Improve photo loading and full-screen gallery swiping

lib/app/layouts/conversation_view/widgets/message/attachment/image_viewer.dart

@@ -2,7 +2,7 @@ import 'dart:async';
 import 'dart:math';
 
 import 'package:bluebubbles/app/wrappers/stateful_boilerplate.dart';
-import 'package:bluebubbles/helpers/helpers.dart';
+import 'package:bluebubbles/app/layouts/conversation_view/widgets/message/attachment/image_viewer_decode_dimensions.dart';
 import 'package:bluebubbles/database/models.dart';
 import 'package:bluebubbles/services/services.dart';
 import 'package:flutter/cupertino.dart';
@@ -55,11 +55,12 @@ class _ImageViewerState extends OptimizedState<ImageViewer> with AutomaticKeepAl
       final completer = Completer<Uint8List>();
       controller!.queueImage(Tuple4(attachment, file, context, completer));
       final newData = await completer.future;
-      if (newData.isEmpty) return;
+      if (!mounted || newData.isEmpty) return;
       setState(() {
         data = newData;
       });
     } else {
+      if (!mounted) return;
       setState(() {
         data = tmpData;
       });
@@ -78,13 +79,20 @@ class _ImageViewerState extends OptimizedState<ImageViewer> with AutomaticKeepAl
         height: min((attachment.height?.toDouble() ?? ns.width(context) * 0.5 / attachment.aspectRatio), ns.width(context) * 0.5 / attachment.aspectRatio),
       );
     }
+    final decodeDimensions = calculateImageViewerDecodeDimensions(
+      maximumDisplayWidth: ns.width(context) * 0.5,
+      pixelRatio: Get.pixelRatio,
+      sourceWidth: attachment.width,
+      sourceHeight: attachment.height,
+      aspectRatio: attachment.aspectRatio,
+    );
     return Image.memory(
       data!,
       // prevents the image widget from "refreshing" when the provider changes
       gaplessPlayback: true,
       filterQuality: FilterQuality.none,
-      cacheWidth: (min((attachment.width ?? 0), ns.width(context) * 0.5) * Get.pixelRatio / 2).round().abs().nonZero,
-      cacheHeight: (min((attachment.height ?? 0), ns.width(context) * 0.5 / attachment.aspectRatio) * Get.pixelRatio / 2).round().abs().nonZero,
+      cacheWidth: decodeDimensions.width,
+      cacheHeight: decodeDimensions.height,
       fit: BoxFit.cover,
       frameBuilder: (context, w, frame, wasSyncLoaded) {
         return AnimatedCrossFade(

lib/app/layouts/conversation_view/widgets/message/attachment/image_viewer_decode_dimensions.dart

@@ -0,0 +1,47 @@
+import 'dart:math';
+
+class ImageViewerDecodeDimensions {
+  const ImageViewerDecodeDimensions(
+      {required this.width, required this.height});
+
+  final int width;
+  final int height;
+}
+
+ImageViewerDecodeDimensions calculateImageViewerDecodeDimensions({
+  required double maximumDisplayWidth,
+  required double pixelRatio,
+  required int? sourceWidth,
+  required int? sourceHeight,
+  required double aspectRatio,
+}) {
+  final safeMaximumDisplayWidth =
+      maximumDisplayWidth.isFinite && maximumDisplayWidth > 0
+          ? maximumDisplayWidth
+          : 1.0;
+  final safePixelRatio =
+      pixelRatio.isFinite && pixelRatio > 0 ? pixelRatio : 1.0;
+  final safeAspectRatio =
+      aspectRatio.isFinite && aspectRatio > 0 ? aspectRatio : 1.0;
+  final displayWidth = min(
+    sourceWidth != null && sourceWidth > 0
+        ? sourceWidth.toDouble()
+        : safeMaximumDisplayWidth,
+    safeMaximumDisplayWidth,
+  );
+  final fallbackHeight = safeMaximumDisplayWidth / safeAspectRatio;
+  final displayHeight = min(
+    sourceHeight != null && sourceHeight > 0
+        ? sourceHeight.toDouble()
+        : fallbackHeight,
+    fallbackHeight,
+  );
+
+  int cacheDimension(double displayDimension) =>
+      (displayDimension * safePixelRatio / 2).round().clamp(1, 1024).toInt();
+
+  return ImageViewerDecodeDimensions(
+    width: cacheDimension(displayWidth),
+    height: cacheDimension(displayHeight),
+  );
+}

lib/app/layouts/fullscreen_media/fullscreen_holder.dart

@@ -14,6 +14,7 @@ import "package:flutter/material.dart";
 import 'package:flutter/services.dart';
 import 'package:gesture_x_detector/gesture_x_detector.dart';
 import 'package:get/get.dart';
+import 'package:photo_view/photo_view.dart' show PhotoViewGestureDetectorScope;
 
 class FullscreenMediaHolder extends StatefulWidget {
   FullscreenMediaHolder({
@@ -151,7 +152,12 @@ class FullscreenMediaHolderState extends OptimizedState<FullscreenMediaHolder> {
                   }
                   return KeyEventResult.ignored;
                 },
-                child: PageView.builder(
+                child: PhotoViewGestureDetectorScope(
+                  // Lets a contained image yield horizontal drags to the
+                  // PageView. A zoomed image keeps its own pan gesture, and
+                  // FullscreenImage disables this PageView while zoomed.
+                  axis: Axis.horizontal,
+                  child: PageView.builder(
                   physics: physics ??
                       (attachments.length == 1
                           ? const NeverScrollableScrollPhysics()
@@ -302,6 +308,7 @@ class FullscreenMediaHolderState extends OptimizedState<FullscreenMediaHolder> {
                       );
                     }
                   },
+                  ),
                 ),
               ),
             ),

test/app/layouts/conversation_view/widgets/message/attachment/image_viewer_decode_dimensions_test.dart

@@ -0,0 +1,43 @@
+import 'package:bluebubbles/app/layouts/conversation_view/widgets/message/attachment/image_viewer_decode_dimensions.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  test('bounds decoded dimensions to the displayed image size', () {
+    final dimensions = calculateImageViewerDecodeDimensions(
+      maximumDisplayWidth: 200,
+      pixelRatio: 3,
+      sourceWidth: 4000,
+      sourceHeight: 3000,
+      aspectRatio: 4 / 3,
+    );
+
+    expect(dimensions.width, 300);
+    expect(dimensions.height, 225);
+  });
+
+  test('uses safe positive fallbacks for missing or invalid metadata', () {
+    final dimensions = calculateImageViewerDecodeDimensions(
+      maximumDisplayWidth: double.nan,
+      pixelRatio: double.infinity,
+      sourceWidth: 0,
+      sourceHeight: null,
+      aspectRatio: 0,
+    );
+
+    expect(dimensions.width, 1);
+    expect(dimensions.height, 1);
+  });
+
+  test('caps large device-scaled decode dimensions', () {
+    final dimensions = calculateImageViewerDecodeDimensions(
+      maximumDisplayWidth: 4000,
+      pixelRatio: 4,
+      sourceWidth: 4000,
+      sourceHeight: 4000,
+      aspectRatio: 1,
+    );
+
+    expect(dimensions.width, 1024);
+    expect(dimensions.height, 1024);
+  });
+}