fix(zpl): UPC-A and UPC-E render the mandatory check digit

Pre-existing bug surfaced during the rotation refactor review:
- `^BU` (UPC-A) was emitted with the 5th parameter (printCheckDigit)
  hardcoded to `N`. Zebra's own default is `Y`; with `N` the printer
  omits the check digit from the HRI line. Industry retail UPC-A
  always shows it floated right of the bars, mirror of the system
  digit on the left.
- `^B9` (UPC-E) likewise hardcoded the 4th parameter to `N`. Same
  fix: switch to `Y` to match Zebra/Labelary default and the print
  convention. The canvas overlay already had `trail()` wired for
  UPC-E, so the visual side needed no change for it.
- UPC-A canvas overlay (`eanUpcDigitNodes.tsx`) now renders the
  trailing check digit (slice[11]) symmetric to UPC-E's trail node,
  with `clipRight` extended so the floated digit stays visible past
  the bar bbox. Stale comment claiming Labelary suppresses the
  digit was wrong — Labelary suppressed it only because we asked it
  to via the hardcoded `N`.

Labelary fixtures regenerated with the new ZPL; sync test fixtures
updated accordingly.

No new prop introduced — UPC-A/E HRI is a fixed retail format, the
check digit isn't an opt-in display setting.

Author: u8array

src/components/Canvas/eanUpcDigitNodes.tsx

@@ -81,13 +81,18 @@ export function buildEanUpcDigitOverlay(args: BuildArgs): EanUpcDigitOverlay {
         ],
       };
     case "upca":
+      // UPC-A HRI: number system (1) | 5 manuf | 5 product | check (1).
+      // System digit floats left of the bars, check digit floats right —
+      // matches Zebra's ^BU default (checkDigit=Y) which the generator
+      // now emits.
       return {
         clipLeft: ldW,
-        clipRight: 0,
+        clipRight: ldW,
         nodes: [
           sys(displayText[0] ?? ""),
           main("left", xLeft, halfW, displayText.slice(1, 6)),
           main("right", xRight, halfW, displayText.slice(6, 11)),
+          trail(displayText[11] ?? ""),
         ],
       };
     case "upce":

src/registry/upca.tsx

@@ -12,7 +12,12 @@ export const upca = createBarcode1D({
   contentSpec: { charset: '0-9', maxLength: 11 },
   zplCommand: (p) => {
     const interp = p.printInterpretation ? 'Y' : 'N';
-    return `^BU${p.rotation},${p.height},${interp},N,N`;
+    // ^BU params: rotation, height, interpretation, above, checkDigit.
+    // checkDigit=Y matches Zebra's own default (we previously forced N
+    // and the HRI line dropped the 12th digit) and the retail/UPC-A
+    // print convention — the 12th digit floats right of the bars,
+    // analogous to the system digit on the left.
+    return `^BU${p.rotation},${p.height},${interp},N,Y`;
   },
   hri: { formatHri: formatUpcaHri },
 });

src/registry/upce.tsx

@@ -12,7 +12,10 @@ export const upce = createBarcode1D({
   contentSpec: { charset: '0-9', maxLength: 6 },
   zplCommand: (p) => {
     const interp = p.printInterpretation ? 'Y' : 'N';
-    return `^B9${p.rotation},${p.height},${interp},N`;
+    // ^B9 params: rotation, height, interpretation, checkDigit.
+    // checkDigit=Y matches Zebra's own default and the print
+    // convention — the check digit floats right of the bars.
+    return `^B9${p.rotation},${p.height},${interp},Y`;
   },
   hri: { formatHri: formatUpceHri },
 });

tests/fixtures/labelary_images/barcode_upca_standard.png

@@ -101,7 +101,7 @@
     },
     {
       "id": "barcode_upca_standard",
-      "zpl_input": "^XA^BY2^FO50,50^BUN,100,N,N,N^FD01234567890^FS^XZ",
+      "zpl_input": "^XA^BY2^FO50,50^BUN,100,N,N,Y^FD01234567890^FS^XZ",
       "expected_bounds": {
         "x": 50,
         "y": 50,
@@ -321,7 +321,7 @@
     },
     {
       "id": "barcode_upce_standard",
-      "zpl_input": "^XA^BY2^FO50,50^B9N,100,N,N^FD012345^FS^XZ",
+      "zpl_input": "^XA^BY2^FO50,50^B9N,100,N,Y^FD012345^FS^XZ",
       "expected_bounds": {
         "x": 50,
         "y": 50,

tests/fixtures/labelary_images/barcode_upce_standard.png

@@ -68,7 +68,7 @@ export const testCases: TestCase[] = [
   },
   {
     id: "barcode_upca_standard",
-    zpl_input: "^XA^BY2^FO50,50^BUN,100,N,N,N^FD01234567890^FS^XZ",
+    zpl_input: "^XA^BY2^FO50,50^BUN,100,N,N,Y^FD01234567890^FS^XZ",
     expected_bounds: { x: 50, y: 50, width: 200, height: 100 },
     image_ref: "barcode_upca_standard.png",
   },
@@ -224,7 +224,7 @@ export const testCases: TestCase[] = [
   // The ZPL roundtrip is covered by a unit test in zplGenerator.test.ts.
   {
     id: "barcode_upce_standard",
-    zpl_input: "^XA^BY2^FO50,50^B9N,100,N,N^FD012345^FS^XZ",
+    zpl_input: "^XA^BY2^FO50,50^B9N,100,N,Y^FD012345^FS^XZ",
     expected_bounds: { x: 50, y: 50, width: 102, height: 113 },
     image_ref: "barcode_upce_standard.png",
   },