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Posts
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Hi,
I’m trying to set the datasources possible resolutions to 200, 300, or 600. We have our own barcode decoding logic, and those are the only resolutions it supports.
Currently we check the resolution via the imageinfo after the TransferReady message comes through. If the resolution isn’t supported we tell the user to pick out of our supported list. We haven’t been able to cleanly return to the DataSource UI after the transfer ready message comes in.
To fix this, I thought it would be nice to limit the resolutions shown on the DS UI. When I try to get the resoluion I end up with an array with a couple valid DPI numbers interleaved with 0s and then some off the wall numbers. I’ve attempted to change the Units to each possible and I’m still unable to receive a clean array of possible resolutions.
What could I be doing wrong?
Vb.Net
Enum class
Friend Class Tw_Enum
Public ItemType As Short
Public NumItem As Short
Public CurrentIndex As Short
Public DefaultIndex As Short
End Class
Capability Class
Friend Class TwCapabilityEnum
Public Cap As Short
Public ConType As Short
Public Handle As IntPtr
Public Sub TwCapability(ByVal capIn As TwCap)
Cap = CType(capIn, Short)
ConType = -1
End Sub
Public Sub New(ByVal capIn As TwCap, ByVal sval As Short)
Cap = CType(capIn, Short)
ConType = CType(TwOn.Enum, UShort)
Handle = Win32.GlobalAlloc(&H42, 6)
Dim pv As IntPtr = Win32.GlobalLock(Handle)
Marshal.WriteInt16(pv, 0, CType(TwType.Fix32, Short))
Marshal.WriteInt32(pv, 2, CType(sval, Integer))
Win32.GlobalUnlock(Handle)
End Sub
Public Sub Dispose()
If Not Equals(Handle, IntPtr.Zero) Then
Win32.GlobalFree(Handle)
End If
End Sub
Protected Overrides Sub Finalize()
If Not Equals(Handle, IntPtr.Zero) Then
Win32.GlobalFree(Handle)
End If
End Sub
End Class
Get Resolution Capability (returncode is success):
p_oCapEnum = New TwCapabilityEnum(TwCap.IXNativeRes, 0)
rcResult = DScap(p_oApp, p_oDataSource, TwDG.Control, TwDAT.Capability, TwMSG.Get, p_oCapEnum)
Reading of Cap Enum:
Dim twResolutions As Tw_Enum
Dim pPointerToStructure As IntPtr
If p_rcLastResult = TwRC.Success Then
twResolutions = New Tw_Enum
pPointerToStructure = GlobalLock(p_oCapEnum.Handle)
Marshal.PtrToStructure(pPointerToStructure, twResolutions)
End If
twResolutions.Item contains several numbers that don’t seem like valid resolutions no matter what Unit is set at.
DSEntry:
Friend Shared Function DScap( _
<[In](), Out()> ByVal origin As TwIdentity, _
<[In]()> ByVal dest As TwIdentity, ByVal dg As TwDG, _
ByVal dat As TwDAT, _
ByVal msg As TwMSG, <[In](), Out()> ByVal capa As TwCapabilityEnum) As TwRC
End Function
I know the post was code heavy, but I’ve hit a wall. I’m not sure where to go from here. Any information is greatly appreciated.
Side note:
I’ve downloaded Twacker32 and sent the message to get the XRes Capabilities in an enum container, the result was a nice: 150, 200, 300, 600 … When I attempted to set the Xres Capability using twacker and an enum container I wasn’t able to change the values. I’d set the number of items to 3 and 3 0s would populate in the list and I couldn’t edit them.
Hi,
From what you wrote, I believe you are checking the resolution in state 6.
Why don’t you just check the current resolution in state 4 using ICAP_XRESOLUTION/ICAP_YRESOLUTION?
Then you can restrict the DS to use only 200, 300, or 600 dpi and display the UI if the current resolution is not supported by your application.I think the problem might be that you are trying to change capabilities while in state 6 which is not allowed.
By the way, which scanner are you using?
I apologize, but I accidently deleted Rogers account while trying to clean up the SPAM.
Roger, please register again. Sorry for the inconvenience.
Dim twResolutions As Tw_Enum
Dim pPointerToStructure As IntPtrIf p_rcLastResult = TwRC.Success Then
twResolutions = New Tw_Enum
pPointerToStructure = GlobalLock(p_oCapEnum.Handle)
Marshal.PtrToStructure(pPointerToStructure, twResolutions)
End If
_________________________________________________________
I dont think that this is going to work. When i tried it like this i got some
wierd numbers in my structure. I had to code it like this to get it to work ::
_________________________________________________________Dim twResolutions As Tw_Enum
If p_rcLastResult = TwRC.Success Then
twResolutions = Marshal.PtrToStructure(GlobalLock(p_oCapEnum.Handle), GetType(Tw_Enum))
End IfThat should give you your values successfully..
I tried it your way, and for some reason when you Lock the Handle outside of that call, the Memory location becomes LOCKED so you cannot access Protected Memory. Your PtrToStructure shouldn’t work.Ah. Well, rogers, may not be around anymore to see your solution, but hopefully it will help future searchers.
—
Software consultingLol ya I noticed after I posted, He was one of the few I see trying in VB as well. Now I may never know if that would solve the problem but… I think it will 😉
@Roger Holland wrote:
Hi,
I’m trying to set the datasources possible resolutions to 200, 300, or 600. We have our own barcode decoding logic, and those are the only resolutions it supports.
Currently we check the resolution via the imageinfo after the TransferReady message comes through. If the resolution isn’t supported we tell the user to pick out of our supported list. We haven’t been able to cleanly return to the DataSource UI after the transfer ready message comes in.
To fix this, I thought it would be nice to limit the resolutions shown on the DS UI. When I try to get the resoluion I end up with an array with a couple valid DPI numbers interleaved with 0s and then some off the wall numbers. I’ve attempted to change the Units to each possible and I’m still unable to receive a clean array of possible resolutions.
What could I be doing wrong?
Vb.Net
Enum class
Friend Class Tw_Enum
Public ItemType As Short
Public NumItem As Short
Public CurrentIndex As Short
Public DefaultIndex As Short
End Class
Capability Class
Friend Class TwCapabilityEnum
Public Cap As Short
Public ConType As Short
Public Handle As IntPtr
Public Sub TwCapability(ByVal capIn As TwCap)
Cap = CType(capIn, Short)
ConType = -1
End Sub
Public Sub New(ByVal capIn As TwCap, ByVal sval As Short)
Cap = CType(capIn, Short)
ConType = CType(TwOn.Enum, UShort)
Handle = Win32.GlobalAlloc(&H42, 6)
Dim pv As IntPtr = Win32.GlobalLock(Handle)
Marshal.WriteInt16(pv, 0, CType(TwType.Fix32, Short))
Marshal.WriteInt32(pv, 2, CType(sval, Integer))
Win32.GlobalUnlock(Handle)
End Sub
Public Sub Dispose()
If Not Equals(Handle, IntPtr.Zero) Then
Win32.GlobalFree(Handle)
End If
End Sub
Protected Overrides Sub Finalize()
If Not Equals(Handle, IntPtr.Zero) Then
Win32.GlobalFree(Handle)
End If
End Sub
End Class
Get Resolution Capability (returncode is success):
p_oCapEnum = New TwCapabilityEnum(TwCap.IXNativeRes, 0)
rcResult = DScap(p_oApp, p_oDataSource, TwDG.Control, TwDAT.Capability, TwMSG.Get, p_oCapEnum)
Reading of Cap Enum:
Dim twResolutions As Tw_Enum
Dim pPointerToStructure As IntPtr
If p_rcLastResult = TwRC.Success Then
twResolutions = New Tw_Enum
pPointerToStructure = GlobalLock(p_oCapEnum.Handle)
Marshal.PtrToStructure(pPointerToStructure, twResolutions)
End If
twResolutions.Item contains several numbers that don’t seem like valid resolutions no matter what Unit is set at.
DSEntry:
Friend Shared Function DScap( _
<[In](), Out()> ByVal origin As TwIdentity, _
<[In]()> ByVal dest As TwIdentity, ByVal dg As TwDG, _
ByVal dat As TwDAT, _
ByVal msg As TwMSG, <[In](), Out()> ByVal capa As TwCapabilityEnum) As TwRC
End Function
I know the post was code heavy, but I’ve hit a wall. I’m not sure where to go from here. Any information is greatly appreciated.
Side note:
I’ve downloaded Twacker32 and sent the message to get the XRes Capabilities in an enum container, the result was a nice: 150, 200, 300, 600 … When I attempted to set the Xres Capability using twacker and an enum container I wasn’t able to change the values. I’d set the number of items to 3 and 3 0s would populate in the list and I couldn’t edit them.
I wonder whether it supports a 3rd party barcode reading toolkits as well?
Best regards,
Arron