cornerEffects.js
Area: Geometry
Applies Rounded, Inverse Rounded, Bevel, Inset, or Fancy corner effects to selected curve points, with a pattern picker (all points, first/last, odd/even, and more). It decomposes each curve into anchors with incoming/outgoing handles, rebuilds the affected points with CurveBuilder, and writes the result back with DocumentCommand.createSetCurves. Previews live.
Source: cornerEffects.js
Example scripts
cornerEffects.js
cornerEffects.js
/*
BSD 3-Clause License
Copyright (c) 2026, Canva Pty Ltd.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
Redistributions of source code must retain the above copyright notice, this
list of conditions and the following disclaimer.
Redistributions in binary form must reproduce the above copyright notice,
this list of conditions and the following disclaimer in the documentation
and/or other materials provided with the distribution.
Neither the name of the copyright holder nor the names of its
contributors may be used to endorse or promote products derived from
this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
'use strict';
const { CompoundCommandBuilder, DocumentCommand } = require('/commands.js');
const { Dialog, DialogResult } = require('/dialog.js');
const { Document } = require('/document.js');
const { CurveBuilder, PolyCurve } = require('/geometry.js');
const { UnitType } = require('/units.js');
const CornerType = Object.freeze({ Rounded: 0, InverseRounded: 1, Bevel: 2, Inset: 3, Fancy: 4 });
const CornerNames = ["Rounded", "Inverse Rounded", "Bevel", "Inset", "Fancy"];
const Patterns = [
"all points", "first point", "last point", "second point", "third point", "fourth point",
"first two", "second and third", "last two", "first and last", "odd points", "even points"
];
function isOk(result) {
return (result?.value ?? result) == DialogResult.Ok.value;
}
function compound(cmds) {
if (cmds.length == 0)
return null;
const builder = CompoundCommandBuilder.create();
for (const cmd of cmds)
builder.addCommand(cmd);
return builder.createCommand();
}
function samePoint(a, b) {
return Math.abs(a.x - b.x) < 1e-6 && Math.abs(a.y - b.y) < 1e-6;
}
function decompose(curve) {
const bez = curve.beziers.toArray();
if (bez.length == 0)
return null;
const closed = curve.isClosed;
const wraps = closed && samePoint(bez[bez.length - 1].end, bez[0].start);
const pts = bez.map(b => ({ anchor: b.start, left: null, right: b.c1 }));
if (!wraps)
pts.push({ anchor: bez[bez.length - 1].end, left: null, right: null });
for (let i = 0; i < bez.length; ++i)
pts[(i + 1) % pts.length].left = bez[i].c2;
for (const p of pts) {
p.left ??= p.anchor;
p.right ??= p.anchor;
}
return { pts, closed };
}
function rebuild(pts, closed) {
const b = CurveBuilder.create().beginXY(pts[0].anchor.x, pts[0].anchor.y);
const segments = closed ? pts.length : pts.length - 1;
for (let i = 0; i < segments; ++i) {
const p = pts[i], q = pts[(i + 1) % pts.length];
b.addBezierXY(p.right.x, p.right.y, q.left.x, q.left.y, q.anchor.x, q.anchor.y);
}
if (closed)
b.close();
return b.createCurve();
}
function pointQualifies(index, count, closed, pattern) {
if (!closed && (index == 0 || index == count - 1))
return false;
switch (pattern) {
case "all points": return true;
case "first point": return index == 0;
case "last point": return index == count - 1;
case "second point": return index == 1;
case "third point": return index == 2;
case "fourth point": return index == 3;
case "first two": return index <= 1;
case "second and third": return index == 1 || index == 2;
case "last two": return index >= count - 2;
case "first and last": return index == 0 || index == count - 1;
case "even points": return index % 2 != 0;
case "odd points": return index % 2 == 0;
}
return false;
}
// Point at `offset` along the line from `from` toward `to`.
function towards(from, to, offset) {
const len = Math.hypot(to.x - from.x, to.y - from.y);
if (len == 0)
return { x: from.x, y: from.y };
return { x: from.x + (to.x - from.x) / len * offset, y: from.y + (to.y - from.y) / len * offset };
}
function retracted(p) {
return { anchor: p, left: p, right: p };
}
function cornerPoints(corner, next, prev, cornerType, offset) {
const p1 = towards(corner, next, offset); // on the outgoing edge
const p2 = towards(corner, prev, offset); // on the incoming edge
const z = { x: p2.x + p1.x - corner.x, y: p2.y + p1.y - corner.y };
switch (cornerType) {
case CornerType.Rounded:
return [{ anchor: p2, left: p2, right: corner }, retracted(p1)];
case CornerType.InverseRounded:
return [{ anchor: p2, left: p2, right: z }, retracted(p1)];
case CornerType.Bevel:
return [retracted(p2), retracted(p1)];
case CornerType.Inset:
return [retracted(p2), retracted(z), retracted(p1)];
case CornerType.Fancy: {
const third = 1 / 3, twoThirds = 2 / 3;
const t1 = { x: (corner.x - p2.x) * twoThirds, y: (corner.y - p2.y) * twoThirds };
const t2 = { x: (corner.x - p1.x) * twoThirds, y: (corner.y - p1.y) * twoThirds };
const d = { x: z.x + third * (p1.x - z.x), y: z.y + third * (p1.y - z.y) };
const e = { x: z.x + third * (p2.x - z.x), y: z.y + third * (p2.y - z.y) };
const f = { x: d.x + twoThirds * (corner.x - t1.x - d.x), y: d.y + twoThirds * (corner.y - t1.y - d.y) };
const g = { x: e.x + twoThirds * (corner.x - t2.x - e.x), y: e.y + twoThirds * (corner.y - t2.y - e.y) };
const h = { x: z.x + t1.x + t2.x, y: z.y + t1.y + t2.y };
return [p2, e, g, h, f, d, p1].map(retracted);
}
}
return [{ anchor: corner, left: corner, right: corner }];
}
function transformCurve(curve, opts) {
const d = decompose(curve);
if (!d)
return curve.clone();
const { pts, closed } = d;
const count = pts.length;
const out = [];
for (let i = 0; i < count; ++i) {
if (!pointQualifies(i, count, closed, opts.pattern)) {
out.push(pts[i]);
continue;
}
const next = pts[(i + 1) % count].anchor;
const prev = pts[(i + count - 1) % count].anchor;
out.push(...cornerPoints(pts[i].anchor, next, prev, opts.cornerType, opts.offset));
}
return rebuild(out, closed);
}
// Previews modify the nodes' curves, so always work from snapshots of the originals.
function createCornerCommand(sources, opts) {
const cmds = [];
for (const { node, original } of sources) {
const poly = PolyCurve.create();
for (const curve of original.curves)
poly.addCurve(transformCurve(curve, opts));
if (poly.curveCount > 0)
cmds.push(DocumentCommand.createSetCurves(node.curvesInterface, poly));
}
return compound(cmds);
}
function readOptions(dlg) {
return {
cornerType: dlg.cornerType.selectedIndex,
offset: dlg.offset.value,
pattern: Patterns[dlg.pattern.selectedIndex]
};
}
function buildDialog(doc) {
const pt = doc.dpi / 72;
const dlg = Dialog.create("Corner Effects");
const col = dlg.addColumn();
const type = col.addGroup("Corner Type");
dlg.cornerType = type.addRadioGroup("", CornerNames, CornerType.Rounded);
const opts = col.addGroup("Options");
dlg.offset = opts.addUnitValueEditor("Offset", UnitType.Pixel, doc.units, 12 * pt, 0).setNoMaxValue();
dlg.pattern = opts.addComboBox("Pattern", Patterns, 0);
return dlg;
}
function main() {
const doc = Document.current;
if (!doc) {
alert("This script requires an open document");
return;
}
const nodes = doc.selection.nodes.filter(n => n.isPolyCurveNode).toArray();
if (nodes.length == 0) {
alert("Please select one or more curve objects (convert shapes or text to curves first)");
return;
}
const sources = nodes.map(node => ({ node, original: node.polyCurve.clone() }));
const dlg = buildDialog(doc);
const update = (preview) => {
const cmd = createCornerCommand(sources, readOptions(dlg));
if (cmd)
doc.executeCommand(cmd, preview);
else
doc.clearPreviews();
};
dlg.onControlValueChangedHandler = () => update(true);
update(true);
if (isOk(dlg.runModal()))
update(false);
doc.clearPreviews();
}
module.exports.main = main;