Support arcs in fp_poly polygons (#162)

* Handle fp_poly arc segments

* Render filled fp_poly copper polygons

* Fix fp_poly arc sampling orientation

* Remove unused point deduplication logic

Author: techmannih

src/convert-kicad-json-to-tscircuit-soup.ts

@@ -51,6 +51,14 @@ const getAxisAlignedRectFromPoints = (
   }
 }
 
+const fpPolyHasFill = (fill?: string) => {
+  if (!fill) return false
+  const normalized = fill.toLowerCase()
+  return (
+    normalized !== "no" && normalized !== "none" && normalized !== "outline"
+  )
+}
+
 const getRotationDeg = (at: number[] | undefined) => {
   if (!at) return 0
   if (Array.isArray(at) && at.length >= 3 && typeof at[2] === "number") {
@@ -577,9 +585,52 @@ export const convertKicadJsonToTsCircuitSoup = async (
 
   if (fp_polys) {
     for (const fp_poly of fp_polys) {
-      const route = fp_poly.pts.map((p) => ({ x: p[0], y: -p[1] }))
+      const route: Array<{ x: number; y: number }> = []
+      const pushRoutePoint = (point: { x: number; y: number }) => {
+        if (!Number.isFinite(point.x) || !Number.isFinite(point.y)) {
+          return
+        }
+        route.push(point)
+      }
+      for (const segment of fp_poly.pts) {
+        if (Array.isArray(segment)) {
+          pushRoutePoint({ x: segment[0], y: -segment[1] })
+          continue
+        }
+        if (segment && typeof segment === "object" && "kind" in segment) {
+          if (segment.kind === "arc") {
+            const start = makePoint(segment.start)
+            const mid = makePoint(segment.mid)
+            const end = makePoint(segment.end)
+            const arcLength = getArcLength(start, mid, end)
+            const numPoints = Math.max(8, Math.ceil(arcLength))
+            const adjustedNumPoints = Math.max(2, Math.ceil(arcLength / 0.1))
+            const arcPoints = generateArcPath(
+              start,
+              mid,
+              end,
+              adjustedNumPoints,
+            ).map((p) => ({
+              x: p.x,
+              y: -p.y,
+            }))
+            for (const point of arcPoints) {
+              pushRoutePoint(point)
+            }
+          }
+          continue
+        }
+      }
+      const routePoints = route
+      const isClosed =
+        routePoints.length > 2 &&
+        routePoints[0]!.x === routePoints[routePoints.length - 1]!.x &&
+        routePoints[0]!.y === routePoints[routePoints.length - 1]!.y
+      const polygonPoints = isClosed ? routePoints.slice(0, -1) : routePoints
+      if (routePoints.length === 0) continue
+      const strokeWidth = fp_poly.stroke?.width ?? 0
       if (fp_poly.layer.endsWith(".Cu")) {
-        const rect = getAxisAlignedRectFromPoints(route)
+        const rect = getAxisAlignedRectFromPoints(polygonPoints)
         if (rect) {
           circuitJson.push({
             type: "pcb_smtpad",
@@ -592,14 +643,34 @@ export const convertKicadJsonToTsCircuitSoup = async (
             layer: convertKicadLayerToTscircuitLayer(fp_poly.layer)!,
             pcb_component_id,
           } as any)
-        } else {
+        } else if (fpPolyHasFill(fp_poly.fill)) {
+          if (polygonPoints.length >= 3) {
+            circuitJson.push({
+              type: "pcb_smtpad",
+              pcb_smtpad_id: `pcb_smtpad_${smtpadId++}`,
+              shape: "polygon",
+              points: polygonPoints,
+              layer: convertKicadLayerToTscircuitLayer(fp_poly.layer)!,
+              pcb_component_id,
+            } as any)
+          } else if (polygonPoints.length >= 2) {
+            circuitJson.push({
+              type: "pcb_trace",
+              pcb_trace_id: `pcb_trace_${traceId++}`,
+              pcb_component_id,
+              layer: convertKicadLayerToTscircuitLayer(fp_poly.layer)!,
+              route: polygonPoints,
+              thickness: strokeWidth,
+            } as any)
+          }
+        } else if (polygonPoints.length >= 2) {
           circuitJson.push({
             type: "pcb_trace",
             pcb_trace_id: `pcb_trace_${traceId++}`,
             pcb_component_id,
             layer: convertKicadLayerToTscircuitLayer(fp_poly.layer)!,
-            route,
-            thickness: fp_poly.stroke.width,
+            route: polygonPoints,
+            thickness: strokeWidth,
           } as any)
         }
       } else if (fp_poly.layer.endsWith(".SilkS")) {
@@ -608,17 +679,17 @@ export const convertKicadJsonToTsCircuitSoup = async (
           pcb_silkscreen_path_id: `pcb_silkscreen_path_${silkPathId++}`,
           pcb_component_id,
           layer: convertKicadLayerToTscircuitLayer(fp_poly.layer)!,
-          route,
-          stroke_width: fp_poly.stroke.width,
+          route: routePoints,
+          stroke_width: strokeWidth,
         } as any)
       } else if (fp_poly.layer.endsWith(".Fab")) {
         circuitJson.push({
           type: "pcb_fabrication_note_path",
           fabrication_note_path_id: `fabrication_note_path_${fabPathId++}`,
           pcb_component_id,
           layer: convertKicadLayerToTscircuitLayer(fp_poly.layer)!,
-          route,
-          stroke_width: fp_poly.stroke.width,
+          route: polygonPoints,
+          stroke_width: strokeWidth,
           port_hints: [],
         } as any)
       } else {

src/get-attr.ts

@@ -24,10 +24,24 @@ export const formatAttr = (val: any, attrKey: string) => {
     return effects_def.parse(effectsObj)
   }
   if (attrKey === "pts") {
-    // val is like [ [ 'xy', -1.25, -0.625 ], [ 'xy', 1.25, -0.625 ], ... ]
-    return val.map((xy_pair: any[]) =>
-      xy_pair.slice(1).map((n: any) => Number.parseFloat(n.valueOf())),
-    )
+    // val can include coordinate tuples as well as arc definitions.
+    return val.map((segment: any[]) => {
+      const segmentType = segment[0]?.valueOf?.() ?? segment[0]
+      if (segmentType === "xy") {
+        return segment.slice(1).map((n: any) => Number.parseFloat(n.valueOf()))
+      }
+      if (segmentType === "arc") {
+        const arcObj: Record<string, any> = { kind: "arc" }
+        for (const arcAttr of segment.slice(1)) {
+          const key = arcAttr[0].valueOf()
+          arcObj[key] = arcAttr
+            .slice(1)
+            .map((n: any) => Number.parseFloat(n.valueOf()))
+        }
+        return arcObj
+      }
+      return segment
+    })
   }
   if (attrKey === "stroke") {
     const strokeObj: any = {}

src/kicad-zod.ts

@@ -6,6 +6,15 @@ export const point = z.union([point2, point3])
 
 type MakeRequired<T, K extends keyof T> = Omit<T, K> & Required<Pick<T, K>>
 
+export const fp_poly_arc_segment_def = z.object({
+  kind: z.literal("arc"),
+  start: point2,
+  mid: point2,
+  end: point2,
+})
+
+export const fp_poly_point_def = z.union([point2, fp_poly_arc_segment_def])
+
 export const attributes_def = z
   .object({
     at: point,
@@ -185,7 +194,7 @@ export const fp_circle_def = z.object({
 
 export const fp_poly_def = z
   .object({
-    pts: z.array(point2),
+    pts: z.array(fp_poly_point_def),
     stroke: z
       .object({
         width: z.number(),
@@ -195,6 +204,7 @@ export const fp_poly_def = z
     width: z.number().optional(),
     layer: z.string(),
     uuid: z.string().optional(),
+    fill: z.string().optional(),
   })
   // Old kicad versions don't have "stroke"
   .transform((data) => {

src/math/arc-utils.ts

@@ -3,6 +3,22 @@ export interface Point {
   y: number
 }
 
+const TWO_PI = Math.PI * 2
+
+const normalizeAngle = (angle: number) => {
+  let result = angle % TWO_PI
+  if (result < 0) result += TWO_PI
+  return result
+}
+
+const directedAngleCCW = (start: number, target: number) => {
+  const startNorm = normalizeAngle(start)
+  let targetNorm = normalizeAngle(target)
+  let delta = targetNorm - startNorm
+  if (delta < 0) delta += TWO_PI
+  return delta
+}
+
 export function calculateCenter(start: Point, mid: Point, end: Point): Point {
   const mid1 = { x: (start.x + mid.x) / 2, y: (start.y + mid.y) / 2 }
   const mid2 = { x: (mid.x + end.x) / 2, y: (mid.y + end.y) / 2 }
@@ -30,14 +46,18 @@ export const getArcLength = (start: Point, mid: Point, end: Point) => {
   const radius = calculateRadius(center, start)
 
   const angleStart = calculateAngle(center, start)
+  const angleMid = calculateAngle(center, mid)
   const angleEnd = calculateAngle(center, end)
 
-  let angleDelta = angleEnd - angleStart
-  if (angleDelta < 0) {
-    angleDelta += 2 * Math.PI
+  const ccwToMid = directedAngleCCW(angleStart, angleMid)
+  const ccwToEnd = directedAngleCCW(angleStart, angleEnd)
+
+  let angleDelta = ccwToEnd
+  if (ccwToMid > ccwToEnd) {
+    angleDelta = ccwToEnd - TWO_PI
   }
 
-  return radius * angleDelta
+  return Math.abs(radius * angleDelta)
 }
 
 export function generateArcPath(
@@ -50,11 +70,15 @@ export function generateArcPath(
   const radius = calculateRadius(center, start)
 
   const angleStart = calculateAngle(center, start)
+  const angleMid = calculateAngle(center, mid)
   const angleEnd = calculateAngle(center, end)
 
-  let angleDelta = angleEnd - angleStart
-  if (angleDelta < 0) {
-    angleDelta += 2 * Math.PI
+  const ccwToMid = directedAngleCCW(angleStart, angleMid)
+  const ccwToEnd = directedAngleCCW(angleStart, angleEnd)
+
+  let angleDelta = ccwToEnd
+  if (ccwToMid > ccwToEnd) {
+    angleDelta = ccwToEnd - TWO_PI
   }
 
   const path: Point[] = []

src/parse-kicad-mod-to-kicad-json.ts

@@ -209,14 +209,27 @@ export const parseKicadModToKicadJson = (fileContent: string): KicadModJson => {
   for (const fp_poly_row of fp_polys_rows) {
     const pts = getAttr(fp_poly_row, "pts")
     const stroke = getAttr(fp_poly_row, "stroke")
+    const width = getAttr(fp_poly_row, "width")
     const layer = getAttr(fp_poly_row, "layer")
     const uuid = getAttr(fp_poly_row, "uuid")
-
+    const fill = getAttr(fp_poly_row, "fill")
+    let normalizedStroke = stroke
+    if (!normalizedStroke && typeof width === "number") {
+      normalizedStroke = { width, type: "solid" }
+    } else if (
+      normalizedStroke &&
+      typeof normalizedStroke === "object" &&
+      typeof width === "number" &&
+      normalizedStroke.width === undefined
+    ) {
+      normalizedStroke = { ...normalizedStroke, width }
+    }
     fp_polys.push({
       pts,
-      stroke,
+      stroke: normalizedStroke,
       layer,
       uuid,
+      fill,
     })
   }
 

tests/__snapshots__/poly.snap.svg

@@ -0,0 +1,79 @@
+(footprint "viaGrid-pacman-1"
+  (version 20241229)
+  (generator "pcbnew")
+  (generator_version "9.0")
+  (layer "F.Cu")
+  (property "Reference" "REF**"
+    (at 0 -0.5 0)
+    (unlocked yes)
+    (layer "F.SilkS")
+    (hide yes)
+    (uuid "cbfffe61-1e92-4daa-bd46-ae32e0dbad92")
+    (effects
+      (font
+        (size 0.5 0.5)
+        (thickness 0.1)
+      )
+    )
+  )
+  (property "Value" "viaGrid-pacman-1"
+    (at 0 1 0)
+    (unlocked yes)
+    (layer "F.Fab")
+    (hide yes)
+    (uuid "60d7fc8a-65be-4914-a046-de64475a184c")
+    (effects
+      (font
+        (size 0.5 0.5)
+        (thickness 0.15)
+      )
+    )
+  )
+  (property "Datasheet" ""
+    (at 0 0 0)
+    (unlocked yes)
+    (layer "F.Fab")
+    (hide yes)
+    (uuid "1143702b-768c-463c-8287-7c8084dfab91")
+    (effects
+      (font
+        (size 1 1)
+        (thickness 0.15)
+      )
+    )
+  )
+  (property "Description" ""
+    (at 0 0 0)
+    (unlocked yes)
+    (layer "F.Fab")
+    (hide yes)
+    (uuid "515226c9-0c16-4433-b704-16fa13d28a16")
+    (effects
+      (font
+        (size 1 1)
+        (thickness 0.15)
+      )
+    )
+  )
+  (attr smd)
+  (fp_poly
+    (pts
+      (xy 2.5 0.2)
+      (xy -0.2 0.2)
+      (xy -0.199996 -2.5)
+      (arc
+        (start -0.199999 -2.5)
+        (mid -1.773415 1.773415)
+        (end 2.5 0.199999)
+      )
+    )
+    (stroke
+      (width 0)
+      (type solid)
+    )
+    (fill yes)
+    (layer "F.Cu")
+    (uuid "f37eddc0-cfe3-474b-b8ab-9a4c0ef62518")
+  )
+  (embedded_fonts no)
+)