feat(cpr): useStretchedMode accepts null argument

Author: bruyeret

Sources/Rendering/Core/ImageCPRMapper/index.d.ts

@@ -215,7 +215,7 @@ export interface vtkImageCPRMapper extends vtkAbstractMapper3D {
 	 * Configure the mapper and the centerline to be in strectched CPR mode
 	 * @param centerPoint The center point, optional, default to the first point of the centerline or [0, 0, 0]
 	 */
-	useStretchedMode(centerPoint?: vec3): void;
+	useStretchedMode(centerPoint?: Nullable<vec3>): void;
 
 	/**
 	 * Set the polydata used as a centerline

Sources/Rendering/Core/ImageCPRMapper/index.js

@@ -280,7 +280,7 @@ function vtkImageCPRMapper(publicAPI, model) {
   publicAPI.useStretchedMode = (centerPoint) => {
     const centerline = publicAPI.getOrientedCenterline();
     // Set center point
-    if (centerPoint === undefined) {
+    if (!centerPoint) {
       // Get the first point of the centerline if there is one
       const centerlinePoints = centerline.getPoints();
       const newCenterPoint =