| Win32 Systems (Win95, 98,
Me, NT, and 2000)
This sample program shows
you how to build a Visual Basic program for the PXD1000 frame grabber.
Visual Basic Interface
Information
When we released the PXD1000
we did not have support for Visual Basic, so there is no mention of it
in our manual. However, all but one of the functions described in the
manual can also be used with Visual Basic. Therefore you should use the
manual as a guide when building Visual Basic programs. The manual explains
all of the functions and all of the parameters that need to be passed
to each one. The function that will NOT work with Visual Basic is identified
and explained at the bottom of this page. In order to use Visual Basic
with the PXD, you need two interface files that describe the functionality
of the two DLLs you will use:
PXD_V6.BAS describes
the functionality of the PXD_32.DLL, and
FRAME_V6.BAS describes
the functionality of the FRAME_32.DLL.
You need to make both of
the above BAS files part of your project.
The VIDEO_32.DLL
There is a third DLL and
corresponding description file:
VIDEO_32.BAS describes
the functionality of the VIDEO_32.DLL.
The Video_32.dll is not
required, but it is useful for displaying video. Visual Basic does not
provide a direct method for displaying video in a window. You can do it
by including the Windows API functions in your project, but it is a bit
messy. Therefore we have provided a DLL with only two functions to simplify
the process for you. The two functions are described as follows:
pxSetWindowSize (x, y, dx, dy)
You call pxSetWindowSize
once during initialization or any time you choose to change the window
size. pxSetWindowSize tells the DLL the size of your target window in
pixels. x and y should always be 0, dx and dy are the width and height
of the target window respectively.
pxPaintDisplay (hDC, frm, x, y, dx, dy)
pxPaintDisplay moves the
video from a buffer to the window specified by the hDC (Device Context
handle). The parameters x, y, dx, dy specify the size of your buffer
not the target window. If you want to display the entire buffer, then
x and y are always 0. dx and dy are the width and height respectively
of the buffer. The Video_32.dll uses StretchDIBits to achieve display,
therefore it will be a bit slower than our samples that are written
in C.
PXDBASIC consists of
the following files:
CONTROL.FRM: Main control form
DISPLAY.FRM: Display form
FRMBMP.FRM: Special form for reading BMP files
GLOBAL.BAS: Declarations for
global variables
VIDEO_32.BAS: Declarations Video Display DLL
FRAME_V6.BAS: Declarations
for Frame library
PXD_V6.BAS: Declarations for PXD series functions
When you run PXDBASIC,
you will need the following 3 DLLs in your path:
FRAME_32.DLL
PXD_32.DLL
VIDEO_32.DLL
To put the DLLs in your
path, you have 3 options:
- Put the DLLs in the directory
with the sample.
- Put the DLLs in the Windows\System
directory.
- Modify your PATH variable
to point to the directory where the DLLs are located.
PXD functions that will
NOT work with Visual Basic
GetInterface
The GetInterface() function
does not translate to Visual Basic because it returns a pointer to a structure
that contains string pointers. If it were not for the string pointers
we could make it work in VB. Strings are handled differently in C and
in VB. There is no way to make it work. Typically, this function is not
needed. It would only be used if you were going to build a CAM file from
within your program. You can build those files with ConfigPXD.
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