C / C++ / MFC

3-Apr-07 3:43

Hi all,
I want to create a bitmap by the function CreateDIBSection, and share the bitmap with other process.
HBITMAP CreateDIBSection(
HDC hdc, // handle to DC
CONST BITMAPINFO *pbmi, // bitmap data
UINT iUsage, // data type indicator
VOID **ppvBits, // bit values
HANDLE hSection, // handle to file mapping object
DWORD dwOffset // offset to bitmap bit values
);
Following MSDN, hSection is handle that created by CreateFileMapping.
Now I want ask that: in the shared-memory that hold by handle hSection: what is shared data? it is ppvBits?. If not, what is relating between ppvBits and data shared in the memory. I don't see any word in MSDN about this.
That is good if anyone give me a sample code.

Thank you.

The world is not enough!

A freeware MFC class to encapsulate Memory Mapped Files[^]

KaЯl3-Apr-07 4:42

KaЯl

3-Apr-07 4:42

You could have a look to these two articles:

Share variables in the shared memory across processes[^]

Where do you expect us to go when the bombs fall?

Fold with us! ¤ flickr

Mark Salsbery3-Apr-07 7:32

3-Apr-07 7:32

phieu wrote:
what is shared data? it is ppvBits?.

If you've provided a file mapping (hSection) then the data pointed to by ppvBits can be shared
through the file mapping. To do that, refer to the links suggested above Smile | :)

Mark

"If you can dodge a wrench, you can dodge a ball."

phieu3-Apr-07 18:29

3-Apr-07 18:29

Thanks Mark.

OK, Now I see the data pointed to by ppvBits can be shared
through the file mapping.

But now I don’t know why: error code = 87 (ERROR_INVALID_PARAMETER) when
I call CreateDIBSection thought out but bitmap is valid.

Someone can tell me why?
Thank you.

Here is my code:

#define BITMAP_MMF_NAME "Global\\PRJ_IMS"
HANDLE m_hMMF;
HBITMAP m_hBitmap;
void CBitmapMMFDlg::OnButton3()
{
// TODO: この位置にコントロール通知ハンドラ用のコードを追加してください
int nWidth = 100, nHeight = 100;
long nSize = nWidth*nHeight*3;
// Create a file-mapping
m_hMMF = ::CreateFileMapping(
(HANDLE)0xFFFFFFFF,
NULL,
PAGE_READWRITE,
0,
nSize,
BITMAP_MMF_NAME);
DWORD dw = GetLastError();
if (m_hMMF)
{
// Create bitmap and map this bitmap to File-mapping
m_hBitmap = NULL;
HDC hdc = ::GetDC(NULL); // entire screen
//off-screen bitmap/image size - width must be DWORD aligned (multiples of 4)
LONG sizeImage = ((nWidth * 3 + 3) & 0xfffffffc) * nHeight;
BITMAPINFO bmpInfo;
memset(&bmpInfo,0,sizeof(bmpInfo));
bmpInfo.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
bmpInfo.bmiHeader.biWidth = nWidth;
bmpInfo.bmiHeader.biHeight = -nHeight;
bmpInfo.bmiHeader.biPlanes = 1;
bmpInfo.bmiHeader.biBitCount = 24;
bmpInfo.bmiHeader.biCompression = BI_RGB;
bmpInfo.bmiHeader.biSizeImage = sizeImage ;
bmpInfo.bmiHeader.biXPelsPerMeter = 0;
bmpInfo.bmiHeader.biYPelsPerMeter = 0;
bmpInfo.bmiHeader.biClrUsed = 0;
bmpInfo.bmiHeader.biClrImportant = 0;

//Create DIB Section - off screen bitmap
void* pBits = NULL;
DWORD dwOffset = 0;
m_hBitmap = CreateDIBSection(hdc, &bmpInfo, DIB_RGB_COLORS, &pBits, m_hMMF, dwOffset);
TRACE("Error code = %d \n", GetLastError());
// change bitmap bit data -> to test output
if(pBits != NULL)
{
for (int i = 0; i < 30000; i ++)
{
*((char*)(pBits) +i) = i%255;
}
}
/////////////////////////////////////////////////
// display bitmap
if (m_hBitmap != NULL)
{
CDC* pDC = GetDlgItem(IDC_STATIC)->GetDC();
if (pDC)
{
CDC dcMem;
dcMem.CreateCompatibleDC(pDC);
CBitmap* pBmp = CBitmap::FromHandle(m_hBitmap);
CBitmap* pOldBmp= dcMem.SelectObject(pBmp);
pDC->BitBlt(0,0, 100, 100, &dcMem, 0, 0, SRCCOPY);
}
}
}
}

Mark Salsbery3-Apr-07 19:43

3-Apr-07 19:43

I don't see anything right away...
Try changing to
bmpInfo.bmiHeader.biSizeImage = 0;

Also you calculate your file mapping size like this:
long nSize = nWidth*nHeight*3;
and your bmpInfo.bmiHeader.biSizeImage like this
LONG sizeImage = ((nWidth * 3 + 3) & 0xfffffffc) * nHeight;

Both should use the same calculation and the second method is better since DIB rows should be
aligned to a 4-byte boundary. In this case it's ok with a rowsize of 100 Smile | :)

Mark

"If you can dodge a wrench, you can dodge a ball."

Mark Salsbery3-Apr-07 19:51

3-Apr-07 19:51

Is m_hBitmap NULL after the CreateDIBSection call?

"If you can dodge a wrench, you can dodge a ball."

phieu4-Apr-07 1:15

4-Apr-07 1:15

m_hBitmap is not NULL, and I can display it ok, but GetLastError() = 87, INVALID_PARAMETER. I don't know why?

Mark Salsbery4-Apr-07 7:24

4-Apr-07 7:24

If it's not NULL then it was successful and calling GetLastError() isn't necessarily valid.
You only need to call that on failure.

From the docs:
"Most functions that set the thread's last-error code set it when they fail. However, some
functions also set the last-error code when they succeed. If the function is not documented to
set the last-error code, the value returned by this function is simply the most recent last-error
code to have been set; some functions set the last-error code to 0 on success and others do not."

Generally errors are checked for and handled something like:

m_hBitmap = CreateDIBSection(hdc, &bmpInfo, DIB_RGB_COLORS, &pBits, m_hMMF, dwOffset);
if (NULL == m_hBitmap)
{
TRACE("Error code = %d \n", GetLastError());
...do appropriate error handling/cleanup here
}

"If you can dodge a wrench, you can dodge a ball."

phieu4-Apr-07 17:04

4-Apr-07 17:04

Ok, thanks Mark!

GINA and the net

SeaSol3-Apr-07 3:29

SeaSol

3-Apr-07 3:29

I am trying to write a GINA, but am faced with a problem... I need to retrieve some info over the internet/intranet. Does anyone know if this is possible, if so how would I go about it? Confused | :confused:

I have samples of writing a GINA, but all point to simply adding the password either from biometric readers or smartcards, I need to fetch a template over the net, scramble it and present it to the logon user (in a webpage).

Any ideas?

Thank you,
SeaSol

RichEditCtrl - RTF

Ashok Panchal3-Apr-07 3:27

Ashok Panchal

3-Apr-07 3:27

Hi,

I want to read RTF file in Chunk by chunk.
And I want to append in StreamIn i.e. RichEditCtrl.

But Chunk by chunk upending is not working. If I read
whole file in buffer and append/insert, it works fine.

I set SF_RTF and SFF_SELECTION flags for StreamIn.

If anyone knows about RTF & RichEdit control,
please help me.

Ashok

Re: RichEditCtrl - RTF

Mark Salsbery3-Apr-07 7:36

3-Apr-07 7:36

Is there a reason you are using SFF_SELECTION? Are you reading an entire file/stream to fill
the richtext control or appending/replacing existing text in the control?

What isn't working? Does your callback get called?

Mark

"If you can dodge a wrench, you can dodge a ball."

Get Sub-Directories

Programm3r3-Apr-07 3:19

3-Apr-07 3:19

Hi all ( again Smile | :)

),

Can someone please tell me what functions I can use to get all the sub-directories of a directory.
For example:
C:\<dirMain>

dirMain has the following directories inside of it:
dir1
dir2
dir2

Many thanx ( again Smile | :)

)
Regards,

The only programmers that are better than C programmers are those who code in 1's and 0's..... Smile | :)

Programm3r
My Blog: ^_^

_AnsHUMAN_ 3-Apr-07 3:21

_AnsHUMAN_

3-Apr-07 3:21

Programm3r wrote:
I can use to get all the sub-directories of a directory.

Use WIN32_FIND_DATA,FindFirstFile(),FindNextFile(), you can write a recursive function.

Somethings seem HARD to do, until we know how to do them.
Wink | ;-)

_AnShUmAn_

Programm3r3-Apr-07 4:01

3-Apr-07 4:01

Like this ??

WIN32_FIND_DATA mystruct;
    mystruct.dwFileAttributes = FILE_ATTRIBUTE_DIRECTORY;
HANDLE myHandle = FindFirstFile("C:\\<dirMain>\\subdir", &mystruct);
BOOL myBOOL = FindNextFile(myHandle, &mystruct);
DWORD bw = GetLastError();

18 There are no more files. ERROR_NO_MORE_FILES

It doesn't work ??

The only programmers that are better than C programmers are those who code in 1's and 0's..... Smile | :)

Programm3r
My Blog: ^_^

Roger Stoltz3-Apr-07 3:26

Roger Stoltz

3-Apr-07 3:26

Set up the search with ::FindFirstFileEx() and limit the search to directories.
Call ::FindNextFile() until the call fails, i.e. returns FALSE and ::GetLastError() returns ERROR_NO_MORE_FILES.

"It's supposed to be hard, otherwise anybody could do it!" - selfquote
"High speed never compensates for wrong direction!" - unknown

Programm3r3-Apr-07 5:06

3-Apr-07 5:06

I have tried the following, but I can't seem to get it right.
All I want is to get all the names of directories and not the files.
Can someone please help me???

HANDLE Handle;
WIN32_FIND_DATA FindData;
char Temp[256];
char tempBuffer[100];

sprintf((char *)Temp, "C:\\dirMain\\subDir");
Handle = FindFirstFile((char *)Temp, &FindData);
while(1)
{
   if(FindData.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
   {
       printf("Dir Name : %s\n",FindData.cFileName);
   }
   else
   {
       break;
   }
   if(!FindNextFile(Handle, &FindData))
       break;
}

Many Thanx
Regards,

The only programmers that are better than C programmers are those who code in 1's and 0's..... Smile | :)

Programm3r
My Blog: ^_^

Programm3r3-Apr-07 5:14

3-Apr-07 5:14

This works:

void ChangeDirectoryAttribute(TCHAR* m_szFdPath)
{
   HANDLE hFile;                       // Handle to directory
   WIN32_FIND_DATA FileInformation;    // File information
   TCHAR m_szPath[MAX_PATH];
   TCHAR m_szFolderInitialPath[MAX_PATH];
   TCHAR wildCard[MAX_PATH] = "\\*.*";

   strcpy(m_szPath,m_szFdPath);
   strcpy(m_szFolderInitialPath,m_szFdPath);
   strcat(m_szFolderInitialPath,wildCard);

   hFile = ::FindFirstFile(m_szFolderInitialPath, &FileInformation);
   if(hFile != INVALID_HANDLE_VALUE)
   {
      do{
         if(FileInformation.cFileName[0] != '.')
         {
            strcpy(m_szPath,m_szFdPath);
            strcat(m_szPath,"\\");
            strcat(m_szPath,FileInformation.cFileName);
            if(FileInformation.dwFileAttributes &
               FILE_ATTRIBUTE_DIRECTORY)
            {
               //it is a sub directory
               ::SetFileAttributes(m_szPath,FILE_ATTRIBUTE_NORMAL);
			   printf("Dir name: %s\n", m_szPath);
               ChangeDirectoryAttribute(m_szPath);
            }
            else
            {
               //it is a file
               ::SetFileAttributes(m_szPath,FILE_ATTRIBUTE_NORMAL);
            }
         }
      }while(::FindNextFile(hFile, &FileInformation) == TRUE);
      // Close handle
      ::FindClose(hFile);
      DWORD dwError = ::GetLastError();
      if(dwError == ERROR_NO_MORE_FILES)
      {
         //Attributes successfully changed
      }
   }
}

int _tmain(int argc, _TCHAR* argv[])
{
   TCHAR m_szFolderPath[MAX_PATH] = "C:\\Program Files\\MyFolder";
   ChangeDirectoryAttribute(m_szFolderPath);
   return 0;
}

Source: CodeGuru How to Change the Attributes of a Directory Through Visual C++
[^]

Regards,

The only programmers that are better than C programmers are those who code in 1's and 0's..... Smile | :)

Programm3r
My Blog: ^_^

David Crow3-Apr-07 5:58

David Crow

3-Apr-07 5:58

Programm3r wrote:
This works:

I should hope so, since it uses the two functions mentioned twice already.

"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15

"Judge not by the eye but by the heart." - Native American Proverb

Programm3r3-Apr-07 6:20

3-Apr-07 6:20

DavidCrow wrote:
since it uses the two functions mentioned twice already.

Kinda hard to get those functions working like one wants too. Hmmm | :|

The only programmers that are better than C programmers are those who code in 1's and 0's..... Smile | :)

Programm3r
My Blog: ^_^