more cropbox work

Program.cs

@@ -639,7 +639,6 @@ public class Game : GameWindow {
   int ribbonIndex = 0;
   Vector2i mouseDragStart;
   Vector2i mouseDragEnd;
-  bool mouseDragging;
   Shader shader = new();
   Matrix4 projection;
   float zoomLevel = 0f;
@@ -655,44 +654,48 @@ public class Game : GameWindow {
 
     // FIXME: add a confirm dialog before closing. (Also for the window-close button.)
     // FIXME: don't quit if there's pending file-write operations.
-    // Close when Escape is pressed.
-    if (input.IsKeyPressed(Keys.Escape)) {
+    // Close when Ctrl-Q is pressed.
+    if (input.IsKeyPressed(Keys.Q) && ctrlIsDown) {
       Close();
     }
 
+    int lastPhotoIndex = photoIndex;
+
+    Vector2i mousePosition = (Vector2i) MouseState.Position;
+
     // Look for mouse clicks on thumbnails or stars.
     //
     // Note that we don't bounds-check photoIndex until after all the possible
     // inputs that might affect it. That simplifies this logic significantly.
     if (MouseState.IsButtonPressed(MouseButton.Button1)) {
-      Vector2i click = (Vector2i) MouseState.Position;
 
       for (int i = 0; i < geometry.StarBoxes.Count; i++) {
-        if (geometry.StarBoxes[i].ContainsInclusive(click)) {
+        if (geometry.StarBoxes[i].ContainsInclusive(mousePosition)) {
           photos[photoIndex].Rating = i + 1;
         }
       }
 
       for (int i = 0; i < geometry.ThumbnailBoxes.Count; i++) {
-        if (geometry.ThumbnailBoxes[i].ContainsInclusive(click)) {
+        if (geometry.ThumbnailBoxes[i].ContainsInclusive(mousePosition)) {
           photoIndex = ribbonIndex + i;
         }
       }
 
-      if (geometry.PhotoBox.ContainsInclusive(click)) {
-        mouseDragging = true;
-        mouseDragStart = click;
+      if (geometry.PhotoBox.ContainsInclusive(mousePosition)) {
+        mouseDragStart = mousePosition;
       }
     }
 
-
     if (MouseState.IsButtonDown(MouseButton.Button1)) {
-      // FIXME: really this should be clipped to the active photo's drawable area, not the whole photobox.
-      mouseDragEnd = new Vector2i(
-          Math.Clamp((int) MouseState.Position.X, geometry.PhotoBox.Min.X, geometry.PhotoBox.Max.X),
-          Math.Clamp((int) MouseState.Position.Y, geometry.PhotoBox.Min.Y, geometry.PhotoBox.Max.Y));
-    } else {
-      mouseDragging = false;
+      if (geometry.PhotoBox.ContainsInclusive(mousePosition)) {
+        // FIXME: really this should be clipped to the active photo's drawable area, not the whole photobox.
+        mouseDragEnd = mousePosition;
+      }
+    }
+
+    if (input.IsKeyPressed(Keys.Escape)) {
+      mouseDragStart = new(-1, -1);
+      mouseDragEnd = new(-1, -1);
     }
 
     if (MouseState.IsButtonPressed(MouseButton.Button4)) {
@@ -745,6 +748,11 @@ public class Game : GameWindow {
       photoIndex = Math.Clamp(photoIndex, 0, photos.Count - 1);
     }
 
+    if (photoIndex != lastPhotoIndex) {
+      mouseDragStart = new(-1, -1);
+      mouseDragEnd = new(-1, -1);
+    }
+
     // Handle presses of the "rating" keys -- 0-5 and `.
     // A normal press just sets the rating of the current photo.
     // If the user is holding "shift", we instead filter to only show photos of that rating or higher.
@@ -980,19 +988,30 @@ public class Game : GameWindow {
       DrawText("No photos found.", 10, 10);
     }
 
-    if (mouseDragging) {
-      DrawCropBox();
-    }
+    DrawCropBox();
 
     SwapBuffers();
   }
 
   void DrawCropBox() {
-    int left = Math.Min(mouseDragStart.X, mouseDragEnd.X);
-    int right = Math.Max(mouseDragStart.X, mouseDragEnd.X);
-    int top = Math.Min(mouseDragStart.Y, mouseDragEnd.Y);
-    int bottom = Math.Max(mouseDragStart.Y, mouseDragEnd.Y);
-
+    Vector2i start = mouseDragStart;
+    Vector2i end = mouseDragEnd;
+    end.Y = Math.Min(end.Y, start.Y + (end.X - start.X) * 4 / 6);
+    end.X = start.X + (end.Y - start.Y) * 6 / 4;
+    int left = Math.Min(start.X, end.X);
+    int right = Math.Max(start.X, end.X);
+    int top = Math.Min(start.Y, end.Y);
+    int bottom = Math.Max(start.Y, end.Y);
+    int area = (right - left) * (bottom - top);
+
+    if (area < 100) {
+      return;
+    }
+    Color4 shadeColor = new Color4(0, 0, 0, 0.75f);
+    DrawFilledBox(new Box2i(0, 0, left, geometry.PhotoBox.Max.Y), shadeColor);
+    DrawFilledBox(new Box2i(left, 0, geometry.PhotoBox.Max.X, top), shadeColor);
+    DrawFilledBox(new Box2i(left, bottom, geometry.PhotoBox.Max.X, geometry.PhotoBox.Max.Y), shadeColor);
+    DrawFilledBox(new Box2i(right, top, geometry.PhotoBox.Max.X, bottom), shadeColor);
     DrawBox(new Box2i(left, top, right, bottom), 1, Color4.White);
     DrawBox(new Box2i(left - 1, top - 1 , right + 1, bottom + 1), 1, Color4.Black);
     DrawBox(new Box2i(left - 2, top - 2 , right + 2, bottom + 2), 1, Color4.White);