C / C++ / MFC Discussion Boards

Re: CString Problerm

Zayax21-Aug-02 6:16

Zayax

21-Aug-02 6:16

Thanks. I never thought it was so simple. What a shame.
What if I want to force it to make a newline?

Newbies

Re: CString Problerm

-Dy21-Aug-02 6:23

-Dy

21-Aug-02 6:23

A new line in the text? Use \n, there's others too like \t for tab, \\ for '\', etc. Look these up (or 'escape sequences') in MSDN for more info

Dylan Kenneally
London, UK

Re: CString Problerm

Zayax21-Aug-02 6:46

Zayax

21-Aug-02 6:46

Thanks
I've look at MSDN and you were right.

but when I want to type like this

CString welcome_string
= "Hello\ \n
World";

so that Hello and World are in different line, there was a "newline is constant" error. Confused | :confused:

Newbies

Re: CString Problerm

lucy21-Aug-02 6:51

lucy

21-Aug-02 6:51

CString welcome_string
= "Hello\ \n\
World";

Re: CString Problerm

Zayax21-Aug-02 7:08

Zayax

21-Aug-02 7:08

lucy wrote:
CString welcome_string
= "Hello\ \n\
World";

Thanks again. I've tried that but this came out

warning C4129: ' ' : unrecognized character escape sequence

and the line was still in one line. Confused | :confused:

Newbies

Re: CString Problerm

lucy21-Aug-02 7:16

lucy

21-Aug-02 7:16

oops, sorry, should be
CString welcome_string
= "Hello\n\
World";

Re: CString Problerm

Zayax21-Aug-02 7:28

Zayax

21-Aug-02 7:28

A lot of thanks for your reply Smile | :)

BUT the output was

Hello|World

and not

Hello
World

this was my code

void CMyView::OnDraw(CDC* pDC)<br />
{<br />
CString welcome_string <br />
= "Hello\n\<br />
World";<br />
pDC->TextOut(0,0,welcome_string);<br />
}

Newbies

Re: CString Problerm

lucy21-Aug-02 7:36

lucy

21-Aug-02 7:36

I'm afraid TextOut couldn't handle the "\n", but MessageBox() can. Try

MessageBox(welcome_string);

and see.

Re: CString Problerm

Zayax21-Aug-02 7:43

Zayax

21-Aug-02 7:43

Thanks

Is this means only messagebox can handle "\n"? How about editbox or listbox ia a dialog?

Newbies

Re: CString Problerm

lucy21-Aug-02 7:42

lucy

21-Aug-02 7:42

I'm not sure. You'd better check that out.

Re: CString Problerm

Zayax21-Aug-02 7:53

Zayax

21-Aug-02 7:53

Thanks

Newbies

Re: CString Problerm

PJ Arends21-Aug-02 8:18

PJ Arends

21-Aug-02 8:18

As Lucy said, TextOut() can not handle newlines, but DrawText() can. If you want to output multi line text use DrawText().

HTH

CPUA 0x5041

Sonork 100.11743 Chicken Little

"So it can now be written in stone as a testament to humanities achievments "PJ did Pi at CP"." Colin Davies

Within you lies the power for good - Use it!

Re: CString Problerm

Shay Harel21-Aug-02 6:12

Shay Harel

21-Aug-02 6:12

this is easy:

CString t=
"hello \
world";

Pay attention to the backslash, type ENTER after it and go on

Re: CString Problerm

Rashid Thadha21-Aug-02 6:14

Rashid Thadha

21-Aug-02 6:14

or you can do this

CString t = "Hello"
"World";

without the '\' slash character

A Shading algorithm ?

yarp21-Aug-02 6:01

yarp

21-Aug-02 6:01

I'm looking for a shading algorithm that would fill a polygon with a simple pattern according to a shade ratio.
Like this:

+  +  +
  +  +

A simple algo would do. I'm using the bresenham line algorithm to scan my lines and I simply want to plot my pixels according to this rule.
Thanks

Yarp
http://www.senosoft.com/

Re: A Shading algorithm ?

C^hris L^osinger21-Aug-02 7:13

C^hris L^osinger

21-Aug-02 7:13

try a google search for "Polygon scanline conversion"; that's the 'technical' term for finding the edges of a polygon, given the points. additional hints: "Paul Heckbert" and "Graphics Gems" Smile | :)

-c

Though the cough, hough and hiccough so unsought would plough me through,
enough that I o'er life's dark lough my thorough course pursue.
--Stuart Kidd

image effects!

Re: A Shading algorithm ?

Stephane Rodriguez.21-Aug-02 7:27

Stephane Rodriguez.

21-Aug-02 7:27

Try with the "raster" keyword as well, Big Grin | :-D

And I swallow a small raisin.

Re: A Shading algorithm ?

yarp21-Aug-02 21:54

yarp

21-Aug-02 21:54

Hard to find indeed, even with the "raster" key word. The Internet is full of 3D Gouraud shading,... luckily one day I intend to do some 3D programming and I'll probably find my algo that time Wink | ;)

It doesn't matter, I'll do it myself.
Thanks

Yarp
http://www.senosoft.com/

Chris Maudre Datagrid

Mazdak21-Aug-02 5:35

Mazdak

21-Aug-02 5:35

In Chris Maunder datagrid,does anybody know how can I overriden EndEdit() for a cell in my class?

Mazy

"If I go crazy then will you still
Call me Superman
If I’m alive and well, will you be
There holding my hand
I’ll keep you by my side with
My superhuman might
Kryptonite"Kryptonite-3 Doors Down

Re: Chris Maudre Datagrid

C^hris L^osinger21-Aug-02 5:36

C^hris L^osinger

21-Aug-02 5:36

why don't you post this question on the grid article?

Though the cough, hough and hiccough so unsought would plough me through,
enough that I o'er life's dark lough my thorough course pursue.
--Stuart Kidd

image effects!

Re: Chris Maudre Datagrid

Mazdak21-Aug-02 7:29

Mazdak

21-Aug-02 7:29

More people see it here.I post it there too.

Mazy

"If I go crazy then will you still
Call me Superman
If I’m alive and well, will you be
There holding my hand
I’ll keep you by my side with
My superhuman might
Kryptonite"Kryptonite-3 Doors Down

terminate a worker thread

lucy21-Aug-02 5:31

lucy

21-Aug-02 5:31

I have a Dialog based MFC program, and in CMyDialogDlg::OnCreate I start my worker thread like this:

m_bThreadRun = TRUE;
HANDLE hThread = AfxBeginThread(MyWorkerThread, this);
if ( hThread == NULL )
    MessageBox("Cannot start worker thread.");

While in my worker thread, I check for the flag from parent:

UINT MyWorkerThread(LPVOID pParam)
{
    CMyDialogDlg * pDlg = (CMyDialogDlg *)pParam;
    while ( pDlg->m_bThreadRun)
    {
        // do something
    }
    TRACE("exit from the worker thread");
    return 0;
}

In order to terminate this worker thread, I did this:

CMyDialogDlg::OnClose()
{
   m_bThreadRun = FALSE;
   CDialog::OnClose();
}

But what troubles me is:
1. The trace line of my worker thread function "exit from the worker thread" was never printed.
2. When the program ended, this will appear in my Visual studio debug window:

etected memory leaks!
Dumping objects ->
thrdcore.cpp(166) : {54} client block at 0x017B4558, subtype 0, 112 bytes long.
a CWinThread object at $017B4558, 112 bytes long
Object dump complete.

what I am missing here? How can I terminate this worker thread gracefully?

Thanks a lot for your help!

Re: terminate a worker thread

Tomasz Sowinski21-Aug-02 5:38

Tomasz Sowinski

21-Aug-02 5:38

You should WaitForSingleObject after setting m_bThreadRun to FALSE. Also, add 'volatile' modifier to m_bThreadRun.

Tomasz Sowinski -- http://www.shooltz.com

"Yields falsehood when preceded by its quotation" yields falsehood when preceded by its quotation.

Re: terminate a worker thread

lucy21-Aug-02 6:01

lucy

21-Aug-02 6:01

I add the following modifications:

OnCreate()
{
   m_hMyThread = AfxBeginThread(...);
}


OnClose()
{
   m_bThreadRun = FALSE;
   WaitForSingleObject(m_hMyThread, 1000);
}

but WaitForSingleObject will fail and the reason is "The handle is invalid. ". why? Confused | :confused:

FYI, I have added the volatile specifier to my worker thread checking.

Re: terminate a worker thread

RChin21-Aug-02 23:43

RChin

21-Aug-02 23:43

When the worker thread terminates, the Object (CWinThread) will clean up and deallocate any resources associated with it, including itself. So after termination, the CWinThread variable will be invalid as stated.

To avoid this you will need to tell the class not to automatically delete itself on termination.

try this:

OnClose()
{
   // do not automatically delete me
   //
   m_hMyThread.m_bAutoDelete = FALSE; 

   m_bThreadRun = FALSE;   // signal thread for termination ..
   WaitForSingleObject(m_hMyThread, 1000); // .. and wait.

   delete m_hMyThread; // remember to clean up
   m_hMyThread = NULL; // not neccessary, but just to be clean.
}

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