MATLAB IMAGE ACQUISITION TOOLBOX - RELEASE NOTES Guide de l'utilisateur télécharger pdf (Page 94)

5 Acquiring Image Data

5-16

The PostThreadMessage() function accepts these parameters:

BOOL PostThreadMessage( DWORD idThread,

UINT Msg,

WPARAM wParam,

LPARAM lParam

);

The following table describes how to set these parameters for an adaptor. For more

information about sending thread messages, see the documentation at the Microsoft

Developer Network Web site (msdn.microsoft.com).

Parameter Description

idThread Identifier of the thread to which the message is to be posted, returned

by CreateThread().

Msg Message to be posted. Microsoft defines a range of values for user

messages, beginning with the value WM_USER.

wParam Additional message-specific information

lParam Additional message-specific information

Example: Initiating Acquisition

This example illustrates a simple startCapture() function. This function takes no

arguments and returns a Boolean value indicating whether the video input object is in

start state.

Replace the stub implementation in the MyDeviceAdaptor.cpp file with this code

and then rebuild your adaptor.

bool MyDeviceAdaptor::startCapture(){

// Check if device is already acquiring frames.

if (isAcquiring())

return false;

// Send start message to acquisition thread

PostThreadMessage(_acquireThreadID, WM_USER, 0, 0);

return true;

}

Start the MATLAB software and run your adaptor to verify that your acquisition

thread gets the start message from startCapture().

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MATLAB IMAGE ACQUISITION TOOLBOX - RELEASE NOTES Guide de l'utilisateur Page 94