Add docs for VecVec* operator[] (#350)

* add docs for VecVec* operator [], format code

* format code

* dart format ✅

Author: rainyl

packages/dartcv/analysis_options.yaml

@@ -39,7 +39,7 @@ analyzer:
     non_constant_identifier_names: ignore
     parameter_assignments: error
 formatter:
-  pagewidth: 110
+  page_width: 110
 
 linter:
   rules:
@@ -217,7 +217,6 @@ linter:
     - unnecessary_this
     - unnecessary_to_list_in_spreads
     - unrelated_type_equality_checks
-    - unsafe_html
     - use_build_context_synchronously
     - use_colored_box
     - use_decorated_box

packages/dartcv/lib/src/core/dmatch.dart

@@ -196,6 +196,10 @@ class VecVecDMatch extends VecUnmodifible<cvg.VecVecDMatch, VecDMatch> {
   @override
   ffi.Pointer<ffi.Void> asVoid() => ref.ptr.cast<ffi.Void>();
 
+  /// Returns a **reference**
+  ///
+  /// Note: the memory of returned [VecDMatch] is owned by this [VecVecDMatch],
+  /// explicitly call [VecDMatch.clone] if the parent [VecVecDMatch] may be disposed.
   @override
   VecDMatch operator [](int idx) =>
       VecDMatch.fromPointer(ccore.std_VecVecDMatch_get_p(ptr, idx), attach: false);

packages/dartcv/lib/src/core/point.dart

@@ -635,6 +635,10 @@ class VecVecPoint extends VecUnmodifible<cvg.VecVecPoint, VecPoint> {
   @override
   ffi.Pointer<ffi.Void> asVoid() => ref.ptr.cast<ffi.Void>();
 
+  /// Returns a **reference**
+  ///
+  /// Note: the memory of returned [VecPoint] is owned by this [VecVecPoint],
+  /// explicitly call [VecPoint.clone] if the parent [VecVecPoint] may be disposed.
   @override
   VecPoint operator [](int idx) => VecPoint.fromPointer(ccore.std_VecVecPoint_get_p(ptr, idx), attach: false);
 
@@ -711,6 +715,10 @@ class VecVecPoint2f extends VecUnmodifible<cvg.VecVecPoint2f, VecPoint2f> {
   @override
   ffi.Pointer<ffi.Void> asVoid() => ref.ptr.cast<ffi.Void>();
 
+  /// Returns a **reference**
+  ///
+  /// Note: the memory of returned [VecPoint2f] is owned by this [VecVecPoint2f],
+  /// explicitly call [VecPoint2f.clone] if the parent [VecVecPoint2f] may be disposed.
   @override
   VecPoint2f operator [](int idx) =>
       VecPoint2f.fromPointer(ccore.std_VecVecPoint2f_get_p(ptr, idx), attach: false);
@@ -789,6 +797,10 @@ class VecVecPoint3f extends VecUnmodifible<cvg.VecVecPoint3f, VecPoint3f> {
   @override
   ffi.Pointer<ffi.Void> asVoid() => ref.ptr.cast<ffi.Void>();
 
+  /// Returns a **reference**
+  ///
+  /// Note: the memory of returned [VecPoint3f] is owned by this [VecVecPoint3f],
+  /// explicitly call [VecPoint3f.clone] if the parent [VecVecPoint3f] may be disposed.
   @override
   VecPoint3f operator [](int idx) =>
       VecPoint3f.fromPointer(ccore.std_VecVecPoint3f_get_p(ptr, idx), attach: false);

packages/dartcv/lib/src/core/vec.dart

@@ -349,6 +349,10 @@ class VecVecChar extends VecUnmodifible<cvg.VecVecChar, VecChar> {
   @override
   ffi.Pointer<ffi.Void> asVoid() => throw UnsupportedError('Not supported');
 
+  /// Returns a **reference**
+  ///
+  /// Note: the memory of returned [VecChar] is owned by this [VecVecChar],
+  /// explicitly call [VecChar.clone] if the parent [VecVecChar] may be disposed.
   @override
   VecChar operator [](int idx) => VecChar.fromPointer(ccore.std_VecVecChar_get(ptr, idx), attach: false);