fix: TTF font + last_page→feed propagation (Phase 1i smoke-test live-bugs)

[strausmann]

Bug 1: font_size wird ignoriert

Symptom (Live): Templates mit unterschiedlichen font_size rendern visuell identisch große Texte.

Root Cause: Container hat keine TrueType-Fonts installiert. ImageFont.truetype('DejaVuSans.ttf', N) schlägt fehl mit OSError('cannot open resource'). _load_font_cached fällt auf ImageFont.load_default() zurück — Pillow's Default ist eine fixe-Größe Bitmap-Font die das size-Argument ignoriert.

Fix: fonts-dejavu-core apt-Paket in der runtime-Stage des Dockerfiles installieren → /usr/share/fonts/truetype/dejavu/DejaVuSans.ttf verfügbar, Pillow findet es via Pfad-Suche.

Test: test_label_renderer_uses_truetype_font verifiziert FreeTypeFont-Typ und tatsächliche Größenskalierung (Glyphe bei size=22 muss >1.5x größer sein als bei size=10).

---

Bug 2: last_page wird weggeworfen → 22.5mm Pre-Roll überall

Symptom (Live): Multi-Label-Batch mit half_cut=True erzeugt 22.5mm Tape-Vorlauf vor jedem Label statt ~5mm Half-Cut (wie Brother iOS App).

Root Cause: ptouch-py 1.1.0 LabelPrinter.print() hat einen feed: bool = True Parameter der den Tape-Feed nach dem Print steuert. _ptouch_print in ptouch_backend.py akzeptierte last_page nicht und übergab kein feed an die ptouch-Lib → Default feed=True → voller Pre-Roll für JEDES Item im Batch.

batch_dispatch.py berechnete use_last_page korrekt (False für alle außer letztem Item), aber der Wert verschwand in PTouchBackend.print_image mit # noqa: ARG002 (unused arg) Marker.

Fix:

• _ptouch_print Signature: last_page: bool = True Parameter hinzugefügt
• _ptouch_print Body: printer.print(..., feed=last_page) übergeben
• PTouchBackend.print_image: # noqa: ARG002 entfernt, last_page=last_page durchgereicht
• TypeError-Fallback (ältere ptouch-Lib): unverändert

last_page=False (Intermediate-Item) → feed=False → ~5mm Half-Cut Trennung
last_page=True (Last-Item/Default) → feed=True → voller Tape-Feed für Trennung

---

Tests

• +1 test_label_renderer_uses_truetype_font — verifiziert FreeTypeFont + Skalierung
• +3 test_print_image_passes_last_page_false_to_ptouch, test_ptouch_print_calls_printer_with_feed_false, test_ptouch_print_calls_printer_with_feed_true_by_default
• 3 bestehende fake_print-Stubs um last_page-Parameter erweitert (hatten keinen Platz für das neue kwarg)

Gesamt: 949 passed (Baseline 945, +4 neue Tests), 5 skipped, ruff + mypy clean.

Refs Phase 1i live smoke-test bugs.

[gemini-code-assist]

Summary of Changes

Hello, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request addresses two critical bugs identified during live smoke testing. The first fix ensures consistent text rendering by providing the necessary TrueType font files in the container environment. The second fix resolves an issue where tape was being wasted due to incorrect feed settings in multi-label batches, by properly passing the 'last_page' status to the underlying printer driver.

Highlights

• Font Rendering Fix: Installed 'fonts-dejavu-core' in the Dockerfile to ensure TrueType fonts are available for Pillow, preventing a fallback to bitmap fonts that ignored font size settings.
• Tape Feed Propagation: Correctly propagated the 'last_page' parameter through the PTouch backend to the printer library, ensuring that intermediate labels in a batch use minimal tape feed (~5mm) instead of a full pre-roll (~22.5mm).
• Regression Testing: Added comprehensive unit tests to verify font scaling behavior and correct feed parameter propagation to the printer backend.

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[gemini-code-assist]

Code Review

This pull request installs the fonts-dejavu-core package in the Dockerfile to ensure that DejaVuSans.ttf is available, preventing Pillow from falling back to a fixed-size bitmap font. It also introduces a last_page parameter to the ptouch backend to control tape feed during batch printing, and adds corresponding unit tests. The feedback suggests skipping the new font-scaling test on local developer machines if the font is not installed system-wide, ensuring the local TDD workflow is not disrupted outside of Docker.

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[gemini-code-assist]

Der Test test_label_renderer_uses_truetype_font schlägt auf Entwickler-Rechnern (z. B. macOS/Windows) fehl, wenn die Schriftart DejaVuSans.ttf nicht systemweit installiert ist. Dies beeinträchtigt den lokalen TDD-Workflow außerhalb von Docker.

Um dies zu beheben, ohne die Validierung in der CI/Docker-Umgebung zu schwächen, können wir den Test überspringen (pytest.skip), falls die Schriftart fehlt, wir uns aber nicht in einer CI- oder Container-Umgebung befinden.

Suggested change

	from app.services.label_renderer import _load_font_cached
	from PIL import ImageFont
	# Cache leeren damit der Test sauber von Null startet
	_load_font_cached.cache_clear()
	font = _load_font_cached(22)
	assert isinstance(font, ImageFont.FreeTypeFont), (
	f"Erwartet FreeTypeFont (TTF), bekommen {type(font).__name__}. "
	"Stelle sicher dass fonts-dejavu-core im Dockerfile installiert ist "
	"(/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf muss existieren)."
	)
	from app.services.label_renderer import _load_font_cached
	from PIL import ImageFont
	import os
	# Cache leeren damit der Test sauber von Null startet
	_load_font_cached.cache_clear()
	font = _load_font_cached(22)
	if not isinstance(font, ImageFont.FreeTypeFont):
	is_ci_or_docker = os.path.exists("/.dockerenv") or os.environ.get("CI") == "true"
	if not is_ci_or_docker:
	pytest.skip("DejaVuSans.ttf ist lokal nicht verfügbar (außerhalb von Docker/CI übersprungen)")
	assert isinstance(font, ImageFont.FreeTypeFont), (
	f"Erwartet FreeTypeFont (TTF), bekommen {type(font).__name__}. "
	"Stelle sicher dass fonts-dejavu-core im Dockerfile installiert ist "
	"(/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf muss existieren)."
	)

[Copilot]

Pull request overview

Fixes two live “Phase 1i” regressions in the backend: (1) Pillow was silently falling back to a fixed-size bitmap font in containers (ignoring font_size), and (2) last_page was not propagated to the ptouch library, causing unintended full tape feed between batch items.

Changes:

• Install fonts-dejavu-core in the backend runtime Docker image so ImageFont.truetype("DejaVuSans.ttf", size) succeeds and font_size actually scales.
• Propagate last_page through PTouchBackend.print_image → _ptouch_print and map it to ptouch.LabelPrinter.print(feed=last_page).
• Add unit tests covering TrueType usage/scaling and last_page→feed forwarding behavior.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
backend/tests/unit/services/test_label_renderer.py	Adds a unit test ensuring a real TTF font is used and font_size affects glyph size.
backend/tests/unit/printer_backends/test_ptouch_backend.py	Updates existing stubs and adds tests verifying last_page is forwarded and translated to feed.
backend/Dockerfile	Installs fonts-dejavu-core in runtime stage to make DejaVuSans.ttf available in containers.
backend/app/printer_backends/ptouch_backend.py	Adds last_page parameter to _ptouch_print and forwards it from print_image to ptouch as feed.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.52%. Comparing base (8df1be3) to head (9507432).
⚠️ Report is 4 commits behind head on main.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #100      +/-   ##
==========================================
- Coverage   89.57%   89.52%   -0.05%     
==========================================
  Files          95       95              
  Lines        4316     4316              
  Branches      368      368              
==========================================
- Hits         3866     3864       -2     
- Misses        357      360       +3     
+ Partials       93       92       -1     

Components	Coverage Δ
Printer Backends (transport)	87.18% <ø> (ø)
Printer Models (drivers)	83.42% <ø> (ø)
Services	91.09% <ø> (-0.08%)	⬇️
REST API	85.02% <ø> (ø)
Pydantic Schemas	100.00% <ø> (ø)
Integration Plugins	100.00% <ø> (ø)

Files with missing lines	Coverage Δ
backend/app/printer_backends/ptouch_backend.py	96.82% <ø> (ø)

... and 3 files with indirect coverage changes

Flag	Coverage Δ
backend	89.52% <ø> (-0.05%)	⬇️

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