initState method

  1. @override
void initState()
override

Called when this object is inserted into the tree.

The framework will call this method exactly once for each State object it creates.

Override this method to perform initialization that depends on the location at which this object was inserted into the tree (i.e., context) or on the widget used to configure this object (i.e., widget).

If a State's build method depends on an object that can itself change state, for example a ChangeNotifier or Stream, or some other object to which one can subscribe to receive notifications, then be sure to subscribe and unsubscribe properly in initState, didUpdateWidget, and dispose:

  • In initState, subscribe to the object.
  • In didUpdateWidget unsubscribe from the old object and subscribe to the new one if the updated widget configuration requires replacing the object.
  • In dispose, unsubscribe from the object.

You should not use BuildContext.dependOnInheritedWidgetOfExactType from this method. However, didChangeDependencies will be called immediately following this method, and BuildContext.dependOnInheritedWidgetOfExactType can be used there.

Implementations of this method should start with a call to the inherited method, as in super.initState().

Implementation

@override
void initState() {
  super.initState();

  // Initialize debouncers
  _onScaleEndDebounce = Debounce(const Duration(milliseconds: 10));
  _onScaleAllowUpdateDebounce = Debounce(const Duration(milliseconds: 1));
  _scrollHistoryDebounce = Debounce(const Duration(milliseconds: 350));

  // Initialize controllers
  _bottomBarScrollCtrl = ScrollController();
  _fakeHeroTransformConfigs = transformConfigs ?? TransformConfigs.empty();
  _interactiveCornerArea = isDesktop
      ? cropRotateEditorConfigs.desktopCornerDragArea
      : cropRotateEditorConfigs.mobileCornerDragArea;
  _desktopInteractionManager =
      CropDesktopInteractionManager(context: context);
  ServicesBinding.instance.keyboard.addHandler(_onKeyEvent);

  // Initialize image and layers
  _imageNeedDecode = mainImageSize == null;
  _imageSizeIsDecoded = !_imageNeedDecode;
  _layers = initConfigs.layers ?? [];
  _setRawLayers();

  // Initialize rotate animation
  double initAngle = transformConfigs?.angle ?? 0.0;
  rotateCtrl = AnimationController(
      duration: cropRotateEditorConfigs.animationDuration, vsync: this);
  rotateCtrl.addStatusListener((status) {
    if (status == AnimationStatus.completed) {
      if (_blockInteraction) {
        addHistory(scaleRotation: oldScaleFactor);
      }
      _blockInteraction = false;
      cropRotateEditorCallbacks?.handleRotateEnd(rotateAnimation.value);
    }
  });
  rotateAnimation =
      Tween<double>(begin: initAngle, end: initAngle).animate(rotateCtrl);

  // Initialize scale animation
  double initScale = (transformConfigs?.scaleRotation ?? 1);
  scaleCtrl = AnimationController(
      duration: cropRotateEditorConfigs.animationDuration, vsync: this);
  scaleAnimation =
      Tween<double>(begin: initScale, end: initScale).animate(scaleCtrl);

  // Initialize aspect ratio
  aspectRatio =
      cropRotateEditorConfigs.initAspectRatio ?? CropAspectRatios.custom;

  // Set pixel ratio if needed
  if (widget.initConfigs.convertToUint8List) {
    setImageInfos(activeHistory: activeHistory);
  }

  // Initialize transform configs if available
  if (transformConfigs != null && transformConfigs!.isNotEmpty) {
    rotationCount = (transformConfigs!.angle * 2 / pi).abs().toInt();
    flipX = transformConfigs!.flipX;
    flipY = transformConfigs!.flipY;
    translate = transformConfigs!.offset;
    userScaleFactor = transformConfigs!.scaleUser;
    aspectRatio = transformConfigs!.aspectRatio;
    cropRect = transformConfigs!.cropRect;
    _viewRect = transformConfigs!.cropRect;
    oldScaleFactor = transformConfigs!.scaleRotation;
    _rotationScaleFactor = oldScaleFactor;

    setInitHistory(transformConfigs!);
  }

  // Initialize fake hero settings
  enableFakeHero = initConfigs.enableFakeHero;
  _showFakeHero = enableFakeHero;

  // Perform post-frame initialization
  cropRotateEditorCallbacks?.onInit?.call();
  WidgetsBinding.instance.addPostFrameCallback((timeStamp) {
    cropRotateEditorCallbacks?.onAfterViewInit?.call();
    initialized = true;
    if (transformConfigs != null &&
        transformConfigs!.isNotEmpty &&
        transformConfigs!.aspectRatio < 0) {
      aspectRatio = transformConfigs!.cropRect.size.aspectRatio;
      calcCropRect(onlyViewRect: transformConfigs?.isEmpty == false);
      aspectRatio = -1;
    } else {
      calcCropRect(onlyViewRect: transformConfigs?.isEmpty == false);
    }

    if (!enableFakeHero) hideFakeHero();
    _updateAllStates();
    _setRawLayers();

    /// Skip one frame to ensure the image is correctly transformed
    Size? originalSize = transformConfigs?.originalSize;
    if (originalSize != null && !originalSize.isInfinite) {
      WidgetsBinding.instance.addPostFrameCallback((_) async {
        /// Fit to the screen and set duration to zero
        double oldScaleAnimationValue = scaleAnimation.value;
        scaleCtrl.duration = Duration.zero;
        calcFitToScreen();
        scaleCtrl.duration = cropRotateEditorConfigs.animationDuration;

        _setCropRectBoundings(oldScaleAnimationValue: oldScaleAnimationValue);
      });
    }
  });
}