C / C++ / MFC

31-May-07 5:27

This link shows available codecs: http://support.microsoft.com/default.aspx?scid=kb;en-us;899113[^]

Depending on what compression manager you end up using, there should be APIs to list/choose
codecs. For example, acmFormatChoose() shows a dialog for selecting audio formats in the audio
compression manager.

Mark

"Posting a VB.NET question in the C++ forum will end in tears." Chris Maunder

Monochrome Bitmap Issue

CoffeeAddict1930-May-07 12:23

30-May-07 12:23

I'm having a problem with memory device contexts and bitmaps in MFC. I've gotten to the point to where I can create and use them, but natrually they are all in black in white. See here:

http://img.photobucket.com/albums/v50/blackdwarf/piegraphcontrol.jpg[^]

With a CreateCompatibleDC(NULL) call, a monochrome bitmap gets created for and selected into the CDC. When I actually create my bitmap based off of that CDC, I'm stuck with the monochrome. So my question is, how do I initialize the bitmaps with color outside of OnPaint when I can't just use CPaintDC?

Here is some of the code...

Creating the two bitmaps without a CPaintDC (where I think the problem is):

BOOL CPieGraph::Create(CWnd* pParentWnd, const RECT& rect, UINT nID, DWORD dwStyle /*=WS_VISIBLE*/)
{
	BOOL OverallSuccess = FALSE;
	BOOL CreateResult = FALSE,
		TextDCResult = FALSE,
		PieDCResult = FALSE;
	int SelectText = 0, SelectPie = 0;

	CreateResult = CWnd::Create(CPIEGRAPH_CLASSNAME, _T(""), dwStyle, rect, pParentWnd, nID);

	TextDCResult = TextMemDC.CreateCompatibleDC(NULL);
	PieDCResult = PieMemDC.CreateCompatibleDC(NULL);
	SelectText = m_textBitmap.CreateCompatibleBitmap(&TextMemDC, 250, 20);
	SelectPie = m_pieBitmap.CreateCompatibleBitmap(&PieMemDC, 300, 300);
	OldtextBitmap = TextMemDC.SelectObject(&m_textBitmap);
	OldpieBitmap = PieMemDC.SelectObject(&m_pieBitmap);
	TextMemDC.SetBkColor(RGB(255,255,255));
	PieMemDC.SetBkColor(RGB(255,255,255));
	if((CreateResult == TRUE) && (TextDCResult == TRUE) && (PieDCResult == TRUE) && (SelectText != 0) && (SelectPie != 0))
	{
		OverallSuccess = TRUE;
		ControlRect = rect;
	}
	else
		OverallSuccess = FALSE;

	return OverallSuccess;
}

And OnPaintDC:

afx_msg void CPieGraph::OnPaint()
{
	CPaintDC dc(this);

	CDC ControlMemDC;
	CBitmap ControlBitmap;
	CBitmap* OldBitmap = NULL;

	ControlMemDC.CreateCompatibleDC(&dc);
	ControlBitmap.CreateCompatibleBitmap(&ControlMemDC, 300, 360);
	OldBitmap = ControlMemDC.SelectObject(&ControlBitmap);
	ControlMemDC.SetBkColor(RGB(255,255,255));

	if(UpdateNeeded == true)
	{
		RedrawPieText(TextMemDC);
		RedrawPieChart(PieMemDC);
		ControlMemDC.BitBlt(0, 0, 250, 20, &TextMemDC, 0, 0, SRCCOPY);
		ControlMemDC.BitBlt(0, 25, MainPieGraph.radius * 2, 
			MainPieGraph.radius * 2, &PieMemDC, 0, 0, SRCCOPY);
		//UpdateNeeded = false;
		UpdateNeeded = true;
	}

	dc.BitBlt(ControlRect.left, ControlRect.top, 250, 320, &ControlMemDC, 0, 0, SRCCOPY);
	ControlMemDC.SelectObject(OldBitmap);
}

Bram van Kampen30-May-07 14:28

Bram van Kampen

30-May-07 14:28

Don't know an awfull lot about the issues, but it appears to be at first sight to be a problem about loss of information.It would appear to me that you first create a monochrome bitmap from a source, which you select into the CDC. At that stage the Die is cast as far as the CDC is concerned. The Monochrome bitmap is all it knows about. The CDC has built a Monochrome picture which it knows your Device can display. All Colour Info has been discarded. If at a later stage you want the Bitmap in colour, you have to start again from scratch in the same or another CDC, This time indicating yont to keep the colour. Mind you,to do so you could recycle most of the code. Just leave an indication somewhere about what way you want it, Monocrome or Colour. A Device Context is a Uniform Construct that Converts things like bitmaps etc into something your Hardware can display. (That's the way device-independence is Implemented).

Hope this is Usefull. Smile | :)

LateNightsInNewry

Mark Salsbery30-May-07 15:16

30-May-07 15:16

To add to LateNightsInNewry's reply...

To fix it...

When you call CreateCompatibleBitmap(), you should use the screen or paint DC, not the memory
DC. The memory DC you created with CreateCompatibleDC() is the one with a monochrome bitmap
selected into it. If you create a bitmap compatible with that, it will also be monochrome.

Outside of OnPaint, you can get a screen DC with

::GetDC(0)

or something like

CDC ScreenDC;
ScreenDC.CreateCompatibleDC(0);

Mark

"Posting a VB.NET question in the C++ forum will end in tears." Chris Maunder

CoffeeAddict1930-May-07 17:08

30-May-07 17:08

Thanks, both of you. I think it'll work. I'll try it tommorow when I wake up.

Mark Salsbery31-May-07 5:36

31-May-07 5:36

"Posting a VB.NET question in the C++ forum will end in tears." Chris Maunder

CoffeeAddict1931-May-07 8:19

31-May-07 8:19

Actually I just got a cup about 30 minutes ago. Smile | :)

Unfortunatly, the problem still remains. Frown | :(

I tried using GetDC:

CDC* ScreenDC = NULL;
CreateResult = CWnd::Create(CPIEGRAPH_CLASSNAME, _T(""), dwStyle, rect, pParentWnd, nID);

TextDCResult = TextMemDC.CreateCompatibleDC(NULL);
PieDCResult = PieMemDC.CreateCompatibleDC(NULL);

ScreenDC = GetDC();
ASSERT(ScreenDC == NULL);
SelectText = m_textBitmap.CreateCompatibleBitmap(ScreenDC, 250, 20);
SelectPie = m_pieBitmap.CreateCompatibleBitmap(ScreenDC, 300, 300);
ReleaseDC(ScreenDC);

At first the assert statement wasn't in there and I just got black and white, then I put it in and I got a debug assertation on the same line, indicating that ScreenDC was null, and that GetDC didn't do the job. Any idea why?

CoffeeAddict1931-May-07 8:38

31-May-07 8:38

Well the assert statement was wrong...it should have been ASSERT(ScreenDC != NULL), but it is still not rendering color for some reason. Fonts, brushes, and pens work fine, just not color.

Mark Salsbery31-May-07 8:53

Re: Monochrome Bitmap Issue [modified]

31-May-07 8:53

CoffeeAddict19 wrote:
but it is still not rendering color for some reason.

Hopefully my modified post below will help Smile | :)

"Posting a VB.NET question in the C++ forum will end in tears." Chris Maunder

Mark Salsbery31-May-07 8:43

31-May-07 8:43

CoffeeAddict19 wrote:
indicating that ScreenDC was null

~~Is Create() failing?~~ Never mind, I see you fixed the ASSERT

I steered you wrong with the CreateCompatibleDC, sorry D'Oh! | :doh:

*EDIT* I DID show you a way to do what you were already doing though :)

This should work from anywhere:

CWindowDC ScreenDC(0);
 
CBitmap bitmap;
bitmap.CreateCompatibleBitmap(&ScreenDC, 20, 20);
 
//**Test - Check the resulting bitmap's format...
BITMAP bitmapstruct;
bitmap.GetObject(sizeof(BITMAP), &bitmapstruct);

You'll see in the BITMAP struct, the format matches the screen format.

Try this:

CreateResult = CWnd::Create(CPIEGRAPH_CLASSNAME, _T(""), dwStyle, rect, pParentWnd, nID);
CWindowDC ScreenDC(0);
TextDCResult = TextMemDC.CreateCompatibleDC(&ScreenDC);
PieDCResult = PieMemDC.CreateCompatibleDC(&ScreenDC);
SelectText = m_textBitmap.CreateCompatibleBitmap(&ScreenDC, 250, 20);
SelectPie = m_pieBitmap.CreateCompatibleBitmap(&ScreenDC, 300, 300);

Mark

-- modified at 14:54 Thursday 31st May, 2007

"Posting a VB.NET question in the C++ forum will end in tears." Chris Maunder

CoffeeAddict1931-May-07 9:58

31-May-07 9:58

Thanks mark! I HAVE MADE COLOR! Check it out:

http://img.photobucket.com/albums/v50/blackdwarf/piechart_color.jpg[^]

Shouldn't take me long to get long of the pesky black area around the edges. Maybe I'll write a simple tutorial on making controls someday. There already is one, but another viewpoint couldn't hurt.

Mark Salsbery31-May-07 10:05

Re: table and vector, C++

31-May-07 10:05

mmmm Pie!

Cool!

"Posting a VB.NET question in the C++ forum will end in tears." Chris Maunder

table and vector, C++

C_Zealot30-May-07 11:39

C_Zealot

30-May-07 11:39

Hi all:

I declared a variable of map type as below:

typedef vector<streampos> OccurrenceList;<br />
  map<string, OccurrenceList> table;

I just do not know how to "insert" a new instance of map into this list.

Normally, I will use:

table.insert(make_pair(a_new_string, a_new_something);    //a_new_something is only a variable of simpler type, like a int.

Can anyone help?

Thank you

C_Zealot30-May-07 11:42

C_Zealot

30-May-07 11:42

typedef vector <<streampos>> OccurrenceList;
map <<string, occurrencelist="">> table;

Re: table and vector, C++

Rajkumar R31-May-07 1:16

Rajkumar R

31-May-07 1:16

<br />
typedef vector <<streampos>>OccurrenceList;<br />
map <<string, OccurrenceList>> table;<br />

new instance can be inserted into the map of simpler/complex type
if the necessary operators are implemented for that type.

<br />
OccurrenceList list;<br />
list.push_back(somedata); // insert data<br />
table.insert(make_pair("a_new_string", list); <br />

this will work. note: map stores a new copy of "list"

Re: table and vector, C++

C_Zealot31-May-07 1:18

C_Zealot

31-May-07 1:18

Thank you.

Directshow : Connect to another process's graph...

Akin Ocal30-May-07 11:36

Akin Ocal

30-May-07 11:36

I have a media player from microsoft playing a file.
When the player plays the file a graph is produced.
What additiionally I wanted was to get some code to connect to the microsoft media players
graph and a add some filter and configure the filters.

BEST REGARDS

Re: Directshow : Connect to another process's graph...

Mark Salsbery30-May-07 15:19

Connect to another process's graph...

30-May-07 15:19

I don't have a solution for you but I bet if/how it can be done can be found in the Windows
Media Player SDK which can be found here[^].

Mark

"Posting a VB.NET question in the C++ forum will end in tears." Chris Maunder

Akin Ocal30-May-07 11:35

Akin Ocal

30-May-07 11:35

Monitor Memory for Alterations

Jeffrey Walton30-May-07 11:25

Jeffrey Walton

30-May-07 11:25

Hi All,

Does the Windows API provide a function which allows one to monitor a chunk of memory for modifications (similar to watching a directory for changes using FindFirstChangeNotification())?

Jeff

microsoft.public.vc.mfc received one response with, 'What are you trying to do'? Monitor Memory for Alteration[^]
microsoft.public.win32.programmer.kernel received no responses. Monitor Memory for Alterations[^]

Matthew Faithfull30-May-07 12:58

Matthew Faithfull

30-May-07 12:58

You can do this with the VS Debugger, i.e. set a memory breakpoint but only one and only monitoring 4 bytes. That's because it uses an internal feature of Intel architecture compatible processors to achieve this at a very low level. I guess it's probably an interrupt or something. I don't know of any other way if you want to be certain of catching changes as they happen.

Nothing is exactly what it seems but everything with seems can be unpicked.

Jeffrey Walton30-May-07 14:03

Jeffrey Walton

30-May-07 14:03

Hi Matthew,

Matthew Faithfull wrote:
You can do this with the VS Debugger

My bad - I want to do it from a Userland program - no debugger required.

BTW, I did try and think how we could do it by acting as if we were a debugger - but I don't think vanilla userland programs (i.e., not running under privlidged accounts) will allow it.

Jeff

Matthew Faithfull30-May-07 22:40

Matthew Faithfull

30-May-07 22:40

I'm not sure about Vista but on previous Windows versions at least the VS Debugger is pretty much a vanilla userland program.
If I remember rightly the code to set up a memory watch style breakpoint is in John Robbins book 'Debugging Applications' which is a great book, worth a read anyway if you haven't already. I can't be sure the technique would work from 'ordinary' code but it may and if a switch to Kernel mode is required I'm sure Robbins explains how to do it. I think the book code is downloadable if you give it search Smile | :)

Nothing is exactly what it seems but everything with seems can be unpicked.