The easiest way to start building an adaptor is to create a stub implementation, compile and link it, and then test your work. This method can be effective because it provides immediate results and lets you verify that your build environment is setup properly.
This section shows a stub implementations of an adaptor that
you can copy and paste into a file in your adaptor Microsoft®
Visual C++® project.
After compiling and linking this code, you can see your adaptor included
in the list of available adaptors returned by the imaqhwinfo function.
Note
You will not be able to instantiate an object of your adaptor class, however. That is described in Defining Your Adaptor Class.
To create a stub adaptor, follow this procedure:
Add a C++ source file to the adaptor
C++ project. See Setting up a Build Environment on Windows Systems for information about
creating an adaptor C++ project. This source file will hold your implementations
of your adaptor's exported C++ functions. You can give this file any
name. This example uses the name of the adaptor for this file, with
the character vector "_exported_fcns" appended
to it, mydevice_exported_fcns.cpp
Copy the following lines of C++ code
into this new file. This code provides stub implementations of the
required adaptor exported functions. Note that you must include the
adaptor kit header file mwadaptorimaq.h. This header
file includes all other required adaptor kit header files. The getDeviceAttributes() stub
defines a video source—see Identifying Video Sources for more
information.
#include "mwadaptorimaq.h"
void initializeAdaptor(){
}
void getAvailHW(imaqkit::IHardwareInfo* hardwareInfo){
}
void getDeviceAttributes(const imaqkit::IDeviceInfo* deviceInfo,
const char* formatName,
imaqkit::IPropFactory* devicePropFact,
imaqkit::IVideoSourceInfo* sourceContainer,
imaqkit::ITriggerInfo* hwTriggerInfo){
// Create a video source
sourceContainer->addAdaptorSource("MyDeviceSource", 1);
}
imaqkit::IAdaptor* createInstance(imaqkit::IEngine* engine, const
imaqkit::IDeviceInfo* deviceInfo, const
char* formatName){
imaqkit::IAdaptor* adaptor = NULL;
return adaptor;
}
void uninitializeAdaptor(){
}
Build the adaptor DLL. Select the Build Solution option on the Build menu.
Start the MATLAB® software.
Tell the toolbox where to find this
new adaptor using the imaqregister function. See Registering an Adaptor with the Toolbox for more information.
You only need to perform this step once.
Call the imaqhwinfo function.
Note that the stub adaptor, named mydeviceimaq,
is included in the list of available adaptors returned.
imaqhwinfo
ans =
InstalledAdaptors: {'demo' 'mydeviceimaq' 'winvideo'}
MATLABVersion: '7.12 (R2011a)'
ToolboxName: 'Image Acquisition Toolbox'
ToolboxVersion: '4.1 (R2011a)'To get more information about the stub adaptor, call imaqhwinfo again,
this time specifying the name of the adaptor.
Note
At this point in your adaptor development, the DeviceIDs field
and the DeviceInfo fields are empty.
imaqhwinfo('mydeviceimaq')
ans =
AdaptorDllName: 'C\My_Adaptor\mydeviceimaq.dll'
AdaptorDllVersion: '4.1 (R2011a)'
AdaptorName: 'mydeviceimaq'
DeviceIDs: {1x0 cell}
DeviceInfo: [1x0 struct]