scanning under windows WIA with custom settings (dpi / etc )
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From: News123 on 25 Nov 2009 03:08 News123 wrote: > Hi, > > I'm trying to scan a document from a python 2.6 script without user > interaction. > > I found a code snippet, that allows me to scan under Vista, but that > doesn't allow me to select the dpi / color mode / etc. I'm still stuck. I'll try to look at any solution (visual C++, C#, Basic) first. Then it's perhaps easier to pythonize it via python .net. However I don't know whether python .net exists for 2.6 and whether it is stable enough. N > > The snippet uses win32com.client > > # ##################### script start > import win32com.client,os > > WIA_IMG_FORMAT_PNG = "{B96B3CAF-0728-11D3-9D7B-0000F81EF32E}" > WIA_COMMAND_TAKE_PICTURE = "{AF933CAC-ACAD-11D2-A093-00C04F72DC3C}" > > os.chdir('c:/temp') > wia = win32com.client.Dispatch("WIA.CommonDialog") > dev = wia.ShowSelectDevice() > for command in dev.Commands: > if command.CommandID==WIA_COMMAND_TAKE_PICTURE: > foo=dev.ExecuteCommand(WIA_COMMAND_TAKE_PICTURE) > i=1 > for item in dev.Items: > if i==dev.Items.Count: > image=item.Transfer(WIA_IMG_FORMAT_PNG) > break > i=i+1 > > image.SaveFile("test.png") > ######################### script end > > > My problems are: > > - This script works fine for me under Windows 7, however I'm > unable to specify additional parameters, like dpi and > color mode. > > - The script doesn't work under windows XP, though the scanner driver is > installed. (Gimp finds the scanner (as WIA scanner)). > Perhaps 'WIA.CommonDialig' has another name or I need to install some DLL. > The error message is: > -------------------------------------------------------------------- > Traceback (most recent call last): > File "C:\work\python\minidemos\wia_get_simple.py", line 7, in <module> > wia = win32com.client.Dispatch("WIA.CommonDialog") > File "C:\Python26\lib\site-packages\win32com\client\__init__.py", line > 95, in Dispatch > dispatch, userName = > dynamic._GetGoodDispatchAndUserName(dispatch,userName,clsctx) > File "C:\Python26\lib\site-packages\win32com\client\dynamic.py", line > 104, in _GetGoodDispatchAndUserName > return (_GetGoodDispatch(IDispatch, clsctx), userName) > File "C:\Python26\lib\site-packages\win32com\client\dynamic.py", line > 84, in _GetGoodDispatch > IDispatch = pythoncom.CoCreateInstance(IDispatch, None, clsctx, > pythoncom.IID_IDispatch) > com_error: (-2147221005, 'Invalid class string', None, None) > --------------------------------------------------------------------- > > > As I have no knowledge of Win32com and WIA I would appreciate some help > or good documentation about wincom32 / WIA with python > > > > thanks for your help and bye > > > N > > > > > >
From: News123 on 28 Nov 2009 16:11 r wrote: > more *maybe useful dump? > >>>> for i in dev.Items: > for p in i.Properties: > if not p.IsReadOnly: > print p.Name, '->', p.Value > .. . . > Horizontal Resolution -> 200 > Vertical Resolution -> 200 > Horizontal Start Position -> 0 .. . . > > Now how to set the values... hmmm? > How to set the values? This is THE magic question. At least I found out how to set the values in C# : foreach (Property prop in item.Properties){ if (prop.IsReadOnly) continue; if (prop.Name == "Horizontal Resolution") { IProperty iprop = (IProperty)prop; Object val = 75; iprop.set_Value(ref val); } } Below my most recent complete script: (still not able to set params, though I can with C#) import win32com.client, os WIA_COM = "WIA.CommonDialog" WIA_IMG_FORMAT_PNG = "{B96B3CAF-0728-11D3-9D7B-0000F81EF32E}" WIA_COMMAND_TAKE_PICTURE="{AF933CAC-ACAD-11D2-A093-00C04F72DC3C}" def takePictureOrNot(dev): # cameras have to call TakePicture for command in dev.Commands: if command.CommandID==WIA_COMMAND_TAKE_PICTURE: print "take PICK" foo=dev.ExecuteCommand(WIA_COMMAND_TAKE_PICTURE) def setImgProps(item): # here scan properties should be set for prop in item.Properties: if prop.IsReadOnly: continue if(prop.Name == "Horizontal Resolution"): res = 250 print "trying to set",prop.Name,prop,"to ",res ### unfortunately the next line (if uncommented) fails #prop.set_Value(res) def transferImg(dev): # set properties and scan image i=1 image = None for item in dev.Items: if i==dev.Items.Count: setImgProps(item) image=item.Transfer(WIA_IMG_FORMAT_PNG) break i=i+1 return image def scan_image_wia(): wia = win32com.client.Dispatch(WIA_COM) # CommonDialog object dev = wia.ShowSelectDevice() takePictureOrNot(dev) image = transferImg(dev) return image image = scan_image_wia() fname = 'wia-test.jpg' if os.path.exists(fname): os.remove(fname) image.SaveFile(fname) bye N
From: News123 on 28 Nov 2009 16:18 Meanwhile I found out, why my script worked only on windows 7/Vista and not on my XP host. The WIA 2.0 Scripting Model is by default not installed on Windows XP. Install instructions can be found at http://msdn.microsoft.com/en-us/library/ms630827%28VS.85%29.aspx My second problem (changing parameters) is still not solved in python. bye N News123 wrote: > Hi, > > I'm trying to scan a document from a python 2.6 script without user > interaction. > > I found a code snippet, that allows me to scan under Vista, but that > doesn't allow me to select the dpi / color mode / etc. > > The snippet uses win32com.client > > # ##################### script start > import win32com.client,os > > WIA_IMG_FORMAT_PNG = "{B96B3CAF-0728-11D3-9D7B-0000F81EF32E}" > WIA_COMMAND_TAKE_PICTURE = "{AF933CAC-ACAD-11D2-A093-00C04F72DC3C}" > > os.chdir('c:/temp') > wia = win32com.client.Dispatch("WIA.CommonDialog") > dev = wia.ShowSelectDevice() > for command in dev.Commands: > if command.CommandID==WIA_COMMAND_TAKE_PICTURE: > foo=dev.ExecuteCommand(WIA_COMMAND_TAKE_PICTURE) > i=1 > for item in dev.Items: > if i==dev.Items.Count: > image=item.Transfer(WIA_IMG_FORMAT_PNG) > break > i=i+1 > > image.SaveFile("test.png") > ######################### script end > > > My problems are: > > - This script works fine for me under Windows 7, however I'm > unable to specify additional parameters, like dpi and > color mode. > > - The script doesn't work under windows XP, though the scanner driver is > installed. (Gimp finds the scanner (as WIA scanner)). > Perhaps 'WIA.CommonDialig' has another name or I need to install some DLL. > The error message is: > -------------------------------------------------------------------- > Traceback (most recent call last): > File "C:\work\python\minidemos\wia_get_simple.py", line 7, in <module> > wia = win32com.client.Dispatch("WIA.CommonDialog") > File "C:\Python26\lib\site-packages\win32com\client\__init__.py", line > 95, in Dispatch > dispatch, userName = > dynamic._GetGoodDispatchAndUserName(dispatch,userName,clsctx) > File "C:\Python26\lib\site-packages\win32com\client\dynamic.py", line > 104, in _GetGoodDispatchAndUserName > return (_GetGoodDispatch(IDispatch, clsctx), userName) > File "C:\Python26\lib\site-packages\win32com\client\dynamic.py", line > 84, in _GetGoodDispatch > IDispatch = pythoncom.CoCreateInstance(IDispatch, None, clsctx, > pythoncom.IID_IDispatch) > com_error: (-2147221005, 'Invalid class string', None, None) > ---------------------------------------------------------------------
From: MRAB on 28 Nov 2009 17:28 News123 wrote: > r wrote: >> more *maybe useful dump? >> >>>>> for i in dev.Items: >> for p in i.Properties: >> if not p.IsReadOnly: >> print p.Name, '->', p.Value >> > . . . >> Horizontal Resolution -> 200 >> Vertical Resolution -> 200 >> Horizontal Start Position -> 0 > . . . >> Now how to set the values... hmmm? >> Well, according to that they /aren't/ read-only because it says: if not p.IsReadOnly: ^^^
From: News123 on 28 Nov 2009 18:10
MRAB wrote: > News123 wrote: >> r wrote: >>> more *maybe useful dump? >>> >>>>>> for i in dev.Items: >>> for p in i.Properties: >>> if not p.IsReadOnly: >>> print p.Name, '->', p.Value >>> >> . . . >>> Horizontal Resolution -> 200 >>> Vertical Resolution -> 200 >>> Horizontal Start Position -> 0 >> . . . >>> Now how to set the values... hmmm? >>> > Well, according to that they /aren't/ read-only because it says: > > if not p.IsReadOnly: > ^^^ > Exactly they are NOT read only, which means they are supposed to be writable. the python code is for p in i.Properties: if not.p.ISReadOnly: # if I'm here I'm supposed to change them, but how? the C# code, which succeds changing the property is: foreach (Property prop in item.Properties){ if (prop.IsReadOnly) continue; // skip rest of loop // if property cannot // be modified // now change property if (prop.Name == "Horizontal Resolution") { IProperty iprop = (IProperty)prop; Object val = 75; iprop.set_Value(ref val); } } The main question is the correct python method to change the property prop = 300 # doesn't work as it just replaces the property with an integer prop.set_Value(res) # doesn't work as the method set_Value doesn't seem to exist > Traceback (most recent call last): > File "C:\WIA\scan_wia.py", line 41, in <module> > image = scan_image_wia() > File "C:\WIA\scan_wia.py", line 37, in scan_image_wia > image = transferImg(dev) > File "C:\WIA\scan_wia.py", line 27, in transferImg > setImgProps(item) > File "C:\WIA\scan_wia.py", line 20, in setImgProps > prop.set_Value(res) > File "C:\Python26\lib\site-packages\win32com\client\dynamic.py", line 512, in > __getattr__ > raise AttributeError("%s.%s" % (self._username_, attr)) > AttributeError: <unknown>.set_Value bye N |