feat(readImageLocalFile): Support casting options

src/core/castImage.ts

@@ -10,16 +10,16 @@ import FloatTypes from './FloatTypes.js'
  * @param {Image} image - The input image
  * @param {CastImageOptions} options - specify the componentType and/or pixelType of the output
  */
-function castImage (inputImage: Image, options: CastImageOptions): Image {
+function castImage (inputImage: Image, options?: CastImageOptions): Image {
   const outputImageType = { ...inputImage.imageType }
 
-  if (typeof options.pixelType !== 'undefined') {
+  if (typeof options !== 'undefined' && typeof options.pixelType !== 'undefined') {
     outputImageType.pixelType = options.pixelType
     if (options.pixelType === PixelTypes.Scalar && outputImageType.components !== 1) {
       throw new Error('Cannot cast multi-component image to a scalar image')
     }
   }
-  if (typeof options.componentType !== 'undefined' && options.componentType !== inputImage.imageType.componentType) {
+  if (typeof options !== 'undefined' && typeof options.componentType !== 'undefined' && options.componentType !== inputImage.imageType.componentType) {
     outputImageType.componentType = options.componentType
   }
 
@@ -33,7 +33,7 @@ function castImage (inputImage: Image, options: CastImageOptions): Image {
   outputImage.metadata = { ...inputImage.metadata }
 
   if (inputImage.data !== null) {
-    if (typeof options.componentType !== 'undefined' && options.componentType !== inputImage.imageType.componentType) {
+    if (typeof options !== 'undefined' && typeof options.componentType !== 'undefined' && options.componentType !== inputImage.imageType.componentType) {
       switch (inputImage.imageType.componentType) {
         case IntTypes.UInt8:
         case IntTypes.Int8:

src/io/readImageLocalFile.ts

@@ -14,13 +14,16 @@ import PipelineEmscriptenModule from '../pipeline/PipelineEmscriptenModule.js'
 import findLocalImageIOPath from './internal/findLocalImageIOPath.js'
 import InterfaceTypes from '../core/InterfaceTypes.js'
 import PipelineInput from '../pipeline/PipelineInput.js'
+import CastImageOptions from '../core/CastImageOptions.js'
+import castImage from '../core/castImage.js'
 
 /**
  * Read an image from a file on the local filesystem in Node.js.
  *
  * @param: filePath path to the file on the local filesystem.
+ * @param {CastImageOptions} options - specify the componentType and/or pixelType of the output
  */
-async function readImageLocalFile (filePath: string): Promise<Image> {
+async function readImageLocalFile (filePath: string, options?: CastImageOptions): Promise<Image> {
   const imageIOsPath = findLocalImageIOPath()
   const absoluteFilePath = path.resolve(filePath)
   const mimeType = mime.lookup(absoluteFilePath)
@@ -58,7 +61,13 @@ async function readImageLocalFile (filePath: string): Promise<Image> {
   const mountedFilePath = readImageModule.mountContainingDir(absoluteFilePath)
   const { outputs } = runPipelineEmscripten(readImageModule, args, desiredOutputs, inputs)
   readImageModule.unmountContainingDir(mountedFilePath)
-  return outputs[0].data as Image
+  let result = outputs[0].data as Image
+
+  if (typeof options !== 'undefined') {
+    result = castImage(result, options)
+  }
+
+  return result
 }
 
 export default readImageLocalFile

test/node/io/image/readImageLocalFileTest.js

@@ -5,22 +5,41 @@ import { IntTypes, PixelTypes, getMatrixElement, readImageLocalFile } from '../.
 
 const testFilePath = path.resolve('build-emscripten', 'ExternalData', 'test', 'Input', 'cthead1.png')
 
-test('readImageLocalFile reads a file path given on the local filesystem', t => {
-  return readImageLocalFile(testFilePath).then(function (image) {
-    t.is(image.imageType.dimension, 2)
-    t.is(image.imageType.componentType, IntTypes.UInt8)
-    t.is(image.imageType.pixelType, PixelTypes.RGB)
-    t.is(image.imageType.components, 3)
-    t.is(image.origin[0], 0.0)
-    t.is(image.origin[1], 0.0)
-    t.is(image.spacing[0], 1.0)
-    t.is(image.spacing[1], 1.0)
-    t.is(getMatrixElement(image.direction, 2, 0, 0), 1.0)
-    t.is(getMatrixElement(image.direction, 2, 0, 1), 0.0)
-    t.is(getMatrixElement(image.direction, 2, 1, 0), 0.0)
-    t.is(getMatrixElement(image.direction, 2, 1, 1), 1.0)
-    t.is(image.size[0], 256)
-    t.is(image.size[1], 256)
-    t.is(image.data.length, 196608)
-  })
+function verifyImage(t, image, componentType, pixelType) {
+  t.is(image.imageType.dimension, 2)
+  t.is(image.imageType.componentType, componentType)
+  t.is(image.imageType.pixelType, pixelType)
+  t.is(image.imageType.components, 3)
+  t.is(image.origin[0], 0.0)
+  t.is(image.origin[1], 0.0)
+  t.is(image.spacing[0], 1.0)
+  t.is(image.spacing[1], 1.0)
+  t.is(getMatrixElement(image.direction, 2, 0, 0), 1.0)
+  t.is(getMatrixElement(image.direction, 2, 0, 1), 0.0)
+  t.is(getMatrixElement(image.direction, 2, 1, 0), 0.0)
+  t.is(getMatrixElement(image.direction, 2, 1, 1), 1.0)
+  t.is(image.size[0], 256)
+  t.is(image.size[1], 256)
+  t.is(image.data.length, 196608)
+}
+
+test('readImageLocalFile reads a file path given on the local filesystem', async t => {
+  const image = await readImageLocalFile(testFilePath)
+  const componentType = IntTypes.UInt8
+  const pixelType = PixelTypes.RGB
+  verifyImage(t, image, componentType, pixelType)
+})
+
+test('readImageLocalFile casts to the specified componentType', async t => {
+  const componentType = IntTypes.UInt16
+  const image = await readImageLocalFile(testFilePath, { componentType })
+  const pixelType = PixelTypes.RGB
+  verifyImage(t, image, componentType, pixelType)
 })
+
+test('readImageLocalFile casts to the specified pixelType', async t => {
+  const pixelType = PixelTypes.Vector
+  const image = await readImageLocalFile(testFilePath, { pixelType })
+  const componentType = IntTypes.UInt8
+  verifyImage(t, image, componentType, pixelType)
+})