info: highlight titles with custom decoration instead of gradient

lib/widgets/common/fx/highlight_decoration.dart

@@ -0,0 +1,28 @@
+import 'package:flutter/material.dart';
+
+class HighlightDecoration extends Decoration {
+  final Color color;
+
+  const HighlightDecoration({@required this.color});
+
+  @override
+  HighlightDecorationPainter createBoxPainter([VoidCallback onChanged]) {
+    return HighlightDecorationPainter(this, onChanged);
+  }
+}
+
+class HighlightDecorationPainter extends BoxPainter {
+  final HighlightDecoration decoration;
+
+  const HighlightDecorationPainter(this.decoration, VoidCallback onChanged) : super(onChanged);
+
+  @override
+  void paint(Canvas canvas, Offset offset, ImageConfiguration configuration) {
+    final size = configuration.size;
+    final confHeight = size.height;
+    final paintHeight = confHeight * .4;
+    final rect = Rect.fromLTWH(offset.dx, offset.dy + confHeight - paintHeight, size.width, paintHeight);
+    final paint = Paint()..color = decoration.color;
+    canvas.drawRect(rect, paint);
+  }
+}

lib/widgets/fullscreen/info/metadata_section.dart

@@ -3,6 +3,7 @@ import 'dart:async';
 import 'package:aves/model/image_entry.dart';
 import 'package:aves/model/metadata_service.dart';
 import 'package:aves/utils/color_utils.dart';
+import 'package:aves/widgets/common/fx/highlight_decoration.dart';
 import 'package:aves/widgets/fullscreen/info/info_page.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_staggered_grid_view/flutter_staggered_grid_view.dart';
@@ -112,7 +113,7 @@ class _Directory extends StatelessWidget {
       children: [
         if (directoryName.isNotEmpty)
           Container(
-            decoration: _DirectoryTitleDecoration(
+            decoration: HighlightDecoration(
               color: stringToColor(directoryName),
             ),
             margin: const EdgeInsets.symmetric(vertical: 4.0),
@@ -141,15 +142,3 @@ class _Directory extends StatelessWidget {
     );
   }
 }
-
-class _DirectoryTitleDecoration extends BoxDecoration {
-  _DirectoryTitleDecoration({@required Color color})
-      : super(
-          gradient: LinearGradient(
-            begin: Alignment.bottomCenter,
-            end: Alignment.topCenter,
-            stops: [0, .4, .4],
-            colors: [color, color, Colors.transparent],
-          ),
-        );
-}