outline stroke to stroke

Hi,

You could try this script by John Wundes:

// Divide and Dash:
// Modified from Original Divide code from SATO Hiroyuki
// 2006-06-30
// JavaScript Script for Adobe Illustrator CS
// by SATO Hiroyuki http://www.ne.jp/asahi/life/cycle/
//
// Divide and Dash attempts to build on the original divide script
// to provide a vector cuttable dashed line for laser cutting.
// 2016-06-05
// by John Wundes http://wundes.com/JS4AI/
var ver10 = version.indexOf('10') == 0;

main();

function main() {
if (documents.length < 1) return;
var sel = activeDocument.selection;
if (!(sel instanceof Array) || sel.length < 1) return;
var s = extractPathes(sel, 1);
if (s.length < 1) return;

// Settings ====================

var n = 12; // default dividing number

// =============================
// not ver.10 : input a number with a prompt box
if (!ver10) {
n = prompt("Enter dash length (in pixels)", n);
if (!n) {
return;
} else if (isNaN(n) || n < 2) {
alert("Please input a number greater than 1 with 1 byte characters.");
return;
}
n = parseInt(n);
}

var j, k, p, q;
var pnts, len, ar, redrawflg, desiredPointsForThisSegment;

for (var h = 0; h < s.length; h++) {
redrawflg = false;
pnts = [];
p = s[h].pathPoints;

for (i = 0; i < p.length; i++) {
j = parseIdx(p, i + 1);
if (j < 0) break;
if (!sideSelection(p[i], p[j])) continue;
ar = [i];
q = [p[i].anchor, p[i].rightDirection,
p[j].leftDirection, p[j].anchor
];
t4Len = getT4Len(q, 0)

// divide by how many times segment goes into length
// (this is the only modification to the original Divide, which divided segments evenly.
desiredPointsForThisSegment = t4Len / n;
len = t4Len / desiredPointsForThisSegment;
if (len <= 0) continue;
redrawflg = true;
for (k = 1; k < desiredPointsForThisSegment; k++) {
ar.push(getT4Len(q, len * k));
}
pnts.push(ar);
}
if (redrawflg) addPnts(s[h], pnts, false);
}
activeDocument.selection = sel;
}

// ----------------------------------------------
// addPnts: adds anchors to pathitem "pi"
// an example of usage:
/* var pi=activeDocument.selection[0];
var pnts = [ [0, 0.3,0.8,0.5],
[3, 0.5] ]; // [ [i, t,t,t,t...],[i, t,t..
addPnts(pi,pnts,true);
*/
function addPnts(pi, pnts, need2sort) { // target pathItem, list, need to sort the parameters
// pnts = [ [index, t,t,t,t...],[index, t,t..
// items must be ordered by index
// an item without t ([index]) is acceptable. an empty allay is not acceptable.
// an index out of bounds is acceptable. the range of t is 0 < t < 1.
var p = pi.pathPoints;
var pnts2 = [];
var adjNextLDir = 0;
var adjFirstLDir = 0;
var idx = (pi.closed && pnts[pnts.length - 1][0] == p.length - 1) ? 0 : pnts[0][0];
var ar = pnts.shift();
var nidx = ar.shift();
var j, pnt, q;
for (var i = idx; i < p.length; i++) {
pnts2.push(getDat(p[i])); //
if (adjNextLDir > 0) pnts2[pnts2.length - 1][2] = adjHanP(p[i], 0, 1 - adjNextLDir); //
if (nidx == i) {
if (ar.length > 0) {
if (need2sort) {
ar.sort();
ar = getUniq(ar); //
}
if (i == p.length - 1 && idx == 0) adjFirstLDir = ar[ar.length - 1];
pnts2[pnts2.length - 1][1] = adjHanP(p[i], 1, ar[0]),
ar.unshift(0);
ar.push(1);
nxi = parseIdx(p, i + 1); //
if (nxi < 0) break;
q = [p[i].anchor, p[i].rightDirection, p[nxi].leftDirection, p[nxi].anchor];
if (arrEq(q[0], q[1]) && arrEq(q[2], q[3])) { //
for (j = 1; j < ar.length - 1; j++) {
pnt = bezier(q, ar[j]); //
pnts2.push([pnt, pnt, pnt, PointType.CORNER]);
}
} else {
for (j = 1; j < ar.length - 1; j++) pnts2.push(getDivPnt(q, ar[j - 1], ar[j], ar[j + 1])); //
}
adjNextLDir = ar[ar.length - 2];
} else {
adjNextLDir = 0;
}
if (pnts.length > 0) {
ar = pnts.shift();
nidx = ar.shift();
}
} else {
adjNextLDir = 0;
}
}
if (adjFirstLDir > 0) pnts2[0][2] = adjHanP(p[0], 0, 1 - adjFirstLDir);
if (pnts2.length > 0) applyData2AfterIdx(p, pnts2, idx - 1); //
}
// ----------------------------------------------
function getUniq(ar) { // Array (sorted)
if (ar.length < 2) return ar;
var ar2 = [ar[0]];
var gosa = 0.01;
for (var i = 1; i < ar.length; i++) {
if (ar[i] - ar2[ar2.length - 1] > gosa) ar2[ar2.length] = ar[i];
}
return ar2;
}
// ----------------------------------------------
// returns an array for properties of a pathpoint
function getDat(p) { // pathPoint
with(p) return [anchor, rightDirection, leftDirection, pointType];
}
// ----------------------------------------------
// magnifies a handle by m
function adjHanP(p, n, m) { // p=pathpoint, n=0:leftDir, n=1:rightDir, m=magnification rate
with(p) {
var d = n == 1 ? rightDirection : leftDirection;
return [anchor[0] + (d[0] - anchor[0]) * m, anchor[1] + (d[1] - anchor[1]) * m];
}
}
// ----------------------------------------------
// returns an array for properties of a pathpoint
// that corresponds to the parameter "t1"
// q=4 points, t0-2=parameters, anc=coordinate of anchor
function getDivPnt(q, t0, t1, t2, anc) {
if (!anc) anc = bezier(q, t1);
var r = defDir(q, 1, t1, anc, (t2 - t1) / (1 - t1));
var l = defDir(q, 0, t1, anc, (t1 - t0) / t1);
return [anc, r, l, PointType.SMOOTH];
}
// ----------------------------------------------
// returns the [x, y] coordinate of the handle of the point on the bezier curve
// that corresponds to the parameter "t"
// q=4 points, t=paramter, anc=coordinate of anchor, m=magnification ratio
function defDir(q, n, t, anc, m) { // n=0:ldir, n=1:rdir
var dir = [t * (t * (q[n][0] - 2 * q[n + 1][0] + q[n + 2][0]) + 2 * (q[n + 1][0] - q[n][0])) + q[n][0],
t * (t * (q[n][1] - 2 * q[n + 1][1] + q[n + 2][1]) + 2 * (q[n + 1][1] - q[n][1])) + q[n][1]
]
return [anc[0] + (dir[0] - anc[0]) * m, anc[1] + (dir[1] - anc[1]) * m];
}
// ----------------------------------------------
// return the [x, y] coordinate on the bezier curve
// that corresponds to the paramter "t"
function bezier(q, t) {
var u = 1 - t;
return [u * u * u * q[0][0] + 3 * u * t * (u * q[1][0] + t * q[2][0]) + t * t * t * q[3][0],
u * u * u * q[0][1] + 3 * u * t * (u * q[1][1] + t * q[2][1]) + t * t * t * q[3][1]
];
}
// ----------------------------------------------
function applyData2Path(p, pnts) { // pathpoint, list
// (format:[[ anchor, rightDirection, leftDirection, poinType ],...]
if (pnts.length < 1) return;
var pt;
while (p.length > pnts.length) p[p.length - 1].remove();
for (var i in pnts) {
pt = i < p.length ? p[i] : p.add();
with(pt) {
anchor = pnts[i][0];
rightDirection = pnts[i][1];
leftDirection = pnts[i][2];
pointType = pnts[i][3];
}
}
}
// ----------------------------------------------
function applyData2AfterIdx(p, pnts, idx) { // pathpoint, list, index
if (idx == null || idx < 0) {
applyData2Path(p, pnts);
return;
}
var pt;
while (p.length - 1 > idx) p[p.length - 1].remove();
for (var i in pnts) {
pt = p.add();
with(pt) {
anchor = pnts[i][0];
rightDirection = pnts[i][1];
leftDirection = pnts[i][2];
pointType = pnts[i][3];
}
}
}

// ------------------------------------------------
// returns true, if a segment between pathpoints ps1 and ps2 is selected
function sideSelection(ps1, ps2) {
if (ps1.selected != PathPointSelection.NOSELECTION && ps1.selected != PathPointSelection.LEFTDIRECTION && ps2.selected != PathPointSelection.NOSELECTION && ps2.selected != PathPointSelection.RIGHTDIRECTION) {
return true;
}
return false;
}
// ------------------------------------------------
// if the contents of both arrays are equal, return true (lengthes must be same)
function arrEq(arr1, arr2) {
for (var i in arr1)
if (arr1[i] != arr2[i]) return false;
return true;
}

// ------------------------------------------------
// return the bezier curve parameter "t"
// at the point which the length of the bezier curve segment
// (from the point start drawing) is "len"
// when "len" is 0, return the length of whole this segment.
function getT4Len(q, len) {
var m = [q[3][0] - q[0][0] + 3 * (q[1][0] - q[2][0]),
q[0][0] - 2 * q[1][0] + q[2][0], q[1][0] - q[0][0]
];
var n = [q[3][1] - q[0][1] + 3 * (q[1][1] - q[2][1]),
q[0][1] - 2 * q[1][1] + q[2][1], q[1][1] - q[0][1]
];
var k = [m[0] * m[0] + n[0] * n[0], 4 * (m[0] * m[1] + n[0] * n[1]),
2 * ((m[0] * m[2] + n[0] * n[2]) + 2 * (m[1] * m[1] + n[1] * n[1])),
4 * (m[1] * m[2] + n[1] * n[2]), m[2] * m[2] + n[2] * n[2]
];

var fullLen = getLength(k, 1);

if (len == 0) {
return fullLen;
} else if (len < 0) {
len += fullLen;
if (len < 0) return 0;
} else if (len > fullLen) {
return 1;
}
var t, d;
var t0 = 0;
var t1 = 1;
var gosa = 0.001;
for (var h = 1; h < 30; h++) {
t = t0 + (t1 - t0) / 2;
d = len - getLength(k, t);
if (Math.abs(d) < gosa) break;
else if (d < 0) t1 = t;
else t0 = t;
}
return t;
}

// ------------------------------------------------
// return the length of bezier curve segment
// in range of parameter from 0 to "t"
// "m" and "n" are coefficients.
function getLength(k, t) {
var h = t / 64;
var hh = h * 2;
var fc = function(t, k) {
return Math.sqrt(t * (t * (t * (t * k[0] + k[1]) + k[2]) + k[3]) + k[4]) || 0
}; // ###1
var sm = (fc(0, k) - fc(t, k)) / 2;
for (var i = h; i < t; i += hh) sm += 2 * fc(i, k) + fc(i + h, k);
return sm * hh;
}

// --------------------------------------
function extractPathes(s, pp_length_limit) {
var ary = [];
for (var i = 0; i < s.length; i++) {
if (s[i].typename == "PathItem") {
if (pp_length_limit && s[i].pathPoints.length <= pp_length_limit) continue;
ary.push(s[i]);
} else if (s[i].typename == "GroupItem") {
ary = ary.concat(extractPathes(s[i].pageItems));
} else if (s[i].typename == "CompoundPathItem") {
ary = ary.concat(extractPathes(s[i].pathItems));
}
}
return ary;
}
// ----------------------------------------------
// return pathpoint's index. when the argument is out of bounds,
// fixes it if the path is closed (ex. next of last index is 0),
// or return -1 if the path is not closed.
function parseIdx(p, n) { // PathPoints, number for index
var len = p.length;
if (p.parent.closed) {
return n >= 0 ? n % len : len - Math.abs(n % len);
} else {
return (n < 0 || n > len - 1) ? -1 : n;
}
}

////// New 'Dash' code here:

var sel = activeDocument.selection;

var ps = extractPathes(sel, 1);

//capture selection as array:
var capturedSelection = [];
for (var s = ps.length - 1; s >= 0; s--) {
capturedSelection.push(ps[s]);
}

for (var cs = capturedSelection.length - 1; cs >= 0; cs--) {
var cstemp = ps[cs];
var dottedSeg = removeAlternateSegments(cstemp);

cstemp.selected = false;
cstemp.remove();
dottedSeg.selected = true;
}

function getPointArray(obj) {
return [obj[0], obj[1]];
}

function removeAlternateSegments(path) {
var pathPoints = path.selectedPathPoints;

var dashGroup = app.activeDocument.groupItems.add();
dashGroup.move(path, ElementPlacement.PLACEBEFORE);
for (var pmc = 0; pmc < pathPoints.length; pmc++) {
if (pmc % 2 !== 0 || pmc > pathPoints.length - 2) {
continue;
} else {
var dashPath = dashGroup.pathItems.add();
dashPath.filled = false;
var newPoint = dashPath.pathPoints.add();
newPoint.anchor = getPointArray(pathPoints[pmc].anchor);
newPoint.leftDirection = getPointArray(pathPoints[pmc].leftDirection);
newPoint.rightDirection = getPointArray(pathPoints[pmc].rightDirection);
newPoint.pointType = PointType.CORNER;

newPoint = dashPath.pathPoints.add();
newPoint.anchor = getPointArray(pathPoints[pmc + 1].anchor);
newPoint.leftDirection = getPointArray(pathPoints[pmc + 1].leftDirection);
newPoint.rightDirection = getPointArray(pathPoints[pmc + 1].rightDirection);
newPoint.pointType = PointType.CORNER;
}
}
return dashGroup;
}