Building vtkITK Lib with Emscripten

I just read @matt.mccormick answer to @prashanth.dumpuri about building with Emscripten for beginners (Building ITK with emscripten - #5 by matt.mccormick) and it helped me a lot.

I am using insighttoolkit/itk-js in docker and it works great for both examples mentioned there (Hello World and Median filter test). I can build javascript (as well as wasm), run it with runPipelineNode and runPipelineBrowser.

Can I do the same with the content of vtkItk Library (Slicer/Libs/vtkITK at 08789e8f2224f89206b2d6a49d1d452d4e677994 · Slicer/Slicer · GitHub)? Is it possible to define CmakeLists.txt and a proper pipeline for vtkItkLevelTracingImageFilter in main function, so it can be converted to javascript?

I need to use vtkItkLevelTracingImageFilter to generate vtkPolyData. However, I do not know if I can convert vtkItk Library with Emscripten to js at all.
I did a small experiment : just added #include “vtkItkLevelTracingImageFilter.h” to MedianFilterTest.cxx code and then I had error as below

I will appreciate any help

shared:ERROR: '/emsdk_portable/fastcomp/fastcomp/bin/clang++ -target asmjs-unknown-emscripten -D__EMSCRIPTEN_major__=1 -D__EMSCRIPTEN_minor__=39 -D__EMSCRIPTEN_tiny__=10 -D_LIBCPP_ABI_VERSION=2 -Werror=implicit-function-declaration -Xclang -nostdsysteminc -Xclang -isystem/emsdk_portable/fastcomp/emscripten/system/include/libcxx -Xclang -isystem/emsdk_portable/fastcomp/emscripten/system/lib/libcxxabi/include -Xclang -isystem/emsdk_portable/fastcomp/emscripten/system/include/compat -Xclang -isystem/emsdk_portable/fastcomp/emscripten/system/include -Xclang -isystem/emsdk_portable/fastcomp/emscripten/system/include/libc -Xclang -isystem/emsdk_portable/fastcomp/emscripten/system/lib/libc/musl/arch/emscripten -Xclang -isystem/emsdk_portable/fastcomp/emscripten/system/local/include -Xclang -isystem/emsdk_portable/.data/cache/asmjs/include -DITK_IO_FACTORY_REGISTER_MANAGER -IITKFactoryRegistration -I/ITK/Modules/Filtering/Smoothing/include -I/ITK/Modules/Filtering/ImageFilterBase/include -I/ITK/Modules/Core/Transform/include -I/ITK-build/Modules/ThirdParty/Netlib -I/ITK/Modules/Numerics/Statistics/include -I/ITK/Modules/Core/ImageAdaptors/include -I/ITK/Modules/Core/ImageFunction/include -I/ITK/Modules/IO/ImageBase/include -I/ITK-build/Modules/IO/ImageBase -I/ITK-build/Modules/ThirdParty/VNL/src/vxl/core -I/ITK-build/Modules/ThirdParty/VNL/src/vxl/vcl -I/ITK-build/Modules/ThirdParty/VNL/src/vxl/v3p/netlib -I/ITK/Modules/ThirdParty/VNL/src/vxl/core -I/ITK/Modules/ThirdParty/KWIML/src -I/ITK-build/Modules/ThirdParty/KWIML/src -I/ITK-build/Modules/ThirdParty/Eigen3/src -I/ITK/Modules/Core/Common/include -I/ITK-build/Modules/Core/Common -I/ITKBridgeJavaScript-build/include -I/ITKBridgeJavaScript/include -isystem /ITK/Modules/ThirdParty/VNL/src/vxl/vcl -isystem /ITK/Modules/ThirdParty/VNL/src/vxl/v3p/netlib -isystem /ITK-build/Modules/ThirdParty/KWSys/src -isystem /ITK/Modules/ThirdParty/Eigen3/src/itkeigen/.. -isystem /ITK/Modules/ThirdParty/VNL/src/vxl/core/vnl/algo -isystem /ITK/Modules/ThirdParty/VNL/src/vxl/core/vnl -isystem /ITK-build/Modules/ThirdParty/VNL/src/vxl/core/vnl -std=c++11 -DNDEBUG -O2 -std=gnu++11 -MD -MT CMakeFiles/MedianFilterTest.dir/MedianFilterTest.cxx.o -MF CMakeFiles/MedianFilterTest.dir/MedianFilterTest.cxx.o.d -c -DEMSCRIPTEN -mllvm -disable-llvm-optzns ../MedianFilterTest.cxx -Xclang -disable-O0-optnone -Xclang -isystem/emsdk_portable/fastcomp/emscripten/system/include/SDL -c -o CMakeFiles/MedianFilterTest.dir/MedianFilterTest.cxx.o -emit-llvm' failed (1)
ninja: build stopped: subcommand failed.
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Hi @Andrzej_Marciniak ,

Thanks for sharing your success with itk.js!

Yes, it should be possible. A Docker image is provided with both ITK and VTK available, and if your CMakeList.txt contains find_package(ITK) or find_package(VTK), they will be found without any other steps required. To use this kitware/itk-js-vtk image, specify it via the itk-js CLI:

$ itk-js build --image kitware/itk-js-vtk:latest my/source/path

Also, note that recent versions of itk-js Docker images ship with support for SlicerExecutionModel CLI’s.

Thank you Matt! It is a very helpful answer!

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I am new to itk-wasm and itk.js. I want to use both in my application. i am trying NodeHelloWorld example from itk-wasm. this is what i have done:
if you read the example in the itk-wasm you would see after you do npx itk-wasm build the running docker downloads and calls itk-wasm/emscripten toolchain and build everything into web-build folder. at the last stage i have following code in index.js file:

const path = require(‘path’)
const runPipelineNode = require(‘itk/runPipelineNode’)

const pipelinePath = path.resolve(__dirname, ‘web-build’, ‘hello’)

and then i run [npx run index.js] i get the following error:

npx node .\index.js
throw err;

Error: Cannot find module ‘itk/runPipelineNode’
Require stack:

  • E:\Projects\vs2019\react\ITK-JS\NodeHelloWorld_1\index.js
    at Function.Module._resolveFilename (node:internal/modules/cjs/loader:933:15)
    at Function.Module._load (node:internal/modules/cjs/loader:778:27)
    at Module.require (node:internal/modules/cjs/loader:1005:19)
    at require (node:internal/modules/cjs/helpers:102:18)
    at Object. (E:\Projects\vs2019\react\ITK-JS\NodeHelloWorld_1\index.js:2:25)
    at Module._compile (node:internal/modules/cjs/loader:1105:14)
    at Object.Module._extensions…js (node:internal/modules/cjs/loader:1159:10)
    at Module.load (node:internal/modules/cjs/loader:981:32)
    at Function.Module._load (node:internal/modules/cjs/loader:822:12)
    at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:77:12) {
    code: ‘MODULE_NOT_FOUND’,
    requireStack: [ ‘E:\Projects\vs2019\react\ITK-JS\NodeHelloWorld_1\index.js’ ]

why it does not run the helloworld example in node.js? am i missing something here? should i import 'itk/runPipelineNode?

i appreciate if you send me these examples you shared with matt maccormic, I am basically image processing developer, and i need to work with web as well to build an application, so i need some median filter from itk or some segmentation or registration example.
I could not find itk.js repo? because i get forwarded to the itk-wasm?!

i apprecaite your help.
date: 2022-06-02

I am sorry that I will not be able to help you much, but I haven’t been touching itk for over a year, and I do not remember details. Since the .js code generated by Emscripten was not meeting my performance requirements, I have decided to not use it (implement my own filters in js).

Moreover, I have never been using itk-wasm - I was just using itk v.“9.3.2”. According to what you wrote, it seems to me that you just do not have dependecies in node_modules. Please look at my package.json and package-lock.json files below - I had installed itk in node_modules with “runPipelineNode”. Maybe
npm i itk
would make it work?

As I wrote, I do not remember what exactly I was doing, but I made this short instruction for myself (below you will find files) so maybe this will help:

Compilation and running of pipelines with Emscripten

  1. Be sure that docker is running.

  2. Use Ubuntu or git bash

    cd ../WebstormProjects/nodehelloworld

  3. Prepare CMakeLists.txt file (see examples) and execute in Ubuntu bash:

    ./insighttoolkit-itk-js-latest web-build

  4. Prepare runPipelineNode (see index.js, medianTest.js) and execute for example:

npx node ./medianTest.js
npx node ./index.js


Example of segmentation pipeline written ITK / C++ (see links inside):

package.json (328 Bytes)
package-lock.json (6.3 KB)

medianTest.js (199 Bytes)
MedianFilterTest.cxx (3.4 KB)

index.js (185 Bytes)
hello.cxx (98 Bytes)
CMakeLists.txt_old2 (562 Bytes)
CMakeLists.txt_old (235 Bytes)
insighttoolkit-itk-js-latest (5.7 KB)
CMakeLists.txt (468 Bytes)

I hope this will help, because really I am not an expert with this (i managed to compile a few simple examples, that’s all)
Good luck!

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