feat(vl53l1x): Add radar screen example with OLED.

[Kaanoz-en]

Summary

Add a radar_screen.py example for the VL53L1X sensor. It displays a real-time distance bar on the SSD1327 OLED screen using the SPI bus. The closer the object, the longer and brighter the bar. The layout has been specifically adapted for a round display bezel, including a static outline frame to indicate the maximum range.

Closes #326

Changes

• Created lib/vl53l1x/examples/radar_screen.py.
• Initialized the VL53L1X sensor over I2C and the SSD1327 OLED display over SPI.
• Implemented a continuous loop mapping the distance to a horizontal bar's width (up to 80 pixels to fit the round screen) and brightness (1 to 15 grayscale levels).
• Added a minimum visibility clamp to ensure at least 1 pixel/brightness level is shown when an object is within the 1000 mm detection range.
• Added a bounding box (framebuf.rect) around the filled bar (framebuf.fill_rect) to clearly show the scale.
• Included a try...finally block to ensure the OLED screen is properly cleared when the script is interrupted.

Checklist

• ruff check passes
• python -m pytest tests/ -k mock -v passes (no mock test broken)
• Tested on hardware (if applicable)
• README updated (if adding/changing public API)
• Examples added/updated (if applicable)
• Commit messages follow <scope>: <Description.> format

[Copilot]

Pull request overview

Adds a new VL53L1X example that visualizes measured distance as a “radar/parking sensor” style bar on an SSD1327 128×128 OLED over SPI, tuned for a round bezel layout (issue #326).

Changes:

• Added radar_screen.py example wiring up VL53L1X (I2C) + SSD1327 (SPI).
• Implemented distance→bar-width and distance→brightness mapping plus a static outline frame.
• Ensured the display is cleared on exit via try...finally.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Copilot]

This loop does per-frame floating point math (ratio = 1.0 - (clamped_dist / MAX_DISTANCE_MM)), which can be relatively expensive on many MicroPython targets. Since the mapping is linear, consider using integer arithmetic (e.g., compute a proximity = MAX_DISTANCE_MM - clamped_dist and scale with //) to reduce CPU overhead and make behavior fully deterministic.

Suggested change

	# Clamp distance to maximum range to avoid negative ratios
	clamped_dist = max(0, min(distance, MAX_DISTANCE_MM))
	# Calculate ratio (1.0 = extremely close, 0.0 = MAX_DISTANCE_MM or further)
	ratio = 1.0 - (clamped_dist / MAX_DISTANCE_MM)
	# Map ratio to a maximum width of 80 pixels (to fit the round screen) and brightness (15 levels)
	bar_width = int(80 * ratio)
	brightness = int(15 * ratio)
	# Clamp distance to maximum range and compute integer proximity
	clamped_dist = max(0, min(distance, MAX_DISTANCE_MM))
	proximity = MAX_DISTANCE_MM - clamped_dist
	# Map proximity linearly to a maximum width of 80 pixels and brightness (15 levels) using integer math
	bar_width = (80 * proximity) // MAX_DISTANCE_MM
	brightness = (15 * proximity) // MAX_DISTANCE_MM

[Kaanoz-en]

This is a fantastic optimization, thank you! I completely overlooked the performance cost of floating-point operations on microcontrollers. Switching to purely integer arithmetic using // is a much smarter approach to keep the loop fast and efficient. I've applied both this and the inclusive boundary fix locally. Updating the PR now.

[nedseb]

Salut Kaan,

docstring, try/finally, commentaires propres, c'est nickel.

---

✅ Points positifs

• Docstring en début de fichier — bien retenu de la review précédente 👍
• try/finally pour nettoyer l'écran à la sortie — parfait
• Arithmétique entière pour le mapping distance→barre — bon réflexe (ou bon suivi du commentaire Copilot, dans les deux cas c'est bien)
• Outline box autour de la barre — bon choix UX, ça donne un repère visuel pour le max
• Constante MAX_DISTANCE_MM nommée et en haut — propre
• L'initialisation SPI suit exactement le pattern des autres exemples SSD1327

---

📝 À corriger

1. Commit message incomplet

Le deuxième commit fix(vl53l1x): Optimize radar math, fix boundaries ne termine pas par un point. La convention du projet est :

fix(vl53l1x): Optimize radar math and fix boundaries.

Le commitlint CI n'a pas bloqué ici parce qu'il vérifie le header-max-length et le type-enum mais pas le point final (subject-full-stop est désactivé dans commitlint.config.js). Cependant, la convention documentée dans CONTRIBUTING.md demande un point final. C'est bon de prendre l'habitude.

2. Commentaire un peu long (ligne 37)

# Map proximity linearly to a maximum width of 80 pixels and brightness (15 levels) using integer math

Ça dépasse la longueur de ligne recommandée (99 chars). Ruff ne le détecte pas (E501 est ignoré) mais pour la lisibilité, tu peux le couper :

# Map proximity to bar width (max 80px) and brightness (max 15)

3. Magic numbers pour le layout

Les positions 23, 69, 82, 17, 24, 70, 80, 15, 28, 35, 36, 50 sont des constantes de layout éparpillées. Pour un exemple c'est acceptable, mais si tu veux aller plus loin, tu pourrais les regrouper en haut :

BAR_X = 24
BAR_Y = 70
BAR_MAX_WIDTH = 80
BAR_HEIGHT = 15

Ce n'est pas bloquant — c'est un exemple, pas du code de production. Mais c'est un bon réflexe à développer.

4. Suggestion : afficher aussi la barre quand distance > MAX

Actuellement, si l'objet est hors portée (> 1000 mm), la barre est vide (width=0, brightness=0) mais l'outline est toujours dessinée. C'est cohérent, mais afficher "Out of range" au lieu de "1234 mm" quand distance > MAX_DISTANCE_MM rendrait l'UX plus claire. Optionnel.

[semantic-release-updater]

🎉 This PR is included in version 0.12.0 🎉

The release is available on:

• v0.12.0
• GitHub release

Your semantic-release bot 📦🚀