[WIP - DONT MERGE] fix(fov): fov was not working correctly for other planes

packages/core/src/RenderingEngine/Viewport.ts

@@ -1129,8 +1129,25 @@ class Viewport {
       const extent = imageData.getExtent();
       const spacing = imageData.getSpacing();
 
-      widthWorld = (extent[1] - extent[0]) * spacing[0];
-      heightWorld = (extent[3] - extent[2]) * spacing[1];
+      // Determine which dimensions to use based on view plane normal
+      // The view plane normal tells us which axis we're looking along
+      const absNormal = viewPlaneNormal.map(Math.abs);
+      const maxIndex = absNormal.indexOf(Math.max(...absNormal));
+
+      // Based on which axis we're looking along, use the appropriate extents
+      if (maxIndex === 0) {
+        // Sagittal view (looking along X axis) - use Y for width, Z for height
+        widthWorld = (extent[3] - extent[2]) * spacing[1];
+        heightWorld = (extent[5] - extent[4]) * spacing[2];
+      } else if (maxIndex === 1) {
+        // Coronal view (looking along Y axis) - use X for width, Z for height
+        widthWorld = (extent[1] - extent[0]) * spacing[0];
+        heightWorld = (extent[5] - extent[4]) * spacing[2];
+      } else {
+        // Axial view (looking along Z axis) - use X for width, Y for height
+        widthWorld = (extent[1] - extent[0]) * spacing[0];
+        heightWorld = (extent[3] - extent[2]) * spacing[1];
+      }
     } else {
       ({ widthWorld, heightWorld } = this._getWorldDistanceViewUpAndViewRight(
         bounds,