Powerbuilder 网络摄像头

Question

我正在使用 powerbuilder 应用程序中的 EZTWAIN 从 HP 扫描仪获取图像。最近我尝试了柯达型号（i1120），似乎不支持。具体来说，应用程序在扫描过程中冻结（可能问题与双面扫描有关）。

您能否推荐另一个您已使用过且运行良好的库，并为可在 Powerbuilder 中使用的 TWAIN API 提供易于使用的包装器？

Answer 1

看看这家公司：http://www.data-tech.com/ 我们使用他们的 ImageMan ActiveX 套件与 PB 10.5 一起工作，没有问题。

Answer 2

我在使用多个库进行双面扫描时遇到了类似的问题。解决方案是在使用双面扫描时直接使用扫描仪的界面而不是ActiveX组件。大多数库都有一个选项，可以即时启用以使用扫描仪界面。

我目前使用 Viscomsoft Scanner Pro ActiveX 库。

Answer 3

**object : n_webcam**
================================================================================

forward 
global  type nvo_webcam from nonvisualobject
 end  type 
end  forward

global  type nvo_webcam from nonvisualobject autoinstantiate 
end  type

 prototype type

function  ulong capCreateCaptureWindowA ( string lpszWindowName, ulong dwStyle, long li_x, long li_y, long nWidth, long nHeight, ulong ParentWin, long nId) LIBRARY  'AVICAP32.DLL'  alias  for  "capCreateCaptureWindowA; ansi"



Function  ulong GetDC ( ulong hWnd) Library  "user32.dll" 
Function  long ReleaseDC ( ulong hWnd, ulong hdcr) Library  "USER32.DLL" 
Function  ulong CreateCompatibleDC ( ulong hdc) Library  "gdi32.dll" 
Function  ulong CreateCompatibleBitmap ( ulong hdc, ulong nWidth, ulong nHeight) Library  "gdi32.dll" 
Function  boolean DeleteDC ( ulong hDC) Library "Gdi32.dll"

Function  boolean BitBlt ( ulong hdcDest, long nXDest, long nYDest, long nWidth, long nHeight, ulong hdcSrc, long nXSrc, long nYSrc, long dwRop) Library  "gdi32.dll" 
Function  boolean StretchBlt ( ulong hdcDest, long nXOriginDest, long nYOriginDest, long nWidthDest, long nHeightDest, ulong hdcSrc, long nXOriginSrc, longnYOriginSrc, long nWidthSrc, long nHeightSrc, long dwRop) Library  "gdi32.dll"

Function  ulong SelectObject ( ulong hdc, ulong HGDIOBJ) Library  "gdi32.dll"

Function  along GetDIBits ( ulong hdc, ulong hbmp, uint uStartScan, uint cScanLines, Ref  blob lpvBits, Ref BITMAPINFO lpbi, uint uUsage) Library  "gdi32.dll"  alias  for  "GetDIBits" 
Function  long GetDIBits ( ulong hdc, ulong hbmp, uint uStartScan , uint cScanLines, ulong lpvBits, ref bitmapinfo lpbi, uint uUsage) Library "gdi32.dll"  alias  for  "GetDIBits"

Subroutine CopyBitmapFileHeader ( Blob Ref  Destination, bitmapfileheader Source, long Length) Library "kernel32.dll" Alias For "RtlMoveMemory" Subroutine CopyBitmapInfo ( Blob Ref Destination, Source bitmapinfo, long Length) Library "kernel32.dll" Alias For "RtlMoveMemory"    


Function  boolean OpenClipboard ( ulong hWndNewOwner) Library  "user32.dll" 
Function  boolean CloseClipboard () Library  "user32.dll" 
Function  boolean EmptyClipboard () Library  "user32.dll" 
Function  ulong GetClipboardData ( ulong uFormat) Library  "user32.dll"

end  prototypes

such  variables 
Uint LHand
Constant  long GET_FRAME = 1084
Constant  long COPY = 1054
Constant  long WM_USER = 1024
Constant  long WM_CAP_START = WM_USER
Constant  long WM_CAP_STOP = WM_CAP_START + 68
Constant  long WM_CAP_DRIVER_CONNECT = WM_CAP_START + 10
Constant  long WM_CAP_DRIVER_DISCONNECT = WM_CAP_START + 11
Constant  long WM_CAP_SAVEDIB = WM_CAP_START + 25
Constant  Long WM_CAP_GRAB_FRAME = WM_CAP_START + 60
Constant  LongWM_CAP_SEQUENCE = WM_CAP_START + 62
Constant  long WM_CAP_FILE_SET_CAPTURE_FILEA = WM_CAP_START + 20
Constant  long WM_CAP_FILE_SAVEAS = WM_CAP_START + 23
Constant  long WM_CAP_SEQUENCE_NOFILE = WM_CAP_START + 63
Constant  long WM_CAP_SET_OVERLAY = WM_CAP_START + 51
Constant  long WM_CAP_SET_PREVIEW = WM_CAP_START + 50
Constant  long WM_CAP_SET_CALLBACK_VIDEOSTREAM = WM_CAP_START +6
Constant  long WM_CAP_SET_CALLBACK_ERROR = WM_CAP_START + 2
Constant  Long WM_CAP_SET_CALLBACK_STATUSA = WM_CAP_START +3
Long Constant WM_CAP_SET_CALLBACK_FRAME = WM_CAP_START +5
Long Constant  WM_CAP_SET_SCALE = WM_CAP_START + 53
Long Constant WM_CAP_SET_PREVIEWRATE = WM_CAP_START + 52 
end  variables

forward  prototypes 
public  subroutine of_close ()
public  subroutine of_initialize_webcam ( unsignedlong a_handle, string a_title, integer a_width, integer a_height)
public  function  blob of_copy_clipboard_to_blob ()
public  subroutine of_capture_pic ()
end  prototypes

public  subroutine of_close (); send (lhand, WM_CAP_DRIVER_DISCONNECT, 0, 0)
end  subroutine

public  subroutine of_initialize_webcam ( unsigned long a_handle, string a_title, integer a_width, integer a_height); string lpszName

lpszName = a_title
if lhand = 0 then
lhand = capCreateCaptureWindowA (lpszName, 262144 + 12582912 + 1073741824 + 268435456, 1.40, a_width, a_height, a_handle, 0)
end  if 
if lhand <> 0 then
send (lhand, WM_CAP_SET_CALLBACK_VIDEOSTREAM, 0, 0)
send (lhand, WM_CAP_SET_CALLBACK_ERROR, 0, 0)
send (lhand, WM_CAP_SET_CALLBACK_STATUSA, 0, 0)

send (lhand, WM_CAP_DRIVER_CONNECT, 0, 0)
send (lhand, WM_CAP_SET_SCALE, 1, 0)
send (lhand, WM_CAP_SET_PREVIEWRATE, 66, 0)
send (lhand, WM_CAP_SET_OVERLAY, 1, 0)
send (lhand, WM_CAP_SET_PREVIEW, 1, 0)
end  if 
end  subroutine

public  function  blob of_copy_clipboard_to_blob (); BitmapInfo lstr_Info
BitmapFileHeader lstr_Header
Blob   lblb_header, lblb_info, lblb_bitmap, lbl_final
ULong lul_hdc, lul_hdcMem, lul_hBitmap, lul_hWnd, lul_blpos
UInt DIB_RGB_COLORS
Integer li_pixels
Boolean lb_result
long al_width, ll_height, ll_ret

constant  integer BITMAPTYPE = 19778 // 4D42 = BM
constant  integer CF_BITMAP = 2
constant  integer CF_DIB = 8

lul_hWnd = Handle ( this )
lb_result = OpenClipboard (lul_hWnd)

// Get the device context and allocate memory
lul_hdc = GetDC (lul_hWnd)
lul_hdcMem = CreateCompatibleDC (lul_hdc)
lul_hBitmap = getclipboarddata (CF_BITMAP)

// try to store the bitmap into a blob so we can save it
lstr_Info.bmiHeader.biSize = 40
ll_height = 480 // ... 480 should be enough for everyone? ;)
DIB_RGB_COLORS = 0
// Get the bitmapinfo
If GetDIBits (lul_hdcMem, lul_hBitmap, 0, ll_height, 0, lstr_Info, DIB_RGB_COLORS)> 0 Then
li_pixels = lstr_Info.bmiHeader.biBitCount
lstr_Info.bmiColors [li_pixels] = 0
lblb_bitmap = Blob (Space (lstr_Info.bmiHeader.biSizeImage), EncodingANSI!)
ll_height = lstr_Info.bmiHeader.biheight
// get the actual bits
ll_ret = GetDIBits (lul_hdcMem, lul_hBitmap, 0, ll_height, lblb_bitmap, lstr_Info, DIB_RGB_COLORS) 
// ls_msg = hexdump_blob (lblb_bitmap, false)
// create a bitmap header
lstr_Header.bfType = BITMAPTYPE
lstr_Header.bfSize = lstr_Info.bmiHeader.biSizeImage
lstr_Header.bfOffBits = 54 + (li_pixels * 4)
// copy the header structure to a blob
lblb_header = Blob (Space (7)) //
14/2 CopyBitmapFileHeader (lblb_header, lstr_Header, 14)
// copy the info structure to a blob
lblb_Info = Blob (Space (40 + li_pixels * 4) / 2))
CopyBitmapInfo (lblb_Info, lstr_Info, len (lblb_Info))
// add all together and we have a window bitmap in a blob
lbl_final = lblb_header + lblb_info + lblb_bitmap
End  If

CloseClipboard ()
ReleaseDC (lul_hwnd, lul_hdc)
DeleteDC (lul_hdcMem)

return lbl_final
end  function

public  subroutine of_capture_pic (); Send (lhand, GET_FRAME, 0, 0)
Send (lhand, COPY, 0, 0)


end  subroutine

we have nvo_webcam. create 
call  super :: create 
TriggerEvent ( this , "constructor" )
end  on

we have nvo_webcam. destroy 
TriggerEvent ( this , "destructor" )
call  super :: destroy 
end  on

**instantiate the object and initialize it:**
================================================================================

n_webcam.of_initialize_webcam (handle ( this ), "Webcam" , il_width, il_height)

**capture:**
================================================================================

n_webcam.of_capture_pic ()

**image processing:**
================================================================================

lb_blob = n_webcam..of_copy_clipboard_to_blob ()
 // reinitialize for the webcam to continue live
 i_nvo_webcam.of_initialize_webcam (handle ( this ), "Webcam" , il_width, il_height)

**Close:**
================================================================================

n_webcam.of_close ()

观看视频 https://youtu.be/ojcJs1ajWRc