Add PCB teardrop controls and saved path width interpolation by seveibar · Pull Request #869 · tscircuit/props

seveibar · 2026-09-26T17:22:44Z

Adds trace-level teardrop controls and explicit width interpolation for saved pcbTracePaths.

Trace controls

Optional booleans pcbTeardrops, pcbTeardropStart, and pcbTeardropEnd request automatic teardrops. Explicit endpoint values override the trace-wide setting. Omitted endpoint values inherit it; omitted pcbTeardrops is disabled. No defaults are inserted by parsing and no curve shape is prescribed by these controls.

<trace from=".U1 > .pin1" to=".J1 > .pin1" pcbTeardrops pcbTeardropEnd={false} />

Saved route geometry

Wire points in pcbTracePaths accept width_interpolation_mode: "linear" | "quadratic". Each point retains its existing width; the mode controls interpolation to the next point's width. This is shared by fanout/breakout and autorouting-phase saved paths.

pcbTracePaths={[
  {
    connection: "U1.1",
    route: [
      { route_type: "wire", x: 0, y: 0, width: 0.8, layer: "top", width_interpolation_mode: "quadratic" },
      { route_type: "wire", x: 1, y: 0, width: 0.2, layer: "top" },
      { route_type: "wire", x: 3, y: 0, width: 0.2, layer: "top" },
    ],
  },
]}

Interpolation requires a distinct next wire point on the same layer. To terminate at a via, put the endpoint wire at the via coordinates. Terminal, coincident, direct-to-via, and cross-layer interpolation are rejected. Omitting the mode retains existing constant-width segment behavior, including paths with differing point widths. Distances still accept units and normalize to millimeters. No aliases or migration are required; pcbPath is unchanged.

Core implementation: tscircuit/core#4162 includes saved-route interpolation and automatic trace teardrops in a post-routing render phase.

Validation: 567 tests, TypeScript, and build pass. All four required generation scripts ran. README unchanged.

graphite-app · 2026-09-26T17:24:46Z

+test("trace paths preserve taper fields and convert widths to millimeters", () => {
+  const input: TraceProps = {
+    from: "U1.1",
+    to: "J1.1",
+    pcbPath: [taper, "J1.1"],
+    pcbPaths: [[taper, { x: 1, y: 0 }]],
+  }
+  const parsed = traceProps.parse(input)
+  const expected = { ...taper, startWidth: 0.6, endWidth: 0.2 }
+  expect(parsed.pcbPath).toEqual([expected, "J1.1"])
+  expect(parsed.pcbPaths).toEqual([[expected, { x: 1, y: 0 }]])
+})
+
+test("both profiles allow narrowing, widening and constant width", () => {
+  for (const widthInterpolationMode of ["linear", "quadratic"] as const) {
+    for (const [startWidth, endWidth] of [
+      [0.6, 0.2],
+      [0.2, 0.6],
+      [0.2, 0.2],
+    ]) {
+      const point = { x: 0, y: 0, startWidth, endWidth, widthInterpolationMode }
+      expect(pcbPathPoint.parse(point)).toEqual(point)
+    }
+  }
+})
+
+test("ordinary points and vias keep their existing output without taper defaults", () => {
+  for (const point of [
+    { x: 0, y: 0 },
+    { x: 1, y: 0, via: true, toLayer: "bottom" as const },
+  ]) {
+    expect(pcbPathPoint.parse(point)).toEqual(point)
+  }
+})
+
+test("taper fields must be supplied together and cannot belong to a via", () => {
+  for (const field of ["startWidth", "endWidth", "widthInterpolationMode"]) {
+    expect(
+      pcbPathPoint.safeParse({ ...taper, [field]: undefined }).success,
+    ).toBe(false)
+  }
+  expect(
+    pcbPathPoint.safeParse({ ...taper, via: true, toLayer: "bottom" }).success,
+  ).toBe(false)
+})
+
+test("widths must be positive and finite and profiles must be supported", () => {
+  for (const field of ["startWidth", "endWidth"]) {
+    for (const value of [0, -1, Infinity, NaN, "-1mm"]) {
+      expect(pcbPathPoint.safeParse({ ...taper, [field]: value }).success).toBe(
+        false,
+      )
+    }
+  }
+  expect(
+    pcbPathPoint.safeParse({ ...taper, widthInterpolationMode: "unsupported" })
+      .success,
+  ).toBe(false)
+})


This file contains 5 test(...) calls (lines 13, 26, 39, 48, 59), but the style guide states that a *.test.ts file may have AT MOST one test(...). The remaining tests should be split into multiple numbered files, e.g., pcb-path-taper1.test.ts, pcb-path-taper2.test.ts, pcb-path-taper3.test.ts, pcb-path-taper4.test.ts, and pcb-path-taper5.test.ts, each containing exactly one test(...) call.

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graphite-app · 2026-09-26T17:51:46Z

+import { expect, test } from "bun:test"
+import { traceProps, type TraceProps } from "lib/components/trace"
+
+test("teardrop booleans preserve explicit endpoint overrides for all connection forms", () => {
+  for (const connection of [
+    { from: "U1.1", to: "J1.1" },
+    { path: ["U1.1", "J1.1"] },
+  ]) {
+    for (const pcbTeardrops of [true, false, undefined]) {
+      for (const pcbTeardropStart of [true, false, undefined]) {
+        for (const pcbTeardropEnd of [true, false, undefined]) {
+          const input: TraceProps = {
+            ...connection,
+            pcbTeardrops,
+            pcbTeardropStart,
+            pcbTeardropEnd,
+            pcbPath: [
+              { x: 0, y: 0 },
+              { x: 1, y: 0 },
+            ],
+          }
+          const parsed = traceProps.parse(input)
+          expect(parsed.pcbTeardrops).toBe(pcbTeardrops)
+          expect(parsed.pcbTeardropStart).toBe(pcbTeardropStart)
+          expect(parsed.pcbTeardropEnd).toBe(pcbTeardropEnd)
+        }
+      }
+    }
+  }
+})
+
+test("teardrop props reject non-booleans and introduce no defaults", () => {
+  const connection = { from: "U1.1", to: "J1.1" }
+  const parsed = traceProps.parse(connection)
+  for (const prop of [
+    "pcbTeardrops",
+    "pcbTeardropStart",
+    "pcbTeardropEnd",
+  ] as const) {
+    expect(parsed).not.toHaveProperty(prop)
+    for (const value of ["yes", 1, null]) {
+      expect(
+        traceProps.safeParse({ ...connection, [prop]: value }).success,
+      ).toBe(false)
+    }
+  }
+})


This file contains two test(...) calls (one at line 4 and another at line 32), which violates the rule that a *.test.ts file may have AT MOST one test(...). Please split this into two separate numbered files, e.g. trace-teardrops1.test.ts (containing the 'teardrop booleans preserve explicit endpoint overrides for all connection forms' test) and trace-teardrops2.test.ts (containing the 'teardrop props reject non-booleans and introduce no defaults' test).

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graphite-app · 2026-09-26T18:10:49Z

+test("saved route interpolation retains modes and normalizes point widths", () => {
+  for (const schema of [breakoutProps, autoroutingPhaseProps]) {
+    for (const mode of ["linear", "quadratic"] as const) {
+      const path: FanoutTracePath = {
+        connection: "U1.1",
+        route: [
+          { ...wire, width: "800um", width_interpolation_mode: mode },
+          { ...end, width: "0.2mm", width_interpolation_mode: mode },
+          { ...wire, x: 2 },
+        ],
+      }
+      const parsed = schema.parse({ pcbTracePaths: [path] })
+      expect(parsed.pcbTracePaths?.[0]?.route).toEqual([
+        { ...wire, width_interpolation_mode: mode },
+        { ...end, width_interpolation_mode: mode },
+        { ...wire, x: 2 },
+      ])
+    }
+  }
+})
+
+test("ordinary differing widths remain unchanged and interpolation can end at a via contact", () => {
+  const route = [wire, end]
+  expect(fanoutTracePath.parse({ connection: "U1.1", route }).route).toEqual(
+    route,
+  )
+  const input = {
+    connection: "U1.1",
+    route: [
+      { ...wire, width_interpolation_mode: "quadratic" },
+      end,
+      { route_type: "via", x: 1, y: 0, from_layer: "top", to_layer: "bottom" },
+    ],
+  } as const
+  expect(fanoutTracePath.safeParse(input).success).toBe(true)
+})
+
+test("interpolation rejects terminal, coincident, via and cross-layer endpoints", () => {
+  const start = { ...wire, width_interpolation_mode: "quadratic" }
+  for (const route of [
+    [wire, { ...end, width_interpolation_mode: "quadratic" }],
+    [start, { ...end, x: 0 }],
+    [start, { ...end, layer: "bottom" }],
+    [
+      start,
+      { route_type: "via", x: 1, y: 0, from_layer: "top", to_layer: "bottom" },
+    ],
+    [{ ...start, width_interpolation_mode: "unsupported" }, end],
+  ]) {
+    expect(
+      fanoutTracePath.safeParse({ connection: "U1.1", route }).success,
+    ).toBe(false)
+  }
+})


This file contains three test(...) calls (at lines 18, 39, and 55), but the rule states that a *.test.ts file may have AT MOST one test(...). Please split this into multiple numbered files, e.g. fanout-trace-path-interpolation1.test.ts, fanout-trace-path-interpolation2.test.ts, and fanout-trace-path-interpolation3.test.ts.

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tscircuitbot · 2026-09-27T18:02:43Z

Thank you for your contribution! 🎉

PR Rating: ⭐⭐
Impact: Minor

Track your contributions and see the leaderboard at: tscircuit Contribution Tracker

Add outgoing wire taper fields to pcbPath points

5c5b30a

graphite-app Bot reviewed Sep 26, 2026

View reviewed changes

Replace path point taper fields with trace-level pcbTeardrops

603ac52

seveibar changed the title ~~Add wire taper props to pcbPath points~~ Add pcbTeardrops trace prop for automatic teardrops Sep 26, 2026

Add endpoint teardrop controls and generalize prop descriptions

a86b962

seveibar changed the title ~~Add pcbTeardrops trace prop for automatic teardrops~~ Add trace-level and endpoint PCB teardrop props Sep 26, 2026

graphite-app Bot reviewed Sep 26, 2026

View reviewed changes

seveibar added 2 commits September 26, 2026 10:57

Clarify teardrop endpoint descriptions

7d0cdee

Support outgoing width interpolation in saved PCB trace paths

50e353f

seveibar changed the title ~~Add trace-level and endpoint PCB teardrop props~~ Add PCB teardrop controls and saved path width interpolation Sep 26, 2026

graphite-app Bot reviewed Sep 26, 2026

View reviewed changes

seveibar mentioned this pull request Sep 26, 2026

Add post-routing teardrops and saved path width interpolation tscircuit/core#4162

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seveibar merged commit 4c48e5f into main Sep 26, 2026
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Add PCB teardrop controls and saved path width interpolation - #869

Add PCB teardrop controls and saved path width interpolation#869
seveibar merged 5 commits into
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feat/pcb-path-wire-tapers

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Trace controls

Saved route geometry

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seveibar commented Sep 26, 2026 •

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