add PageUp/PageDown/Home/End keybindings for going through photos

Program.cs

@@ -10,6 +10,7 @@ using SixLabors.ImageSharp.Metadata.Profiles.Exif;
 using SixLabors.ImageSharp.Metadata.Profiles.Xmp;
 using SixLabors.ImageSharp.Drawing.Processing;
 using SixLabors.ImageSharp.Drawing;
+using System.Diagnostics;
 using System.Runtime.CompilerServices;
 using System.Xml.Linq;
 
@@ -360,7 +361,7 @@ public class Texture : IDisposable {
 
     Handle = GL.GenTexture();
     if (Handle > maxHandle) {
-      Console.WriteLine("GL.GenTexture #" + Handle);
+      // Console.WriteLine("GL.GenTexture #" + Handle);
       maxHandle = Handle;
     }
     GL.ActiveTexture(TextureUnit.Texture0);
@@ -582,6 +583,22 @@ public class Game : GameWindow {
       photoIndex--;
     }
 
+    if (input.IsKeyPressed(Keys.Home)) {
+      photoIndex = 0;
+    }
+
+    if (input.IsKeyPressed(Keys.End)) {
+      photoIndex = photos.Count - 1;
+    }
+
+    if (input.IsKeyPressed(Keys.PageDown)) {
+      photoIndex += 10;
+    }
+
+    if (input.IsKeyPressed(Keys.PageUp)) {
+      photoIndex -= 10;
+    }
+
     // Make sure the photoIndex is actually valid.
     photoIndex = Math.Clamp(photoIndex, 0, photos.Count - 1);
 
@@ -685,17 +702,25 @@ public class Game : GameWindow {
     int minLoadedImage = Math.Max(0, photoIndex - 20);
     int maxLoadedImage = Math.Min(photoIndex + 20, photos.Count - 1);
     // First, unload images that are far outside our window.
+    // FIXME: also cancel any in-progress loading tasks that have moved outside our window.
+    Stopwatch stopwatch = new Stopwatch();
+    stopwatch.Start();
     foreach (int i in loadedImages) {
       if (i < minUnloadedImage || i > maxUnloadedImage) {
         loadedImages.Remove(i);
         photos[i].Unload();
-        Console.WriteLine("unloading " + i);
+        // Console.WriteLine("unloading " + i);
       }
     }
+    stopwatch.Stop();
+    if (stopwatch.Elapsed.TotalMilliseconds > 1) {
+      Console.WriteLine(stopwatch.Elapsed.TotalMilliseconds);
+    }
+
     // Then, start loading any images that aren't in our window.
     for (int i = minLoadedImage; i <= maxLoadedImage; i++) {
       if (!loadedImages.Contains(i)) {
-        Console.WriteLine("loading " + i);
+        // Console.WriteLine("loading " + i);
         loadedImages.Add(i);
         await Task.Run( () => { photos[i].LoadAsync(); });
       }