pyxpo-camera

A camera preview, photos, videos and barcode scanning for pyxpo apps. The API follows expo-camera. iOS uses AVFoundation, plus Vision to scan image files. Android uses CameraX and ML Kit barcode scanning (the bundled model, no Google Play services).

pip install pyxpo-camera

[tool.pyxpo]
modules = ["camera"]

# Optional: the text of the iOS permission prompts.
[tool.pyxpo.module_options.camera]
cameraPermission = "Scan tickets."
microphonePermission = "Record sound with videos."

import pyxpo_camera as Camera
from pyxpo import Button, Text, View, component, use_ref

@component
def Scanner():
    perm, request, _ = Camera.use_camera_permissions()
    cam = use_ref(None)
    if perm is None:
        return View()
    if not perm["granted"]:
        return Button(title="Allow the camera", on_press=request)

    async def snap():
        photo = await cam.current.take_picture_async({"quality": 0.8})
        print(photo["uri"], photo["width"], photo["height"])

    return View(
        Camera.CameraView(ref=cam, facing="back", style={"flex": 1},
                          barcode_scanner_settings={"barcode_types": ["qr"]},
                          on_barcode_scanned=lambda r: print(r["type"], r["data"])),
        Button(title="Take a photo", on_press=snap),
        style={"flex": 1},
    )

CameraView

Size it with style. It has no children.

Barcode types: aztec, ean13, ean8, qr, pdf417, upc_e, datamatrix, code39, code93, itf14, codabar, code128, upc_a (BarcodeType.QR, ...). On iOS, upc_a codes are reported as ean13 with a leading 0, and codabar needs iOS 15.4.

ref.current

Functions

camelCase names work too (takePictureAsync, Camera.requestCameraPermissionsAsync).

Platforms

iOS 15+ and Android 7+ (API 24). The iOS Simulator has no camera: is_available_async() returns False and a CameraView calls on_mount_error; scan_from_url_async reads only QR codes there (Vision finds no barcodes in the Simulator). On desktop the functions raise NotSupportedError, except is_available_async(), which returns False, and a CameraView renders as an empty view.

Android adds the CAMERA and RECORD_AUDIO permissions to the app, and marks the camera as optional, so the app also installs on devices without one.