feat: crop save (save visible area at original resolution) v1.4.0

- Save visible area at original resolution as JPEG q90 (title bar button or Ctrl+S)
- Output name: original name + _HHmmss suffix; no overwrite, warning shown
- Active color effects baked in; rotation saves bounding box
- New: crop_save_service, l10n strings TR/EN, docs/plan-crop-save.md

lib/widgets/custom_title_bar.dart

@@ -3,9 +3,10 @@ import 'package:window_manager/window_manager.dart';
 
 class CustomTitleBar extends StatelessWidget {
   final VoidCallback? onSettings;
+  final VoidCallback? onSaveCrop;
   final bool visible;
 
-  const CustomTitleBar({super.key, this.onSettings, this.visible = true});
+  const CustomTitleBar({super.key, this.onSettings, this.onSaveCrop, this.visible = true});
 
   @override
   Widget build(BuildContext context) {
@@ -43,6 +44,11 @@ class CustomTitleBar extends StatelessWidget {
                 child: Row(
                   mainAxisSize: MainAxisSize.min,
                   children: [
+                    if (onSaveCrop != null)
+                      _BarButton(
+                        icon: Icons.save_outlined,
+                        onTap: onSaveCrop!,
+                      ),
                     _BarButton(
                       icon: Icons.horizontal_rule,
                       onTap: () => windowManager.minimize(),

lib/widgets/image_canvas.dart

@@ -10,10 +10,10 @@ class ImageCanvas extends StatefulWidget {
   final String filePath;
   const ImageCanvas({super.key, required this.filePath});
   @override
-  State<ImageCanvas> createState() => _ImageCanvasState();
+  State<ImageCanvas> createState() => ImageCanvasState();
 }
 
-class _ImageCanvasState extends State<ImageCanvas> {
+class ImageCanvasState extends State<ImageCanvas> {
   bool _isFilled = true;
   final GlobalKey _imageKey = GlobalKey();
   double _tx = 0, _ty = 0, _sc = 1.0;
@@ -314,6 +314,7 @@ class _ImageCanvasState extends State<ImageCanvas> {
   static const double _bLum = 0.0722;
 
   ColorFilter? _cachedFilter;
+  List<double>? _cachedMatrix;
   double _cachedSat = -1;
   double _cachedCon = -1;
   double _cachedBri = double.nan;
@@ -380,11 +381,60 @@ class _ImageCanvasState extends State<ImageCanvas> {
     ];
 
     // M_final = M_contrast * M_brightness * M_saturation
-    _cachedFilter = ColorFilter.matrix(
-        _multiply4x5(_multiply4x5(contrastMatrix, brightnessMatrix), saturationMatrix));
+    final matrix =
+        _multiply4x5(_multiply4x5(contrastMatrix, brightnessMatrix), saturationMatrix);
+    _cachedMatrix = matrix;
+    _cachedFilter = ColorFilter.matrix(matrix);
     return _cachedFilter!;
   }
 
+  /// Aktif renk matrisi (4x5 row-major); identity ise null.
+  /// CropSaveService'e aynen taşınır (aynı alan/semantik: 0-255).
+  List<double>? get activeColorMatrix {
+    if (_saturation == 1.0 && _contrast == 1.0 && _brightness == 0.0) return null;
+    _buildCombinedFilter();
+    return _cachedMatrix;
+  }
+
+  /// Viewport'un görünen bölgesini kaynak (tam çözünürlük) uzayına eşler.
+  /// [w]x[h] = gerçek dosya boyutu. Degrade durumda null.
+  Rect? cropSourceRect(int w, int h) {
+    if (_vpSize.width <= 0 || _vpSize.height <= 0 || w <= 0 || h <= 0) return null;
+    final cx = _vpSize.width / 2, cy = _vpSize.height / 2;
+    final rad = -_angle * math.pi / 180;
+    final cos = math.cos(rad), sin = math.sin(rad);
+
+    Offset toSrc(Offset p) {
+      final double qx = (p.dx - _tx) / _sc, qy = (p.dy - _ty) / _sc;
+      final double rx = (_angle == 0) ? qx : (cos * (qx - cx) - sin * (qy - cy) + cx);
+      final double ry = (_angle == 0) ? qy : (sin * (qx - cx) + cos * (qy - cy) + cy);
+      final double k = _isFilled
+          ? math.max(_vpSize.width / w, _vpSize.height / h)
+          : math.min(_vpSize.width / w, _vpSize.height / h);
+      final double ox = (_vpSize.width - w * k) / 2, oy = (_vpSize.height - h * k) / 2;
+      return Offset((rx - ox) / k, (ry - oy) / k);
+    }
+
+    final corners = [
+      toSrc(Offset.zero),
+      toSrc(Offset(_vpSize.width, 0)),
+      toSrc(Offset(_vpSize.width, _vpSize.height)),
+      toSrc(Offset(0, _vpSize.height)),
+    ];
+    double xmin = double.infinity, xmax = -double.infinity;
+    double ymin = double.infinity, ymax = -double.infinity;
+    for (final c in corners) {
+      xmin = math.min(xmin, c.dx); xmax = math.max(xmax, c.dx);
+      ymin = math.min(ymin, c.dy); ymax = math.max(ymax, c.dy);
+    }
+    return Rect.fromLTRB(
+      xmin.clamp(0.0, w.toDouble()),
+      ymin.clamp(0.0, h.toDouble()),
+      xmax.clamp(0.0, w.toDouble()),
+      ymax.clamp(0.0, h.toDouble()),
+    );
+  }
+
   FileImage? _cachedFileImage;
   ImageProvider<Object>? _cachedProvider;
   String? _cachedPath;