imajviewer/lib/widgets/image_canvas.dart

import 'dart:io';
import 'package:flutter/material.dart';
import 'package:flutter/gestures.dart';

class ImageCanvas extends StatefulWidget {
  final String filePath;

  const ImageCanvas({super.key, required this.filePath});

  @override
  State<ImageCanvas> createState() => _ImageCanvasState();
}

class _ImageCanvasState extends State<ImageCanvas> {
  late TransformationController _controller;
  double _currentScale = 1.0;
  bool _isFilled = true; // varsayılan: ekranı doldur

  @override
  void initState() {
    super.initState();
    _controller = TransformationController();
    _controller.addListener(_onTransformChanged);
  }

  @override
  void didUpdateWidget(ImageCanvas oldWidget) {
    super.didUpdateWidget(oldWidget);
    if (oldWidget.filePath != widget.filePath) {
      _resetView();
    }
  }

  void _resetView() {
    _controller.value = Matrix4.identity();
    _currentScale = 1.0;
    _isFilled = true;
  }

  void _onTransformChanged() {
    _currentScale = _controller.value.getMaxScaleOnAxis();
  }

  void _toggleFillFit() {
    setState(() {
      _isFilled = !_isFilled;
      _controller.value = Matrix4.identity();
      _currentScale = 1.0;
    });
  }

  void _handleDoubleTap() {
    _toggleFillFit();
  }

  void _handleScroll(PointerScrollEvent event) {
    final renderBox = context.findRenderObject() as RenderBox?;
    if (renderBox == null) return;

    final localPosition = renderBox.globalToLocal(event.position);

    final delta = event.scrollDelta.dy;
    final scaleFactor = delta < 0 ? 1.1 : 1 / 1.1;

    final newScale = (_currentScale * scaleFactor).clamp(0.1, 10.0);
    if (newScale <= 0.1 || newScale >= 10.0) return;

    final actualScale = newScale / _currentScale;

    // Fare altındaki child-space noktayı hesapla
    final matrix = _controller.value;
    final tx = matrix.getTranslation().x;
    final ty = matrix.getTranslation().y;

    final childX = (localPosition.dx - tx) / _currentScale;
    final childY = (localPosition.dy - ty) / _currentScale;

    // controller * zoomAroundPoint sırasıyla uygula
    final newMatrix = Matrix4.copy(_controller.value)
      // ignore: deprecated_member_use
      ..translate(childX, childY)
      // ignore: deprecated_member_use
      ..scale(actualScale)
      // ignore: deprecated_member_use
      ..translate(-childX, -childY);

    _controller.value = newMatrix;
  }

  @override
  void dispose() {
    _controller.removeListener(_onTransformChanged);
    _controller.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return LayoutBuilder(
      builder: (context, constraints) {
        return Listener(
          onPointerSignal: (event) {
            if (event is PointerScrollEvent) {
              _handleScroll(event);
            }
          },
          child: GestureDetector(
            onDoubleTap: _handleDoubleTap,
            child: InteractiveViewer(
              transformationController: _controller,
              boundaryMargin: const EdgeInsets.all(double.infinity),
              minScale: 0.1,
              maxScale: 10.0,
              panEnabled: true,
              scaleEnabled: false,
              child: _isFilled
                  ? SizedBox.expand(
                      child: Image.file(
                        File(widget.filePath),
                        fit: BoxFit.cover,
                        filterQuality: FilterQuality.high,
                        errorBuilder: (context, error, stackTrace) {
                          return const Center(
                            child: Column(
                              mainAxisSize: MainAxisSize.min,
                              children: [
                                Icon(Icons.broken_image, size: 48, color: Colors.white38),
                                SizedBox(height: 8),
                                Text('Resim yüklenemedi',
                                    style: TextStyle(color: Colors.white38)),
                              ],
                            ),
                          );
                        },
                      ),
                    )
                  : Center(
                      child: Image.file(
                        File(widget.filePath),
                        fit: BoxFit.contain,
                        filterQuality: FilterQuality.high,
                        errorBuilder: (context, error, stackTrace) {
                          return const Center(
                            child: Column(
                              mainAxisSize: MainAxisSize.min,
                              children: [
                                Icon(Icons.broken_image, size: 48, color: Colors.white38),
                                SizedBox(height: 8),
                                Text('Resim yüklenemedi',
                                    style: TextStyle(color: Colors.white38)),
                              ],
                            ),
                          );
                        },
                      ),
                    ),
            ),
          ),
        );
      },
    );
  }
}