fix: hide FNC1 invocations from Code 128 text

src/barcodes/code128.rs

@@ -20,6 +20,22 @@ pub fn prepare_ucc_mode_data(content: &str) -> String {
     format!("{}{}{}", ESCAPE_FNC_1, padded, check)
 }
 
+/// Prepare field data and human-readable text for ^BC mode D (UCC/EAN mode).
+///
+/// Parentheses and spaces are retained in the interpretation line but omitted
+/// from the encoded symbol. The ZPL `>8` invocation inserts FNC1 into the
+/// symbol and is not itself printable field data.
+pub fn prepare_ean_mode_data(content: &str) -> (String, String) {
+    let fnc1 = ESCAPE_FNC_1.to_string();
+    let encoded: String = content
+        .replace(">8", &fnc1)
+        .chars()
+        .filter(|c| *c != '(' && *c != ')' && *c != ' ')
+        .collect();
+    let display = content.replace(">8", "");
+    (format!("{}{}", ESCAPE_FNC_1, encoded), display)
+}
+
 /// GS1 Mod-10 check digit calculation.
 /// Rightmost digit gets weight 3, alternating 3/1 from right to left.
 fn gs1_mod10_check(digits: &str) -> char {

src/drawers/renderer.rs

@@ -520,31 +520,29 @@ impl Renderer {
             }
             _ => {
                 // Modes U and D (UCC/EAN) automatically insert FNC1 at start per ZPL spec
-                let content_to_encode = match bc.barcode.mode {
+                let (content_to_encode, display_text) = match bc.barcode.mode {
                     BarcodeMode::Ucc => {
                         // Mode U: truncate to 19 digits, append GS1 Mod-10 check digit, prepend FNC1
-                        barcodes::code128::prepare_ucc_mode_data(content)
+                        (
+                            barcodes::code128::prepare_ucc_mode_data(content),
+                            content.clone(),
+                        )
                     }
                     BarcodeMode::Ean => {
                         // Mode D: FNC1 prepended automatically; >8 in data = embedded FNC1 separator
                         // for chaining GS1 application identifiers; parentheses and spaces stripped
-                        // from encoding but preserved in display text per ZPL spec.
-                        let fnc1 = barcodes::code128::ESCAPE_FNC_1.to_string();
-                        let for_encoding: String = content
-                            .replace(">8", &fnc1)
-                            .chars()
-                            .filter(|c| *c != '(' && *c != ')' && *c != ' ')
-                            .collect();
-                        format!("{}{}", barcodes::code128::ESCAPE_FNC_1, for_encoding)
+                        // from encoding but preserved in display text per ZPL spec. Invocation
+                        // codes affect the symbol only and must not be printed as glyphs.
+                        barcodes::code128::prepare_ean_mode_data(content)
                     }
-                    _ => content.clone(),
+                    _ => (content.clone(), content.clone()),
                 };
                 let img = barcodes::code128::encode_auto(
                     &content_to_encode,
                     bc.barcode.height,
                     bc.width,
                 )?;
-                (img, content.clone())
+                (img, display_text)
             }
         };
 

testdata/diffs/diff_report_unit.txt

@@ -19,6 +19,7 @@
 ║ barcode128_rotated             │ zpl  │    0.24% │      813x1626 │      813x1626 │ GOOD(<1%)    ║
 ║ cf_font_designator             │ zpl  │    0.38% │      813x1626 │      812x1624 │ GOOD(<1%)    ║
 ║ cf_font_no_orientation         │ zpl  │    0.43% │      813x1626 │      812x1624 │ GOOD(<1%)    ║
+║ code128_mode_d_fnc1            │ zpl  │    0.74% │      813x1626 │      812x1624 │ GOOD(<1%)    ║
 ║ cp850_hex_chars                │ zpl  │    0.56% │      813x1626 │      812x1624 │ GOOD(<1%)    ║
 ║ dhlparceluk_dhl_text           │ zpl  │    0.45% │      813x1626 │      813x1626 │ GOOD(<1%)    ║
 ║ dhlparceluk_ver                │ zpl  │    0.05% │      813x1626 │      813x1626 │ GOOD(<1%)    ║
@@ -66,5 +67,5 @@
 ║ usps_priority_mail             │ zpl  │    0.54% │      813x1626 │      813x1626 │ GOOD(<1%)    ║
 ║ usps_test_merchant             │ zpl  │    0.16% │      813x1626 │      813x1626 │ GOOD(<1%)    ║
 ╠══════════════════════════════════════════════════════════════════════════════╣
-║ Summary: 62 total │ 8 perfect │ 44 good │ 7 minor │ 3 moderate │ 0 high │ 0 skip │ 0 err
+║ Summary: 63 total │ 8 perfect │ 45 good │ 7 minor │ 3 moderate │ 0 high │ 0 skip │ 0 err
 ╚══════════════════════════════════════════════════════════════════════════════╝

testdata/unit/code128_mode_d_fnc1.zpl

@@ -0,0 +1,7 @@
+^XA
+^PW812^LL400
+^BY2,2.5,145
+^FO30,30
+^BCN,,Y,N,N,D
+^FD(91)0005886>8(10)0000410549>8(99)05^FS
+^XZ

tests/e2e_golden.rs

@@ -203,6 +203,10 @@ fn golden_barcode128_mode_d() {
     golden_zpl_with_tolerance("barcode128_mode_d", 2.0);
 }
 #[test]
+fn golden_code128_mode_d_fnc1() {
+    golden_zpl_with_tolerance("code128_mode_d_fnc1", 1.0);
+}
+#[test]
 fn golden_barcode128_mode_n() {
     golden_zpl_with_tolerance("barcode128_mode_n", 2.0);
 }

tests/unit_barcodes.rs

@@ -98,6 +98,19 @@ fn code39_empty_input_handled() {
     let _result = code39::encode("", 100, 3, 2);
 }
 
+#[test]
+fn code128_ean_mode_keeps_ai_formatting_but_hides_fnc1_invocations() {
+    let (encoded, display) = code128::prepare_ean_mode_data("(91)0005886>8(10)0000410549>8(99)05");
+    let fnc1 = code128::ESCAPE_FNC_1;
+
+    assert_eq!(
+        encoded,
+        format!("{fnc1}910005886{fnc1}100000410549{fnc1}9905")
+    );
+    assert_eq!(display, "(91)0005886(10)0000410549(99)05");
+    assert!(!display.contains(">8"));
+}
+
 // --- EAN-13 ---
 
 #[test]