Improve BorderRadius extension (#195)

- Rename file to border_radius_extension
- Add outer method
- Fix typo in comment
- Fix negative radius in inner method when padding too large
- Add unit tests

lib/src/extensions/border_radius_extension.dart

@@ -0,0 +1,56 @@
+import 'package:flutter/widgets.dart';
+
+extension BorderRadiusExtension on BorderRadius {
+  /// Compute an inner border radius from a given padding
+  BorderRadius inner(EdgeInsets padding) {
+    final topLeftX = topLeft.x - padding.left / 2;
+    final topLeftY = topLeft.y - padding.top / 2;
+    final topRightX = topRight.x - padding.right / 2;
+    final topRightY = topRight.y - padding.top / 2;
+    final bottomLeftX = bottomLeft.x - padding.left / 2;
+    final bottomLeftY = bottomLeft.y - padding.bottom / 2;
+    final bottomRightX = bottomRight.x - padding.right / 2;
+    final bottomRightY = bottomRight.y - padding.bottom / 2;
+
+    return BorderRadius.only(
+      topLeft: Radius.elliptical(
+        topLeftX < 0 ? 0 : topLeftX,
+        topLeftY < 0 ? 0 : topLeftY,
+      ),
+      topRight: Radius.elliptical(
+        topRightX < 0 ? 0 : topRightX,
+        topRightY < 0 ? 0 : topRightY,
+      ),
+      bottomRight: Radius.elliptical(
+        bottomRightX < 0 ? 0 : bottomRightX,
+        bottomRightY < 0 ? 0 : bottomRightY,
+      ),
+      bottomLeft: Radius.elliptical(
+        bottomLeftX < 0 ? 0 : bottomLeftX,
+        bottomLeftY < 0 ? 0 : bottomLeftY,
+      ),
+    );
+  }
+
+  /// Compute an outer border radius from a given margin
+  BorderRadius outer(EdgeInsets margin) {
+    return BorderRadius.only(
+      topLeft: Radius.elliptical(
+        topLeft.x + margin.left / 2,
+        topLeft.y + margin.top / 2,
+      ),
+      topRight: Radius.elliptical(
+        topRight.x + margin.right / 2,
+        topRight.y + margin.top / 2,
+      ),
+      bottomRight: Radius.elliptical(
+        bottomRight.x + margin.right / 2,
+        bottomRight.y + margin.bottom / 2,
+      ),
+      bottomLeft: Radius.elliptical(
+        bottomLeft.x + margin.left / 2,
+        bottomLeft.y + margin.bottom / 2,
+      ),
+    );
+  }
+}

lib/src/utilities/yaru_selectable_container.dart

@@ -1,6 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:yaru_widgets/src/constants.dart';
-import 'package:yaru_widgets/src/extensions/inner_border_radius.dart';
+import 'package:yaru_widgets/src/extensions/border_radius_extension.dart';
 
 class YaruSelectableContainer extends StatelessWidget {
   /// Creates a Image Tile from the image path given in the path property.

lib/yaru_widgets.dart

@@ -35,4 +35,4 @@ export 'src/pages/rows/yaru_switch_row.dart';
 export 'src/pages/yaru_tabbed_page.dart';
 export 'src/pages/rows/yaru_toggle_buttons_row.dart';
 export 'src/pages/layouts/yaru_wide_layout.dart';
-export 'src/extensions/inner_border_radius.dart';
+export 'src/extensions/border_radius_extension.dart';

pubspec.yaml

@@ -17,6 +17,7 @@ dev_dependencies:
     sdk: flutter
 
   flutter_lints: ^1.0.0
+  test: ^1.21.4
 
 flutter:
   assets:

test/extensions/inner_border_radius_test.dart

@@ -0,0 +1,88 @@
+import 'package:flutter/material.dart';
+import 'package:test/test.dart';
+import 'package:yaru_widgets/src/extensions/border_radius_extension.dart';
+
+void main() {
+  group('- BorderRadiusExtension.inner() test -', () {
+    test('With no padding', () {
+      testBorderRadiusInner(
+        BorderRadius.circular(10),
+        const EdgeInsets.all(0),
+        BorderRadius.circular(10),
+      );
+    });
+
+    test('With same side padding', () {
+      testBorderRadiusInner(
+        BorderRadius.circular(10),
+        const EdgeInsets.all(4),
+        BorderRadius.circular(8),
+      );
+    });
+
+    test('With large padding', () {
+      testBorderRadiusInner(
+        BorderRadius.circular(10),
+        const EdgeInsets.all(40),
+        BorderRadius.zero,
+      );
+    });
+
+    test('With different side padding', () {
+      testBorderRadiusInner(
+        BorderRadius.circular(10),
+        const EdgeInsets.fromLTRB(2, 4, 6, 8),
+        const BorderRadius.only(
+          topLeft: Radius.elliptical(9, 8),
+          topRight: Radius.elliptical(7, 8),
+          bottomRight: Radius.elliptical(7, 6),
+          bottomLeft: Radius.elliptical(9, 6),
+        ),
+      );
+    });
+
+    test('With different corner radius', () {
+      testBorderRadiusInner(
+        const BorderRadius.only(
+          topLeft: Radius.elliptical(2, 4),
+          topRight: Radius.elliptical(6, 8),
+          bottomLeft: Radius.elliptical(10, 12),
+          bottomRight: Radius.elliptical(14, 16),
+        ),
+        const EdgeInsets.all(2),
+        const BorderRadius.only(
+          topLeft: Radius.elliptical(1, 3),
+          topRight: Radius.elliptical(5, 7),
+          bottomLeft: Radius.elliptical(9, 11),
+          bottomRight: Radius.elliptical(13, 15),
+        ),
+      );
+    });
+
+    test('With different corner radius and side padding', () {
+      testBorderRadiusInner(
+        const BorderRadius.only(
+          topLeft: Radius.elliptical(10, 12),
+          topRight: Radius.elliptical(14, 16),
+          bottomLeft: Radius.elliptical(18, 20),
+          bottomRight: Radius.elliptical(22, 24),
+        ),
+        const EdgeInsets.fromLTRB(2, 4, 6, 8),
+        const BorderRadius.only(
+          topLeft: Radius.elliptical(9, 10),
+          topRight: Radius.elliptical(11, 14),
+          bottomLeft: Radius.elliptical(17, 16),
+          bottomRight: Radius.elliptical(19, 20),
+        ),
+      );
+    });
+  });
+}
+
+void testBorderRadiusInner(
+  BorderRadius initial,
+  EdgeInsets padding,
+  BorderRadius expected,
+) {
+  expect(initial.inner(padding), expected);
+}