Fix issue with advanced image preview

lib/core/models/pictr_media_extension.dart

@@ -20,7 +20,7 @@ abstract class PictrsMediaExtension {
     try {
       if (url.contains("/pictrs/image/")) {
         MediaType mediaType = MediaType.image;
-        Size result = await retrieveImageDimensions(url);
+        Size result = await retrieveImageDimensions(imageUrl: url);
 
         Size size = MediaExtension.getScaledMediaSize(width: result.width, height: result.height);
         mediaList.add(Media(mediaUrl: url, originalUrl: url, width: size.width, height: size.height, mediaType: mediaType));

lib/post/utils/post.dart

@@ -133,7 +133,7 @@ Future<PostViewMedia> parsePostView(PostView postView, bool fetchImageDimensions
       MediaType mediaType = MediaType.image;
 
       if (fetchImageDimensions) {
-        Size result = await retrieveImageDimensions(url);
+        Size result = await retrieveImageDimensions(imageUrl: url);
         Size size = MediaExtension.getScaledMediaSize(width: result.width, height: result.height, offset: edgeToEdgeImages ? 0 : 24, tabletMode: tabletMode);
         media.add(Media(mediaUrl: url, originalUrl: url, width: size.width, height: size.height, mediaType: mediaType));
       } else {
@@ -147,7 +147,7 @@ Future<PostViewMedia> parsePostView(PostView postView, bool fetchImageDimensions
     if (fetchImageDimensions) {
       if (postView.post.thumbnailUrl?.isNotEmpty == true) {
         try {
-          Size result = await retrieveImageDimensions(postView.post.thumbnailUrl!);
+          Size result = await retrieveImageDimensions(imageUrl: postView.post.thumbnailUrl!);
           Size size = MediaExtension.getScaledMediaSize(width: result.width, height: result.height, offset: edgeToEdgeImages ? 0 : 24, tabletMode: tabletMode);
           media.add(Media(
             mediaUrl: postView.post.thumbnailUrl!,
@@ -166,7 +166,7 @@ Future<PostViewMedia> parsePostView(PostView postView, bool fetchImageDimensions
           LinkInfo linkInfo = await getLinkInfo(url);
 
           if (linkInfo.imageURL != null && linkInfo.imageURL!.isNotEmpty) {
-            Size result = await retrieveImageDimensions(linkInfo.imageURL!);
+            Size result = await retrieveImageDimensions(imageUrl: linkInfo.imageURL!);
 
             int mediaHeight = result.height.toInt();
             int mediaWidth = result.width.toInt();

lib/shared/image_viewer.dart

@@ -111,8 +111,8 @@ class _ImageViewerState extends State<ImageViewer> with TickerProviderStateMixin
     );
   }
 
-  Future<void> getImageSize(String imageUrl, context) async {
-    Size decodedImage = await retrieveImageDimensions(imageUrl);
+  Future<void> getImageSize() async {
+    Size decodedImage = await retrieveImageDimensions(imageUrl: widget.url, imageBytes: widget.bytes);
 
     setState(() {
       imageWidth = decodedImage.width;
@@ -127,7 +127,7 @@ class _ImageViewerState extends State<ImageViewer> with TickerProviderStateMixin
   void initState() {
     super.initState();
     WidgetsBinding.instance.addPostFrameCallback((_) {
-      getImageSize(widget.url!, context);
+      getImageSize();
     });
   }
 
@@ -347,8 +347,14 @@ class _ImageViewerState extends State<ImageViewer> with TickerProviderStateMixin
                                       ),
                               ),
                             )
-                          : const Center(
-                              child: CircularProgressIndicator(),
+                          : Center(
+                              child: SizedBox(
+                                height: 20,
+                                width: 20,
+                                child: CircularProgressIndicator(
+                                  color: Colors.white.withOpacity(0.90),
+                                ),
+                              ),
                             )),
                 ),
                 AnimatedOpacity(

lib/utils/image.dart

@@ -59,35 +59,47 @@ Future<bool> isImageUriSvg(Uri? imageUri) async {
   }
 }
 
-Future<Size> retrieveImageDimensions(String imageUrl) async {
-  try {
-    bool isImage = isImageUrl(imageUrl);
-    if (!isImage) throw Exception('The URL provided was not an image');
-
-    final uri = Uri.parse(imageUrl);
-    final path = uri.path.toLowerCase();
-
-    // We'll just retrieve the first part of the image
-    final rangeResponse = await http.get(
-      uri,
-      headers: {'Range': 'bytes=0-1000'},
-    );
+/// Retrieves the size of the given image.
+/// Must provide either [imageUrl] or [imageBytes].
+Future<Size> retrieveImageDimensions({String? imageUrl, Uint8List? imageBytes}) async {
+  assert(imageUrl != null || imageBytes != null);
 
-    // Read the response body as bytes
-    final imageData = rangeResponse.bodyBytes;
-
-    // Get the image dimensions
-    if (path.endsWith('jpg') || path.endsWith('jpeg')) {
-      return getJPEGImageDimensions(imageData);
-    }
-    if (path.endsWith('gif')) {
-      return getGIFImageDimensions(imageData);
-    }
-    if (path.endsWith('png')) {
-      return getPNGImageDimensions(imageData);
+  try {
+    if (imageBytes != null) {
+      // We assume that byte-based images, which are only generated in-app by Thunder
+      // are all PNGs.
+      return getPNGImageDimensions(imageBytes);
     }
-    if (path.endsWith('webp')) {
-      return getWEBPImageDimensions(imageData);
+    // We know imageUrl is not null here due to the assertion.
+    else {
+      bool isImage = isImageUrl(imageUrl!);
+      if (!isImage) throw Exception('The URL provided was not an image');
+
+      final uri = Uri.parse(imageUrl);
+      final path = uri.path.toLowerCase();
+
+      // We'll just retrieve the first part of the image
+      final rangeResponse = await http.get(
+        uri,
+        headers: {'Range': 'bytes=0-1000'},
+      );
+
+      // Read the response body as bytes
+      final imageData = rangeResponse.bodyBytes;
+
+      // Get the image dimensions
+      if (path.endsWith('jpg') || path.endsWith('jpeg')) {
+        return getJPEGImageDimensions(imageData);
+      }
+      if (path.endsWith('gif')) {
+        return getGIFImageDimensions(imageData);
+      }
+      if (path.endsWith('png')) {
+        return getPNGImageDimensions(imageData);
+      }
+      if (path.endsWith('webp')) {
+        return getWEBPImageDimensions(imageData);
+      }
     }
   } catch (e) {
     throw Exception('Failed to retrieve image dimensions');