Status bar part allignment - C / C++ / MFC Discussion Boards

walter761-Mar-06 0:28

1-Mar-06 0:28

Hi there,

i have written this function to draw a image held in raw pixel data in my own class to a window. It is not working as expected, say it doesn't draw a single pixel. Where is the fault? I am trying to solve this for days now and can't see where i made the mistake. Here comes the code.

void CImageViewerView::drawImage(CDC* pDC, CpilImage* pImage) {
    // create compatible memory dc
    CDC memDC;
    memDC.CreateCompatibleDC(pDC);

    // draw image into the bitmap
    CBitmap imageBitmap;
    BITMAP bmp;
    BYTE* imageBits;
    BYTE* pImageBits;

    imageBitmap.CreateBitmap(pImage->getWidth(), pImage->getHeight(), 1, 24, NULL);
    imageBitmap.GetBitmap(&bmp);
    imageBits = (BYTE*) GlobalAlloc(GPTR, bmp.bmHeight * bmp.bmWidthBytes);

    for (unsigned int y = 0; y < pImage->getHeight(); y++) {
        unsigned int* line = pImage->getPixelRegion(0, y, pImage->getWidth(), 1);
        unsigned int* pLine = line;

        pImageBits = imageBits + (bmp.bmWidthBytes * y);
        for (unsigned int x = 0; x < pImage->getWidth(); x++) {
            pImageBits[0] = getRedValue(pLine);
            pImageBits[1] = getGreenValue(pLine);
            pImageBits[2] = getBlueValue(pLine);
            pImageBits += 3;
            pLine++;
        }
    }
    if (imageBitmap.SetBitmapBits(bmp.bmHeight * bmp.bmWidthBytes, imageBits) == 0) {
        AfxMessageBox("Could not set bitmap bits.");
    }

    GlobalFree((HGLOBAL) imageBits);

    // draw bitmap
    CBitmap* pOldBitmap = memDC.SelectObject(&imageBitmap);
    if (pDC->BitBlt(0, 0, pImage->getWidth(), pImage->getHeight(), &memDC, 0, 0, SRCCOPY) ==0) {
        AfxMessageBox("BitBlt failed.");
    }
    memDC.SelectObject(pOldBitmap);
}

CpilImage is a class which stores a image plus the pixel data in rgb-quads. The getXXXValue()-functions are utility functions which extract the red, green and blue values from the quads. The class and functions are working, cause if i alter the function to work with CDC::SetPixelV() the image is drawn. But as this is very slow i tryed to speed it up with SetBitmapBits() and BitBlt() which seems to not work.

Walter

Re: SetBitmapBits not Working as Expected

includeh101-Mar-06 2:11

includeh10

1-Mar-06 2:11

i am prety sure no one wants to read long code as in ur post.

1. bitmap width must be aligned with 2 or 4 bytes.
2. bottom-up or top-down bitmap is determined by BITMAPINFIHEADER.dbHeight.

A nice tool for optimizing your Microsoft html-help contents.

Includeh10

-- modified at 8:12 Wednesday 1st March, 2006

Re: SetBitmapBits not Working as Expected

walter761-Mar-06 2:25

walter76

1-Mar-06 2:25

I tryed to cut it down, but i thought everything could be important. But your post shows that you haven't read the code, either. I use the calculated width from the bitmap info header bmWidthBytes. This is calculated by windows and 4 bytes aligned. I put traces in there and the height is calculated correct. If any of this values would be false there should be something on the screen at last and if it is only crap. But there is nothing, not a single pixel.

I try to break the code down a bit:

// create compatible memory dc
CDC memDC;
memDC.CreateCompatibleDC(pDC);

// draw image into the bitmap
CBitmap imageBitmap;
BITMAP bmp;
BYTE* imageBits;
BYTE* pImageBits;

imageBitmap.CreateBitmap(pImage->getWidth(), pImage->getHeight(), 1, 24, NULL);
imageBitmap.GetBitmap(&bmp);
imageBits = (BYTE*) GlobalAlloc(GPTR, bmp.bmHeight * bmp.bmWidthBytes);

//... doing some pixel transform stuff

if (imageBitmap.SetBitmapBits(bmp.bmHeight * bmp.bmWidthBytes, imageBits) == 0) {
    AfxMessageBox("Could not set bitmap bits.");
}

GlobalFree((HGLOBAL) imageBits);

// draw bitmap
CBitmap* pOldBitmap = memDC.SelectObject(&imageBitmap);
if (pDC->BitBlt(0, 0, pImage->getWidth(), pImage->getHeight(), &memDC, 0, 0, SRCCOPY) ==0) {
    AfxMessageBox("BitBlt failed.");
}
memDC.SelectObject(pOldBitmap);

Re: SetBitmapBits not Working as Expected

Ryan Binns1-Mar-06 2:53

Ryan Binns

1-Mar-06 2:53

Instead of using CreateBitmap(), use CreateCompatibleBitmap() passing pDC as the DC parameter, and then use the contents of the BITMAP structure to determine what format the bitmap is in. You may very well find that it's a 32-bpp bitmap, not a 24-bpp bitmap. Remember BitBlt() only works if the source bitmap is monochrome or in the same format as the device context - hence the CreateCompatibleBitmap() function.

Ryan

"Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late" John Nichol "Point Of Impact"

Re: SetBitmapBits not Working as Expected

walter761-Mar-06 2:59

walter76

1-Mar-06 2:59

Yeah! Just found out that this is the problem. It seems SelectObject() for the bitmap is returning an error, because of the bitmap is not compatible with the device context. I think i change my strategy and have a look into device independent bitmaps (DIB). Maybe this solves my problem.

Programming Windows API can be frustrating sometimes. The only thing i want to do is to put some raw 24bit RGB pixel data fast on to the screen. This can't be that difficult.

Thanks for your help!

Re: SetBitmapBits not Working as Expected

Ryan Binns1-Mar-06 2:55

Ryan Binns

1-Mar-06 2:55

I just noticed what you're trying to do Blush | :O

Have a look at CreateDIBitmap() and SetDIBitsToDevice(). They will work with any bitmap format and will convert between them when displaying the bitmap. Slower than BitBlt(), but the performance will be substantially quicker than what you are doing here.

Ryan

"Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late" John Nichol "Point Of Impact"

Re: SetBitmapBits not Working as Expected

walter761-Mar-06 3:00

walter76

1-Mar-06 3:00

Looks like i am on the right way now. Thanks again.

Status bar part allignment

Waldermort1-Mar-06 0:03

Waldermort

1-Mar-06 0:03

How is it possible to correctly allign the seperate parts of a status bar under Win32? I know we have to create an array of ints each defining the right side of the part and send the SB_SETPARTS message. But what about alligning the parts on the right hand side?

I want my bar to look similar to this one http://www.codeproject.com/miscctrl/ProgressBar.asp[^]

The only method I can think of is by getting the status bar rect and setting the parts according to the width, but this kinda gets screwed up when it comes to resizing. Even so, in the picture there is a large space blank space before the parts which I am so far unable to reproduce.

Re: Status bar part allignment

Nibu babu thomas1-Mar-06 0:32

Nibu babu thomas

1-Mar-06 0:32

waldermort wrote:
I want my bar to look similar to this one http://www.codeproject.com/miscctrl/ProgressBar.asp[^]

<font color=blue>int</font> CMainFrame::OnCreate(LPCREATESTRUCT lpCreateStruct)
{
    <font color=green>//rest of the code...
    //after creating statusbar</font>
    m_wndStatusBar.SetPaneInfo( 0, m_wndStatusBar.GetItemID( 0 ), SBPS_STRETCH, NULL );
    <font color=green>//rest of the code</font>

}

NOTE: Only one pane of the status bar can have this style set.

Nibu thomas
Software Developer

creating child process in c++

Aqueel28-Feb-06 23:58

Aqueel

28-Feb-06 23:58

Hello
I want to ask how can i create a child process in Win32 as we do in linux with the help of fork().
Thank you.

We Believe in Excellence

Re: creating child process in c++

Nibu babu thomas1-Mar-06 0:03

Nibu babu thomas

1-Mar-06 0:03

CreateProcess(...)

Nibu thomas
Software Developer

Re: creating child process in c++

Vinaya1-Mar-06 0:08

Vinaya

1-Mar-06 0:08

see _execvp() [^]

Vini

Re: creating child process in c++

John R. Shaw1-Mar-06 0:23

John R. Shaw

1-Mar-06 0:23

I am not going to give you an answer, because you did no give an explanation of what fork() does. You have received a couple of answers about generating a child process.

What do you want to know precisely?

INTP
Every thing is relative...

Re: creating child process in c++

Cedric Moonen1-Mar-06 0:47

Cedric Moonen

1-Mar-06 0:47

I'm not a linux expert but I think fork() creates a new thread and not a new process. Am I right (not sure at all about that). The previous answers you get was how to create a process (so run another executable). If you want to run a thread in parallel, then you have to look for CreateThread[^]

Re: creating child process in c++

Ryan Binns1-Mar-06 2:58

Ryan Binns

1-Mar-06 2:58

fork() creates a new process - an exact duplicate of the current process, including the current code location. You can do this:

switch(fork())
{
case 0:
  // child process comes here
  exit(0);
default:
  // parent process comes here
  break;
}

Ryan

"Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late" John Nichol "Point Of Impact"

Re: creating child process in c++

Aqueel1-Mar-06 0:48

Aqueel

1-Mar-06 0:48

Here is the discription of fork() function.
"fork creates a child process that differs from the parent process only in its PID and PPID, and in the fact that resource utilizations are set to 0."
I wanted to do the same thing in win32. I do not want operating system to allocate saperate resourses to new process. Infact i want the process to share the same resourses that it's parent is using. Are you getting my point?
Thank you.

We Believe in Excellence

Re: creating child process in c++

Ryan Binns1-Mar-06 2:59

Ryan Binns

1-Mar-06 2:59

Look at CreateThread(). It's exactly what you're after. But read up on multithreading, because you obviously don't know a lot about it. It can be quite tricky to learn...

Ryan

"Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late" John Nichol "Point Of Impact"

Re: creating child process in c++

Nemanja Trifunovic1-Mar-06 1:48

Nemanja Trifunovic

1-Mar-06 1:48

There is no fork equivalent under Windows. I suggest you consider using threads rather than processes - that is the Windows way of handling concurrency.

My programming blahblahblah blog. If you ever find anything useful here, please let me know to remove it.

Re: creating child process in c++

jhwurmbach1-Mar-06 3:05

jhwurmbach

1-Mar-06 3:05

Nemanja Trifunovic wrote:
I suggest you consider using threads rather than processes - that is the Windows way of handling concurrency.

Actually, its becoming more and more the Linux way of concurrency.
NPTL is a stable working thread implementation.

"We trained hard, but it seemed that every time we were beginning to form up into teams we would be reorganised. I was to learn later in life that we tend to meet any new situation by reorganising: and a wonderful method it can be for creating the illusion of progress, while producing confusion, inefficiency and demoralisation."

-- Caius Petronius, Roman Consul, 66 A.D.

placing landline call from cyber cafe node

Martin Akula28-Feb-06 23:41

Martin Akula

28-Feb-06 23:41

how would i go about that

martin reagan akula

Re: placing landline call from cyber cafe node

toxcct28-Feb-06 23:49

toxcct

28-Feb-06 23:49

sorry, i don't understand your request...

TOXCCT >>> GEII power
[toxcct][VisualCalc 2.24][3.0 soon...]

Re: placing landline call from cyber cafe node

Maximilien1-Mar-06 2:22

Maximilien

1-Mar-06 2:22

your cyber cafe must have a VoIP client ( whtever the real name is ).

Maximilien Lincourt
Your Head A Splode - Strong Bad

Parallel Data Calculation ( reduce calculation time)

zahid_ash28-Feb-06 23:34

zahid_ash

28-Feb-06 23:34

Hi,

I want to do calcualtions on different datafile parallely, that is if i do on them sequencialy then Let say if it take one munite to perform calcualtion on file then it will take 60 minutes to perfeorm calculation on 60 files.

but i want that the calcualtion should be done in parllal so that i can reduce the calcualtion time on 60 files.

Any Idea?

I have a Uni processor machine

I hope you undesrtand my point

thanks

Regards.

Re: Parallel Data Calculation ( reduce calculation time)

Cedric Moonen28-Feb-06 23:54

Cedric Moonen

28-Feb-06 23:54

Make a new calculation in a new thread. But you will need to read some documentation on, take a look at the MSDN (for CreateThread) or on this website.
But this won't reduce the total time because if you are running 60 threads in parallel (don't even know if this is possible), each thread will have less CPU time for its own so it will run slower thus it will take more time to finish. I don't think this is a good solution.

Re: Parallel Data Calculation ( reduce calculation time)

John R. Shaw1-Mar-06 0:08

John R. Shaw

1-Mar-06 0:08

I do not know the answer, but I think there may be an article at CP some where. Depending on the operating system, compiler, and how you wrote the code it may already be doing what you want. Before asking the question you need to determine if both processors are handling the problem. Then you need to fuigure out how to hand off individule problems to each processor.

I know it does sound simple but it is not [realy].

INTP
Every thing is relative...

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.