# mac m1 and vtk
**URL:** https://discourse.vtk.org/t/mac-m1-and-vtk/13305
**Category:** Support
**Tags:** python
**Created:** [February 12, 2024, 8:34pm UTC](https://discourse.vtk.org/t/mac-m1-and-vtk/13305 "2024-02-12T20:34:57Z")
**Posts on this page:** 7
**Page:** 1
### Author:  [@DrMainIT](https://discourse.vtk.org/u/DrMainIT)
#### Post date: [February 12, 2024, 8:34pm UTC](https://discourse.vtk.org/t/mac-m1-and-vtk/13305/1 "2024-02-12T20:34:57Z")
i’m trying to run this function using vtk on a mac m1. i think the problem is with my OS and not the code itself since on another OS like windows it works
```auto
def get_thumbnail(PDF, axis):
## some code that work and create the actor
renderer = vtkRenderer()
renderer.AddActor(actor)
window = vtkRenderWindow()
window.SetOffScreenRendering(1)
window.AddRenderer(renderer)
interactor = vtkRenderWindowInteractor()
interactor.SetInteractorStyle(vtkInteractorStyleImage())
window.SetInteractor(interactor)
## HERE THE CODE GIVES THE ERROR
window.Render()
w2if = vtkWindowToImageFilter() # noqa
w2if.SetInput(window)
w2if.Update()
return w2if
```
getting the following error the problem suggest that i have to handle the invalidation on the Main Thread is there a way to do so that provide vtk itself
```auto
2024-02-11 21:29:43.958 python[29661:3966927] *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'NSWindow drag regions should only be invalidated on the Main Thread!'
*** First throw call stack:
(
0 CoreFoundation 0x000000018cb27154 __exceptionPreprocess + 176
1 libobjc.A.dylib 0x000000018c6464d4 objc_exception_throw + 60
2 CoreFoundation 0x000000018cb503a0 _CFBundleGetValueForInfoKey + 0
3 AppKit 0x000000018fcf0a00 -[NSWindow(NSWindow_Theme) _postWindowNeedsToResetDragMarginsUnlessPostingDisabled] + 320
4 AppKit 0x000000018fcdecd4 -[NSWindow _initContent:styleMask:backing:defer:contentView:] + 816
5 AppKit 0x000000018fcde998 -[NSWindow initWithContentRect:styleMask:backing:defer:] + 48
6 libvtkRenderingOpenGL2-9.3.dylib 0x000000010ad8fdf8 _ZN20vtkCocoaRenderWindow13CreateAWindowEv + 1280
7 libvtkRenderingOpenGL2-9.3.dylib 0x000000010ad90440 _ZN20vtkCocoaRenderWindow5StartEv + 64
8 libvtkRenderingUI-9.3.dylib 0x0000000104ff13b0 _ZN30vtkCocoaRenderWindowInteractor10InitializeEv + 384
9 libvtkRenderingCore-9.3.dylib 0x0000000106ea4574 _ZN15vtkRenderWindow6RenderEv + 148
10 libvtkRenderingOpenGL2-9.3.dylib 0x000000010ae2f41c _ZN21vtkOpenGLRenderWindow6RenderEv + 104
11 libvtkRenderingOpenGL2-9.3.dylib 0x000000010ad904d8 _ZN20vtkCocoaRenderWindow6RenderEv + 24
12 vtkRenderingOpenGL2.cpython-39-darw 0x000000010e5c8cb4 _ZL29PyvtkCocoaRenderWindow_RenderP7_objectS0_ + 136
13 libpython3.9.dylib 0x000000010291e870 cfunction_call + 172
14 libpython3.9.dylib 0x00000001028dab70 _PyObject_MakeTpCall + 360
15 libpython3.9.dylib 0x00000001029ad25c call_function + 536
16 libpython3.9.dylib 0x00000001029aa374 _PyEval_EvalFrameDefault + 22672
17 libpython3.9.dylib 0x00000001028db34c function_code_fastcall + 112
18 libpython3.9.dylib 0x00000001029ad1fc call_function + 440
19 libpython3.9.dylib 0x00000001029aa374 _PyEval_EvalFrameDefault + 22672
20 libpython3.9.dylib 0x00000001028db34c function_code_fastcall + 112
21 libpython3.9.dylib 0x00000001029aa648 _PyEval_EvalFrameDefault + 23396
22 libpython3.9.dylib 0x00000001029ae0a4 _PyEval_EvalCode + 2860
23 libpython3.9.dylib 0x00000001028db294 _PyFunction_Vectorcall + 236
24 libpython3.9.dylib 0x00000001029aa648 _PyEval_EvalFrameDefault + 23396
25 libpython3.9.dylib 0x00000001028db34c function_code_fastcall + 112
26 libpython3.9.dylib 0x00000001029ad1fc call_function + 440
27 libpython3.9.dylib 0x00000001029aa350 _PyEval_EvalFrameDefault + 22636
28 libpython3.9.dylib 0x00000001028db34c function_code_fastcall + 112
29 libpython3.9.dylib 0x00000001029ad1fc call_function + 440
30 libpython3.9.dylib 0x00000001029aa350 _PyEval_EvalFrameDefault + 22636
31 libpython3.9.dylib 0x00000001028db34c function_code_fastcall + 112
32 libpython3.9.dylib 0x00000001029ad1fc call_function + 440
33 libpython3.9.dylib 0x00000001029aa350 _PyEval_EvalFrameDefault + 22636
34 libpython3.9.dylib 0x00000001028db34c function_code_fastcall + 112
35 libpython3.9.dylib 0x00000001028da998 _PyObject_FastCallDictTstate + 272
36 libpython3.9.dylib 0x00000001028db674 _PyObject_Call_Prepend + 148
37 libpython3.9.dylib 0x000000010293ef7c slot_tp_call + 104
38 libpython3.9.dylib 0x00000001028dab70 _PyObject_MakeTpCall + 360
39 libpython3.9.dylib 0x00000001029ad25c call_function + 536
40 libpython3.9.dylib 0x00000001029aa374 _PyEval_EvalFrameDefault + 22672
41 libpython3.9.dylib 0x00000001028ee260 gen_send_ex + 308
42 libpython3.9.dylib 0x00000001029a9da0 _PyEval_EvalFrameDefault + 21180
43 libpython3.9.dylib 0x00000001029ae0a4 _PyEval_EvalCode + 2860
44 libpython3.9.dylib 0x00000001028db294 _PyFunction_Vectorcall + 236
45 libpython3.9.dylib 0x00000001029ad1fc call_function + 440
46 libpython3.9.dylib 0x00000001029aa3f0 _PyEval_EvalFrameDefault + 22796
47 libpython3.9.dylib 0x00000001029ae0a4 _PyEval_EvalCode + 2860
48 libpython3.9.dylib 0x00000001028db294 _PyFunction_Vectorcall + 236
49 libpython3.9.dylib 0x00000001028dd448 method_vectorcall + 168
50 libpython3.9.dylib 0x00000001029ad1fc call_function + 440
51 libpython3.9.dylib 0x00000001029aa3f0 _PyEval_EvalFrameDefault + 22796
52 libpython3.9.dylib 0x00000001028db34c function_code_fastcall + 112
53 libpython3.9.dylib 0x00000001028dd448 method_vectorcall + 168
54 libpython3.9.dylib 0x00000001029ad1fc call_function + 440
55 libpython3.9.dylib 0x00000001029aa374 _PyEval_EvalFrameDefault + 22672
56 libpython3.9.dylib 0x00000001028db34c function_code_fastcall + 112
57 libpython3.9.dylib 0x00000001028dd448 method_vectorcall + 168
58 libpython3.9.dylib 0x00000001029ad1fc call_function + 440
59 libpython3.9.dylib 0x00000001029aa374 _PyEval_EvalFrameDefault + 22672
60 libpython3.9.dylib 0x00000001029ae0a4 _PyEval_EvalCode + 2860
61 libpython3.9.dylib 0x00000001028db294 _PyFunction_Vectorcall + 236
62 libpython3.9.dylib 0x00000001028dd448 method_vectorcall + 168
63 libpython3.9.dylib 0x00000001029ad1fc call_function + 440
64 libpython3.9.dylib 0x00000001029aa374 _PyEval_EvalFrameDefault + 22672
65 libpython3.9.dylib 0x00000001028db34c function_code_fastcall + 112
66 libpython3.9.dylib 0x00000001028da998 _PyObject_FastCallDictTstate + 272
67 libpython3.9.dylib 0x00000001028db674 _PyObject_Call_Prepend + 148
68 libpython3.9.dylib 0x0000000102940320 slot_tp_init + 104
69 libpython3.9.dylib 0x0000000102937800 type_call + 372
70 libpython3.9.dylib 0x00000001028dab70 _PyObject_MakeTpCall + 360
71 libpython3.9.dylib 0x00000001029ad25c call_function + 536
72 libpython3.9.dylib 0x00000001029aa374 _PyEval_EvalFrameDefault + 22672
73 libpython3.9.dylib 0x00000001028db34c function_code_fastcall + 112
74 libpython3.9.dylib 0x00000001029ad1fc call_function + 440
75 libpython3.9.dylib 0x00000001029aa350 _PyEval_EvalFrameDefault + 22636
76 libpython3.9.dylib 0x00000001028db34c function_code_fastcall + 112
77 libpython3.9.dylib 0x00000001028dd55c method_vectorcall + 444
78 libpython3.9.dylib 0x00000001029aa648 _PyEval_EvalFrameDefault + 23396
79 libpython3.9.dylib 0x00000001028db34c function_code_fastcall + 112
80 libpython3.9.dylib 0x00000001029ad1fc call_function + 440
81 libpython3.9.dylib 0x00000001029aa350 _PyEval_EvalFrameDefault + 22636
82 libpython3.9.dylib 0x00000001028db34c function_code_fastcall + 112
83 libpython3.9.dylib 0x00000001029ad1fc call_function + 440
84 libpython3.9.dylib 0x00000001029aa350 _PyEval_EvalFrameDefault + 22636
85 libpython3.9.dylib 0x00000001028db34c function_code_fastcall + 112
86 libpython3.9.dylib 0x00000001028dd4d4 method_vectorcall + 308
87 libpython3.9.dylib 0x0000000102a448c4 t_bootstrap + 72
88 libpython3.9.dylib 0x00000001029f5448 pythread_wrapper + 28
89 libsystem_pthread.dylib 0x000000018c9cffa8 _pthread_start + 148
90 libsystem_pthread.dylib 0x000000018c9cada0 thread_start + 8
)
libc++abi: terminating due to uncaught exception of type NSException
/Users/user/.pyenv/versions/3.9.18/lib/python3.9/multiprocessing/resource_tracker.py:216: UserWarning: resource_tracker: There appear to be 1 leaked semaphore objects to clean up at shutdown
warnings.warn('resource_tracker: There appear to be %d '
```
---
### Author:  [@jaswantp](https://discourse.vtk.org/u/jaswantp)
#### Post date: [February 12, 2024, 9:05pm UTC](https://discourse.vtk.org/t/mac-m1-and-vtk/13305/2 "2024-02-12T21:05:38Z")
Hello @DrMainIT
This error is known to occur when a thread that is not the main thread calls `vtkRenderWindow::Render` on mac. You can try to use an asyncio event loop or some other method to schedule the render call on main thread.
The main thread in this case would be the one that called `int main()` from the python executable.
---
### Author:  [@DrMainIT](https://discourse.vtk.org/u/DrMainIT)
#### Post date: [February 12, 2024, 9:54pm UTC](https://discourse.vtk.org/t/mac-m1-and-vtk/13305/3 "2024-02-12T21:54:32Z")
could you provide me an example
---
### Author:  [@rexthor](https://discourse.vtk.org/u/rexthor)
#### Post date: [February 13, 2024, 2:31pm UTC](https://discourse.vtk.org/t/mac-m1-and-vtk/13305/4 "2024-02-13T14:31:06Z")
I don’t have a Mac, and asyncio hurts my head, but [this might help](https://stackoverflow.com/questions/54477773/asyncio-background-thread-run-function-in-main-thread-blocking)?
---
### Author:  [@jaswantp](https://discourse.vtk.org/u/jaswantp)
#### Post date: [February 14, 2024, 5:54pm UTC](https://discourse.vtk.org/t/mac-m1-and-vtk/13305/5 "2024-02-14T17:54:03Z")
> [@DrMainIT](#):
>
> ```auto
> 86 libpython3.9.dylib 0x00000001028dd4d4 method_vectorcall + 308
> 87 libpython3.9.dylib 0x0000000102a448c4 t_bootstrap + 72
> 88 libpython3.9.dylib 0x00000001029f5448 pythread_wrapper + 28
> 89 libsystem_pthread.dylib 0x000000018c9cffa8 _pthread_start + 148
> 90 libsystem_pthread.dylib 0x000000018c9cada0 thread_start + 8
>
> ```
These last few lines from your stack trace show that you called `get_thumbnail()` from a new thread. The simplest fix is to call that from main thread.
---
### Author:  [@DrMainIT](https://discourse.vtk.org/u/DrMainIT)
#### Post date: [February 14, 2024, 7:10pm UTC](https://discourse.vtk.org/t/mac-m1-and-vtk/13305/6 "2024-02-14T19:10:03Z")
the problem is that i’m using flask and i’m calling this function inside a route, i think i should use the main thread of flask not pretty sure how to do it
---
### Author:  [@jaswantp](https://discourse.vtk.org/u/jaswantp)
#### Post date: [February 14, 2024, 7:51pm UTC](https://discourse.vtk.org/t/mac-m1-and-vtk/13305/7 "2024-02-14T19:51:56Z")
Afraid I can’t help you with flask. If I were you, I’d start looking at their docs, examples and unit tests to see if there’s a way to schedule a function on the main thread.