Add KiCad nonpolarized resistor silkscreen and support _nonpolarized passive flag

src/footprinter.ts

@@ -33,6 +33,7 @@ type CommonPassiveOptionKey =
   | "ph"
   | "w"
   | "h"
+  | "nonpolarized"
   | "textbottom"
 
 export type Footprinter = {

src/helpers/passive-fn.ts

@@ -21,6 +21,11 @@ type StandardSize = {
   w_mm_min: number // body width
   courtyard_width_mm?: number
   courtyard_height_mm?: number
+  nonpolarizedSilkscreen?: {
+    line_half_length_mm?: number
+    line_y_mm?: number
+    stroke_width_mm?: number
+  }
 }
 
 // Updated footprint sizes
@@ -55,6 +60,11 @@ export const footprintSizes: StandardSize[] = [
     h_mm_min: 3.4,
     courtyard_width_mm: 5.9,
     courtyard_height_mm: 3.9,
+    nonpolarizedSilkscreen: {
+      line_half_length_mm: 1.386252,
+      line_y_mm: 1.71,
+      stroke_width_mm: 0.12,
+    },
   },
   {
     imperial: "0201",
@@ -77,6 +87,11 @@ export const footprintSizes: StandardSize[] = [
     h_mm_min: 0.64,
     courtyard_width_mm: 1.86,
     courtyard_height_mm: 0.94,
+    nonpolarizedSilkscreen: {
+      line_half_length_mm: 0.153641,
+      line_y_mm: 0.38,
+      stroke_width_mm: 0.12,
+    },
   },
   {
     imperial: "0603",
@@ -88,6 +103,11 @@ export const footprintSizes: StandardSize[] = [
     h_mm_min: 0.95,
     courtyard_width_mm: 2.96,
     courtyard_height_mm: 1.46,
+    nonpolarizedSilkscreen: {
+      line_half_length_mm: 0.237258,
+      line_y_mm: 0.5225,
+      stroke_width_mm: 0.12,
+    },
   },
   {
     imperial: "0805",
@@ -99,6 +119,11 @@ export const footprintSizes: StandardSize[] = [
     h_mm_min: 1.4,
     courtyard_width_mm: 3.36,
     courtyard_height_mm: 1.9,
+    nonpolarizedSilkscreen: {
+      line_half_length_mm: 0.227064,
+      line_y_mm: 0.735,
+      stroke_width_mm: 0.12,
+    },
   },
   {
     imperial: "1206",
@@ -110,6 +135,11 @@ export const footprintSizes: StandardSize[] = [
     h_mm_min: 1.75,
     courtyard_width_mm: 4.56,
     courtyard_height_mm: 2.26,
+    nonpolarizedSilkscreen: {
+      line_half_length_mm: 0.727064,
+      line_y_mm: 0.91,
+      stroke_width_mm: 0.12,
+    },
   },
   {
     imperial: "1210",
@@ -121,6 +151,11 @@ export const footprintSizes: StandardSize[] = [
     h_mm_min: 2.65,
     courtyard_width_mm: 4.56,
     courtyard_height_mm: 3.16,
+    nonpolarizedSilkscreen: {
+      line_half_length_mm: 0.723737,
+      line_y_mm: 1.355,
+      stroke_width_mm: 0.12,
+    },
   },
   {
     imperial: "2010",
@@ -132,6 +167,11 @@ export const footprintSizes: StandardSize[] = [
     h_mm_min: 2.65,
     courtyard_width_mm: 6.36,
     courtyard_height_mm: 3.16,
+    nonpolarizedSilkscreen: {
+      line_half_length_mm: 1.527064,
+      line_y_mm: 1.36,
+      stroke_width_mm: 0.12,
+    },
   },
   {
     imperial: "2512",
@@ -143,6 +183,11 @@ export const footprintSizes: StandardSize[] = [
     h_mm_min: 3.35,
     courtyard_width_mm: 7.66,
     courtyard_height_mm: 3.86,
+    nonpolarizedSilkscreen: {
+      line_half_length_mm: 2.177064,
+      line_y_mm: 1.71,
+      stroke_width_mm: 0.12,
+    },
   },
 ]
 
@@ -175,6 +220,7 @@ export const passive_def = base_def.extend({
   imperial: distance.optional(),
   w: length.optional(),
   h: length.optional(),
+  nonpolarized: z.boolean().optional(),
   textbottom: z.boolean().optional(),
 })
 
@@ -191,6 +237,7 @@ export const passive = (params: PassiveDef): AnyCircuitElement[] => {
     imperial,
     w,
     h,
+    nonpolarized,
     textbottom,
     string: footprintString,
   } = params
@@ -223,39 +270,42 @@ export const passive = (params: PassiveDef): AnyCircuitElement[] => {
     throw new Error("Could not determine required pad dimensions (p, pw, ph)")
   }
 
-  const lineLength = (p - pw) * 0.6
-  const lineY = ph / 2 + 0.06
   let silkscreenLines: PcbSilkscreenPath[] = []
-
-  // `res0402` uses the nonpolarized silkscreen style: two symmetric lines
-  // instead of the polarized-style 3-sided outline used to show orientation.
-  const usesNonPolarized0402ResistorSilkscreen =
+  const nonpolarizedSilkscreen =
     fn === "res" &&
-    typeof footprintString === "string" &&
-    /^res0402(?:_|$)/i.test(footprintString)
+    (nonpolarized === true ||
+      typeof footprintString !== "string" ||
+      /^res(?:\d{4}|\d{5})(?:_|$)/i.test(footprintString))
+      ? sz?.nonpolarizedSilkscreen
+      : undefined
 
-  if (usesNonPolarized0402ResistorSilkscreen) {
+  if (nonpolarizedSilkscreen?.stroke_width_mm) {
+    const {
+      line_half_length_mm = 0,
+      line_y_mm = 0,
+      stroke_width_mm,
+    } = nonpolarizedSilkscreen
     silkscreenLines = [
       {
         type: "pcb_silkscreen_path",
         layer: "top",
         pcb_component_id: "",
         route: [
-          { x: -lineLength / 2, y: lineY },
-          { x: lineLength / 2, y: lineY },
+          { x: -line_half_length_mm, y: line_y_mm },
+          { x: line_half_length_mm, y: line_y_mm },
         ],
-        stroke_width: 0.12,
+        stroke_width: stroke_width_mm,
         pcb_silkscreen_path_id: "",
       },
       {
         type: "pcb_silkscreen_path",
         layer: "top",
         pcb_component_id: "",
         route: [
-          { x: -lineLength / 2, y: -lineY },
-          { x: lineLength / 2, y: -lineY },
+          { x: -line_half_length_mm, y: -line_y_mm },
+          { x: line_half_length_mm, y: -line_y_mm },
         ],
-        stroke_width: 0.12,
+        stroke_width: stroke_width_mm,
         pcb_silkscreen_path_id: "",
       },
     ]

tests/kicad-parity/0402_nonpolarized_kicad_parity.test.ts

@@ -0,0 +1,28 @@
+import { expect, test } from "bun:test"
+import { compareFootprinterVsKicad } from "../fixtures/compareFootprinterVsKicad"
+import { convertCircuitJsonToPcbSvg } from "circuit-to-svg"
+
+test("parity/0402_nonpolarized", async () => {
+  const {
+    avgRelDiff,
+    combinedFootprintElements,
+    booleanDifferenceSvg,
+    courtyardDiffPercent,
+  } = await compareFootprinterVsKicad(
+    "0402_nonpolarized",
+    "Resistor_SMD.pretty/R_0402_1005Metric.circuit.json",
+  )
+
+  const svgContent = convertCircuitJsonToPcbSvg(combinedFootprintElements, {
+    showCourtyards: true,
+  })
+  expect(courtyardDiffPercent).toBeLessThan(5)
+  expect(svgContent).toMatchSvgSnapshot(
+    import.meta.path,
+    "0402_nonpolarized_parity",
+  )
+  expect(booleanDifferenceSvg).toMatchSvgSnapshot(
+    import.meta.path,
+    "0402_nonpolarized_parity._boolean_difference",
+  )
+}, 15_000)