load thumbnails for everything, async'ly on load

Photo.cs

@@ -29,12 +29,15 @@ public class Photo {
   private static long touchCounter = 0;
   private Texture texture;
   private Texture placeholder;
+  private Texture thumbnailTexture;
   private Image<Rgba32>? image = null;
+  private Image<Rgba32>? thumbnail = null;
 
   public Photo(string filename, Texture placeholder) {
     Filename = filename;
     this.placeholder = placeholder;
     texture = placeholder;
+    thumbnailTexture = placeholder;
 
     DateTime creationTime = File.GetCreationTime(filename);  // Local time.
     DateTimeOriginal = creationTime;
@@ -49,12 +52,18 @@ public class Photo {
     // edit the image due to rotation (etc) and don't want to try generating
     // a texture for it until that's already happened.
     LastTouch = touchCounter++;
+    Image<Rgba32> tmp = await Image.LoadAsync<Rgba32>(Filename);
+    Util.RotateImageFromExif(tmp, Orientation);
+    image = tmp;
+  }
+
+  public async void LoadThumbnailAsync() {
     DecoderOptions options = new DecoderOptions {
       TargetSize = new Size(256, 256)
     };
     Image<Rgba32> tmp = await Image.LoadAsync<Rgba32>(options, Filename);
     Util.RotateImageFromExif(tmp, Orientation);
-    image = tmp;
+    thumbnail = tmp;
   }
 
   public void Unload() {
@@ -273,16 +282,21 @@ public class Photo {
 
   public Texture Texture() {
     LastTouch = touchCounter++;
+    if (thumbnailTexture == placeholder && thumbnail != null) {
+      thumbnailTexture = new(thumbnail);
+      thumbnail.Dispose();
+      thumbnail = null;
+    }
     if (texture == placeholder && image != null) {
       // The texture needs to be created on the GL thread, so we instantiate
       // it here (since this is called from OnRenderFrame), as long as the
       // image is ready to go.
-      texture = new Texture(image);
+      texture = new(image);
       image.Dispose();
       image = null;
       Loaded = true;
     }
-    return texture;
+    return texture != placeholder ? texture : thumbnailTexture;
   }
 
   public string Description() {

Program.cs

@@ -652,6 +652,8 @@ public class Game : GameWindow {
 
     allPhotos.Sort(ComparePhotosByDate);
     photos = allPhotos;
+
+    LoadThumbnailsAsync();
   }
 
   private static int ComparePhotosByDate(Photo x, Photo y) {
@@ -669,11 +671,9 @@ public class Game : GameWindow {
   }
 
   private void UnloadImages() {
-    return;
     // Unload images that haven't been touched in a while.
-    // FIXME: keep around thumbnail-sized textures?
     lock (loadedImagesLock) {
-      while (loadedImages.Count > 100) {
+      while (loadedImages.Count > 30) {
         long earliestTime = long.MaxValue;
         Photo? earliest = null;
         foreach (Photo photo in loadedImages) {
@@ -704,9 +704,8 @@ public class Game : GameWindow {
       }
     }
     // Start loading any images that are in our window but not yet loaded.
-    int minLoadedImage = Math.Max(0, photoIndex - 30);
-    // int maxLoadedImage = Math.Min(photoIndex + 30, photos.Count - 1);
-    int maxLoadedImage = photos.Count - 1;
+    int minLoadedImage = Math.Max(0, photoIndex - 10);
+    int maxLoadedImage = Math.Min(photoIndex + 10, photos.Count - 1);
     List<Photo> toLoad = new();
     for (int i = minLoadedImage; i <= maxLoadedImage; i++) {
       lock (loadedImagesLock) {
@@ -722,6 +721,12 @@ public class Game : GameWindow {
     }
   }
 
+  private async void LoadThumbnailsAsync() {
+    foreach (Photo p in allPhotos) {
+      await Task.Run( () => { p.LoadThumbnailAsync(); });
+    }
+  }
+
   // To find the JPEG compression level of a file from the command line:
   // $ identify -verbose image.jpg | grep Quality:
   // FIXME: don't ExportPhotos() if another export is already active.
@@ -988,9 +993,9 @@ static class Program {
     nwSettings.CurrentMonitor = bestMonitor.Handle;
     nwSettings.Location = new Vector2i(bestMonitor.WorkArea.Min.X + 1,
                                        bestMonitor.WorkArea.Min.Y + 31);
-    // nwSettings.Size = new Vector2i(bestMonitor.WorkArea.Size.X - 2,
-    //                                bestMonitor.WorkArea.Size.Y - 32);
-    nwSettings.Size = new Vector2i(1600, 900);
+    nwSettings.Size = new Vector2i(bestMonitor.WorkArea.Size.X - 2,
+                                   bestMonitor.WorkArea.Size.Y - 32);
+    // nwSettings.Size = new Vector2i(1600, 900);
     nwSettings.MinimumSize = UiGeometry.MIN_WINDOW_SIZE;
     nwSettings.Title = "Totte";
     nwSettings.IsEventDriven = true;