various minor fixes

lib/ref/xmp.dart

@@ -4,11 +4,13 @@ class XMP {
 
   // cf https://exiftool.org/TagNames/XMP.html
   static const Map<String, String> namespaces = {
-    'aux': 'Auxiliary Exif',
+    'aux': 'Exif Aux',
     'Camera': 'Camera',
     'crs': 'Camera Raw Settings',
     'dc': 'Dublin Core',
     'exif': 'Exif',
+    'exifEX': 'Exif Ex',
+    'GettyImagesGIFT': 'Getty Images',
     'GIMP': 'GIMP',
     'illustrator': 'Illustrator',
     'Iptc4xmpCore': 'IPTC Core',
@@ -19,6 +21,7 @@ class XMP {
     'pdfx': 'PDF/X',
     'photomechanic': 'Photo Mechanic',
     'photoshop': 'Photoshop',
+    'plus': 'PLUS',
     'tiff': 'TIFF',
     'xmp': 'Basic',
     'xmpBJ': 'Basic Job Ticket',

lib/widgets/about/licenses.dart

@@ -87,6 +87,7 @@ class _LicensesState extends State<Licenses> {
 
   Widget _buildHeader() {
     return Column(
+      crossAxisAlignment: CrossAxisAlignment.start,
       children: [
         Padding(
           padding: EdgeInsetsDirectional.only(start: 8),

lib/widgets/collection/grid/list_section_layout.dart

@@ -3,7 +3,6 @@ import 'dart:math';
 import 'package:aves/model/image_entry.dart';
 import 'package:aves/model/source/collection_lens.dart';
 import 'package:aves/widgets/collection/grid/header_generic.dart';
-import 'package:aves/widgets/collection/thumbnail_collection.dart';
 import 'package:flutter/material.dart';
 import 'package:provider/provider.dart';
 
@@ -15,14 +14,14 @@ class SectionedListLayoutProvider extends StatelessWidget {
   final Widget Function(ImageEntry entry) thumbnailBuilder;
   final Widget child;
 
-  SectionedListLayoutProvider({
+  const SectionedListLayoutProvider({
     @required this.collection,
     @required this.scrollableWidth,
     @required this.tileExtent,
+    @required this.columnCount,
     @required this.thumbnailBuilder,
     @required this.child,
-  })  : assert(scrollableWidth != 0),
+  }) : assert(scrollableWidth != 0);
-        columnCount = max((scrollableWidth / tileExtent).round(), ThumbnailCollection.columnCountMin);
 
   @override
   Widget build(BuildContext context) {

lib/widgets/collection/thumbnail_collection.dart

@@ -31,9 +31,9 @@ class ThumbnailCollection extends StatelessWidget {
   final ValueNotifier<bool> _isScrollingNotifier = ValueNotifier(false);
   final GlobalKey _scrollableKey = GlobalKey();
 
-  static const columnCountMin = 2;
   static const columnCountDefault = 4;
   static const extentMin = 46.0;
+  static const spacing = 0.0;
 
   @override
   Widget build(BuildContext context) {
@@ -47,11 +47,10 @@ class ThumbnailCollection extends StatelessWidget {
 
             final tileExtentManager = TileExtentManager(
               settingsRouteKey: context.currentRouteName,
-              columnCountMin: columnCountMin,
+              extentNotifier: _tileExtentNotifier,
               columnCountDefault: columnCountDefault,
               extentMin: extentMin,
-              extentNotifier: _tileExtentNotifier,
+              spacing: spacing,
-              spacing: 0,
             )..applyTileExtent(viewportSize: viewportSize);
             final cacheExtent = tileExtentManager.getEffectiveExtentMax(viewportSize) * 2;
 
@@ -77,7 +76,18 @@ class ThumbnailCollection extends StatelessWidget {
                   scrollableKey: _scrollableKey,
                   appBarHeightNotifier: _appBarHeightNotifier,
                   viewportSize: viewportSize,
-                  showScaledGrid: true,
+                  gridBuilder: (center, extent, child) => CustomPaint(
+                    // painting the thumbnail half-border on top of the grid yields artifacts,
+                    // so we use a `foregroundPainter` to cover them instead
+                    foregroundPainter: GridPainter(
+                      center: center,
+                      extent: extent,
+                      spacing: tileExtentManager.spacing,
+                      strokeWidth: DecoratedThumbnail.borderWidth * 2,
+                      color: DecoratedThumbnail.borderColor,
+                    ),
+                    child: child,
+                  ),
                   scaledBuilder: (entry, extent) => DecoratedThumbnail(
                     entry: entry,
                     extent: extent,
@@ -98,6 +108,7 @@ class ThumbnailCollection extends StatelessWidget {
                     collection: collection,
                     scrollableWidth: viewportSize.width,
                     tileExtent: tileExtent,
+                    columnCount: tileExtentManager.getEffectiveColumnCountForExtent(viewportSize, tileExtent),
                     thumbnailBuilder: (entry) => GridThumbnail(
                       key: ValueKey(entry.contentId),
                       collection: collection,

lib/widgets/common/scaling.dart

@@ -2,7 +2,6 @@ import 'dart:math';
 import 'dart:ui' as ui;
 
 import 'package:aves/theme/durations.dart';
-import 'package:aves/widgets/collection/thumbnail/decorated.dart';
 import 'package:aves/widgets/common/providers/media_query_data_provider.dart';
 import 'package:aves/widgets/common/tile_extent_manager.dart';
 import 'package:flutter/material.dart';
@@ -20,7 +19,7 @@ class GridScaleGestureDetector<T> extends StatefulWidget {
   final GlobalKey scrollableKey;
   final ValueNotifier<double> appBarHeightNotifier;
   final Size viewportSize;
-  final bool showScaledGrid;
+  final Widget Function(Offset center, double extent, Widget child) gridBuilder;
   final Widget Function(T item, double extent) scaledBuilder;
   final Rect Function(BuildContext context, T item) getScaledItemTileRect;
   final void Function(T item) onScaled;
@@ -31,7 +30,7 @@ class GridScaleGestureDetector<T> extends StatefulWidget {
     @required this.scrollableKey,
     @required this.appBarHeightNotifier,
     @required this.viewportSize,
-    @required this.showScaledGrid,
+    this.gridBuilder,
     @required this.scaledBuilder,
     @required this.getScaledItemTileRect,
     @required this.onScaled,
@@ -56,10 +55,6 @@ class _GridScaleGestureDetectorState<T> extends State<GridScaleGestureDetector<T
   @override
   Widget build(BuildContext context) {
     return GestureDetector(
-      onHorizontalDragStart: (details) {
-        // if `onHorizontalDragStart` callback is not defined,
-        // horizontal drag gestures are interpreted as scaling
-      },
       onScaleStart: (details) {
         // the gesture detector wrongly detects a new scaling gesture
         // when scaling ends and we apply the new extent, so we prevent this
@@ -91,10 +86,9 @@ class _GridScaleGestureDetectorState<T> extends State<GridScaleGestureDetector<T
           builder: (context) => ScaleOverlay(
             builder: (extent) => widget.scaledBuilder(_metadata.item, extent),
             center: thumbnailCenter,
-            gridWidth: gridWidth,
+            viewportWidth: gridWidth,
-            spacing: tileExtentManager.spacing,
+            gridBuilder: widget.gridBuilder,
             scaledExtentNotifier: _scaledExtentNotifier,
-            showScaledGrid: widget.showScaledGrid,
           ),
         );
         Overlay.of(scrollableContext).insert(_overlayEntry);
@@ -133,7 +127,16 @@ class _GridScaleGestureDetectorState<T> extends State<GridScaleGestureDetector<T
           });
         }
       },
-      child: widget.child,
+      child: GestureDetector(
+        // Horizontal/vertical drag gestures are interpreted as scaling
+        // if they are not handled by `onHorizontalDragStart`/`onVerticalDragStart`
+        // at the scaling `GestureDetector` level, or handled beforehand down the widget tree.
+        // Setting `onHorizontalDragStart`, `onVerticalDragStart`, and `onScaleStart`
+        // all at once is not allowed, so we use another `GestureDetector` for that.
+        onVerticalDragStart: (details) {},
+        onHorizontalDragStart: (details) {},
+        child: widget.child,
+      ),
     );
   }
 
@@ -157,18 +160,16 @@ class _GridScaleGestureDetectorState<T> extends State<GridScaleGestureDetector<T
 class ScaleOverlay extends StatefulWidget {
   final Widget Function(double extent) builder;
   final Offset center;
-  final double gridWidth;
+  final double viewportWidth;
-  final double spacing;
   final ValueNotifier<double> scaledExtentNotifier;
-  final bool showScaledGrid;
+  final Widget Function(Offset center, double extent, Widget child) gridBuilder;
 
   const ScaleOverlay({
     @required this.builder,
     @required this.center,
-    @required this.gridWidth,
+    @required this.viewportWidth,
-    @required this.spacing,
     @required this.scaledExtentNotifier,
-    @required this.showScaledGrid,
+    this.gridBuilder,
   });
 
   @override
@@ -180,7 +181,7 @@ class _ScaleOverlayState extends State<ScaleOverlay> {
 
   Offset get center => widget.center;
 
-  double get gridWidth => widget.gridWidth;
+  double get gridWidth => widget.viewportWidth;
 
   @override
   void initState() {
@@ -241,16 +242,7 @@ class _ScaleOverlayState extends State<ScaleOverlay> {
                   ),
                 ],
               );
-              if (widget.showScaledGrid) {
+              child = widget.gridBuilder?.call(clampedCenter, extent, child) ?? child;
-                child = CustomPaint(
-                  painter: GridPainter(
-                    center: clampedCenter,
-                    extent: extent,
-                    spacing: widget.spacing,
-                  ),
-                  child: child,
-                );
-              }
               return child;
             },
           ),
@@ -263,31 +255,36 @@ class _ScaleOverlayState extends State<ScaleOverlay> {
 class GridPainter extends CustomPainter {
   final Offset center;
   final double extent, spacing;
+  final double strokeWidth;
+  final Color color;
 
   const GridPainter({
     @required this.center,
     @required this.extent,
-    @required this.spacing,
+    this.spacing = 0.0,
+    this.strokeWidth = 1.0,
+    @required this.color,
   });
 
   @override
   void paint(Canvas canvas, Size size) {
+    final radius = extent * 3;
     final paint = Paint()
-      ..strokeWidth = DecoratedThumbnail.borderWidth
+      ..strokeWidth = strokeWidth
       ..shader = ui.Gradient.radial(
         center,
-        size.width * .7,
+        radius,
         [
-          DecoratedThumbnail.borderColor,
+          color,
           Colors.transparent,
         ],
         [
-          min(.5, 2 * extent / size.width),
+          extent / radius,
           1,
         ],
       );
     void draw(Offset topLeft) {
-      for (var i = -2; i <= 3; i++) {
+      for (var i = -1; i <= 2; i++) {
         final ref = (extent + spacing) * i;
         canvas.drawLine(Offset(0, topLeft.dy + ref), Offset(size.width, topLeft.dy + ref), paint);
         canvas.drawLine(Offset(topLeft.dx + ref, 0), Offset(topLeft.dx + ref, size.height), paint);

lib/widgets/common/tile_extent_manager.dart

@@ -6,15 +6,16 @@ import 'package:flutter/widgets.dart';
 class TileExtentManager {
   final String settingsRouteKey;
   final int columnCountMin, columnCountDefault;
-  final double spacing, extentMin;
+  final double spacing, extentMin, extentMax;
   final ValueNotifier<double> extentNotifier;
 
   const TileExtentManager({
     @required this.settingsRouteKey,
-    @required this.columnCountMin,
+    @required this.extentNotifier,
+    this.columnCountMin = 2,
     @required this.columnCountDefault,
     @required this.extentMin,
-    @required this.extentNotifier,
+    this.extentMax = 300,
     @required this.spacing,
   });
 
@@ -46,7 +47,7 @@ class TileExtentManager {
     return newExtent;
   }
 
-  double _extentMax(Size viewportSize) => (viewportSize.shortestSide - spacing * (columnCountMin - 1)) / columnCountMin;
+  double _extentMax(Size viewportSize) => min(extentMax, (viewportSize.shortestSide - spacing * (columnCountMin - 1)) / columnCountMin);
 
   double _columnCountForExtent(Size viewportSize, double extent) => (viewportSize.width + spacing) / (extent + spacing);
 

lib/widgets/filter_grids/common/filter_grid_page.dart

@@ -37,6 +37,8 @@ class FilterGridPage<T extends CollectionFilter> extends StatelessWidget {
   final ValueNotifier<double> _tileExtentNotifier = ValueNotifier(0);
   final GlobalKey _scrollableKey = GlobalKey();
 
+  static const columnCountDefault = 2;
+  static const extentMin = 60.0;
   static const spacing = 8.0;
 
   FilterGridPage({
@@ -71,10 +73,9 @@ class FilterGridPage<T extends CollectionFilter> extends StatelessWidget {
 
                   final tileExtentManager = TileExtentManager(
                     settingsRouteKey: settingsRouteKey ?? context.currentRouteName,
-                    columnCountMin: 2,
-                    columnCountDefault: 2,
-                    extentMin: 60,
                     extentNotifier: _tileExtentNotifier,
+                    columnCountDefault: columnCountDefault,
+                    extentMin: extentMin,
                     spacing: spacing,
                   )..applyTileExtent(viewportSize: viewportSize);
 
@@ -98,7 +99,15 @@ class FilterGridPage<T extends CollectionFilter> extends StatelessWidget {
                             scrollableKey: _scrollableKey,
                             appBarHeightNotifier: _appBarHeightNotifier,
                             viewportSize: viewportSize,
-                            showScaledGrid: true,
+                            gridBuilder: (center, extent, child) => CustomPaint(
+                              painter: GridPainter(
+                                center: center,
+                                extent: extent,
+                                spacing: tileExtentManager.spacing,
+                                color: Colors.grey.shade700,
+                              ),
+                              child: child,
+                            ),
                             scaledBuilder: (item, extent) {
                               final filter = item.filter;
                               return SizedBox(