null){ this.penDownX = this.penX; this.penDownY = this.penY; }
this.onArc(
tX, tY, this._pivotX = this.penX = x, this._pivotY = this.penY = y,
cx, cy, rx, ry, sa, ea, !clockwise, rotation
);
return this;
},
counterArc: function(x, y, rx, ry, outer){
return this.arc(x, y, rx, ry, outer, true);
},
counterArcTo: function(x, y, rx, ry, outer){
return this.arcTo(x, y, rx, ry, outer, true);
},
close: function(){
if (this.penDownX != null){
this.onClose(this.penX, this.penY, this.penX = this.penDownX, this.penY = this.penDownY);
this.penDownX = null;
}
return this;
},
/* overridable handlers */
onReset: function(){
},
onMove: function(sx, sy, ex, ey){
},
onLine: function(sx, sy, ex, ey){
this.onBezierCurve(sx, sy, sx, sy, ex, ey, ex, ey);
},
onBezierCurve: function(sx, sy, c1x, c1y, c2x, c2y, ex, ey){
var gx = ex - sx, gy = ey - sy,
g = gx * gx + gy * gy,
v1, v2, cx, cy, u;
cx = c1x - sx; cy = c1y - sy;
u = cx * gx + cy * gy;
if (u > g){
cx -= gx;
cy -= gy;
} else if (u > 0 && g != 0){
cx -= u/g * gx;
cy -= u/g * gy;
}
v1 = cx * cx + cy * cy;
cx = c2x - sx; cy = c2y - sy;
u = cx * gx + cy * gy;
if (u > g){
cx -= gx;
cy -= gy;
} else if (u > 0 && g != 0){
cx -= u/g * gx;
cy -= u/g * gy;
}
v2 = cx * cx + cy * cy;
if (v1 < 0.01 && v2 < 0.01){
this.onLine(sx, sy, ex, ey);
return;
}
// Avoid infinite recursion
if (isNaN(v1) || isNaN(v2)){
throw new Error('Bad input');
}
// Split curve
var s1x = (c1x + c2x) * 0.5, s1y = (c1y + c2y) * 0.5,
l1x = (c1x + sx) * 0.5, l1y = (c1y + sy) * 0.5,
l2x = (l1x + s1x) * 0.5, l2y = (l1y + s1y) * 0.5,
r2x = (ex + c2x) * 0.5, r2y = (ey + c2y) * 0.5,
r1x = (r2x + s1x) * 0.5, r1y = (r2y + s1y) * 0.5,
l2r1x = (l2x + r1x) * 0.5, l2r1y = (l2y + r1y) * 0.5;
// TODO: Manual stack if necessary. Currently recursive without tail optimization.
this.onBezierCurve(sx, sy, l1x, l1y, l2x, l2y, l2r1x, l2r1y);
this.onBezierCurve(l2r1x, l2r1y, r1x, r1y, r2x, r2y, ex, ey);
},
onArc: function(sx, sy, ex, ey, cx, cy, rx, ry, sa, ea, ccw, rotation){
// Inverse Rotation + Scale Transform
var rad = rotation ? rotation * Math.PI / 180 : 0, cos = Math.cos(rad), sin = Math.sin(rad),
xx = cos * rx, yx = -sin * ry,
xy = sin * rx, yy = cos * ry;
// Bezier Curve Approximation
var arc = ea - sa;
if (arc < 0 && !ccw) arc += Math.PI * 2;
else if (arc > 0 && ccw) arc -= Math.PI * 2;
var n = Math.ceil(Math.abs(arc / (Math.PI / 2))),
step = arc / n,
k = (4 / 3) * Math.tan(step / 4);
var x = Math.cos(sa), y = Math.sin(sa);
for (var i = 0; i < n; i++){
var cp1x = x - k * y, cp1y = y + k * x;
sa += step;
x = Math.cos(sa); y = Math.sin(sa);
var cp2x = x + k * y, cp2y = y - k * x;
this.onBezierCurve(
sx, sy,
cx + xx * cp1x + yx * cp1y, cy + xy * cp1x + yy * cp1y,
cx + xx * cp2x + yx * cp2y, cy + xy * cp2x + yy * cp2y,
(sx = (cx + xx * x + yx * y)), (sy = (cy + xy * x + yy * y))
);
}
},
onClose: function(sx, sy, ex, ey){
this.onLine(sx, sy, ex, ey);
}
});