Tighter UI for Pinhole and when hovering images

crates/re_data_ui/src/pinhole.rs

@@ -11,6 +11,17 @@ impl DataUi for PinholeProjection {
         verbosity: UiVerbosity,
         query: &re_arrow_store::LatestAtQuery,
     ) {
+        if verbosity == UiVerbosity::Small {
+            // See if this is a trivial pinhole, and can be displayed as such:
+            let fl = self.focal_length_in_pixels();
+            let pp = self.principal_point();
+            if *self == Self::from_focal_length_and_principal_point(fl, pp) {
+                ui.label(format!("Focal length: {fl}\nPrincipal point: {pp}"))
+                    .on_hover_ui(|ui| self.data_ui(ctx, ui, UiVerbosity::Reduced, query));
+                return;
+            }
+        }
+
         self.0.data_ui(ctx, ui, verbosity, query);
     }
 }

crates/re_types/src/components/pinhole_projection_ext.rs

@@ -3,6 +3,20 @@ use crate::datatypes::Vec2D;
 use super::PinholeProjection;
 
 impl PinholeProjection {
+    #[inline]
+    pub fn from_focal_length_and_principal_point(
+        focal_length: impl Into<Vec2D>,
+        principal_point: impl Into<Vec2D>,
+    ) -> Self {
+        let fl = focal_length.into();
+        let pp = principal_point.into();
+        Self::from([
+            [fl.x(), 0.0, 0.0],
+            [0.0, fl.y(), 0.0],
+            [pp.x(), pp.y(), 1.0],
+        ])
+    }
+
     /// X & Y focal length in pixels.
     ///
     /// [see definition of intrinsic matrix](https://en.wikipedia.org/wiki/Camera_resectioning#Intrinsic_parameters)
@@ -43,3 +57,12 @@ impl PinholeProjection {
         .extend(pixel.z)
     }
 }
+
+#[test]
+fn test_pinhole() {
+    let fl = Vec2D::from([600.0, 600.0]);
+    let pp = glam::Vec2::from([300.0, 240.0]);
+    let pinhole = PinholeProjection::from_focal_length_and_principal_point(fl, pp);
+    assert_eq!(pinhole.focal_length_in_pixels(), fl);
+    assert_eq!(pinhole.principal_point(), pp);
+}