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Implement new version of #reorient() and merge with #resolveCrossings()

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As proposed by @iconexperience in #854
This commit is contained in:
Jürg Lehni 2015-12-26 12:52:32 +01:00
parent 48c0988546
commit 386632b0be
3 changed files with 113 additions and 54 deletions
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2
examples/Scripts/BooleanOperations.html
View file

@ -256,8 +256,6 @@
// pathA.style = pathStyleBoolean;
// pathB.style = pathStyleBoolean;
// // reorientCompoundPath(pathB)
// // var ixs = pathA.getIntersections(pathB);
// // ixs.map(function(a) { console.log("(" + a.path.id + " , " + a.curve.index + " , "+ a.parameter +")");
// // markPoint(a.point, " ") });

2
src/path/CompoundPath.js
View file

@ -153,6 +153,8 @@ var CompoundPath = PathItem.extend(/** @lends CompoundPath# */{
if (children.length === 0) { // Replace with a simple empty Path
var path = new Path(Item.NO_INSERT);
path.insertAbove(this);
// TODO: Consider using Item#_clone() for this, but find a way to
// not clone children / name (content).
path.setStyle(this._style);
this.remove();
return path;

163
src/path/PathItem.Boolean.js
View file

@ -47,12 +47,12 @@ PathItem.inject(new function() {
/*
* Creates a clone of the path that we can modify freely, with its matrix
* applied to its geometry. Calls #reduce() to simplify compound paths and
* remove empty curves, #resolveCrossings() to resolve self- intersection
* and #reorient() to make sure all paths have correct winding direction.
* remove empty curves, #resolveCrossings() to resolve self-intersection
* make sure all paths have correct winding direction.
*/
function preparePath(path, resolve) {
var res = path.clone(false).reduce().transform(null, true, true);
return resolve ? res.resolveCrossings().reorient() : res;
return resolve ? res.resolveCrossings() : res;
}
function finishBoolean(ctor, paths, path1, path2, reduce) {
@ -758,18 +758,116 @@ PathItem.inject(new function() {
this, path, true);
},
/*
* Resolves all crossings of a path item, first by splitting the path or
* compound-path in each self-intersection and tracing the result, then
* fixing the orientation of the resulting sub-paths by making sure that
* all sub-paths are of different winding direction than the first path,
* except for when individual sub-paths are disjoint, i.e. islands,
* which are reoriented so that:
* - The holes have opposite winding direction.
* - Islands have to have the same winding direction as the first child.
* If possible, the existing path / compound-path is modified if the
* amount of resulting paths allows so, otherwise a new path /
* compound-path is created, replacing the current one.
*/
resolveCrossings: function() {
var crossings = this.getCrossings();
if (!crossings.length)
return this;
divideLocations(CurveLocation.expand(crossings));
var paths = this._children || [this],
segments = [];
for (var i = 0, l = paths.length; i < l; i++) {
segments.push.apply(segments, paths[i]._segments);
var children = this._children,
// Support both path and compound-path items
paths = children || [this],
crossings = this.getCrossings();
// First resolve all self-intersections
if (crossings.length) {
divideLocations(CurveLocation.expand(crossings));
// Resolve self-intersections through tracePaths()
paths = tracePaths(Base.each(paths, function(path) {
this.push.apply(this, path._segments);
}, []));
}
return finishBoolean(CompoundPath, tracePaths(segments),
this, null, false);
// By now, all paths are non-overlapping, but might be fully
// contained inside each other.
// Next we adjust their orientation based on on further checks:
var length = paths.length,
item;
if (length > 1) {
// First order the paths by the area of their bounding boxes.
paths = paths.slice().sort(function (a, b) {
return b.getBounds().getArea() - a.getBounds().getArea();
});
var first = paths[0],
clockwise = first.isClockwise(),
items = [first],
excluded = {},
isNonZero = this.getFillRule() === 'nonzero',
windings = isNonZero && Base.each(paths, function(path) {
this.push(path.isClockwise() ? 1 : -1);
}, []);
// Walk through paths, from largest to smallest.
// The first, largest path can be skipped.
for (var i = 1; i < length; i++) {
var path = paths[i],
point = path.getInteriorPoint(),
isOverlapping = false,
exclude = false,
counter = 0;
for (var j = i - 1; j >= 0; j--) {
if (paths[j].contains(point)) {
if (isNonZero && !isOverlapping) {
windings[i] += windings[j];
// Remove path if rule is nonzero and winding
// changes from nonzero to zero or from zero to
// nonzero between containing path and path.
if (windings[i] && windings[j]) {
exclude = excluded[i] = true;
break;
}
}
isOverlapping = true;
// Increase counter for containing paths only if
// path will not be excluded.
if (!excluded[j])
counter++;
}
}
if (!exclude) {
// Set correct orientation and add to final items.
path.setClockwise((counter % 2 === 0) == clockwise);
items.push(path);
}
}
// Replace paths with the processed items list:
paths = items;
length = items.length;
} else if (length === 1) {
// TODO: Is this really required? We don't do the same for
// compound-paths:
// Paths that are not part of compound paths should never be
// counter- clockwise for boolean operations.
paths[0].setClockwise(true);
}
// First try to recycle the current path / compound-path, if the
// amount of paths do not require a conversion.
if (length > 1 && children) {
if (paths !== children)
this.setChildren(paths);
item = this;
} else if (length === 1 && !children) {
if (paths[0] !== this)
this.setSegments(paths[0].removeSegments());
item = this;
}
// Otherwise create a new compound-path and see if we can reduce it,
// and attempt to replace this item with it.
if (!item) {
item = new CompoundPath(Item.NO_INSERT);
item.setChildren(paths);
item = item.reduce();
// TODO: Consider using Item#_clone() for this, but find a way to
// not clone children / name (content).
item.setStyle(this._style);
this.replaceWith(item);
}
return item;
}
};
});
@ -912,13 +1010,6 @@ Path.inject(/** @lends Path# */{
point.x = (xIntercepts[0] + xIntercepts[1]) / 2;
}
return point;
},
reorient: function() {
// Paths that are not part of compound paths should never be counter-
// clockwise for boolean operations.
this.setClockwise(true);
return this;
}
});
@ -934,37 +1025,5 @@ CompoundPath.inject(/** @lends CompoundPath# */{
for (var i = 0, l = children.length; i < l; i++)
monoCurves.push.apply(monoCurves, children[i]._getMonoCurves());
return monoCurves;
},
/*
* Fixes the orientation of a CompoundPath's child paths by first ordering
* them according to their area, and then making sure that all children are
* of different winding direction than the first child, except for when
* some individual contours are disjoint, i.e. islands, they are reoriented
* so that:
* - The holes have opposite winding direction.
* - Islands have to have the same winding direction as the first child.
*/
// NOTE: Does NOT handle self-intersecting CompoundPaths on itself, but
// the boolean code above resolves these before calling reorient().
reorient: function() {
var children = this.removeChildren().sort(function(a, b) {
return b.getBounds().getArea() - a.getBounds().getArea();
});
if (children.length > 0) {
this.addChildren(children);
var clockwise = children[0].isClockwise();
// Skip the first child
for (var i = 1, l = children.length; i < l; i++) {
var point = children[i].getInteriorPoint(),
counters = 0;
for (var j = i - 1; j >= 0; j--) {
if (children[j].contains(point))
counters++;
}
children[i].setClockwise(counters % 2 === 0 && clockwise);
}
}
return this;
}
});