Fix calculator for image data

Sources/Filters/General/Calculator/index.js

@@ -45,11 +45,14 @@ function vtkCalculator(publicAPI, model) {
     singleValueFormula,
     options = {}
   ) => ({
-    getArrays: () => ({
-      input: publicAPI.augmentInputArrays(
-        locn,
-        arrNames.map((x) => ({ location: locn, name: x }))
-      ),
+    getArrays: (inData) => ({
+      // don't augment input data array in case of structured input dataset
+      input: inData[0].isA('vtkImageData')
+        ? arrNames.map((x) => ({ location: locn, name: x }))
+        : publicAPI.augmentInputArrays(
+            locn,
+            arrNames.map((x) => ({ location: locn, name: x }))
+          ),
       output: [
         {
           location: locn,
@@ -191,7 +194,7 @@ function vtkCalculator(publicAPI, model) {
           [
             FieldDataTypes.POINT,
             (x) => x.getPointData(),
-            (x) => x.getPoints().getNumberOfPoints(),
+            (x) => x.getNumberOfPoints(),
           ],
           [
             FieldDataTypes.CELL,

Sources/Filters/General/Calculator/test/testCalculator.js

@@ -1,6 +1,7 @@
 import test from 'tape-catch';
 
 import vtkCalculator from 'vtk.js/Sources/Filters/General/Calculator';
+import vtkImageGridSource from 'vtk.js/Sources/Filters/Sources/ImageGridSource';
 import vtkPlaneSource from 'vtk.js/Sources/Filters/Sources/PlaneSource';
 import { AttributeTypes } from 'vtk.js/Sources/Common/DataModel/DataSetAttributes/Constants';
 import { FieldDataTypes } from 'vtk.js/Sources/Common/DataModel/DataSet/Constants';
@@ -93,3 +94,42 @@ test('Test vtkCalculator execution', (t) => {
 
   t.end();
 });
+
+test('make sure vtkCalculator does not crash with a vtkImageData input', (t) => {
+  const source = vtkImageGridSource.newInstance();
+  const filter = vtkCalculator.newInstance();
+
+  filter.setInputConnection(source.getOutputPort());
+  filter.setFormulaSimple(FieldDataTypes.POINT, ['scalars'], 'mask', (value) =>
+    value > 10 ? 1 : 0
+  );
+
+  source.update();
+  filter.update();
+
+  const input = source.getOutputData();
+  const output = filter.getOutputData();
+
+  t.ok(output, 'Output dataset exists');
+  t.equal(
+    output.isA('vtkImageData'),
+    true,
+    'The output dataset should be a vtkImagedata'
+  );
+  t.equal(
+    input.getNumberOfPoints(),
+    output.getNumberOfPoints(),
+    `The number of points did not change between input ${input.getNumberOfPoints()} and output ${output.getNumberOfPoints()}`
+  );
+  t.ok(
+    output.getPointData().getScalars(),
+    'Output point-scalars array exists.'
+  );
+  t.equal(
+    output.getPointData().getScalars().getName(),
+    'mask',
+    'Output point-scalars is "mask".'
+  );
+
+  t.end();
+});