Could not display the source user interface

[lisha992610]

Hello

I am implementing an application with Epson scan.
I tried to use this command "ss.RequestAcquire(1,0)" to show the UI. but the UI was not completely opened and was closed again automatically.
How to keep the UI windows alive and trigger the scan directly on the UI?

I added a "while True" loop after "ss.RequestAcquire(1,0)", in order to keep the python program running while the UI is displayed. Only a partial of the UI is able to be displayed and the program crashed.

Could you please help me out here? What could be the problem? Thank you so much.

p.s. how can I avoid the following exception?
Exception ignored in: <bound method SourceManager.del of <twain.SourceManager object at 0x002D5A50>>
Traceback (most recent call last):
File "C:\Users\AppData\Local\conda\conda\envs\py35_32\lib\site-packages\twain.py", line 2066, in del
File "C:\Users\AppData\Local\conda\conda\envs\py35_32\lib\site-packages\twain.py", line 2073, in close
File "C:\Users\AppData\Local\conda\conda\envs\py35_32\lib_weakrefset.py", line 101, in pop
KeyError: 'pop from empty WeakSet'

Best regards,
lisha

[martintan]

The source user interface closes immediately because of Python's garbage collection. The solution I found for this is to use QThread. Here is a part of my code that works:

class ScanPDFThread(QtCore.QThread):
  def __init__(self, parent, folder_path: str, settings:dict={}):
    QtCore.QThread.__init__(self)
    self.parent = parent
    self.scan_pdf(folder_path, settings)

  def scan_pdf(self, folder_path: str, settings):
    try:
      sm, ds = self.initialize_scanner(settings)
      # Source: Twain 2.4 Spec ch.10 p.420
      ds.SetCapability(twain.CAP_XFERCOUNT, twain.TWTY_INT16, -1)
      ds.RequestAcquire(1, 1)

      with tempfile.TemporaryDirectory() as tempdir:
        def temp_file(i): return os.path.join(tempdir, f'temp-{i}.bmp')
        more_to_come = True
        i = 0
        while more_to_come:
          if not ds.GetImageInfo(): continue
          more_to_come = self.transfer_native(ds, temp_file(i))
          i += 1
          time.sleep(0.25)
        
        images = [Image.open(temp_file(i)) for i in range(i)]
        # Source: https://pillow.readthedocs.io/en/stable/handbook/image-file-formats.html#pdf
        file_name = datetime.datetime.now().strftime('%d-%m-%Y_%H-%M-%S') + '.pdf'
        save_path = os.path.join(folder_path, file_name)
        images[0].save(save_path, save_all=True, append_images=images[1:])
        for i in images: i.close()

        sm.destroy()
        ds.destroy()

    except Exception as e:
      ei = sys.exc_info()
      logging.error('Scanner Scan PDF error', exc_info=str(e))
      traceback.print_exception(ei[0], ei[1], ei[2])

  def initialize_scanner(self, settings:dict={}):
    sm = twain.SourceManager(self.parent.winId(), ProductName='Demo')
    ds = sm.OpenSource()

    ds.SetCapability(twain.ICAP_XRESOLUTION, twain.TWTY_FIX32, 200)
    ds.SetCapability(twain.ICAP_YRESOLUTION, twain.TWTY_FIX32, 200)
    _, has_duplex = ds.GetCapability(twain.CAP_DUPLEX)
    if has_duplex == twain.TWDX_1PASSDUPLEX or has_duplex == twain.TWDX_2PASSDUPLEX:
    ds.SetCapability(twain.CAP_DUPLEXENABLED, twain.TWTY_BOOL, True)
    ds.SetCapability(twain.ICAP_AUTOMATICDESKEW, twain.TWTY_BOOL, True)
    ds.SetCapability(twain.ICAP_PIXELTYPE, twain.TWTY_UINT16, twain.TWPT_RGB)
    # ds.SetCapability(twain.ICAP_MAXFRAMES, twain.TWTY_UINT16, 1)

    return (sm, ds)

Edit (11/15/2020):
After some more coding, I found out that you also have to call data_source.modal_loop() after data_source.request_acquire(1, 1) for the source dialog to work properly.

[Dhruv00710]

sir can you help me about multiple file scan and saving
i design a form in form one checkbox and two button
checkbox indicate show 'show_ui' means request_acquire(1, 1) or request_acquire(0, 0)
1st button select scanner from list
2nd button to scan document