cropping works! janky af for now, but it works

Program.cs

@@ -185,6 +185,7 @@ public class Photo {
   public string IsoSpeed = "<unk>";
   public int Rating = 0;
   public ushort Orientation = 1;
+  public Rectangle CropRectangle = Rectangle.Empty;
 
   private static long touchCounter = 0;
   private Texture texture;
@@ -237,6 +238,9 @@ public class Photo {
     // FIXME: warn if the file already exists?
     using (Image<Rgba32> image = await Image.LoadAsync<Rgba32>(Filename)) {
       Util.RotateImageFromExif(image, Orientation);
+      if (CropRectangle != Rectangle.Empty) {
+        image.Mutate(x => x.Crop(CropRectangle));
+      }
 
       ExifProfile exif = image.Metadata.ExifProfile ?? new();
       exif.SetValue<ushort>(ExifTag.Orientation, 1);
@@ -504,7 +508,7 @@ public class UiGeometry {
       ThumbnailBoxes.Add(box);
     }
 
-    int statusBoxHeight = 20;
+    int statusBoxHeight = 40;
     int statusBoxPadding = 4;
     PhotoBox = new Box2i(0, 0, WindowSize.X - thumbnailWidth, WindowSize.Y - statusBoxHeight - statusBoxPadding);
     StatusBox = new Box2i(0, WindowSize.Y - statusBoxHeight, WindowSize.X - thumbnailWidth, WindowSize.Y);
@@ -609,6 +613,9 @@ public static class Util {
 public class Game : GameWindow {
   public Game(GameWindowSettings gwSettings, NativeWindowSettings nwSettings) : base(gwSettings, nwSettings) {}
 
+  private static string outputRoot = @"c:\users\colin\desktop\totte-output";
+  // private static string outputRoot = @"c:\users\colin\pictures\photos";
+
   private static Texture TEXTURE_WHITE = new(new Image<Rgba32>(1, 1, new Rgba32(255, 255, 255)));
   private static Texture TEXTURE_BLACK = new(new Image<Rgba32>(1, 1, new Rgba32(0, 0, 0)));
   private static Texture STAR_FILLED = Util.RenderStar(20, true);
@@ -637,8 +644,11 @@ public class Game : GameWindow {
   readonly object loadedImagesLock = new();
   int photoIndex = 0;
   int ribbonIndex = 0;
+  Vector2i mousePosition;
   Vector2i mouseDragStart;
   Vector2i mouseDragEnd;
+  float activeScale = 1f;
+  Vector2i activeOffset;
   Shader shader = new();
   Matrix4 projection;
   float zoomLevel = 0f;
@@ -661,7 +671,7 @@ public class Game : GameWindow {
 
     int lastPhotoIndex = photoIndex;
 
-    Vector2i mousePosition = (Vector2i) MouseState.Position;
+    mousePosition = (Vector2i) MouseState.Position;
 
     // Look for mouse clicks on thumbnails or stars.
     //
@@ -737,6 +747,11 @@ public class Game : GameWindow {
       photoIndex -= 5;
     }
 
+    // FIXME: crop should be a modal tool that starts with C and ends with Enter or Escape.
+    if (input.IsKeyPressed(Keys.C)) {
+      ApplyCrop();
+    }
+
     if (input.IsKeyPressed(Keys.P) && altIsDown) {
       ExportPhotos();
     }
@@ -964,8 +979,6 @@ public class Game : GameWindow {
   // FIXME: show a progress bar or something.
   private async void ExportPhotos() {
     JpegEncoder encoder = new JpegEncoder() { Quality = 100 };
-    string outputRoot = @"c:\users\colin\desktop\totte-output";
-    // string outputRoot = @"c:\users\colin\pictures\photos";
     foreach (Photo p in photos) {
       await Task.Run( () => { p.SaveAsJpegAsync(outputRoot, encoder); });
     }
@@ -993,7 +1006,11 @@ public class Game : GameWindow {
     SwapBuffers();
   }
 
-  void DrawCropBox() {
+  // left, right, top, bottom
+  (int, int, int, int) GetCrop() {
+    // FIXME: this expects the start point in the top left and the end point
+    // in the bottom right; some sign flipping needs to occur to make anchors
+    // in other direction work well.
     Vector2i start = mouseDragStart;
     Vector2i end = mouseDragEnd;
     end.Y = Math.Min(end.Y, start.Y + (end.X - start.X) * 4 / 6);
@@ -1002,9 +1019,31 @@ public class Game : GameWindow {
     int right = Math.Max(start.X, end.X);
     int top = Math.Min(start.Y, end.Y);
     int bottom = Math.Max(start.Y, end.Y);
+    return (left, right, top, bottom);
+  }
+
+  void ApplyCrop() {
+    var (left, right, top, bottom) = GetCrop();
+    int area = (right - left) * (bottom - top);
+    if (area == 0) {
+      return;
+    }
+
+    Vector2i leftTop = ScreenToImage(left, top);
+    Vector2i rightBottom = ScreenToImage(right, bottom);
+    Rectangle crop = Rectangle.FromLTRB(leftTop.X, leftTop.Y, rightBottom.X, rightBottom.Y);
+    Photo photo = photos[photoIndex];
+    // FIXME: make sure this doesn't exceed image.Bounds.
+    // FIXME: once set, display it properly in the PhotoBox.
+    photo.CropRectangle = crop;
+    Console.WriteLine(crop);
+  }
+
+  void DrawCropBox() {
+    var (left, right, top, bottom) = GetCrop();
     int area = (right - left) * (bottom - top);
 
-    if (area < 100) {
+    if (area == 0) {
       return;
     }
     Color4 shadeColor = new Color4(0, 0, 0, 0.75f);
@@ -1032,10 +1071,12 @@ public class Game : GameWindow {
     if (zoomLevel > 0f) {
       scale = zoomLevel;
     }
+    activeScale = scale;
 
     Vector2i renderSize = (Vector2i) (((Vector2) active.Size) * scale);
     Vector2i center = (Vector2i) geometry.PhotoBox.Center;
     Box2i photoBox = Util.MakeBox(center.X - renderSize.X / 2, center.Y - renderSize.Y / 2, renderSize.X, renderSize.Y);
+    activeOffset = new(photoBox.Min.X, photoBox.Min.Y);
     DrawTexture(active, photoBox);
     for (int i = 0; i < 5; i++) {
       Texture star = (activePhoto.Rating > i) ? STAR_FILLED : STAR_EMPTY;
@@ -1064,13 +1105,29 @@ public class Game : GameWindow {
     // Draw status box.
     int statusPadding = 2;
     DrawFilledBox(geometry.StatusBox, Color4.Black);
-    DrawText(String.Format("{0,4}/{1,-4}", photoIndex + 1, photos.Count), geometry.StatusBox.Min.X + 72, geometry.StatusBox.Min.Y + statusPadding);
+    // First line.
-    DrawText(activePhoto.Description(), geometry.StatusBox.Min.X + 160, geometry.StatusBox.Min.Y + statusPadding);
+    int y = geometry.StatusBox.Min.Y + statusPadding;
-    DrawText(String.Format("FPS: {0,2}", fpsCounter.Fps), geometry.StatusBox.Max.X - 66, geometry.StatusBox.Min.Y + statusPadding);
+    DrawText(activePhoto.Description(), geometry.StatusBox.Min.X, y);
-
+    // Second line.
+    y += 20;
+    DrawText(String.Format("{0,4}/{1,-4}", photoIndex + 1, photos.Count), geometry.StatusBox.Min.X + 72, y);
+    DrawText(String.Format("FPS: {0,2}", fpsCounter.Fps), geometry.StatusBox.Max.X - 66, y);
     if (activePhoto.Loaded) {
-      DrawText($"{(scale * 100):F1}%", geometry.StatusBox.Min.X, geometry.StatusBox.Min.Y + statusPadding);
+      DrawText($"{(scale * 100):F1}%", geometry.StatusBox.Min.X, y);
     }
+    DrawText($"({mousePosition.X}, {mousePosition.Y})", geometry.StatusBox.Min.X + 160, y);
+    Vector2i imagePosition = ScreenToImage(mousePosition);
+    DrawText($"({imagePosition.X}, {imagePosition.Y})", geometry.StatusBox.Min.X + 320, y);
+  }
+
+  Vector2i ScreenToImage(int x, int y) {
+    return new(
+        (int) ((x - activeOffset.X) / activeScale),
+        (int) ((y - activeOffset.Y) / activeScale));
+  }
+
+  Vector2i ScreenToImage(Vector2i position) {
+    return ScreenToImage(position.X, position.Y);
   }
 
   void DrawTexture(Texture texture, int x, int y) {