add focal length to EXIF display & tweak other EXIF display

Program.cs

@@ -142,8 +142,15 @@ void main() {
 
 // FIXME: this should probably be IDisposable?
 public class Photo {
-  public bool Loaded = false;
   public string File;
+  public bool Loaded = false;
+  public string? CameraModel;
+  public string? LensModel;
+  public string FocalLength = "<unk>";
+  public string FNumber = "<unk>";
+  public string ExposureTime = "<unk>";
+  public string IsoSpeed = "<unk>";
+
   private Texture texture;
   private Texture placeholder;
   private Image<Rgba32>? image = null;
@@ -158,11 +165,60 @@ public class Photo {
     image = await Image.LoadAsync<Rgba32>(File);
     ExifProfile? exifs = image.Metadata.ExifProfile;
     if (exifs != null) {
-      foreach (IExifValue exif in exifs.Values) {
-        if (exif.Tag.ToString() == "Model") {
-          Console.WriteLine($"{File} {exif.Tag}: {exif.GetValue()}");
+      // FIXME: handle Orientation
+      IExifValue<string>? model;
+      if (exifs.TryGetValue(ExifTag.Model, out model)) {
+        CameraModel = model.Value;
+      }
+      IExifValue<string>? lensModel;
+      if (exifs.TryGetValue(ExifTag.LensModel, out lensModel)) {
+        LensModel = lensModel.Value;
+      }
+
+      IExifValue<Rational>? focalLength;
+      if (exifs.TryGetValue(ExifTag.FocalLength, out focalLength)) {
+        Rational r = focalLength.Value;
+        FocalLength = $"{r.Numerator / r.Denominator}mm";
+      }
+
+      IExifValue<Rational>? fNumber;
+      if (exifs.TryGetValue(ExifTag.FNumber, out fNumber)) {
+        Rational r = fNumber.Value;
+        if (r.Denominator == 1) {
+          FNumber = $"f/{r.Numerator}";
+        } else {
+          // FIXME: assert that numerator is 10
+          if (r.Numerator % 10 == 0) {
+            FNumber = $"f/{r.Numerator / 10}";
+          } else {
+            FNumber= $"f/{r.Numerator / 10}.{r.Numerator % 10}";
+          }
         }
       }
+
+      IExifValue<Rational>? exposureTime;
+      if (exifs.TryGetValue(ExifTag.ExposureTime, out exposureTime)) {
+        Rational r = exposureTime.Value;
+        if (r.Numerator == 1) {
+          ExposureTime = $"1/{r.Denominator}";
+        } else if (r.Numerator == 10) {
+          ExposureTime = $"1/{r.Denominator / 10}";
+        } else {
+          Console.WriteLine("*** WARNING: unexpected ExposureTime numerator");
+          ExposureTime = r.ToString();
+        }
+      }
+
+      IExifValue<ushort[]>? isoSpeed;
+      if (exifs.TryGetValue(ExifTag.ISOSpeedRatings, out isoSpeed)) {
+        ushort[]? iso = isoSpeed.Value;
+        if (iso != null && iso.Length >= 1) {
+          IsoSpeed = $"ISO {iso[0]}";
+        }
+      }
+      // foreach (IExifValue exif in exifs.Values) {
+      //   Console.WriteLine(exif.Tag.ToString() + " " + exif.GetValue().ToString());
+      // }
     }
   }
 
@@ -175,6 +231,15 @@ public class Photo {
     }
     return texture;
   }
+
+  public string Description() {
+    if (Loaded) {
+      string shootingInfo = $"{FocalLength}, {FNumber} at {ExposureTime}, {IsoSpeed}";
+      return String.Format("{0,-40} {1,-50} {2}", shootingInfo, $"{CameraModel} {LensModel}", File);
+    } else {
+      return String.Format("{0,-90}  {1}", "", File);
+    }
+  }
 }
 
 public class Texture : IDisposable {
@@ -293,7 +358,6 @@ public static class Util {
     image.Dispose();
     return texture;
   }
-
 }
 
 public class Game : GameWindow {
@@ -435,8 +499,10 @@ public class Game : GameWindow {
     // Load textures from JPEGs.
     string[] files = Directory.GetFiles(@"c:\users\colin\desktop\photos-test\");
     // string[] files = Directory.GetFiles(@"c:\users\colin\pictures\photos\2023\07\14\");
+    // string[] files = Directory.GetFiles(@"G:\DCIM\100EOSR6\");
     // string[] files = Directory.GetFiles(@"C:\Users\colin\Pictures\photos\2018\06\23");
     // string[] files = Directory.GetFiles(@"C:\Users\colin\Desktop\Germany all\104D7000");
+    // string[] files = Directory.GetFiles(@"C:\Users\colin\Desktop\many-birds\");
 
     for (int i = 0; i < files.Count(); i++) {
       string file = files[i];
@@ -444,7 +510,9 @@ public class Game : GameWindow {
         Photo photo = new Photo(file, TEXTURE_WHITE);
         photos.Add(photo);
         await Task.Run( () => { photo.Load(); });
-        Console.WriteLine("file " + i);
+        if (photos.Count == 100) {
+          break;
+        }
       }
     }
   }
@@ -494,7 +562,7 @@ public class Game : GameWindow {
     }
 
     // Draw status box.
-    DrawText(activePhoto.File, geometry.StatusBox.Min.X + 80, geometry.StatusBox.Min.Y);
+    DrawText(activePhoto.Description(), geometry.StatusBox.Min.X + 80, geometry.StatusBox.Min.Y);
     if (activePhoto.Loaded) {
       DrawText($"{(scale * 100):F1}%", geometry.StatusBox.Min.X, geometry.StatusBox.Min.Y);
     }