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lib/pages/epub_reader/image_viewer.dart

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+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+
+class ImageViewer extends StatefulWidget {
+  final Uint8List imageData;
+  final VoidCallback onClose;
+  final Rect sourceRect;
+  final ColorScheme colorScheme;
+
+  const ImageViewer({
+    super.key,
+    required this.imageData,
+    required this.onClose,
+    required this.sourceRect,
+    required this.colorScheme,
+  });
+
+  @override
+  State<ImageViewer> createState() => _ImageViewerState();
+}
+
+class _ImageViewerState extends State<ImageViewer>
+    with SingleTickerProviderStateMixin {
+  late final AnimationController _controller;
+  late final Animation<double> _curve;
+
+  double? _imageAspectRatio;
+  bool _isLoading = true;
+  bool _isClosing = false;
+
+  final TransformationController _transformController =
+      TransformationController();
+  Rect? _dynamicCloseRect;
+
+  @override
+  void initState() {
+    super.initState();
+
+    _controller = AnimationController(
+      vsync: this,
+      duration: const Duration(milliseconds: 300),
+    );
+
+    _curve = CurvedAnimation(parent: _controller, curve: Curves.easeOutQuart);
+
+    _resolveImage();
+  }
+
+  @override
+  void dispose() {
+    _controller.dispose();
+    _transformController.dispose();
+    super.dispose();
+  }
+
+  void _resolveImage() {
+    final imageProvider = MemoryImage(widget.imageData);
+    final imageStream = imageProvider.resolve(const ImageConfiguration());
+
+    late ImageStreamListener listener;
+    listener = ImageStreamListener(
+      (ImageInfo info, bool synchronousCall) {
+        if (mounted) {
+          setState(() {
+            _imageAspectRatio = info.image.width / info.image.height;
+            _isLoading = false;
+          });
+          _triggerAnimation();
+        }
+        imageStream.removeListener(listener);
+      },
+      onError: (dynamic error, StackTrace? stackTrace) {
+        debugPrint('Error resolving image info: $error');
+        imageStream.removeListener(listener);
+        _handleLoadError();
+      },
+    );
+
+    imageStream.addListener(listener);
+  }
+
+  void _triggerAnimation() {
+    HapticFeedback.lightImpact();
+    Future.delayed(const Duration(milliseconds: 10), () {
+      if (mounted) {
+        _controller.forward();
+      }
+    });
+  }
+
+  Future<void> _handleClose() async {
+    if (_isClosing) return;
+
+    final Size screenSize = MediaQuery.of(context).size;
+    final Matrix4 matrix = _transformController.value;
+    final double scale = matrix.getMaxScaleOnAxis();
+    final translation = matrix.getTranslation();
+
+    setState(() {
+      _isClosing = true;
+      _dynamicCloseRect = Rect.fromLTWH(
+        translation.x,
+        translation.y,
+        screenSize.width * scale,
+        screenSize.height * scale,
+      );
+      _transformController.value = Matrix4.identity();
+    });
+
+    await _controller.reverse();
+
+    if (mounted) {
+      widget.onClose();
+    }
+  }
+
+  void _handleLoadError() {
+    HapticFeedback.lightImpact();
+    if (mounted) {
+      ScaffoldMessenger.of(context).showSnackBar(
+        const SnackBar(content: Text('Failed to load image')),
+      );
+      _handleClose();
+    }
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final Size screenSize = MediaQuery.of(context).size;
+    final Rect fullscreenRect = Rect.fromLTWH(
+      0,
+      0,
+      screenSize.width,
+      screenSize.height,
+    );
+    final Rect targetEndRect = _dynamicCloseRect ?? fullscreenRect;
+
+    return PopScope(
+      canPop: false,
+      onPopInvokedWithResult: (didPop, result) async {
+        if (didPop) return;
+        await _handleClose();
+      },
+      child: AnimatedBuilder(
+        animation: _controller,
+        builder: (context, child) {
+          final double t = _curve.value;
+          final Rect currentRect = Rect.lerp(
+            widget.sourceRect,
+            targetEndRect,
+            t,
+          )!;
+
+          final bool isExpanded = t == 1.0;
+          final bool canZoom = isExpanded && !_isLoading;
+
+          final double bgOpacity = 0.9 * t;
+
+          return Stack(
+            children: [
+              GestureDetector(
+                onTap: _handleClose,
+                child: Container(
+                  color: widget.colorScheme.scrim.withValues(alpha: bgOpacity),
+                ),
+              ),
+              Positioned.fromRect(
+                rect: currentRect,
+                child: GestureDetector(
+                  onTap: _handleClose,
+                  child: Container(
+                    clipBehavior: Clip.antiAlias,
+                    decoration: const BoxDecoration(
+                      color: Colors.transparent,
+                    ),
+                    child: canZoom
+                        ? _buildInteractiveViewer()
+                        : Opacity(opacity: t, child: _buildStaticImage()),
+                  ),
+                ),
+              ),
+            ],
+          );
+        },
+      ),
+    );
+  }
+
+  Widget _buildImageView(double t) {
+    if (_imageAspectRatio == null) {
+      return const SizedBox();
+    }
+    final curve = Curves.easeOutQuart.transform(t);
+    final backgroundColor = Colors.white.withValues(alpha: curve);
+
+    return Center(
+      child: AspectRatio(
+        aspectRatio: _imageAspectRatio!,
+        child: Container(
+          color: backgroundColor,
+          child: Image.memory(
+            widget.imageData,
+            fit: BoxFit.contain,
+            width: double.infinity,
+            height: double.infinity,
+          ),
+        ),
+      ),
+    );
+  }
+
+  Widget _buildInteractiveViewer() {
+    return InteractiveViewer(
+      transformationController: _transformController,
+      minScale: 0.5,
+      maxScale: 4.0,
+      child: Center(child: _buildImageView(_controller.value)),
+    );
+  }
+
+  Widget _buildStaticImage() {
+    if (_isLoading) {
+      return const SizedBox();
+    }
+    return SizedBox.expand(child: _buildImageView(_controller.value));
+  }
+}