camera_avfoundation_frame #

The iOS implementation of the camera plugin.

This package provides low-level camera access for the iOS platform using AVFoundation, and is used internally by the camera plugin.

🚀 New Feature: Capture Preview Frame (JPEG) #

This version adds capturePreviewFrameJpeg(outputPath, { rotationDegrees, quality }) to grab a single JPEG-compressed frame from the preview stream without interrupting the camera.

• rotationDegrees (optional, int): 0 | 90 | 180 | 270 (pixel rotation, no EXIF).
• quality (optional, int): 0–100 (default 92).

✅ Use Cases #

• Fast preview snapshot capture
• Save current frame to file instantly
• Frame grab for ML/inference
• Lightweight visual logging or scanning

📸 One-time Preview Frame (YUV) #

To capture a single frame (non-streaming) in YUV format:

final CameraImageData frame = await cameraController.capturePreviewFrame();
// Access .planes, .width, .height, .format, etc.

🖼 One-time Preview Frame (JPEG) #

To capture and save a JPEG-compressed preview frame to file:

// Default: rotation 0°, quality 92
final String savedPath = await cameraController.capturePreviewFrameJpeg('/path/to/file.jpg');

// With rotation and quality
final String savedPath2 = await cameraController.capturePreviewFrameJpeg(
  '/path/to/rotated.jpg',
  rotationDegrees: 90,
  quality: 85,
);

🛠 How It Works #

• Captures the current CVPixelBuffer via AVCaptureVideoDataOutput
• Converts NV12/BGRA → CIImage, applies pixel rotation (no EXIF tags)
• Encodes JPEG via CGImageDestination (quality 0–1, mapped from 0–100)
• Capture does not interrupt preview or video recording

❗️Notes #

• capturePreviewFrameJpeg does not trigger autofocus or use shutter animations
• JPEG does not contain EXIF metadata or EXIF orientation (pixels are rotated)
• Supported formats: kCVPixelFormatType_420YpCbCr8BiPlanarFullRange (NV12), kCVPixelFormatType_32BGRA
• iOS 11+