Updated boolean operation methods.

The algorithm is based on paperjs' native segment and curve objects
rather than the generic Node and Link objects.
Also this is much smaller and faster! :)
This commit is contained in:
hkrish 2013-05-02 13:49:07 +02:00
parent f239a3980d
commit 73b018f006

View file

@ -179,184 +179,131 @@ var PathItem = this.PathItem = Item.extend(/** @lends PathItem# */{
/**
* Calculates the Union of two paths
* Boolean API.
* @param {PathItem} path
* @return {CompoundPath} union of this & path
*/
unite: function( path ){
function UnionOp( lnk, isInsidePath1, isInsidePath2 ){
if( isInsidePath1 || isInsidePath2 ){ return false; }
return true;
}
return this._computeBoolean( this, path, UnionOp, 'unite' );
},
/**
* Calculates the Intersection between two paths
* Boolean API.
* @param {PathItem} path
* @return {CompoundPath} Intersection of this & path
*/
intersect: function( path ){
function IntersectionOp( lnk, isInsidePath1, isInsidePath2 ){
if( !isInsidePath1 && !isInsidePath2 ){
return false;
}
return true;
}
return this._computeBoolean( this, path, IntersectionOp, 'intersect' );
},
/**
* Calculates this <minus> path
* Boolean API.
* @param {PathItem} path
* @return {CompoundPath} this <minus> path
*/
subtract: function( path ){
function SubtractionOp( lnk, isInsidePath1, isInsidePath2 ){
var lnkid = lnk.id;
if( lnkid === 1 && isInsidePath2 ){
return false;
} else if( lnkid === 2 && !isInsidePath1 ){
return false;
}
return true;
}
return this._computeBoolean( this, path, SubtractionOp, 'subtract' );
},
// Some constants
// Need to find a home for these
// for _IntersectionID and _UNIQUE_ID, we could use the Base._uid? // tried; doesn't work.
_NORMAL_NODE: 1,
_INTERSECTION_NODE: 2,
_IntersectionID: 1,
_UNIQUE_ID: 1,
/**
* The datastructure for boolean computation:
* _Node - Connects 2 Links, represents a Segment
* _Link - Connects 2 Nodes, represents a Curve
* Graph - List of Links
*/
/**
* Nodes in the graph are analogous to Segment objects
* with additional linkage information to track intersections etc.
* (enough to do a complete graph traversal)
* @param {Point} _point
* @param {Point} _handleIn
* @param {Point} _handleOut
* @param {Any} _id
* A boolean operator is a binary operator function of the form
* f( isPath1:boolean, isInsidePath1:Boolean, isInsidePath2:Boolean ) :Boolean
*
* Boolean operator determines whether a curve segment in the operands is part
* of the boolean result, and will be called for each curve segment in the graph after
* all the intersections between the operands are calculated and curves in the operands
* are split at intersections.
*
* These functions should have a name ( "union", "subtraction" etc. below ), if we need to
* do operator specific operations on paths inside the computeBoolean function.
* for example: if the name of the operator is "subtraction" then we need to reverse the second
* operand. Subtraction is neither associative nor commutative.
*
* The boolean operator should return a Boolean value indicating whether to keep the curve or not.
* return true - keep the curve
* return false - discard the curve
*/
_Node: function( _point, _handleIn, _handleOut, _id, isBaseContour, _uid ){
var _NORMAL_NODE = 1;
var _INTERSECTION_NODE = 2;
this.id = _id;
this.isBaseContour = isBaseContour;
this.type = _NORMAL_NODE;
this.point = _point;
this.handleIn = _handleIn; // handleIn
this.handleOut = _handleOut; // handleOut
this.linkIn = null; // aka linkIn
this.linkOut = null; // linkOut
this.uniqueID = _uid;
// In case of an intersection this will be a merged node.
// And we need space to save the "other _Node's" parameters before merging.
this.idB = null;
this.isBaseContourB = false;
// this.pointB = this.point; // point should be the same
this.handleBIn = null;
this.handleBOut = null;
this.linkBIn = null;
this.linkBOut = null;
this._segment = null;
this.getSegment = function( recalculate ){
if( this.type === _INTERSECTION_NODE && recalculate ){
// point this.linkIn and this.linkOut to those active ones
// also point this.handleIn and this.handleOut to correct in and out handles
// If a link is null, make sure the corresponding handle is also null
this.handleIn = (this.linkIn)? this.handleIn : null;
this.handleOut = (this.linkOut)? this.handleOut : null;
this.handleBIn = (this.linkBIn)? this.handleBIn : null;
this.handleBOut = (this.linkBOut)? this.handleBOut : null;
// Select the valid links
this.linkIn = this.linkIn || this.linkBIn; // linkIn
this.linkOut = this.linkOut || this.linkBOut; // linkOut
// Also update the references in links to point to "this" _Node
if( !this.linkIn || !this.linkOut ){
throw { name: 'Boolean Error', message: 'No matching link found at ixID: ' +
this._intersectionID + " point: " + this.point.toString() };
}
this.linkIn.nodeOut = this; // linkIn.nodeEnd
this.linkOut.nodeIn = this; // linkOut.nodeStart
this.handleIn = this.handleIn || this.handleBIn;
this.handleOut = this.handleOut || this.handleBOut;
this.isBaseContour = this.isBaseContour | this.isBaseContourB;
}
this._segment = this._segment || new Segment( this.point, this.handleIn, this.handleOut );
return this._segment;
};
unite: function( path, _cache ){
var unionOp = function union( isPath1, isInsidePath1, isInsidePath2 ){
return ( isInsidePath1 || isInsidePath2 )? false : true;
};
return computeBoolean( this, path, unionOp, _cache );
},
/**
* Links in the graph are analogous to CUrve objects
* @param {_Node} _nodeIn
* @param {_Node} _nodeOut
* @param {Any} _id
*/
_Link: function( _nodeIn, _nodeOut, _id, isBaseContour, _winding ) {
this.id = _id;
this.isBaseContour = isBaseContour;
this.winding = _winding;
this.nodeIn = _nodeIn; // nodeStart
this.nodeOut = _nodeOut; // nodeEnd
this.nodeIn.linkOut = this; // nodeStart.linkOut
this.nodeOut.linkIn = this; // nodeEnd.linkIn
this._curve = null;
this.intersections = [];
// for reusing the paperjs function we need to (temperorily) build a Curve object from this _Link
// for performance reasons we cache it.
this.getCurve = function() {
this._curve = this._curve || new Curve( this.nodeIn.getSegment(), this.nodeOut.getSegment() );
return this._curve;
};
intersect: function( path, _cache ){
var intersectionOp = function intersection( isPath1, isInsidePath1, isInsidePath2 ){
return ( !isInsidePath1 && !isInsidePath2 )? false : true;
};
return computeBoolean( this, path, intersectionOp, _cache );
},
/**
* makes a graph. Only works on paths, for compound paths we need to
* make graphs for each of the child paths and merge them.
* @param {Path} path
* @param {Integer} id
* @return {Array} Links
subtract: function( path, _cache ){
var subtractionOp = function subtraction( isPath1, isInsidePath1, isInsidePath2 ){
return ( (isPath1 && isInsidePath2) || (!isPath1 && !isInsidePath1) )? false : true;
};
return computeBoolean( this, path, subtractionOp, _cache );
},
/*
* Compound boolean operators combine the basic boolean operations such as union, intersection,
* subtract etc.
*
* TODO: cache the split objects and find a way to properly clone them!
*/
_makeGraph: function( path, id, isBaseContour ){
var graph = [];
var segs = path.segments, prevNode = null, firstNode = null, nuLink, nuNode,
winding = path.clockwise;
for( i = 0, l = segs.length; i < l; i++ ){
// var nuSeg = segs[i].clone();
var nuSeg = segs[i];
nuNode = new this._Node( nuSeg.point, nuSeg.handleIn, nuSeg.handleOut, id, isBaseContour, ++this._UNIQUE_ID );
if( prevNode ) {
nuLink = new this._Link( prevNode, nuNode, id, isBaseContour, winding );
graph.push( nuLink );
}
prevNode = nuNode;
if( !firstNode ){
firstNode = nuNode;
}
}
// the path is closed
nuLink = new this._Link( prevNode, firstNode, id, isBaseContour, winding );
graph.push( nuLink );
return graph;
// a.k.a. eXclusiveOR
exclude: function( path ){
var res1 = this.subtract( path );
var res2 = path.subtract( this );
var res = new Group( [res1, res2] );
return res;
},
// Divide path1 by path2
divide: function( path ){
var res1 = this.subtract( path );
var res2 = this.intersect( path );
var res = new Group( [res1, res2] );
return res;
},
_splitPath: function( _ixs, other ) {
// Sort function for sorting intersections in the descending order
function sortIx( a, b ) { return b.parameter - a.parameter; }
other = other || false;
var i, j, k, l, len, ixs, ix, path, crv, vals;
var ixPoint, nuSeg;
var paths = {}, lastPathId = null;
for (i = 0, l = _ixs.length; i < l; i++) {
ix = ( other )? _ixs[i].getIntersection() : _ixs[i];
if( !paths[ix.path.id] ){
paths[ix.path.id] = ix.path;
}
if( !ix.curve._ixParams ){ix.curve._ixParams = []; }
ix.curve._ixParams.push( { parameter: ix.parameter, pair: ix.getIntersection() } );
}
for (k in paths) {
if( !paths.hasOwnProperty( k ) ){ continue; }
path = paths[k];
var lastNode = path.lastSegment, firstNode = path.firstSegment;
var nextNode = null, left = null, right = null, parts = null, isLinear;
var handleIn, handleOut;
while( nextNode !== firstNode){
nextNode = ( nextNode )? nextNode.previous: lastNode;
if( nextNode.curve._ixParams ){
ixs = nextNode.curve._ixParams;
ixs.sort( sortIx );
crv = nextNode.getCurve();
isLinear = crv.isLinear();
crv = vals = null;
for (i = 0, l = ixs.length; i < l; i++) {
ix = ixs[i];
crv = nextNode.getCurve();
if( !vals ) vals = crv.getValues();
if( ix.parameter === 0.0 || ix.parameter === 1.0 ){
// Intersection is on an existing node
// no need to create a new segment,
// we just link the corresponding intersections together
nuSeg = ( ix.parameter === 0.0 )? crv.segment1 : crv.segment2;
nuSeg._ixPair = ix.pair;
nuSeg._ixPair._segment = nuSeg;
} else {
parts = Curve.subdivide( vals, ix.parameter );
left = parts[0];
right = parts[1];
handleIn = handleOut = null;
ixPoint = new Point( right[0], right[1] );
if( !isLinear ){
crv.segment1.handleOut = new Point( left[2] - left[0], left[3] - left[1] );
crv.segment2.handleIn = new Point( right[4] - right[6], right[5] - right[7] );
handleIn = new Point( left[4] - ixPoint.x, left[5] - ixPoint.y );
handleOut = new Point( right[2] - ixPoint.x, right[3] - ixPoint.y );
}
nuSeg = new Segment( ixPoint, handleIn, handleOut );
nuSeg._ixPair = ix.pair;
nuSeg._ixPair._segment = nuSeg;
path.insert( nextNode.index + 1, nuSeg );
}
for (j = i + 1; j < l; j++) {
ixs[j].parameter = ixs[j].parameter / ix.parameter;
}
vals = left;
}
}
}
}
},
/**
@ -373,420 +320,201 @@ var PathItem = this.PathItem = Item.extend(/** @lends PathItem# */{
* @return {boolean} the winding direction of the base contour( true if clockwise )
*/
_reorientCompoundPath: function( path ){
if( !(path instanceof CompoundPath) ){ return path.clockwise; }
var children = path.children, len = children.length, baseWinding;
var bounds = new Array( len );
var tmparray = new Array( len );
baseWinding = children[0].clockwise;
// Omit the first path
for (i = 0; i < len; i++) {
bounds[i] = children[i].bounds;
tmparray[i] = 0;
}
for (i = 0; i < len; i++) {
var p1 = children[i];
for (j = 0; j < len; j++) {
var p2 = children[j];
if( i !== j && bounds[i].contains( bounds[j] ) ){
tmparray[j]++;
}
}
}
for (i = 1; i < len; i++) {
if ( tmparray[i] % 2 === 0 ) {
children[i].clockwise = baseWinding;
}
}
return baseWinding;
if( !(path instanceof CompoundPath) ){
path.closed = true;
return path.clockwise;
}
var children = path.children, len = children.length, baseWinding;
var bounds = new Array( len );
var tmparray = new Array( len );
baseWinding = children[0].clockwise;
// Omit the first path
for (i = 0; i < len; i++) {
children[i].closed = true;
bounds[i] = children[i].bounds;
tmparray[i] = 0;
}
for (i = 0; i < len; i++) {
var p1 = children[i];
for (j = 0; j < len; j++) {
var p2 = children[j];
if( i !== j && bounds[i].contains( bounds[j] ) ){
tmparray[j]++;
}
}
}
for (i = 1; i < len; i++) {
if ( tmparray[i] % 2 === 0 ) {
children[i].clockwise = baseWinding;
}
}
return baseWinding;
},
_computeBoolean: function( _path1, _path2, operator, operatorName ){
this._IntersectionID = 1;
this._UNIQUE_ID = 1;
// We work on duplicate paths since the algorithm may modify the original paths
var path1 = _path1.clone();
var path2 = _path2.clone();
var i, j, k, l, lnk, crv, node, nuNode, leftLink, rightLink;
var path1Clockwise = true, path2Clockwise = true;
// If one of the operands is empty, resolve self-intersections on the second operand
var childCount1 = (_path1 instanceof CompoundPath)? _path1.children.length : _path1.curves.length;
var childCount2 = (_path2 instanceof CompoundPath)? _path2.children.length : _path2.curves.length;
var resolveSelfIntersections = !childCount1 | !childCount2;
// Reorient the compound paths, i.e. make all the islands wind in the same direction
// and holes in the opposit direction.
// Do this only if we are not resolving selfIntersections:
// Resolving self-intersections work on compound paths, but, we might get different results!
if( !resolveSelfIntersections ){
path1Clockwise = this._reorientCompoundPath( path1 );
path2Clockwise = this._reorientCompoundPath( path2 );
}
// Cache the bounding rectangle of paths
// so we can make the test for containment quite a bit faster
path1._bounds = (childCount1)? path1.bounds : null;
path2._bounds = (childCount2)? path2.bounds : null;
// Prepare the graphs. Graphs are list of Links that retains
// full connectivity information. The order of links in a graph is not important
// That allows us to sort and merge graphs and 'splice' links with their splits easily.
// Also, this is the place to resolve self-intersecting paths
var graph = [], path1Children, path2Children, base;
if( path1 instanceof CompoundPath ){
path1Children = path1.children;
for (i = 0, base = true, l = path1Children.length; i < l; i++, base = false) {
path1Children[i].closed = true;
graph = graph.concat( this._makeGraph( path1Children[i], 1, base ));
}
} else {
path1.closed = true;
path1Clockwise = path1.clockwise;
graph = graph.concat( this._makeGraph( path1, 1, true ) );
}
// if operator is BooleanOps.Subtraction, then reverse path2
// so that the nodes and links will link correctly
var reverse = ( operatorName === 'subtract' )? true: false;
path2Clockwise = (reverse)? !path2Clockwise : path2Clockwise;
if( path2 instanceof CompoundPath ){
path2Children = path2.children;
for (i = 0, base = true, l = path2Children.length; i < l; i++, base = false) {
path2Children[i].closed = true;
if( reverse ){ path2Children[i].reverse(); }
graph = graph.concat( this._makeGraph( path2Children[i], 2, base ));
}
} else {
path2.closed = true;
if( reverse ){ path2.reverse(); }
path2Clockwise = path2.clockwise;
graph = graph.concat( this._makeGraph( path2, 2, true ) );
}
// Sort function to sort intersections according to the 'parameter'(t) in a link (curve)
function ixSort( a, b ){ return a.parameter - b.parameter; }
/*
* Pass 1:
* Calculate the intersections for all graphs
*/
var ix, loc, loc2, ixCount = 0;
for ( i = graph.length - 1; i >= 0; i--) {
var c1 = graph[i].getCurve();
var v1 = c1.getValues();
for ( j = i -1; j >= 0; j-- ) {
if( !resolveSelfIntersections && graph[j].id === graph[i].id ){ continue; }
var c2 = graph[j].getCurve();
var v2 = c2.getValues();
loc = [];
Curve.getIntersections( v1, v2, c1, loc );
if( loc.length ){
for (k = 0, l=loc.length; k<l; k++) {
// Ignore segment overlaps if both curve are part of same contour
// This is a degenerate case while resolving self-intersections,
// after paperjs rev#8d35d92
if( graph[j].id === graph[i].id &&
( loc[k].parameter === 0.0 || loc[k].parameter === 1.0 )) {
continue;
}
graph[i].intersections.push( loc[k] );
loc2 = new CurveLocation( c2, null, loc[k].point );
loc2._id = loc[k]._id;
graph[j].intersections.push( loc2 );
loc[k]._ixpair = loc2;
loc2._ixpair = loc[k];
++ixCount;
}
}
}
}
/*
* Avoid duplicate intersections when a curve that belongs to one contour
* passes through a segment on another contour
*/
len = graph.length;
while( len-- ){
ix = graph[len].intersections;
for (i =0, l=ix.length; i<l; i++) {
// In case of an over lap over the first segment on a link we
// look for duplicates and mark them INVALID
loc = ix[i];
if ( loc.parameter === 0.0 ){
j = graph.length;
while( j-- ) {
var ix2 = graph[j].intersections;
k = ix2.length;
while ( k-- ) {
loc2 = ix2[k];
if( !loc2.INVALID && loc._id !== loc2._id && loc2.parameter !== 1.0 &&
loc2.point.equals( loc.point ) ) {
loc2.INVALID = loc2._ixpair.INVALID = true;
}
}
}
} // if( loc.parameter === 0.0 ) {
}
}
/*
* Pass 2:
* Walk the graph, sort the intersections on each individual link.
* for each link that intersects with another one, replace it with new split links.
*/
var ixPoint, ixHandleI, ixHandleOut, param, isLinear, parts, left, right;
// variable names are (sort of) acronyms of what thay are relative to the link
// niho - link.NodeInHandleOut, for example.
var values, nix, niy,nox, noy, niho, nohi, nihox, nihoy, nohix, nohiy;
for ( i = graph.length - 1; i >= 0; i--) {
if( graph[i].intersections.length ){
ix = graph[i].intersections;
// Sort the intersections if there is more than one
if( graph[i].intersections.length > 1 ){ ix.sort( ixSort ); }
// Remove the graph link, this link has to be split and replaced with the splits
lnk = graph.splice( i, 1 )[0];
nix = lnk.nodeIn.point.x; niy = lnk.nodeIn.point.y;
nox = lnk.nodeOut.point.x; noy = lnk.nodeOut.point.y;
niho = lnk.nodeIn.handleOut; nohi = lnk.nodeOut.handleIn;
nihox = nihoy = nohix = nohiy = 0;
isLinear = true;
if( niho ){ nihox = niho.x; nihoy = niho.y; isLinear = false; }
if( nohi ){ nohix = nohi.x; nohiy = nohi.y; isLinear = false; }
values = [ nix, niy, nihox + nix, nihoy + niy,
nohix + nox, nohiy + noy, nox, noy ];
for (j =0, l=ix.length; j<l && lnk; j++) {
if( ix[j].INVALID ){ continue; }
param = ix[j].parameter;
if( param === 0.0 || param === 1.0) {
// Intersection falls on an existing node
// there is no need to split the link
nuNode = ( param === 0.0 )? lnk.nodeIn : lnk.nodeOut;
nuNode.type = this._INTERSECTION_NODE;
nuNode._intersectionID = ix[j]._id;
if( param === 1.0 ){
leftLink = null;
rightLink = lnk;
} else {
leftLink = lnk;
rightLink = null;
}
} else {
parts = Curve.subdivide(values, param);
left = parts[0];
right = parts[1];
// Make new link and convert handles from absolute to relative
ixPoint = new Point( left[6], left[7] );
if( !isLinear ){
ixHandleIn = new Point(left[4] - ixPoint.x, left[5] - ixPoint.y);
ixHandleOut = new Point(right[2] - ixPoint.x, right[3] - ixPoint.y);
} else {
ixHandleIn = ixHandleOut = null;
right[2] = right[0];
right[3] = right[1];
}
nuNode = new this._Node( ixPoint, ixHandleIn, ixHandleOut, lnk.id, lnk.isBaseContour, ++this._UNIQUE_ID );
nuNode.type = this._INTERSECTION_NODE;
nuNode._intersectionID = ix[j]._id;
// clear the cached Segment on original end nodes and Update their handles
lnk.nodeIn._segment = null;
lnk.nodeOut._segment = null;
if( !isLinear ){
var tmppnt = lnk.nodeIn.point;
lnk.nodeIn.handleOut = new Point( left[2] - tmppnt.x, left[3] - tmppnt.y );
tmppnt = lnk.nodeOut.point;
lnk.nodeOut.handleIn = new Point( right[4] - tmppnt.x, right[5] - tmppnt.y );
}
// Make new links after the split
leftLink = new this._Link( lnk.nodeIn, nuNode, lnk.id, lnk.isBaseContour, lnk.winding );
rightLink = new this._Link( nuNode, lnk.nodeOut, lnk.id, lnk.isBaseContour, lnk.winding );
values = right;
}
// Add the first split link back to the graph, since we sorted the intersections
// already, this link should contain no more intersections to the left.
if( leftLink ){
graph.splice( i, 0, leftLink );
}
// continue with the second split link, to see if
// there are more intersections to deal with
lnk = rightLink;
// Interpolate the rest of the parameters
if( lnk ) {
var one_minus_param = (1.0 - param);
for (k =j + 1, l=ix.length; k<l; k++) {
ix[k]._parameter = ( ix[k].parameter - param ) / one_minus_param;
}
}
}
// Add the last split link back to the graph
if( lnk ){
graph.splice( i, 0, lnk );
}
}
}
/**
* Pass 3:
* Merge matching intersection _Node Pairs (type is _INTERSECTION_NODE &&
* a._intersectionID == b._intersectionID )
*
* Mark each _Link(Curve) according to whether it is
* case 1. inside Path1 ( and only Path1 )
* 2. inside Path2 ( and only Path2 )
* 3. outside (normal case)
*
* Take a test function "operator" which will discard links
* according to the above
* * Union -> discard cases 1 and 2
* * Intersection -> discard case 3
* * Path1-Path2 -> discard cases 2, 3[Path2]
*/
// step 1: discard invalid links according to the boolean operator
for ( i = graph.length - 1; i >= 0; i-- ) {
var insidePath1 = false, insidePath2 = false, contains;
lnk = graph[i];
// if( lnk.SKIP_OPERATOR ) { continue; }
if( !lnk.INVALID ) {
crv = lnk.getCurve();
// var midPoint = new Point(lnk.nodeIn.point);
var midPoint = crv.getPoint( 0.5 );
// If on a base curve, consider points on the curve and inside,
// if not —for example a hole, points on the curve falls outside
if( lnk.id !== 1 ){
contains = path1.contains( midPoint );
insidePath1 = (lnk.winding === path1Clockwise)? contains :
contains && !this._testOnContour( path1, midPoint );
}
if( lnk.id !== 2 ){
contains = path2.contains( midPoint );
insidePath2 = (lnk.winding === path2Clockwise)? contains :
contains && !this._testOnContour( path2, midPoint );
}
}
if( lnk.INVALID || !operator( lnk, insidePath1, insidePath2 ) ){
// lnk = graph.splice( i, 1 )[0];
lnk.INVALID = true;
lnk.nodeIn.linkOut = null;
lnk.nodeOut.linkIn = null;
}
}
// step 2: Match nodes according to their _intersectionID and merge them together
var len = graph.length;
while( len-- ){
node = graph[len].nodeIn;
if( node.type === this._INTERSECTION_NODE ){
var otherNode = null;
for (i = len - 1; i >= 0; i--) {
var tmpnode = graph[i].nodeIn;
if( tmpnode._intersectionID === node._intersectionID &&
tmpnode.uniqueID !== node.uniqueID ) {
otherNode = tmpnode;
break;
}
}
if( otherNode ) {
//Check if it is a self-intersecting _Node
if( node.id === otherNode.id ){
// Swap the outgoing links, this will resolve a knot and create two paths,
// the portion of the original path on one side of a self crossing is counter-clockwise,
// so one of the resulting paths will also be counter-clockwise
var tmp = otherNode.linkOut;
otherNode.linkOut = node.linkOut;
node.linkOut = tmp;
tmp = otherNode.handleOut;
otherNode.handleOut = node.handleOut;
node.handleOut = tmp;
node.type = otherNode.type = this._NORMAL_NODE;
node._intersectionID = null;
node._segment = otherNode._segment = null;
} else {
// Merge the nodes together, by adding this node's information to the other node
// this node becomes a four-way node, i.e. this node will have two sets of linkIns and linkOuts each.
// In this sense this is a multi-graph!
otherNode.idB = node.id;
otherNode.isBaseContourB = node.isBaseContour;
otherNode.handleBIn = node.handleIn;
otherNode.handleBOut = node.handleOut;
otherNode.linkBIn = node.linkIn;
otherNode.linkBOut = node.linkOut;
otherNode._segment = null;
if( node.linkIn ){ node.linkIn.nodeOut = otherNode; }
if( node.linkOut ){ node.linkOut.nodeIn = otherNode; }
// Clear this node's intersectionID, so that we won't iterate over it again
node._intersectionID = null;
}
}
}
}
window.g = graph;
// Final step: Retrieve the resulting paths from the graph
var boolResult = new CompoundPath();
var firstNode = true, nextNode, foundBasePath = false;
while( firstNode ){
firstNode = nextNode = null;
len = graph.length;
while( len-- ){
lnk = graph[len];
if( !lnk.INVALID && !lnk.nodeIn.visited && !firstNode ){
if( !foundBasePath && lnk.isBaseContour ){
firstNode = lnk.nodeIn;
foundBasePath = true;
break;
} else if(foundBasePath){
firstNode = lnk.nodeIn;
break;
}
}
}
if( firstNode ){
var path = new Path();
path.add( firstNode.getSegment( true ) );
firstNode.visited = true;
nextNode = firstNode.linkOut.nodeOut;
var linkCount = graph.length + 1;
while( firstNode.uniqueID !== nextNode.uniqueID && linkCount-- ){
path.add( nextNode.getSegment( true ) );
nextNode.visited = true;
if( !nextNode.linkOut ){
throw { name: 'Boolean Error', message: 'No link found at node id: ' + nextNode.id };
}
nextNode = nextNode.linkOut.nodeOut;
}
path.closed = true;
if( path.segments.length > 1 && linkCount >= 0 ){ // avoid stray segments and incomplete paths
if( path.segments.length > 2 || !path.curves[0].isLinear() ){
boolResult.addChild( path );
}
}
}
}
boolResult = boolResult.reduce();
// Remove the paths we duplicated
path1.remove();
path2.remove();
// I think, we're done.
return boolResult;
reversePath: function( path ){
var baseWinding;
if( path instanceof CompoundPath ){
var children = path.children, i, len;
for (i = 0, len = children.length; i < len; i++) {
children[i].reverse();
children[i]._curves = null;
}
baseWinding = children[0].clockwise;
} else {
path.reverse();
baseWinding = path.clockwise;
path._curves = null;
}
return baseWinding;
},
_computeBoolean: function( path1, path2, operator, _splitCache ){
var _path1, _path2, path1Clockwise, path2Clockwise;
var ixs, path1Id, path2Id;
// We do not modify the operands themselves
// The result might not belong to the same type
// i.e. subtraction( A:Path, B:Path ):CompoundPath etc.
_path1 = path1.clone();
_path2 = path2.clone();
_path1.style = _path2.style = null;
_path1.selected = _path2.selected = false;
path1Clockwise = _reorientCompoundPath( _path1 );
path2Clockwise = _reorientCompoundPath( _path2 );
path1Id = _path1.id;
path2Id = _path2.id;
// Calculate all the intersections
ixs = ( _splitCache && _splitCache.intersections )?
_splitCache.intersections : _path1.getIntersections( _path2 );
// if we have a empty _splitCache object as an operand,
// skip calculating boolean and cache the intersections
if( _splitCache && !_splitCache.intersections ){
_splitCache.intersections = ixs;
return;
}
_splitPath( ixs );
_splitPath( ixs, true );
path1Id = _path1.id;
path2Id = _path2.id;
// Do operator specific calculations before we begin
if( operator.name === "subtraction" ) {
path2Clockwise = _reversePath( _path2 );
}
/**
* _testOnContour
* Tests if the point lies on the countour of a path
*/
_testOnContour: function( path, point ){
var res = 0;
var crv = path.getCurves();
var i = 0;
var bounds = path._bounds;
if( bounds && bounds.contains( point ) ){
for( i = 0; i < crv.length && !res; i++ ){
var crvi = crv[i];
if( crvi.bounds.contains( point ) && crvi.getParameterOf( point ) ){
res = 1;
}
}
}
return res;
var i, j, len, path, crv;
var paths = [];
if( _path1 instanceof CompoundPath ){
paths = paths.concat( _path1.children );
} else {
paths = [ _path1 ];
}
if( _path2 instanceof CompoundPath ){
paths = paths.concat( _path2.children );
} else {
paths.push( _path2 );
}
// step 1: discard invalid links according to the boolean operator
var lastNode, firstNode, nextNode, midPoint, insidePath1, insidePath2;
var thisId, thisWinding, contains, subtractionOp = (operator.name === 'subtraction');
for (i = 0, len = paths.length; i < len; i++) {
insidePath1 = insidePath2 = false;
path = paths[i];
thisId = ( path.parent instanceof CompoundPath )? path.parent.id : path.id;
thisWinding = path.clockwise;
lastNode = path.lastSegment;
firstNode = path.firstSegment;
nextNode = null;
while( nextNode !== firstNode){
nextNode = ( nextNode )? nextNode.previous: lastNode;
crv = nextNode.curve;
midPoint = crv.getPoint( 0.5 );
if( thisId !== path1Id ){
contains = _path1.contains( midPoint );
insidePath1 = (thisWinding === path1Clockwise || subtractionOp )? contains :
contains && !_testOnCurve( _path1, midPoint );
}
if( thisId !== path2Id ){
contains = _path2.contains( midPoint );
insidePath2 = (thisWinding === path2Clockwise )? contains :
contains && !_testOnCurve( _path2, midPoint );
}
if( !operator( thisId === path1Id, insidePath1, insidePath2 ) ){
crv._INVALID = true;
// markPoint( midPoint, '+' );
}
}
}
// Final step: Retrieve the resulting paths from the graph
var boolResult = new CompoundPath();
var node, nuNode, nuPath, nodeList = [], handle;
for (i = 0, len = paths.length; i < len; i++) {
nodeList = nodeList.concat( paths[i].segments );
}
for (i = 0, len = nodeList.length; i < len; i++) {
node = nodeList[i];
if( node.curve._INVALID || node._visited ){ continue; }
path = node.path;
thisId = ( path.parent instanceof CompoundPath )? path.parent.id : path.id;
thisWinding = path.clockwise;
nuPath = new Path();
firstNode = null;
firstNode_ix = null;
if( node.previous.curve._INVALID ) {
node.handleIn = ( node._ixPair )?
node._ixPair.getIntersection()._segment.handleIn : [ 0, 0 ];
}
while( node && !node._visited && ( node !== firstNode && node !== firstNode_ix ) ){
node._visited = true;
firstNode = ( firstNode )? firstNode: node;
firstNode_ix = ( !firstNode_ix && firstNode._ixPair )?
firstNode._ixPair.getIntersection()._segment: firstNode_ix;
// node._ixPair is this node's intersection CurveLocation object
// node._ixPair.getIntersection() is the other CurveLocation object this node intersects with
nextNode = ( node._ixPair && node.curve._INVALID )? node._ixPair.getIntersection()._segment : node;
if( node._ixPair ) {
nextNode._visited = true;
nuNode = new Segment( node.point, node.handleIn, nextNode.handleOut );
nuPath.add( nuNode );
node = nextNode;
path = node.path;
thisWinding = path.clockwise;
} else {
nuPath.add( node );
}
node = node.next;
}
if( nuPath.segments.length > 1 ) {
// avoid stray segments and incomplete paths
if( nuPath.segments.length > 2 || !nuPath.curves[0].isLinear() ){
nuPath.closed = true;
boolResult.addChild( nuPath, true );
}
}
}
// Delete the proxies
_path1.remove();
_path2.remove();
// And then, we are done.
return boolResult.reduce();
},
_testOnCurve: function( path, point ){
var res = 0;
var crv = path.getCurves();
var i = 0;
var bounds = path.bounds;
if( bounds && bounds.contains( point ) ){
for( i = 0; i < crv.length && !res; i++ ){
var crvi = crv[i];
if( crvi.bounds.contains( point ) && crvi.getParameterOf( point ) ){
res = 1;
}
}
}
return res;
}
/**
* Smooth bezier curves without changing the amount of segments or their
* points, by only smoothing and adjusting their handle points, for both