Last active
September 18, 2018 20:09
-
-
Save beardicus/2565d94adec62b77c9d1915c6cd91e5e to your computer and use it in GitHub Desktop.
Paper.js ShapeStroke
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
license: mit | |
border: yes | |
height: 1060 |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
<!DOCTYPE html> | |
<meta charset="UTF-8"> | |
<canvas id="canvas" width="960" height="1060"></canvas> | |
<script type="text/javascript"> | |
window.onload = function() { | |
var canvas = document.getElementById('canvas') | |
paper.setup(canvas) | |
paper.install(window) | |
var tool = new Tool() | |
tool.minDistance = 10 | |
var strokeWidth = 60, | |
strokeRadius = strokeWidth / 2, | |
path | |
var pathStroke = 'grey', | |
pathSelect = 'lightgrey', | |
shapeSelect = 'red' | |
tool.onMouseDown = function(event) { | |
project.clear() | |
path = new Path({ | |
strokeWidth: strokeWidth, | |
strokeCap: 'round', | |
strokeJoin: 'round', | |
strokeColor: pathStroke, | |
selectedColor: pathSelect | |
}) | |
} | |
tool.onMouseDrag = function(event) { | |
path.add(event.point) | |
} | |
tool.onMouseUp = function(event) { | |
path.simplify() | |
path.selected = true | |
// find the offset path on each side of the line | |
var outerPath = OffsetUtils.offsetPath(path, strokeRadius) | |
var innerPath = OffsetUtils.offsetPath(path, -strokeRadius) | |
innerPath.reverse() | |
// create a new path and connect the two offset paths into one shape | |
var pathShape = new Path({ | |
closed: true, | |
selectedColor: shapeSelect | |
}) | |
pathShape.addSegments(outerPath.segments) | |
pathShape.addSegments(innerPath.segments) | |
var endCaps = new CompoundPath({ | |
children: [ | |
new Path.Circle({ | |
center: path.firstSegment.point, | |
radius: strokeRadius | |
}), | |
new Path.Circle({ | |
center: path.lastSegment.point, | |
radius: strokeRadius | |
}) | |
], | |
insert: false | |
}) | |
// unite the shape with the endcaps | |
pathShape = pathShape.unite(endCaps) | |
pathShape.selected = true | |
} | |
view.update() | |
} | |
</script> | |
<script type="text/javascript" src="https://unpkg.com/paper@0.11.5/dist/paper-full.js"></script> | |
<script type="text/javascript" src="offset.js"></script> |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
/* | |
Copyright (c) 2014-2017, Jan Bösenberg & Jürg Lehni | |
Permission is hereby granted, free of charge, to any person obtaining a copy | |
of this software and associated documentation files (the "Software"), to deal | |
in the Software without restriction, including without limitation the rights | |
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
copies of the Software, and to permit persons to whom the Software is | |
furnished to do so, subject to the following conditions: | |
The above copyright notice and this permission notice shall be included in all | |
copies or substantial portions of the Software. | |
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | |
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE | |
SOFTWARE. | |
*/ | |
var OffsetUtils = { | |
offsetPath: function(path, offset, result) { | |
var outerPath = new Path({ insert: false }), | |
epsilon = Numerical.GEOMETRIC_EPSILON, | |
enforeArcs = true; | |
for (var i = 0; i < path.curves.length; i++) { | |
var curve = path.curves[i]; | |
if (curve.hasLength(epsilon)) { | |
var segments = this.getOffsetSegments(curve, offset), | |
start = segments[0]; | |
if (outerPath.isEmpty()) { | |
outerPath.addSegments(segments); | |
} else { | |
var lastCurve = outerPath.lastCurve; | |
if (!lastCurve.point2.isClose(start.point, epsilon)) { | |
if (enforeArcs || lastCurve.getTangentAtTime(1).dot(start.point.subtract(curve.point1)) >= 0) { | |
this.addRoundJoin(outerPath, start.point, curve.point1, Math.abs(offset)); | |
} else { | |
// Connect points with a line | |
outerPath.lineTo(start.point); | |
} | |
} | |
outerPath.lastSegment.handleOut = start.handleOut; | |
outerPath.addSegments(segments.slice(1)); | |
} | |
} | |
} | |
if (path.isClosed()) { | |
if (!outerPath.lastSegment.point.isClose(outerPath.firstSegment.point, epsilon) && (enforeArcs || | |
outerPath.lastCurve.getTangentAtTime(1).dot(outerPath.firstSegment.point.subtract(path.firstSegment.point)) >= 0)) { | |
this.addRoundJoin(outerPath, outerPath.firstSegment.point, path.firstSegment.point, Math.abs(offset)); | |
} | |
outerPath.closePath(); | |
} | |
return outerPath; | |
}, | |
/** | |
* Creates an offset for the specified curve and returns the segments of | |
* that offset path. | |
* | |
* @param {Curve} curve the curve to be offset | |
* @param {Number} offset the offset distance | |
* @returns {Segment[]} an array of segments describing the offset path | |
*/ | |
getOffsetSegments: function(curve, offset) { | |
if (curve.isStraight()) { | |
var n = curve.getNormalAtTime(0.5).multiply(offset), | |
p1 = curve.point1.add(n), | |
p2 = curve.point2.add(n); | |
return [new Segment(p1), new Segment(p2)]; | |
} else { | |
var curves = this.splitCurveForOffseting(curve), | |
segments = []; | |
for (var i = 0, l = curves.length; i < l; i++) { | |
var offsetCurves = this.getOffsetCurves(curves[i], offset, 0), | |
prevSegment; | |
for (var j = 0, m = offsetCurves.length; j < m; j++) { | |
var curve = offsetCurves[j], | |
segment = curve.segment1; | |
if (prevSegment) { | |
prevSegment.handleOut = segment.handleOut; | |
} else { | |
segments.push(segment); | |
} | |
segments.push(prevSegment = curve.segment2); | |
} | |
} | |
return segments; | |
} | |
}, | |
/** | |
* Approach for Curve Offsetting based on: | |
* "A New Shape Control and Classification for Cubic Bézier Curves" | |
* Shi-Nine Yang and Ming-Liang Huang | |
*/ | |
offsetCurve_middle: function(curve, offset) { | |
var v = curve.getValues(), | |
p1 = curve.point1.add(Curve.getNormal(v, 0).multiply(offset)), | |
p2 = curve.point2.add(Curve.getNormal(v, 1).multiply(offset)), | |
pt = Curve.getPoint(v, 0.5).add( | |
Curve.getNormal(v, 0.5).multiply(offset)), | |
t1 = Curve.getTangent(v, 0), | |
t2 = Curve.getTangent(v, 1), | |
div = t1.cross(t2) * 3 / 4, | |
d = pt.multiply(2).subtract(p1.add(p2)), | |
a = d.cross(t2) / div, | |
b = d.cross(t1) / div; | |
return new Curve(p1, t1.multiply(a), t2.multiply(-b), p2); | |
}, | |
offsetCurve_average: function(curve, offset) { | |
var v = curve.getValues(), | |
p1 = curve.point1.add(Curve.getNormal(v, 0).multiply(offset)), | |
p2 = curve.point2.add(Curve.getNormal(v, 1).multiply(offset)), | |
t = this.getAverageTangentTime(v), | |
u = 1 - t, | |
pt = Curve.getPoint(v, t).add( | |
Curve.getNormal(v, t).multiply(offset)), | |
t1 = Curve.getTangent(v, 0), | |
t2 = Curve.getTangent(v, 1), | |
div = t1.cross(t2) * 3 * t * u, | |
v = pt.subtract( | |
p1.multiply(u * u * (1 + 2 * t)).add( | |
p2.multiply(t * t * (3 - 2 * t)))), | |
a = v.cross(t2) / (div * u), | |
b = v.cross(t1) / (div * t); | |
return new Curve(p1, t1.multiply(a), t2.multiply(-b), p2); | |
}, | |
/** | |
* This algorithm simply scales the curve so its end points are at the | |
* calculated offsets of the original end points. | |
*/ | |
offsetCurve_simple: function (crv, dist) { | |
// calculate end points of offset curve | |
var p1 = crv.point1.add(crv.getNormalAtTime(0).multiply(dist)); | |
var p4 = crv.point2.add(crv.getNormalAtTime(1).multiply(dist)); | |
// get scale ratio | |
var pointDist = crv.point1.getDistance(crv.point2); | |
// TODO: Handle cases when pointDist == 0 | |
var f = p1.getDistance(p4) / pointDist; | |
if (crv.point2.subtract(crv.point1).dot(p4.subtract(p1)) < 0) { | |
f = -f; // probably more correct than connecting with line | |
} | |
// Scale handles and generate offset curve | |
return new Curve(p1, crv.handle1.multiply(f), crv.handle2.multiply(f), p4); | |
}, | |
getOffsetCurves: function(curve, offset, method) { | |
var errorThreshold = 0.01, | |
radius = Math.abs(offset), | |
offsetMethod = this['offsetCurve_' + (method || 'middle')], | |
that = this; | |
function offsetCurce(curve, curves, recursion) { | |
var offsetCurve = offsetMethod.call(that, curve, offset), | |
cv = curve.getValues(), | |
ov = offsetCurve.getValues(), | |
count = 16, | |
error = 0; | |
for (var i = 1; i < count; i++) { | |
var t = i / count, | |
p = Curve.getPoint(cv, t), | |
n = Curve.getNormal(cv, t), | |
roots = Curve.getCurveLineIntersections(ov, p.x, p.y, n.x, n.y), | |
dist = 2 * radius; | |
for (var j = 0, l = roots.length; j < l; j++) { | |
var d = Curve.getPoint(ov, roots[j]).getDistance(p); | |
if (d < dist) | |
dist = d; | |
} | |
var err = Math.abs(radius - dist); | |
if (err > error) | |
error = err; | |
} | |
if (error > errorThreshold && recursion++ < 8) { | |
if (error === radius) { | |
// console.log(cv); | |
} | |
var curve2 = curve.divideAtTime(that.getAverageTangentTime(cv)); | |
offsetCurce(curve, curves, recursion); | |
offsetCurce(curve2, curves, recursion); | |
} else { | |
curves.push(offsetCurve); | |
} | |
return curves; | |
} | |
return offsetCurce(curve, [], 0); | |
}, | |
/** | |
* Split curve into sections that can then be treated individually by an | |
* offset algorithm. | |
*/ | |
splitCurveForOffseting: function(curve) { | |
var curves = [curve.clone()], // Clone so path is not modified. | |
that = this; | |
if (curve.isStraight()) | |
return curves; | |
function splitAtRoots(index, roots) { | |
for (var i = 0, prevT, l = roots && roots.length; i < l; i++) { | |
var t = roots[i], | |
curve = curves[index].divideAtTime( | |
// Renormalize curve-time for multiple roots: | |
i ? (t - prevT) / (1 - prevT) : t); | |
prevT = t; | |
if (curve) | |
curves.splice(++index, 0, curve); | |
} | |
} | |
// Recursively splits the specified curve if the angle between the two | |
// handles is too large (we use 60° as a threshold). | |
function splitLargeAngles(index, recursion) { | |
var curve = curves[index], | |
v = curve.getValues(), | |
n1 = Curve.getNormal(v, 0), | |
n2 = Curve.getNormal(v, 1).negate(), | |
cos = n1.dot(n2); | |
if (cos > -0.5 && ++recursion < 4) { | |
curves.splice(index + 1, 0, | |
curve.divideAtTime(that.getAverageTangentTime(v))); | |
splitLargeAngles(index + 1, recursion); | |
splitLargeAngles(index, recursion); | |
} | |
} | |
// Split curves at cusps and inflection points. | |
var info = curve.classify(); | |
if (info.roots && info.type !== 'loop') { | |
splitAtRoots(0, info.roots); | |
} | |
// Split sub-curves at peaks. | |
for (var i = curves.length - 1; i >= 0; i--) { | |
splitAtRoots(i, Curve.getPeaks(curves[i].getValues())); | |
} | |
// Split sub-curves with too large angle between handles. | |
for (var i = curves.length - 1; i >= 0; i--) { | |
//splitLargeAngles(i, 0); | |
} | |
return curves; | |
}, | |
/** | |
* Returns the first curve-time where the curve has its tangent in the same | |
* direction as the average of the tangents at its beginning and end. | |
*/ | |
getAverageTangentTime: function(v) { | |
var tan = Curve.getTangent(v, 0).add(Curve.getTangent(v, 1)), | |
tx = tan.x, | |
ty = tan.y, | |
abs = Math.abs, | |
flip = abs(ty) < abs(tx), | |
s = flip ? ty / tx : tx / ty, | |
ia = flip ? 1 : 0, // the abscissa index | |
io = ia ^ 1, // the ordinate index | |
a0 = v[ia + 0], o0 = v[io + 0], | |
a1 = v[ia + 2], o1 = v[io + 2], | |
a2 = v[ia + 4], o2 = v[io + 4], | |
a3 = v[ia + 6], o3 = v[io + 6], | |
aA = -a0 + 3 * a1 - 3 * a2 + a3, | |
aB = 3 * a0 - 6 * a1 + 3 * a2, | |
aC = -3 * a0 + 3 * a1, | |
oA = -o0 + 3 * o1 - 3 * o2 + o3, | |
oB = 3 * o0 - 6 * o1 + 3 * o2, | |
oC = -3 * o0 + 3 * o1, | |
roots = [], | |
epsilon = Numerical.CURVETIME_EPSILON, | |
count = Numerical.solveQuadratic( | |
3 * (aA - s * oA), | |
2 * (aB - s * oB), | |
aC - s * oC, roots, | |
epsilon, 1 - epsilon); | |
// Fall back to 0.5, so we always have a place to split... | |
return count > 0 ? roots[0] : 0.5; | |
}, | |
addRoundJoin: function(path, dest, center, radius) { | |
// return path.lineTo(dest); | |
var middle = path.lastSegment.point.add(dest).divide(2), | |
through = center.add(middle.subtract(center).normalize(radius)); | |
path.arcTo(through, dest); | |
}, | |
}; |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment