use globalCoordinateSpace.units in defaultProperties rather than assuming meters

Author: chrisj

src/annotation/index.ts

@@ -56,6 +56,7 @@ import { getRandomHexString } from "#src/util/random.js";
 import { NullarySignal, Signal } from "#src/util/signal.js";
 import { formatLength } from "#src/util/spatial_units.js";
 import { Uint64 } from "#src/util/uint64.js";
+import { ALLOWED_UNITS } from "#src/widget/scale_bar.js";
 
 export type AnnotationId = string;
 
@@ -703,6 +704,7 @@ export interface AnnotationTypeHandler<T extends Annotation = Annotation> {
   defaultProperties: (
     annotation: T,
     scales: Float64Array,
+    units: readonly string[],
   ) => {
     properties: AnnotationNumericPropertySpec[];
     values: number[];
@@ -826,30 +828,43 @@ export const annotationTypeHandlers: Record<
       callback(annotation.pointA, false);
       callback(annotation.pointB, false);
     },
-    defaultProperties(annotation: Line, scales: Float64Array) {
+    defaultProperties(
+      annotation: Line,
+      scales: Float64Array,
+      units: readonly string[],
+    ) {
       const properties: AnnotationNumericPropertySpec[] = [];
       const values: number[] = [];
       const rank = scales.length;
       if (
         rank === annotation.pointA.length &&
         rank === annotation.pointB.length
       ) {
-        properties.push({
-          type: "float32",
-          identifier: "Length",
-          default: 0,
-          description: "Length of the line annotation in nanometers",
-          format: formatLength,
-        });
+        let validLength = true;
         let length = 0;
         for (let dim = 0; dim < rank; dim++) {
+          const unitInfo = ALLOWED_UNITS.find((x) => x.unit === units[dim]);
+          if (!unitInfo) {
+            validLength = false;
+            break;
+          }
+          const voxelToNanometers = scales[dim] * unitInfo.lengthInNanometers;
           length +=
-            (((annotation.pointA[dim] - annotation.pointB[dim]) / 1e-9) *
-              scales[dim]) **
+            ((annotation.pointA[dim] - annotation.pointB[dim]) *
+              voxelToNanometers) **
             2;
         }
-        length = Math.sqrt(length);
-        values.push(length);
+        if (validLength) {
+          properties.push({
+            type: "float32",
+            identifier: "Length",
+            default: 0,
+            description: "Length of the line annotation in nanometers",
+            format: formatLength,
+          });
+          length = Math.sqrt(length);
+          values.push(length);
+        }
       }
       return { properties, values };
     },
@@ -897,9 +912,14 @@ export const annotationTypeHandlers: Record<
     visitGeometry(annotation: Point, callback) {
       callback(annotation.point, false);
     },
-    defaultProperties(annotation: Point, scales: Float64Array) {
+    defaultProperties(
+      annotation: Point,
+      scales: Float64Array,
+      units: string[],
+    ) {
       annotation;
       scales;
+      units;
       return { properties: [], values: [] };
     },
   },
@@ -973,9 +993,11 @@ export const annotationTypeHandlers: Record<
     defaultProperties(
       annotation: AxisAlignedBoundingBox,
       scales: Float64Array,
+      units: string[],
     ) {
       annotation;
       scales;
+      units;
       return { properties: [], values: [] };
     },
   },
@@ -1046,9 +1068,14 @@ export const annotationTypeHandlers: Record<
       callback(annotation.center, false);
       callback(annotation.radii, true);
     },
-    defaultProperties(annotation: Ellipsoid, scales: Float64Array) {
+    defaultProperties(
+      annotation: Ellipsoid,
+      scales: Float64Array,
+      units: string[],
+    ) {
       annotation;
       scales;
+      units;
       return { properties: [], values: [] };
     },
   },

src/ui/annotations.ts

@@ -1858,7 +1858,11 @@ export function UserLayerWithAnnotationsMixin<
                   this.manager.root.coordinateSpace.value;
                 const defaultProperties = annotationTypeHandlers[
                   annotation.type
-                ].defaultProperties(annotation, globalCoordinateSpace.scales);
+                ].defaultProperties(
+                  annotation,
+                  globalCoordinateSpace.scales,
+                  globalCoordinateSpace.units,
+                );
                 const allProperties = [
                   ...defaultProperties.properties,
                   ...properties,