Scanning and Saving Multiple Files

[yazilimci1]

I want to scan and save multiple files . If I can give the number of pages in a for loop ,

sm = twain.SourceManager(0)
ss = sm.OpenSource()
ss.RequestAcquire(1,1)

for i in range(3):   //scanned 3 files 
   try:
        rv = ss.XferImageNatively()
        if rv:
            (handle, count) = rv
            twain.DIBToBMFile(handle, '{}.bmp'.format(uuid.uuid4()))
        else:
            break
   except:
        print("Error")

There are no error in this code, working good , scans three file and saves as .bmp file . But user doesn't have to enter number of documents so I must do it dynamically . When I use a infinitive while loop like below,

while True:
    try:
        rv = ss.XferImageNatively()
        if rv:
            (handle, count) = rv
            twain.DIBToBMFile(handle, '{}.bmp'.format(uuid.uuid4()))
        else:
            break
    except:
          print("Error")

This code gives an error , but saves the documents scanned.

Traceback (most recent call last):
  File "C:/Users/PB/PycharmProjects/34Deneme/dene.py", line 18, in <module>
    rv = ss.XferImageNatively()
  File "C:\Python34\lib\site-packages\twain.py", line 1840, in XferImageNatively
    rv, handle = self._get_native_image()
  File "C:\Python34\lib\site-packages\twain.py", line 1786, in _get_native_image
    (TWRC_XFERDONE, TWRC_CANCEL))
  File "C:\Python34\lib\site-packages\twain.py", line 1452, in _call
    return self._sm._call(self._id, dg, dat, msg, buf, expected_returns)
  File "C:\Python34\lib\site-packages\twain.py", line 2097, in _call
    raise exc
twain.excTWCC_SEQERROR

So I don't know what is the problem and differences the for and while loop? Do you know why ?

[denisenkom]

Here you should break the loop if count is zero

[denisenkom]

I added some docs: http://pytwain.readthedocs.org/en/latest/twain.html#twain.Source.xfer_image_natively

I renamed XferImageNatively to xfer_image_natively. XferImageNatively is now deprecated but it still aliased to xfer_image_natively for now.

[yazilimci1]

Thank u denisenkom for your help . I ' ll try it .

[Dhruv00710]

import twain
import uuid
sm = twain.SourceManager(0)
ss = sm.OpenSource()
ss.RequestAcquire(1,1)
for i in range(3):
try:
rv = ss.XferImageNatively()
if rv:
(handle, count) = rv
twain.DIBToBMFile(handle, '{}.bmp'.format(uuid.uuid4()))
else:
break
except:
print("Error")
and its get error like
Error
Error
Error
Exception ignored in: <function SourceManager.del at 0x035A2848>
Traceback (most recent call last):
File "C:\Users\DELL\AppData\Local\Programs\Python\Python311-32\Lib\site-packages\twain.py", line 2066, in del
File "C:\Users\DELL\AppData\Local\Programs\Python\Python311-32\Lib\site-packages\twain.py", line 2073, in close
File "C:\Users\DELL\AppData\Local\Programs\Python\Python311-32\Lib_weakrefset.py", line 105, in pop
KeyError: 'pop from empty WeakSet'