Render thumbnails at correct aspect ratio

ui/timeline.slint

@@ -7,10 +7,11 @@ component ImagePreview inherits Rectangle {
     in property <length> size: 32px;
     width: size;
     height: size;
+    clip: true;
 
     Image {
-        width: 100%;
-        height: 100%;
+        width: preview.ratio < 1.0 ? size : size * preview.ratio;
+        height: preview.ratio > 1.0 ? size : size / preview.ratio;
         source: preview.image;
     }
 

ui/types.slint

@@ -6,7 +6,13 @@ export enum PreviewKind {
 
 export struct ImagePreview {
     asset_id: string,
+
+    // Thumbnail/thumbhash/etc
     image: image,
+
+    // Image aspect ratio. (width/height)
+    ratio: float,
+
     kind: PreviewKind,
 }