C / C++ / MFC

Re: CDC Problem with coordinates

15-Jan-13 9:53

Using API In MFC OnDraw

TextOut(pDC->GetSafeHdc(),1, 20, "HELLO HELLO", 11);

I am not sure if that will print alligned properly.

Argonia15-Jan-13 21:23

Argonia

15-Jan-13 21:23

My problem is finding the right coordinates for the TextOut function but after a talk with my Team manager we decided its better to be done as a header / footer.
Before that i just wanted to get the BoundRectangle with the hopes that it will be describing only the part in the page where the elements will be drown not the whole page itself.
I was wondering if there is a way to get out of the CDC member information about the position of the elements or something like that but i couldn't find any.

DhcpRequestParams()

Man in the mirror13-Jan-13 19:46

Man in the mirror

13-Jan-13 19:46

I want to use the function DhcpRequestParams() to get some information from the DHCP Server,but failes.

Any can help me?
Examples are best.

Re: DhcpRequestParams()

Richard MacCutchan13-Jan-13 22:11

Richard MacCutchan

13-Jan-13 22:11

Try http://msdn.microsoft.com/en-us/library/windows/desktop/aa363345(v=vs.85).aspx[^].

One of these days I'm going to think of a really clever signature.

SOLVED From HANDLE to BITMAPINFO - another basic question for gurus

Vaclav_13-Jan-13 5:30

Re: From HANDLE to BITMAPINFO - another basic question for gurus

13-Jan-13 5:30

<pre lang="text">Found this very useful piece of code to get bitmap info from handle and would like to know HOW it works.
I think if I get how the LPBITAMPINFO gets filled I probably will also understand why using global handle is necessary. Or maybe not.</pre>

// a DIB is in the clipboard, draw it out
GLOBALHANDLE hGMem ;
LPBITMAPINFO lpBI ;
void* pDIBBits;
OpenClipboard() ;
hGMem = GetClipboardData(CF_DIB) ;
ASSERT(hGMem);
TRACE("\nfills LPBITMAPINFO");
lpBI = (LPBITMAPINFO)GlobalLock(hGMem) ;

Appreciate any help.
CHeers Vaclav

-- modified 15-Jan-13 15:54pm.

Richard MacCutchan13-Jan-13 5:44

Richard MacCutchan

13-Jan-13 5:44

C++

// a DIB is in the clipboard, draw it out
GLOBALHANDLE      hGMem ;    // create a global handle
LPBITMAPINFO      lpBI ;     // a pointer to the resultant bitmap
void*             pDIBBits;  // a pointer to the contents of the bitmap

OpenClipboard() ;                   // open the clipboard
hGMem = GetClipboardData(CF_DIB) ;  // get a handle (pointer) to the data in the clipboard
ASSERT(hGMem);                      // make sure it is valid
TRACE("\nfills LPBITMAPINFO"); 
lpBI = (LPBITMAPINFO)GlobalLock(hGMem) ; // lock that memory block and return a pointer to the DIB

At this point you can copy the memory block pointed to by lpBI into your program's address space and process it as required. You should then unlock and release hGMem (which is a system resource), and release the clipboard so other applications can use it.

One of these days I'm going to think of a really clever signature.

Re: From HANDLE to BITMAPINFO - another basic question for gurus

Vaclav_13-Jan-13 6:08

Re: From HANDLE to BITMAPINFO - another basic question for gurus

13-Jan-13 6:08

Richard,
thanks for adding the comments.
I am still unclear how you get from HANDLE (pointer) - returned by GetClipboardData to BITMAPINFO (pointer).

I guess I still do not get the casting.

This may be to stupid , but why this would not work?

lpBI = (LPBITMAPINFO) GetCLipboardData(CF_DIB)

Maybe the key is really in usage of GLOBALHANDLE.

Richard MacCutchan13-Jan-13 6:32

Richard MacCutchan

13-Jan-13 6:32

Vaclav_Sal wrote:
Maybe the key is really in usage of GLOBALHANDLE.

Exactly so. The GetCLipboardData() function returns a global handle, and you then need to use the GlobalLock() function to get a pointer to addressable memory. Remember that HANDLEs are 'opaque' types which you cannot use directly, even though they may at times point to some real memory. This is because they are owned by the Windows system and their contents at any one time is not guaranteed to be useful in user space.

One of these days I'm going to think of a really clever signature.

How to get detail error info from E_FAIL?

Falconapollo11-Jan-13 21:23

Falconapollo

11-Jan-13 21:23

When I use ATL in MFC Application(Don't ask me why, just because I like), sometimes I got the error code: E_FAIL. However, it's almost useless for me to locate the specific reason.

I have googled so many times, but found nothing related. I thought there should be something like try{} catch{} in ATL.

Here's some sample code:

C++

CAxWindow  m_wndView;  // ActiveX host window class.
CComPtr<IWMPPlayer>  m_spWMPPlayer;  // Smart pointer to IWMPPlayer interface.

AtlAxWinInit();
CComPtr<IAxWinHostWindow>  spHost;
HRESULT  hr;
CRect rcClient;
GetClientRect(&rcClient);
m_wndView.Create(m_hWnd, rcClient, NULL, WS_CHILD | WS_VISIBLE | WS_CLIPCHILDREN, WS_EX_CLIENTEDGE);
//when I switch to Static Link to ATL from Dynamic Link to ATL, I always get E_FAIL
hr = m_wndView.QueryHost(&spHost);

«_Superman_»11-Jan-13 23:43

«_Superman_»

11-Jan-13 23:43

Use the _com_error class.
Construct an object of this class by passing in the HRESULT value and then use its WCode or ErrorMessage methods to get the error code mapped to the HRESULT value.

«_Superman_»
I love work. It gives me something to do between weekends.

Microsoft MVP (Visual C++) (October 2009 - September 2013)

Polymorphism in C

Falconapollo12-Jan-13 0:00

Falconapollo

12-Jan-13 0:00

Thank you for your reply.

I have did as what you said, but I only get the error message:
Unspecified error.

Here is my code:

C++

_com_error err(hr);
auto  d = err.WCode();
auto s = err.Description();
auto msg = err.ErrorMessage();//Unspecified error

Jochen Arndt13-Jan-13 21:05

Jochen Arndt

13-Jan-13 21:05

'Unspecified error' is the english error message for E_FAIL. There is no more information available.

Video Capture using DirectShow only works for first time.?

Argonia14-Jan-13 2:01

Argonia

14-Jan-13 2:01

You can try with GetLastError and see if you can get better description of the error . The number returned from the function you can check in msdn.
Good luck Smile | :)

mbatra3110-Jan-13 20:25

mbatra31

10-Jan-13 20:25

Hi,

I have developed an application which captures video stream using DirectShow. While capturing, video is displayed on the canvas area. This works fine for the first time. But when again clicking on Start capturing button, video is getting captured, it doesn't display in the canvas area. Don;t know whether actually the camera is capturing the video or not.

Anybody have any idea regarding this.?

Any help will be appreciated.!

Regards,
mbatra

Re: Video Capture using DirectShow only works for first time.?

_AnsHUMAN_ 11-Jan-13 2:05

_AnsHUMAN_

11-Jan-13 2:05

You can debug to check if the code flow path is different from the first one in the second case.
If this doesn't help consider reinitialization of variables you are using before you display the video on the canvas.

You talk about Being HUMAN. I have it in my name
AnsHUMAN

Re: Video Capture using DirectShow only works for first time.?

Vaclav_14-Jan-13 16:10

how to unsigned int64 to two unsigned int32 values

14-Jan-13 16:10

Can you post some of your code?
I am using VFW API and OpenCV and debugging real time video can be a challenge.
What works for me is using temporary displays in step thru debug mode.

vishalgpt9-Jan-13 22:22

Re: how to unsigned int64 to two unsigned int32 values

9-Jan-13 22:22

How to convert _uint64 into two _uint32 values and vice versa.

Regards,
Vishal

Jochen Arndt9-Jan-13 23:06

Jochen Arndt

9-Jan-13 23:06

By shifting the high part and casting:

C++

_uint64 ui64 = 1234;
_uint32 lo = (_uint32)ui64;
_uint32 hi = (_uint32)(ui64 >> 32);

ui64 = (_uint64)lo | ((_uint64)hi) << 32;

[EDIT:] Added code formatting.

Re: how to unsigned int64 to two unsigned int32 values

vishalgpt9-Jan-13 23:32

Re: how to unsigned int64 to two unsigned int32 values

9-Jan-13 23:32

does it take endianness into consideration, (Little/Big Endian)

Regards,
Vishal

Jochen Arndt9-Jan-13 23:58

Jochen Arndt

9-Jan-13 23:58

Yes, because the endianess does not care for the used logical operations.

If you think of multiplication / division instead of the shift operations and of addition instead of the OR operation it should be clear. The operation values are just high or low parts where the internally used bit or byte order does not care. Casting is similar (extending with high zeroes upon up-casting and masking out the lower bits upon down-casting).

Re: how to unsigned int64 to two unsigned int32 values

vishalgpt10-Jan-13 0:08

Re: [SOLVED] how to unsigned int64 to two unsigned int32 values

10-Jan-13 0:08

Thank you.. Smile | :)

Regards,
Vishal

«_Superman_»10-Jan-13 18:39

«_Superman_»

10-Jan-13 18:39

Here is another way to do it using the LARGE_INTEGER[^] union.

LARGE_INTEGER lint;
lint.QuadPart = 12345;  // Assigning 64-bit value;
// lint.LowPart and lint.HighPart can now be used to split the value;

«_Superman_»
I love work. It gives me something to do between weekends.

Microsoft MVP (Visual C++) (October 2009 - September 2013)

Polymorphism in C

Re: [SOLVED] how to unsigned int64 to two unsigned int32 values

vishalgpt14-Jan-13 15:25