fix(DataArray): update getRanges

add computeRanges arg. If set to false will clone the existing range. If true, will calculate
the ranges. Added the magnitude ranges for multi-component ranges

Author: jmannau

Sources/Common/Core/DataArray/index.js

@@ -281,7 +281,10 @@ function vtkDataArray(publicAPI, model) {
     return model.rangeTuple;
   };
 
-  publicAPI.getRanges = () => {
+  publicAPI.getRanges = (computeRanges = true) => {
+    if (!computeRanges) {
+      return structuredClone(model.ranges);
+    }
     /** @type {import('../../../interfaces').vtkRange[]} */
     const ranges = [];
     for (let i = 0; i < model.numberOfComponents; i++) {
@@ -294,6 +297,18 @@ function vtkDataArray(publicAPI, model) {
       };
       ranges.push(range);
     }
+    // where the number of components is greater than 1, the last element in
+    // the range array is the min,max magnitude of the entire dataset.
+    if (model.numberOfComponents > 1) {
+      /** @type {import('../../../interfaces').vtkRange} */
+      const [min, max] = publicAPI.getRange(-1);
+      const range = {
+        min,
+        max,
+        component: -1,
+      };
+      ranges.push(range);
+    }
     return ranges;
   };
 

Sources/Common/Core/DataArray/test/testDataArray.js

@@ -3,6 +3,10 @@ import vtkDataArray from 'vtk.js/Sources/Common/Core/DataArray';
 import { VtkDataTypes } from 'vtk.js/Sources/Common/Core/DataArray/Constants';
 import * as vtkMath from 'vtk.js/Sources/Common/Core/Math';
 
+function compareFloat(a, b) {
+  return Math.abs(a - b) < Number.EPSILON;
+}
+
 test('Test vtkDataArray instance', (t) => {
   t.ok(vtkDataArray, 'Make sure the class definition exists');
   const instance = vtkDataArray.newInstance({ size: 256 });
@@ -219,7 +223,6 @@ test('Test vtkDataArray getRange function with multi-channel data.', (t) => {
     newArray[i * 3 + 2] = i;
   }
 
-  const compareFloat = (a, b) => Math.abs(a - b) < Number.EPSILON;
   const vecRange = da.getRange(-1);
   t.ok(
     compareFloat(vecRange[0].toFixed(2), 0.0),
@@ -252,15 +255,23 @@ test('Test vtkDataArray getRanges function with multi-channel data.', (t) => {
   const ranges = da.getRanges();
 
   t.ok(
-    ranges.length === 3,
-    'getRanges should return an array of 3 vtkRange objects'
+    ranges.length === 4,
+    'getRanges should return an array of 4 vtkRange objects'
   );
   t.ok(ranges[0].min === 0, 'component:0 minimum value should be 0');
   t.ok(ranges[0].max === 255, 'component:0 maximum value should be 255');
   t.ok(ranges[1].min === 0, 'component:1 minimum value should be 0');
   t.ok(ranges[1].max === 510, 'component:1 maximum value should be 510');
   t.ok(ranges[2].min === 0, 'component:2 minimum value should be 0');
   t.ok(ranges[2].max === 765, 'component:2 maximum value should be 765');
+  t.ok(
+    ranges[2].min === 0,
+    'component:-1 vector magnitude minimum should be 0'
+  );
+  t.ok(
+    compareFloat(ranges[3].max, 954.1226336273551),
+    'component:-1 vector magnitude maximum should be 954.1226336273551'
+  );
 
   t.end();
 });