How to access VisionKit?

emkay_online

Hi,

I'm just dipping my toes into objc_util and have fallen at the first hurdle.

I want to write a small script that calls VisionKit to scan a document and return the result to Pythonista. API is here: https://developer.apple.com/documentation/visionkit

I've started with:

from objc_util import *
VNDocumentCameraViewController = ObjCClass('VNDocumentCameraViewController')

But Pythonista says that the class VNDocumentCameraViewController doesn't exist.

I'd love some help getting past this (and if anyone could take the example further, that would be amazing).

Thank you,

Martin

cvp

@emkay_online said:

VNDocumentCameraViewController = ObjCClass('VNDocumentCameraViewController')

from objc_util import *
load_framework('VisionKit')
VNDocumentCameraViewController = ObjCClass('VNDocumentCameraViewController')

cvp

@emkay_online try this but not finished, only a first step to help you. No time more now

from objc_util import *
import ui
load_framework('VisionKit')

@on_main_thread	
def main():
	VNDocumentCameraViewController = ObjCClass('VNDocumentCameraViewController').alloc().init()
	#print(dir(VNDocumentCameraViewController))

	uiview = ui.View()
	uiview.frame = (0,0,500,500)
	uiview.present('sheet')
		
	objc_uiview = ObjCInstance(uiview)
	SUIViewController = ObjCClass('SUIViewController')
	vc = SUIViewController.viewControllerForView_(objc_uiview)	

	VNDocumentCameraViewController.setModalTransitionStyle_(3)	
	vc.presentViewController_animated_completion_(VNDocumentCameraViewController, True, None)
	
main()

emkay_online

You are amazing - thank you. You have saved me so much frustration and guessing.

Thank you so much,

Martin

cvp

@emkay_online next step but documentCameraViewController_didFinishWith_ not called.
Either my bug either iOS bug (other people seem to meet the same problem)

from objc_util import *
import ui
load_framework('VisionKit')

#========= VNDocumentViewController 
def documentCameraViewController_didFinishWith_(_self, _cmd, _controller, _scan):
	print('documentCameraViewController_didFinishWith_')
	VNDocumentViewController = ObjCInstance(_controller)
	scan = ObjCInstance(_scan)	# VNDocumentCameraScan
	#print(scan)


methods = [documentCameraViewController_didFinishWith_,]
protocols = ['VNDocumentCameraViewControllerDelegate']
try:
		MyVNDocumentCameraViewControllerDelegate = ObjCClass('MyVNDocumentCameraViewControllerDelegate')
except:
	MyVNDocumentCameraViewControllerDelegate = create_objc_class('MyVNDocumentCameraViewControllerDelegate', methods=methods, protocols=protocols)

@on_main_thread	
def main():
	VNDocumentCameraViewController = ObjCClass('VNDocumentCameraViewController').alloc().init()
	#print(dir(VNDocumentCameraViewController))
	delegate = MyVNDocumentCameraViewControllerDelegate.alloc().init()
	VNDocumentCameraViewController.delegate = delegate		

	uiview = ui.View()
	uiview.frame = (0,0,500,500)
	uiview.present('sheet')
	
	objc_uiview = ObjCInstance(uiview)
	SUIViewController = ObjCClass('SUIViewController')
	vc = SUIViewController.viewControllerForView_(objc_uiview)	

	VNDocumentCameraViewController.setModalTransitionStyle_(4)	
	vc.presentViewController_animated_completion_(VNDocumentCameraViewController, True, None)
	
main()

emkay_online

Thank you for your code. I'm as puzzled as you as to why it doesn't work. I added the other methods in case an error or a cancel was being returned, but nothing.

I'll keep playing and hope I stumble on the answer.

Thanks again.

Martin

cvp

@emkay_online I did it also and cancel reacts

def documentCameraViewController_didFailWithError_(_self, _cmd, _controller, _error):
	print('documentCameraViewController_didFailWithError_')
	
def documentCameraViewControllerDidCancel_(_self, _cmd, _controller):
	print('documentCameraViewControllerDidCancel_')

methods = [documentCameraViewController_didFinishWith_, documentCameraViewController_didFailWithError_, documentCameraViewControllerDidCancel_]

cvp

Cancel is called but you still need to tap save to terminate...

stephen

@cvp the recent iPadOS update seems to have effected accesing different areas of the sandbox. and unless someone finds the new access classes, Apple will have some upset developers on thier hands lol

JonB

Have you checked supported?

cvp

@JonB I tried but does not exist in dir(VNDocumentCameraViewController).
And the process seems to be realized, you receive the camera, take a photo, system aligns a frame, you tap save ..... and the viewcontroller closes but does not call the didfinish

mikael

@cvp, @JonB, same behavior on iPhone.

isSupported returns True.

cvp

@mikael @JonB strange, on my iPad mini 4, three different prints and their results

	print('VNDocumentCameraViewController.isSupported')
	print(VNDocumentCameraViewController.isSupported)
	print()
	print('dir(VNDocumentCameraViewController.isSupported)')
	print(dir(VNDocumentCameraViewController.isSupported))
	print()
	print('VNDocumentCameraViewController.isSupported()')
	print(VNDocumentCameraViewController.isSupported())
'''
VNDocumentCameraViewController.isSupported
<objc_util.ObjCInstanceMethodProxy object at 0x113ca84e0>

dir(VNDocumentCameraViewController.isSupported)
['__call__', '__class__', '__delattr__', '__dict__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__gt__', '__hash__', '__init__', '__init_subclass__', '__le__', '__lt__', '__module__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', '__weakref__', 'method_cache', 'name', 'obj']

VNDocumentCameraViewController.isSupported()
Traceback (most recent call last):
  File "_ctypes/callbacks.c", line 234, in 'calling callback function'
  File "/var/containers/Bundle/Application/34BAEE1A-BC33-4D6F-A0C1-B733E4991F31/Pythonista3.app/Frameworks/Py3Kit.framework/pylib/site-packages/objc_util.py", line 1066, in OMMainThreadDispatcher_invoke_imp
    retval = func(*args, **kwargs)
  File "/private/var/mobile/Containers/Shared/AppGroup/668A7D98-7216-47ED-917D-AA0B6173167E/Pythonista3/Documents/VNDocumentCameraViewController.py", line 37, in main
    print(VNDocumentCameraViewController.isSupported())
  File "/var/containers/Bundle/Application/34BAEE1A-BC33-4D6F-A0C1-B733E4991F31/Pythonista3.app/Frameworks/Py3Kit.framework/pylib/site-packages/objc_util.py", line 798, in __call__
    method_name, kwarg_order = resolve_instance_method(obj, self.name, args, kwargs)
  File "/var/containers/Bundle/Application/34BAEE1A-BC33-4D6F-A0C1-B733E4991F31/Pythonista3.app/Frameworks/Py3Kit.framework/pylib/site-packages/objc_util.py", line 405, in resolve_instance_method
    raise AttributeError('No method found for %s' % (name,))
AttributeError: No method found for isSupported
'''

cvp

@mikael @jonb class without alloc and init returns True

	VNDocumentCameraViewController = ObjCClass('VNDocumentCameraViewController')#.alloc().init()
	print('VNDocumentCameraViewController.isSupported()')
	print(VNDocumentCameraViewController.isSupported())

JonB

I bet the function name is wrong, or the arguments are wrong.

Shouldn't it be
documentCameraViewController_didFinishWithScan_?

You could also swizzle respondsToSelector on your delegate, and log what gets queried.
Have you checked what the protocol

cvp

@JonB doc gives this name and we are not alone with this problem, see here

cvp

@JonB said:

documentCameraViewController_didFinishWithScan_

You're right. I sincerely don't understand how I could do so big mistake.
Thanks, I'll try

Édit: save button does not close the view

cvp

The delegate is called but the view is not closed as I though thus I have proven by writing in a file. And restart Pythonista because I could not close the view.

def documentCameraViewController_didFinishWithScan_(_self, _cmd, _controller, _scan):
	with open('a.txt',mode='wt') as fil:
		fil.write('documentCameraViewController_didFinishWithScan_')
	print('documentCameraViewController_didFinishWithScan_')
	VNDocumentViewController = ObjCInstance(_controller)
	scan = ObjCInstance(_scan)	# VNDocumentCameraScan
	#print(scan) 
.
.
.

methods = [documentCameraViewController_didFinishWithScan_, documentCameraViewController_didFailWithError_, documentCameraViewControllerDidCancel_]

JonB

This post is deleted!

JonB

@cvp perhaps you need to dismiss the _controller?