fix: planar freehand roi perimeter calculation (#2341)

* fix: planar freehand roi perimeter calculation

* fix: Perimeter calculation

---------

Co-authored-by: Bill Wallace <[email protected]>

Author: arul-trenser

packages/tools/src/tools/annotation/PlanarFreehandROITool.ts

@@ -865,13 +865,11 @@ class PlanarFreehandROITool extends ContourSegmentationBaseTool {
       } else {
         this.updateOpenCachedStats({
           metadata,
-          canvasCoordinates,
           targetId,
           cachedStats,
           modalityUnit,
           calibratedScale,
-          deltaInX,
-          deltaInY,
+          points,
         });
       }
     }
@@ -946,8 +944,7 @@ class PlanarFreehandROITool extends ContourSegmentationBaseTool {
     // Convert from canvas_pixels ^2 to mm^2
     area *= deltaInX * deltaInY;
 
-    let perimeter = calculatePerimeter(canvasCoordinates, closed) / scale;
-    perimeter *= Math.sqrt(Math.pow(deltaInX, 2) + Math.pow(deltaInY, 2));
+    const perimeter = calculatePerimeter(points, closed) / scale;
 
     // Expand bounding box
     const iDelta = 0.01 * (iMax - iMin);
@@ -1043,17 +1040,14 @@ class PlanarFreehandROITool extends ContourSegmentationBaseTool {
   protected updateOpenCachedStats({
     targetId,
     metadata,
-    canvasCoordinates,
     cachedStats,
     modalityUnit,
     calibratedScale,
-    deltaInX,
-    deltaInY,
+    points,
   }) {
     const { scale, unit } = calibratedScale;
 
-    let length = calculatePerimeter(canvasCoordinates, closed) / scale;
-    length *= Math.sqrt(Math.pow(deltaInX, 2) + Math.pow(deltaInY, 2));
+    const length = calculatePerimeter(points, closed) / scale;
 
     cachedStats[targetId] = {
       Modality: metadata.Modality,

packages/tools/src/utilities/contours/calculatePerimeter.ts

@@ -1,28 +1,30 @@
+import type { Types } from '@cornerstonejs/core';
+import { vec3 } from 'gl-matrix';
+
 /**
  * Calculates the perimeter of a polyline.
  *
  * @param polyline - The polyline represented as an array of points.
  * @param closed - Indicates whether the polyline is closed or not.
  * @returns The perimeter of the polyline.
  */
-function calculatePerimeter(polyline: number[][], closed: boolean): number {
+export function calculatePerimeter(
+  polyline: number[][],
+  closed: boolean
+): number {
   let perimeter = 0;
 
   for (let i = 0; i < polyline.length - 1; i++) {
-    const point1 = polyline[i];
-    const point2 = polyline[i + 1];
-    perimeter += Math.sqrt(
-      Math.pow(point2[0] - point1[0], 2) + Math.pow(point2[1] - point1[1], 2)
-    );
+    const point1 = polyline[i] as Types.Point3;
+    const point2 = polyline[i + 1] as Types.Point3;
+
+    perimeter += vec3.dist(point1, point2);
   }
 
   if (closed) {
-    const firstPoint = polyline[0];
-    const lastPoint = polyline[polyline.length - 1];
-    perimeter += Math.sqrt(
-      Math.pow(lastPoint[0] - firstPoint[0], 2) +
-        Math.pow(lastPoint[1] - firstPoint[1], 2)
-    );
+    const firstPoint = polyline[0] as Types.Point3;
+    const lastPoint = polyline[polyline.length - 1] as Types.Point3;
+    perimeter += vec3.dist(firstPoint, lastPoint);
   }
 
   return perimeter;