feat: add stacSliverPadding widget, parser,example and documentation

docs/docs.json

@@ -68,6 +68,7 @@
                             "widgets/row",
                             "widgets/safe_area",
                             "widgets/sized_box",
+                            "widgets/sliver_padding",
                             "widgets/spacer",
                             "widgets/stack",
                             "widgets/wrap",

docs/widgets/sliver_padding.mdx

@@ -0,0 +1,43 @@
+---
+title: "SliverPadding"
+description: "Documentation for SliverPadding"
+---
+
+The Stac SliverPadding allows you to inset a sliver widget by a given padding using JSON. It is typically used inside a `CustomScrollView`.
+To know more about the sliver padding widget in Flutter, refer to
+the [official documentation](https://api.flutter.dev/flutter/widgets/SliverPadding-class.html).
+
+## Properties
+
+| Property | Type                   | Description                                      |
+|----------|------------------------|--------------------------------------------------|
+| padding  | `Map<String, dynamic>` | The amount of space by which to inset the child. |
+| sliver   | `Map<String, dynamic>` | The sliver widget inside the padding.            |
+
+## Example JSON
+
+```json
+{
+  "type": "sliverPadding",
+  "padding": 16.0,
+  "sliver": {
+    "type": "sliverToBoxAdapter",
+    "child": {
+      "type": "container",
+      "height": 150,
+      "color": "#4CAF50",
+      "child": {
+        "type": "center",
+        "child": {
+          "type": "text",
+          "data": "I am a Box inside a SliverPadding!",
+          "style": {
+            "color": "#FFFFFF",
+            "fontWeight": "bold"
+          }
+        }
+      }
+    }
+  }
+}
+```

examples/stac_gallery/assets/json/home_screen.json

@@ -1236,6 +1236,30 @@
       }
     }
   },
+  {
+    "type": "listTile",
+    "leading": {
+      "type": "icon",
+      "iconType": "cupertino",
+      "icon": "app_fill"
+    },
+    "title": {
+      "type": "text",
+      "data": "Stac Sliver Padding"
+    },
+    "subtitle": {
+      "type": "text",
+      "data": "A SliverPadding widget"
+    },
+    "style": "list",
+    "onTap": {
+      "actionType": "navigate",
+      "widgetJson": {
+        "type": "exampleScreen",
+        "assetPath": "assets/json/sliver_padding_example.json"
+      }
+    }
+  },
   {
     "type": "listTile",
     "leading": {

examples/stac_gallery/assets/json/sliver_padding_example.json

@@ -0,0 +1,31 @@
+{
+    "type": "scaffold",
+    "body": {
+        "type": "customScrollView",
+        "slivers": [
+            {
+                "type": "sliverPadding",
+                "padding": 16.0,
+                "sliver": {
+                    "type": "sliverToBoxAdapter",
+                    "child": {
+                        "type": "container",
+                        "height": 150,
+                        "color": "#4CAF50",
+                        "child": {
+                            "type": "center",
+                            "child": {
+                                "type": "text",
+                                "data": "I am a Box inside a SliverPadding!",
+                                "style": {
+                                    "color": "#FFFFFF",
+                                    "fontWeight": "bold"
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+        ]
+    }
+}

packages/stac/lib/src/framework/stac_service.dart

@@ -114,6 +114,7 @@ class StacService {
     const StacRadioGroupParser(),
     const StacSliderParser(),
     const StacSliverAppBarParser(),
+    const StacSliverPaddingParser(),
     const StacOpacityParser(),
     const StacPlaceholderParser(),
     const StacAspectRatioParser(),

packages/stac/lib/src/parsers/widgets/stac_sliver_padding/stac_sliver_padding_parser.dart

@@ -0,0 +1,25 @@
+import 'package:flutter/material.dart';
+import 'package:stac/src/parsers/core/stac_widget_parser.dart';
+
+import 'package:stac/src/parsers/foundation/geometry/stac_edge_insets_parser.dart';
+import 'package:stac_core/stac_core.dart';
+import 'package:stac_framework/stac_framework.dart';
+
+class StacSliverPaddingParser extends StacParser<StacSliverPadding> {
+  const StacSliverPaddingParser();
+
+  @override
+  String get type => WidgetType.sliverPadding.name;
+
+  @override
+  StacSliverPadding getModel(Map<String, dynamic> json) =>
+      StacSliverPadding.fromJson(json);
+
+  @override
+  Widget parse(BuildContext context, StacSliverPadding model) {
+    return SliverPadding(
+      padding: model.padding.parse,
+      sliver: model.sliver.parse(context),
+    );
+  }
+}

packages/stac/lib/src/parsers/widgets/widgets.dart

@@ -63,6 +63,7 @@ export 'package:stac/src/parsers/widgets/stac_single_child_scroll_view/stac_sing
 export 'package:stac/src/parsers/widgets/stac_sized_box/stac_sized_box_parser.dart';
 export 'package:stac/src/parsers/widgets/stac_slider/stac_slider_parser.dart';
 export 'package:stac/src/parsers/widgets/stac_sliver_app_bar/stac_sliver_app_bar_parser.dart';
+export 'package:stac/src/parsers/widgets/stac_sliver_padding/stac_sliver_padding_parser.dart';
 export 'package:stac/src/parsers/widgets/stac_spacer/stac_spacer_parser.dart';
 export 'package:stac/src/parsers/widgets/stac_stack/stac_stack_parser.dart';
 export 'package:stac/src/parsers/widgets/stac_switch/stac_switch_parser.dart';

packages/stac_core/lib/foundation/specifications/widget_type.dart

@@ -207,6 +207,9 @@ enum WidgetType {
   /// Sliver app bar widget
   sliverAppBar,
 
+  /// Sliver padding widget
+  sliverPadding,
+
   /// Spacer widget
   spacer,
 

packages/stac_core/lib/widgets/sliver_padding/stac_sliver_padding.dart

@@ -0,0 +1,73 @@
+import 'package:json_annotation/json_annotation.dart';
+import 'package:stac_core/core/stac_widget.dart';
+import 'package:stac_core/foundation/foundation.dart';
+part 'stac_sliver_padding.g.dart';
+
+/// A Stac model representing Flutter's [SliverPadding] widget.
+///
+/// Insets its sliver child by the given padding.
+///
+/// {@tool snippet}
+/// Dart Example:
+/// ```dart
+/// const StacSliverPadding(
+///   padding: StacEdgeInsets.all(16),
+///   sliver: StacSliverToBoxAdapter(...),
+/// )
+/// ```
+/// {@end-tool}
+///
+/// {@tool snippet}
+/// JSON Example:
+/// ```json
+/// {
+///     "type": "sliverPadding",
+///     "padding": 16.0,
+///     "sliver": {
+///         "type": "sliverToBoxAdapter",
+///         "child": {
+///             "type": "container",
+///             "height": 150,
+///             "color": "#4CAF50",
+///             "child": {
+///                 "type": "center",
+///                 "child": {
+///                     "type": "text",
+///                     "data": "I am a Box inside a SliverPadding!",
+///                     "style": {
+///                         "color": "#FFFFFF",
+///                         "fontWeight": "bold"
+///                     }
+///                 }
+///             }
+///         }
+///     }
+/// }
+/// ```
+/// {@end-tool}
+///
+/// See also:
+///  * Flutter's [SliverPadding documentation](https://api.flutter.dev/flutter/widgets/SliverPadding-class.html)
+@JsonSerializable(explicitToJson: true)
+class StacSliverPadding extends StacWidget {
+  /// Creates a [StacSliverPadding].
+  const StacSliverPadding({required this.sliver, required this.padding});
+
+  /// The amount of space by which to inset the child sliver.
+  final StacEdgeInsets padding;
+
+  /// The sliver to apply padding to.
+  final StacWidget sliver;
+
+  /// Widget type identifier.
+  @override
+  String get type => WidgetType.sliverPadding.name;
+
+  /// Creates a [StacSliverPadding] from a JSON map.
+  factory StacSliverPadding.fromJson(Map<String, dynamic> json) =>
+      _$StacSliverPaddingFromJson(json);
+
+  /// Converts this [StacSliverPadding] instance to JSON.
+  @override
+  Map<String, dynamic> toJson() => _$StacSliverPaddingToJson(this);
+}

packages/stac_core/lib/widgets/widgets.dart

@@ -67,6 +67,7 @@ export 'single_child_scroll_view/stac_single_child_scroll_view.dart';
 export 'sized_box/stac_sized_box.dart';
 export 'slider/stac_slider.dart';
 export 'sliver_app_bar/stac_sliver_app_bar.dart';
+export 'sliver_padding/stac_sliver_padding.dart';
 export 'spacer/stac_spacer.dart';
 export 'stack/stac_stack.dart';
 export 'switch/stac_switch.dart';