I have tried to allocate buffer of requested size - virtualbox just
crashes on takescreenshot(). It seems I must be in same process to
call it, so it can be used only inside a complete GUI? Maybe it is
possible to use get/setframebuffer - but how? :)
Sent from my iPhone
On 16.09.2009, at 21:56, Klaus Espenlaub <[email protected]>
wrote:
Grigory Petrov schrieb:
Hello.
I'm using VirtualBox to automate old DOS program and need to takes
screenshots of guest OS in order to manipulate a program correctly.
I have tried the following test code:
void main( void )
{
::CoInitialize( 0 );
IVirtualBox* poVbox = 0;
::CoCreateInstance( CLSID_VirtualBox, 0, CLSCTX_ALL,
IID_IVirtualBox, (void**)& poVbox );
SAFEARRAY* poVmList = 0;
poVbox->get_Machines( & poVmList );
IMachine** ppoVmArray = 0;
::SafeArrayAccessData( poVmList, (void**)& ppoVmArray );
BSTR oVmId;
(* ppoVmArray)->get_Id( & oVmId );
ISession* poSession = 0;
HRESULT hRet = ::CoCreateInstance( CLSID_Session, 0, CLSCTX_ALL,
IID_ISession, (void**)& poSession );
IProgress* poProgress = 0;
BSTR oEnvir = ::SysAllocString( L"" );
hRet = poVbox->OpenRemoteSession( poSession,
oVmId, ::SysAllocString( L"gui" ), oEnvir, & poProgress );
// Wait resonable time for VM to start and to display something.
::Sleep( 10000 );
IConsole* poConsole = 0;
hRet = poSession->get_Console( & poConsole );
IDisplay* poDisplay = 0;
hRet = poConsole->get_Display( & poDisplay );
UINT32 anMem[ 100 ] = { 0 };
hRet = poDisplay->TakeScreenShot( (BYTE*)anMem, 10, 10 );
assert( SUCCEEDED( hRet ) );
}
All works, VirtualBox starts and loads guest OS, but after calling
TakeScreenShow() it returns E_NOTIMPL :(. Does anyone know what can
i do? Maybe i need to use other API functions, get screen buffer,
register for updates notifications or something? Host OS is windows
XP SP3, latest VirtualBox and SDK from site. I will be very glad if
someone can share an working example on how to take an screenshot /
image of guest OS desktop, that will help a lot! Or maybe it's some
error in my code?
The error says it all. The code can't deal with scaling, and as you
request a 10x10 pixel screenshot that'll fail. Make sure you request
the width and height of the framebuffer (and have enough buffer size
available for that). An example is in the GUI code, but remember
that this uses different API wrappers so the calling conventions are
a bit different than the normal (xp)com API calls.
Klaus
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