packages/camera/camera_web/lib/src/camera.dart - mirrors/plugins - Git at Google

 // Copyright 2013 The Flutter Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 import 'dart:html' as html;
 import 'dart:ui';

 import 'package:camera_platform_interface/camera_platform_interface.dart';
 import 'package:camera_web/src/camera_service.dart';
 import 'package:camera_web/src/types/types.dart';
 import 'package:flutter/foundation.dart';

 import 'shims/dart_ui.dart' as ui;

 String _getViewType(int cameraId) => 'plugins.flutter.io/camera_$cameraId';

 /// A camera initialized from the media devices in the current window.
 /// See: https://developer.mozilla.org/en-US/docs/Web/API/MediaDevices
 ///
 /// The obtained camera stream is constrained by [options] and fetched
 /// with [CameraService.getMediaStreamForOptions].
 ///
 /// The camera stream is displayed in the [videoElement] wrapped in the
 /// [divElement] to avoid overriding the custom styles applied to
 /// the video element in [_applyDefaultVideoStyles].
 /// See: https://github.com/flutter/flutter/issues/79519
 ///
 /// The camera can be played/stopped by calling [play]/[stop]
 /// or may capture a picture by calling [takePicture].
 ///
 /// The camera zoom may be adjusted with [setZoomLevel]. The provided
 /// zoom level must be a value in the range of [getMinZoomLevel] to
 /// [getMaxZoomLevel].
 ///
 /// The [textureId] is used to register a camera view with the id
 /// defined by [_getViewType].
 class Camera {
   /// Creates a new instance of [Camera]
   /// with the given [textureId] and optional
   /// [options] and [window].
   Camera({
     required this.textureId,
     required CameraService cameraService,
     this.options = const CameraOptions(),
   }) : _cameraService = cameraService;

   // A torch mode constraint name.
   // See: https://w3c.github.io/mediacapture-image/#dom-mediatracksupportedconstraints-torch
   static const _torchModeKey = "torch";

   /// The texture id used to register the camera view.
   final int textureId;

   /// The camera options used to initialize a camera, empty by default.
   final CameraOptions options;

   /// The video element that displays the camera stream.
   /// Initialized in [initialize].
   late final html.VideoElement videoElement;

   /// The wrapping element for the [videoElement] to avoid overriding
   /// the custom styles applied in [_applyDefaultVideoStyles].
   /// Initialized in [initialize].
   late final html.DivElement divElement;

   /// The camera stream displayed in the [videoElement].
   /// Initialized in [initialize] and [play], reset in [stop].
   html.MediaStream? stream;

   /// The camera flash mode.
   @visibleForTesting
   FlashMode? flashMode;

   /// The camera service used to get the media stream for the camera.
   final CameraService _cameraService;

   /// The current browser window used to access media devices.
   @visibleForTesting
   html.Window? window = html.window;

   /// Initializes the camera stream displayed in the [videoElement].
   /// Registers the camera view with [textureId] under [_getViewType] type.
   Future<void> initialize() async {
     stream = await _cameraService.getMediaStreamForOptions(
       options,
       cameraId: textureId,
     );

     videoElement = html.VideoElement();
     _applyDefaultVideoStyles(videoElement);

     divElement = html.DivElement()
       ..style.setProperty('object-fit', 'cover')
       ..append(videoElement);

     ui.platformViewRegistry.registerViewFactory(
       _getViewType(textureId),
       (_) => divElement,
     );

     videoElement
       ..autoplay = false
       ..muted = !options.audio.enabled
       ..srcObject = stream
       ..setAttribute('playsinline', '');
   }

   /// Starts the camera stream.
   ///
   /// Initializes the camera source if the camera was previously stopped.
   Future<void> play() async {
     if (videoElement.srcObject == null) {
       stream = await _cameraService.getMediaStreamForOptions(
         options,
         cameraId: textureId,
       );
       videoElement.srcObject = stream;
     }
     await videoElement.play();
   }

   /// Pauses the camera stream on the current frame.
   void pause() async {
     videoElement.pause();
   }

   /// Stops the camera stream and resets the camera source.
   void stop() {
     final tracks = videoElement.srcObject?.getTracks();
     if (tracks != null) {
       for (final track in tracks) {
         track.stop();
       }
     }
     videoElement.srcObject = null;
     stream = null;
   }

   /// Captures a picture and returns the saved file in a JPEG format.
   ///
   /// Enables the camera flash (torch mode) for a period of taking a picture
   /// if the flash mode is either [FlashMode.auto] or [FlashMode.always].
   Future<XFile> takePicture() async {
     final shouldEnableTorchMode =
         flashMode == FlashMode.auto || flashMode == FlashMode.always;

     if (shouldEnableTorchMode) {
       _setTorchMode(enabled: true);
     }

     final videoWidth = videoElement.videoWidth;
     final videoHeight = videoElement.videoHeight;
     final canvas = html.CanvasElement(width: videoWidth, height: videoHeight);

     canvas.context2D
       ..translate(videoWidth, 0)
       ..scale(-1, 1)
       ..drawImageScaled(videoElement, 0, 0, videoWidth, videoHeight);

     final blob = await canvas.toBlob('image/jpeg');

     if (shouldEnableTorchMode) {
       _setTorchMode(enabled: false);
     }

     return XFile(html.Url.createObjectUrl(blob));
   }

   /// Returns a size of the camera video based on its first video track size.
   ///
   /// Returns [Size.zero] if the camera is missing a video track or
   /// the video track does not include the width or height setting.
   Future<Size> getVideoSize() async {
     final videoTracks = videoElement.srcObject?.getVideoTracks() ?? [];

     if (videoTracks.isEmpty) {
       return Size.zero;
     }

     final defaultVideoTrack = videoTracks.first;
     final defaultVideoTrackSettings = defaultVideoTrack.getSettings();

     final width = defaultVideoTrackSettings['width'];
     final height = defaultVideoTrackSettings['height'];

     if (width != null && height != null) {
       return Size(width, height);
     } else {
       return Size.zero;
     }
   }

   /// Sets the camera flash mode to [mode] by modifying the camera
   /// torch mode constraint.
   ///
   /// The torch mode is enabled for [FlashMode.torch] and
   /// disabled for [FlashMode.off].
   ///
   /// For [FlashMode.auto] and [FlashMode.always] the torch mode is enabled
   /// only for a period of taking a picture in [takePicture].
   ///
   /// Throws a [CameraWebException] if the torch mode is not supported
   /// or the camera has not been initialized or started.
   void setFlashMode(FlashMode mode) {
     final mediaDevices = window?.navigator.mediaDevices;
     final supportedConstraints = mediaDevices?.getSupportedConstraints();
     final torchModeSupported = supportedConstraints?[_torchModeKey] ?? false;

     if (!torchModeSupported) {
       throw CameraWebException(
         textureId,
         CameraErrorCode.torchModeNotSupported,
         'The torch mode is not supported in the current browser.',
       );
     }

     // Save the updated flash mode to be used later when taking a picture.
     flashMode = mode;

     // Enable the torch mode only if the flash mode is torch.
     _setTorchMode(enabled: mode == FlashMode.torch);
   }

   /// Sets the camera torch mode constraint to [enabled].
   ///
   /// Throws a [CameraWebException] if the torch mode is not supported
   /// or the camera has not been initialized or started.
   void _setTorchMode({required bool enabled}) {
     final videoTracks = stream?.getVideoTracks() ?? [];

     if (videoTracks.isNotEmpty) {
       final defaultVideoTrack = videoTracks.first;

       final bool canEnableTorchMode =
           defaultVideoTrack.getCapabilities()[_torchModeKey] ?? false;

       if (canEnableTorchMode) {
         defaultVideoTrack.applyConstraints({
           "advanced": [
             {
               _torchModeKey: enabled,
             }
           ]
         });
       } else {
         throw CameraWebException(
           textureId,
           CameraErrorCode.torchModeNotSupported,
           'The torch mode is not supported by the current camera.',
         );
       }
     } else {
       throw CameraWebException(
         textureId,
         CameraErrorCode.notStarted,
         'The camera has not been initialized or started.',
       );
     }
   }

   /// Returns the camera maximum zoom level.
   ///
   /// Throws a [CameraWebException] if the zoom level is not supported
   /// or the camera has not been initialized or started.
   double getMaxZoomLevel() =>
       _cameraService.getZoomLevelCapabilityForCamera(this).maximum;

   /// Returns the camera minimum zoom level.
   ///
   /// Throws a [CameraWebException] if the zoom level is not supported
   /// or the camera has not been initialized or started.
   double getMinZoomLevel() =>
       _cameraService.getZoomLevelCapabilityForCamera(this).minimum;

   /// Sets the camera zoom level to [zoom].
   ///
   /// Throws a [CameraWebException] if the zoom level is invalid,
   /// not supported or the camera has not been initialized or started.
   void setZoomLevel(double zoom) {
     final zoomLevelCapability =
         _cameraService.getZoomLevelCapabilityForCamera(this);

     if (zoom < zoomLevelCapability.minimum ||
         zoom > zoomLevelCapability.maximum) {
       throw CameraWebException(
         textureId,
         CameraErrorCode.zoomLevelInvalid,
         'The provided zoom level must be in the range of ${zoomLevelCapability.minimum} to ${zoomLevelCapability.maximum}.',
       );
     }

     zoomLevelCapability.videoTrack.applyConstraints({
       "advanced": [
         {
           ZoomLevelCapability.constraintName: zoom,
         }
       ]
     });
   }

   /// Returns the registered view type of the camera.
   String getViewType() => _getViewType(textureId);

   /// Disposes the camera by stopping the camera stream
   /// and reloading the camera source.
   void dispose() {
     /// Stop the camera stream.
     stop();

     /// Reset the [videoElement] to its initial state.
     videoElement
       ..srcObject = null
       ..load();
   }

   /// Applies default styles to the video [element].
   void _applyDefaultVideoStyles(html.VideoElement element) {
     element.style
       ..transformOrigin = 'center'
       ..pointerEvents = 'none'
       ..width = '100%'
       ..height = '100%'
       ..objectFit = 'cover'
       ..transform = 'scaleX(-1)';
   }
 }
	// Copyright 2013 The Flutter Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	import 'dart:html' as html;
	import 'dart:ui';

	import 'package:camera_platform_interface/camera_platform_interface.dart';
	import 'package:camera_web/src/camera_service.dart';
	import 'package:camera_web/src/types/types.dart';
	import 'package:flutter/foundation.dart';

	import 'shims/dart_ui.dart' as ui;

	String _getViewType(int cameraId) => 'plugins.flutter.io/camera_$cameraId';

	/// A camera initialized from the media devices in the current window.
	/// See: https://developer.mozilla.org/en-US/docs/Web/API/MediaDevices
	///
	/// The obtained camera stream is constrained by [options] and fetched
	/// with [CameraService.getMediaStreamForOptions].
	///
	/// The camera stream is displayed in the [videoElement] wrapped in the
	/// [divElement] to avoid overriding the custom styles applied to
	/// the video element in [_applyDefaultVideoStyles].
	/// See: https://github.com/flutter/flutter/issues/79519
	///
	/// The camera can be played/stopped by calling [play]/[stop]
	/// or may capture a picture by calling [takePicture].
	///
	/// The camera zoom may be adjusted with [setZoomLevel]. The provided
	/// zoom level must be a value in the range of [getMinZoomLevel] to
	/// [getMaxZoomLevel].
	///
	/// The [textureId] is used to register a camera view with the id
	/// defined by [_getViewType].
	class Camera {
	/// Creates a new instance of [Camera]
	/// with the given [textureId] and optional
	/// [options] and [window].
	Camera({
	required this.textureId,
	required CameraService cameraService,
	this.options = const CameraOptions(),
	}) : _cameraService = cameraService;

	// A torch mode constraint name.
	// See: https://w3c.github.io/mediacapture-image/#dom-mediatracksupportedconstraints-torch
	static const _torchModeKey = "torch";

	/// The texture id used to register the camera view.
	final int textureId;

	/// The camera options used to initialize a camera, empty by default.
	final CameraOptions options;

	/// The video element that displays the camera stream.
	/// Initialized in [initialize].
	late final html.VideoElement videoElement;

	/// The wrapping element for the [videoElement] to avoid overriding
	/// the custom styles applied in [_applyDefaultVideoStyles].
	/// Initialized in [initialize].
	late final html.DivElement divElement;

	/// The camera stream displayed in the [videoElement].
	/// Initialized in [initialize] and [play], reset in [stop].
	html.MediaStream? stream;

	/// The camera flash mode.
	@visibleForTesting
	FlashMode? flashMode;

	/// The camera service used to get the media stream for the camera.
	final CameraService _cameraService;

	/// The current browser window used to access media devices.
	@visibleForTesting
	html.Window? window = html.window;

	/// Initializes the camera stream displayed in the [videoElement].
	/// Registers the camera view with [textureId] under [_getViewType] type.
	Future<void> initialize() async {
	stream = await _cameraService.getMediaStreamForOptions(
	options,
	cameraId: textureId,
	);

	videoElement = html.VideoElement();
	_applyDefaultVideoStyles(videoElement);

	divElement = html.DivElement()
	..style.setProperty('object-fit', 'cover')
	..append(videoElement);

	ui.platformViewRegistry.registerViewFactory(
	_getViewType(textureId),
	(_) => divElement,
	);

	videoElement
	..autoplay = false
	..muted = !options.audio.enabled
	..srcObject = stream
	..setAttribute('playsinline', '');
	}

	/// Starts the camera stream.
	///
	/// Initializes the camera source if the camera was previously stopped.
	Future<void> play() async {
	if (videoElement.srcObject == null) {
	stream = await _cameraService.getMediaStreamForOptions(
	options,
	cameraId: textureId,
	);
	videoElement.srcObject = stream;
	}
	await videoElement.play();
	}

	/// Pauses the camera stream on the current frame.
	void pause() async {
	videoElement.pause();
	}

	/// Stops the camera stream and resets the camera source.
	void stop() {
	final tracks = videoElement.srcObject?.getTracks();
	if (tracks != null) {
	for (final track in tracks) {
	track.stop();
	}
	}
	videoElement.srcObject = null;
	stream = null;
	}

	/// Captures a picture and returns the saved file in a JPEG format.
	///
	/// Enables the camera flash (torch mode) for a period of taking a picture
	/// if the flash mode is either [FlashMode.auto] or [FlashMode.always].
	Future<XFile> takePicture() async {
	final shouldEnableTorchMode =
	flashMode == FlashMode.auto \|\| flashMode == FlashMode.always;

	if (shouldEnableTorchMode) {
	_setTorchMode(enabled: true);
	}

	final videoWidth = videoElement.videoWidth;
	final videoHeight = videoElement.videoHeight;
	final canvas = html.CanvasElement(width: videoWidth, height: videoHeight);

	canvas.context2D
	..translate(videoWidth, 0)
	..scale(-1, 1)
	..drawImageScaled(videoElement, 0, 0, videoWidth, videoHeight);

	final blob = await canvas.toBlob('image/jpeg');

	if (shouldEnableTorchMode) {
	_setTorchMode(enabled: false);
	}

	return XFile(html.Url.createObjectUrl(blob));
	}

	/// Returns a size of the camera video based on its first video track size.
	///
	/// Returns [Size.zero] if the camera is missing a video track or
	/// the video track does not include the width or height setting.
	Future<Size> getVideoSize() async {
	final videoTracks = videoElement.srcObject?.getVideoTracks() ?? [];

	if (videoTracks.isEmpty) {
	return Size.zero;
	}

	final defaultVideoTrack = videoTracks.first;
	final defaultVideoTrackSettings = defaultVideoTrack.getSettings();

	final width = defaultVideoTrackSettings['width'];
	final height = defaultVideoTrackSettings['height'];

	if (width != null && height != null) {
	return Size(width, height);
	} else {
	return Size.zero;
	}
	}

	/// Sets the camera flash mode to [mode] by modifying the camera
	/// torch mode constraint.
	///
	/// The torch mode is enabled for [FlashMode.torch] and
	/// disabled for [FlashMode.off].
	///
	/// For [FlashMode.auto] and [FlashMode.always] the torch mode is enabled
	/// only for a period of taking a picture in [takePicture].
	///
	/// Throws a [CameraWebException] if the torch mode is not supported
	/// or the camera has not been initialized or started.
	void setFlashMode(FlashMode mode) {
	final mediaDevices = window?.navigator.mediaDevices;
	final supportedConstraints = mediaDevices?.getSupportedConstraints();
	final torchModeSupported = supportedConstraints?[_torchModeKey] ?? false;

	if (!torchModeSupported) {
	throw CameraWebException(
	textureId,
	CameraErrorCode.torchModeNotSupported,
	'The torch mode is not supported in the current browser.',
	);
	}

	// Save the updated flash mode to be used later when taking a picture.
	flashMode = mode;

	// Enable the torch mode only if the flash mode is torch.
	_setTorchMode(enabled: mode == FlashMode.torch);
	}

	/// Sets the camera torch mode constraint to [enabled].
	///
	/// Throws a [CameraWebException] if the torch mode is not supported
	/// or the camera has not been initialized or started.
	void _setTorchMode({required bool enabled}) {
	final videoTracks = stream?.getVideoTracks() ?? [];

	if (videoTracks.isNotEmpty) {
	final defaultVideoTrack = videoTracks.first;

	final bool canEnableTorchMode =
	defaultVideoTrack.getCapabilities()[_torchModeKey] ?? false;

	if (canEnableTorchMode) {
	defaultVideoTrack.applyConstraints({
	"advanced": [
	{
	_torchModeKey: enabled,
	}
	]
	});
	} else {
	throw CameraWebException(
	textureId,
	CameraErrorCode.torchModeNotSupported,
	'The torch mode is not supported by the current camera.',
	);
	}
	} else {
	throw CameraWebException(
	textureId,
	CameraErrorCode.notStarted,
	'The camera has not been initialized or started.',
	);
	}
	}

	/// Returns the camera maximum zoom level.
	///
	/// Throws a [CameraWebException] if the zoom level is not supported
	/// or the camera has not been initialized or started.
	double getMaxZoomLevel() =>
	_cameraService.getZoomLevelCapabilityForCamera(this).maximum;

	/// Returns the camera minimum zoom level.
	///
	/// Throws a [CameraWebException] if the zoom level is not supported
	/// or the camera has not been initialized or started.
	double getMinZoomLevel() =>
	_cameraService.getZoomLevelCapabilityForCamera(this).minimum;

	/// Sets the camera zoom level to [zoom].
	///
	/// Throws a [CameraWebException] if the zoom level is invalid,
	/// not supported or the camera has not been initialized or started.
	void setZoomLevel(double zoom) {
	final zoomLevelCapability =
	_cameraService.getZoomLevelCapabilityForCamera(this);

	if (zoom < zoomLevelCapability.minimum \|\|
	zoom > zoomLevelCapability.maximum) {
	throw CameraWebException(
	textureId,
	CameraErrorCode.zoomLevelInvalid,
	'The provided zoom level must be in the range of ${zoomLevelCapability.minimum} to ${zoomLevelCapability.maximum}.',
	);
	}

	zoomLevelCapability.videoTrack.applyConstraints({
	"advanced": [
	{
	ZoomLevelCapability.constraintName: zoom,
	}
	]
	});
	}

	/// Returns the registered view type of the camera.
	String getViewType() => _getViewType(textureId);

	/// Disposes the camera by stopping the camera stream
	/// and reloading the camera source.
	void dispose() {
	/// Stop the camera stream.
	stop();

	/// Reset the [videoElement] to its initial state.
	videoElement
	..srcObject = null
	..load();
	}

	/// Applies default styles to the video [element].
	void _applyDefaultVideoStyles(html.VideoElement element) {
	element.style
	..transformOrigin = 'center'
	..pointerEvents = 'none'
	..width = '100%'
	..height = '100%'
	..objectFit = 'cover'
	..transform = 'scaleX(-1)';
	}
	}