Fix Bluetooth receipt text regression and add ASCII charset

VERSION

@@ -1 +1 @@
-1.5.0
+1.5.1

pi/backend/app/escpos_render.py

@@ -8,6 +8,7 @@
 import base64
 import logging
 import os
+import unicodedata
 from collections.abc import Callable
 from contextvars import ContextVar
 from io import BytesIO
@@ -18,12 +19,13 @@
 
 log = logging.getLogger(__name__)
 
-ReceiptCharset = Literal["pc858", "pc850", "cp1252"]
+ReceiptCharset = Literal["pc858", "pc850", "cp1252", "ascii"]
 
 RECEIPT_CHARSET_PRESETS: dict[str, tuple[str, int]] = {
     "pc858": ("cp858", 19),
     "pc850": ("cp850", 2),
     "cp1252": ("cp1252", 16),
+    "ascii": ("ascii", 0),
 }
 
 _slip_charset: ContextVar[str | None] = ContextVar("slip_charset", default=None)
@@ -119,13 +121,40 @@ def build_cash_drawer_kick(command: str) -> bytes:
     return escpos_init_preamble() + kick
 
 
+def transliterate_receipt_text(text: str) -> str:
+    """Fold umlauts and accents to ASCII for printers that ignore code pages."""
+    replacements = {
+        "ä": "ae",
+        "ö": "oe",
+        "ü": "ue",
+        "Ä": "Ae",
+        "Ö": "Oe",
+        "Ü": "Ue",
+        "ß": "ss",
+    }
+    out: list[str] = []
+    for ch in str(text):
+        if ch in replacements:
+            out.append(replacements[ch])
+            continue
+        decomposed = unicodedata.normalize("NFD", ch)
+        base = "".join(c for c in decomposed if unicodedata.category(c) != "Mn")
+        out.append(base)
+    return "".join(out)
+
+
 def encode_escpos_text(text: str, *, charset: str | None = None) -> bytes:
     encoding, _ = resolve_escpos_charset(charset)
-    return str(text).encode(encoding, errors="replace")
+    payload = transliterate_receipt_text(text) if encoding == "ascii" else str(text)
+    return payload.encode(encoding, errors="replace")
 
 
-def write_escpos_text(printer: Dummy, text: str, *, newline: bool = True) -> None:
-    printer._raw(encode_escpos_text(text + ("\n" if newline else "")))
+def write_escpos_text(printer: Dummy, text: str, *, newline: bool = True, charset: str | None = None) -> None:
+    _, codepage = resolve_escpos_charset(charset)
+    body = str(text) + ("\n" if newline else "")
+    printer._raw(
+        bytes([0x1B, 0x74, codepage & 0xFF]) + encode_escpos_text(body, charset=charset)
+    )
 
 
 def finish_slip(printer: Dummy, *, feed_lines: int = 1, charset: str | None = None) -> bytes:

pi/backend/app/schemas/edge.py

@@ -19,7 +19,7 @@
 )
 
 ReceiptPaperWidth = Literal["80mm", "58mm", "53mm"]
-ReceiptCharset = Literal["pc858", "pc850", "cp1252"]
+ReceiptCharset = Literal["pc858", "pc850", "cp1252", "ascii"]
 
 
 # --- Request bodies ---

pi/backend/tests/test_escpos_encoding.py

@@ -6,11 +6,19 @@
     escpos_init_preamble,
     render_slip,
     resolve_escpos_charset,
+    transliterate_receipt_text,
     write_line,
 )
 from app.print_worker import build_escpos_station_test_slip, build_payment_receipt_text
 
 
+def _assert_esc_t_before(body: bytes, needle: bytes, *, codepage: int) -> None:
+    idx = body.find(needle)
+    assert idx >= 3, f"{needle!r} not found in slip body"
+    assert body[idx - 3 : idx - 1] == b"\x1b\x74"
+    assert body[idx - 1] == codepage
+
+
 def test_escpos_text_uses_cp858_single_byte():
     for ch in ("ä", "é", "è", "î", "ç"):
         encoded = encode_escpos_text(ch)
@@ -29,14 +37,43 @@ def test_resolve_receipt_charset_presets():
     assert resolve_escpos_charset("pc858") == ("cp858", 19)
     assert resolve_escpos_charset("pc850") == ("cp850", 2)
     assert resolve_escpos_charset("cp1252") == ("cp1252", 16)
-    assert set(RECEIPT_CHARSET_PRESETS) == {"pc858", "pc850", "cp1252"}
+    assert resolve_escpos_charset("ascii") == ("ascii", 0)
+    assert set(RECEIPT_CHARSET_PRESETS) == {"pc858", "pc850", "cp1252", "ascii"}
 
 
 def test_encode_escpos_text_honors_charset_preset():
     assert encode_escpos_text("ä", charset="pc850") == "ä".encode("cp850")
     assert encode_escpos_text("ä", charset="cp1252") == "ä".encode("cp1252")
 
 
+def test_write_escpos_text_prepends_esc_t_codepage():
+    raw = render_slip(lambda p: write_line(p, "Hello"))
+    pre = escpos_init_preamble()
+    body = raw[len(pre) :]
+    _assert_esc_t_before(body, b"Hello", codepage=19)
+
+
+def test_render_slip_esc_t_before_each_text_line():
+    def render(p):
+        write_line(p, "Line one")
+        write_line(p, "Line two")
+
+    raw = render_slip(render, charset="pc850")
+    pre = escpos_init_preamble(charset="pc850")
+    body = raw[len(pre) :]
+    _assert_esc_t_before(body, b"Line one", codepage=2)
+    _assert_esc_t_before(body, b"Line two", codepage=2)
+
+
+def test_render_slip_text_only_has_esc_t_before_text():
+    """Regression: text-only slips must still select code page before each line."""
+    raw = render_slip(lambda p: (write_line(p, "Testdruck"), write_line(p, "Danke")))
+    pre = escpos_init_preamble()
+    body = raw[len(pre) :]
+    _assert_esc_t_before(body, b"Testdruck", codepage=19)
+    _assert_esc_t_before(body, b"Danke", codepage=19)
+
+
 def test_render_slip_body_avoids_esc_t_pc437_reset():
     raw = render_slip(lambda p: write_line(p, "Größe ä"))
     pre = escpos_init_preamble()
@@ -116,6 +153,27 @@ def test_payment_receipt_test_charset_banner():
     assert "Ää Öö Üü ß  Éé Èè Îî Çç" in text
 
 
+def test_transliterate_receipt_text_german():
+    assert transliterate_receipt_text("Größe") == "Groesse"
+    assert transliterate_receipt_text("Zürich") == "Zuerich"
+    assert transliterate_receipt_text("Äpfel") == "Aepfel"
+    assert transliterate_receipt_text("Straße") == "Strasse"
+    assert transliterate_receipt_text("Crème brûlée") == "Creme brulee"
+
+
+def test_encode_escpos_text_ascii_transliterates():
+    assert encode_escpos_text("Größe", charset="ascii") == b"Groesse"
+    assert encode_escpos_text("Zürich", charset="ascii") == b"Zuerich"
+
+
+def test_render_slip_ascii_charset_transliterates():
+    raw = render_slip(lambda p: write_line(p, "Zürich"), charset="ascii")
+    pre = escpos_init_preamble(charset="ascii")
+    body = raw[len(pre) :]
+    assert b"Zuerich" in body
+    _assert_esc_t_before(body, b"Zuerich", codepage=0)
+
+
 def test_payment_receipt_charset_pc850():
     slip = build_payment_receipt_text(
         {

pi/backend/tests/test_escpos_paper_width.py

@@ -11,7 +11,11 @@ def _decode_receipt(raw: bytes) -> str:
 
 
 def _strip_esc(text: str) -> str:
-    cleaned = re.sub(r"\x1b[@-Z\\-_]|\x1b\[[0-?]*[ -/]*[@-~]", "", text)
+    cleaned = re.sub(
+        r"\x1b[@-Z\\-_]|\x1b\[[0-?]*[ -/]*[@-~]|\x1bt.",
+        "",
+        text,
+    )
     return "".join(c for c in cleaned if c.isprintable() or c in " \t\n\r")
 
 

pi/backend/tests/test_escpos_render.py

@@ -60,3 +60,9 @@ def render(p):
     raw = render_slip(render)
     assert b"After logo" in raw
     assert len(raw) > 40
+    pre = escpos_init_preamble()
+    body = raw[len(pre) :]
+    idx = body.find(b"After logo")
+    assert idx >= 3
+    assert body[idx - 3 : idx - 1] == b"\x1b\x74"
+    assert body[idx - 1] == 19

pi/backend/tests/test_print_worker_receipt_config.py

@@ -398,7 +398,11 @@ def test_payment_receipt_currency_only_on_total():
 
 def test_payment_receipt_payment_line_right_aligned():
     def strip_esc(s: str) -> str:
-        cleaned = re.sub(r"\x1b[@-Z\\-_]|\x1b\[[0-?]*[ -/]*[@-~]", "", s)
+        cleaned = re.sub(
+            r"\x1b[@-Z\\-_]|\x1b\[[0-?]*[ -/]*[@-~]|\x1bt.",
+            "",
+            s,
+        )
         return "".join(c for c in cleaned if c.isprintable() or c in " \t\n\r")
 
     raw = _payment_receipt_sample()

pi/frontend/openapi.json

@@ -4634,7 +4634,8 @@
                 "enum": [
                   "pc858",
                   "pc850",
-                  "cp1252"
+                  "cp1252",
+                  "ascii"
                 ]
               },
               {
@@ -5115,7 +5116,8 @@
                 "enum": [
                   "pc858",
                   "pc850",
-                  "cp1252"
+                  "cp1252",
+                  "ascii"
                 ]
               },
               {
@@ -5346,7 +5348,8 @@
                 "enum": [
                   "pc858",
                   "pc850",
-                  "cp1252"
+                  "cp1252",
+                  "ascii"
                 ]
               },
               {
@@ -5567,7 +5570,8 @@
                 "enum": [
                   "pc858",
                   "pc850",
-                  "cp1252"
+                  "cp1252",
+                  "ascii"
                 ]
               },
               {

pi/frontend/src/types/api.generated.ts

@@ -1664,7 +1664,7 @@ export interface components {
             /** Paper Width */
             paper_width?: ("80mm" | "58mm" | "53mm") | null;
             /** Charset */
-            charset?: ("pc858" | "pc850" | "cp1252") | null;
+            charset?: ("pc858" | "pc850" | "cp1252" | "ascii") | null;
         };
         /** PaymentReceiptEscposResponse */
         PaymentReceiptEscposResponse: {
@@ -1818,7 +1818,7 @@ export interface components {
             /** Paper Width */
             paper_width?: ("80mm" | "58mm" | "53mm") | null;
             /** Charset */
-            charset?: ("pc858" | "pc850" | "cp1252") | null;
+            charset?: ("pc858" | "pc850" | "cp1252" | "ascii") | null;
         };
         /** PrinterTestStationPrintsBody */
         PrinterTestStationPrintsBody: {
@@ -1896,7 +1896,7 @@ export interface components {
             /** Paper Width */
             paper_width?: ("80mm" | "58mm" | "53mm") | null;
             /** Charset */
-            charset?: ("pc858" | "pc850" | "cp1252") | null;
+            charset?: ("pc858" | "pc850" | "cp1252" | "ascii") | null;
         };
         /** ShiftSessionEscposResponse */
         ShiftSessionEscposResponse: {
@@ -1965,7 +1965,7 @@ export interface components {
             /** Paper Width */
             paper_width?: ("80mm" | "58mm" | "53mm") | null;
             /** Charset */
-            charset?: ("pc858" | "pc850" | "cp1252") | null;
+            charset?: ("pc858" | "pc850" | "cp1252" | "ascii") | null;
         };
         /** StationTestPrintResult */
         StationTestPrintResult: {

pi/frontend/src/utils/receiptCharset.test.ts

@@ -1,5 +1,6 @@
 import { beforeEach, describe, expect, it, vi } from 'vitest'
 import {
+  CHARSET_ASCII,
   CHARSET_PC850,
   CHARSET_PC858,
   getReceiptCharset,
@@ -32,6 +33,8 @@ describe('receiptCharset', () => {
   it('persists valid charset', () => {
     setReceiptCharset(CHARSET_PC850)
     expect(getReceiptCharset()).toBe(CHARSET_PC850)
+    setReceiptCharset(CHARSET_ASCII)
+    expect(getReceiptCharset()).toBe(CHARSET_ASCII)
   })
 
   it('falls back to pc858 for invalid values', () => {

pi/frontend/src/utils/receiptCharset.ts

@@ -5,11 +5,13 @@ export const RECEIPT_CHARSET_STORAGE_KEY = 'pi_receipt_charset'
 export const CHARSET_PC858 = 'pc858'
 export const CHARSET_PC850 = 'pc850'
 export const CHARSET_CP1252 = 'cp1252'
+export const CHARSET_ASCII = 'ascii'
 
 export const RECEIPT_CHARSET_OPTIONS = [
   { value: CHARSET_PC858, label: 'Standard (PC858)' },
   { value: CHARSET_PC850, label: 'PC850 (viele Bluetooth-Drucker)' },
   { value: CHARSET_CP1252, label: 'Windows-1252 (PC1252)' },
+  { value: CHARSET_ASCII, label: 'ASCII (ae/oe/ue)' },
 ] as const
 
 export type ReceiptCharset = (typeof RECEIPT_CHARSET_OPTIONS)[number]['value']