C / C++ / MFC Discussion Boards

Re: How to draw bitmaps without access to HDC or HWND

hvanzyll4-Oct-07 6:05

4-Oct-07 6:05

I'm trying to do on screen display inside a DirectShow filter.
To show buffering messages.
I figured it would be easy to just create a bitmap the size of the output image, then just draw buffering messages and send it off to the render.

Re: How to draw bitmaps without access to HDC or HWND

Mark Salsbery4-Oct-07 6:19

Mark Salsbery

4-Oct-07 6:19

Assuming you want to use GDI to draw on the video frames...

If you have access to the uncompressed frames before they are rendered,
I would use a DIBSection (see CreateDIBSection).

Create a memory DC (CreateCompatibleDC()), select the DIBSection into it.

For each frame, copy the frame pixel bits into the DIBSection's pixel bits.

Then use GDI to draw to the memory DC.

Copy the pixel bits from the DIBSection back to the frame buffer.

Depending on the renderer you are using, there may be features already there
for overlays.

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Re: How to draw bitmaps without access to HDC or HWND [modified]

hvanzyll4-Oct-07 6:27

hvanzyll

4-Oct-07 6:27

I'll try that...
only difrence is i'll have to create the buffer first, take the previous frame and color convert it to rgb24
then pass it into the CreateDIBSection
draw the message I want,
then color convert it to YUY2 or what ever output format is beeing used.

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
);

it needs a HDC,
I dont' have one...
How do i get one, or do i need a valid value? (pass in NULL?)

edit: just looked into CreateCompatibleDC.
If this handle is NULL, the function creates a memory DC compatible with the application's current screen.
would that be dependent if someone is running their display in 16,24, or 32bit?

-- modified at 12:35 Thursday 4th October, 2007

Re: How to draw bitmaps without access to HDC or HWND

Mark Salsbery4-Oct-07 6:54

Mark Salsbery

4-Oct-07 6:54

hvanzyll wrote:
t needs a HDC,
I dont' have one...

You can pass NULL for the DC when calling CreateDIBSection.
The DC is only used for DIBs requiring a color table, not RGB DIBs.

hvanzyll wrote:
If this handle is NULL, the function creates a memory DC compatible with the application's current screen.
would that be dependent if someone is running their display in 16,24, or 32bit?

The DIBSection will determine the bitmap format so a screen compatible
DC will be fine. Note this is NOT the case with regular DDBs (HBITMAP),
which cannot be selected into an incompatible DC.

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Re: How to draw bitmaps without access to HDC or HWND

hvanzyll4-Oct-07 6:57

hvanzyll

4-Oct-07 6:57

Thank you for your help on this.
hopefully my schedule will clear up in the next few days and I will get a chance to implement this.

what can send WM_ERASEBKGND?

dawka19064-Oct-07 4:05

dawka1906

4-Oct-07 4:05

Hi guys

I am receiving WM_ERASEBKGND in my app's main window event handler. However, i can't find what is in fact sending this event. I know that this may be sent by BeginPaint, when InvalidateRect's last argument is set to true. But, all of InvalidateRect calls in my app are called with false as the last argument, so i know that this is not the case.

Do you know any other functions/cases that are causing WM_ERASEBKGND to be sent to the app?

BR
dwk

Re: what can send WM_ERASEBKGND?

Mark Salsbery4-Oct-07 6:02

Mark Salsbery

4-Oct-07 6:02

Are you doing anything that makes the system mark the window
for repainting, like resizing the window, dragging another window
across it, etc??

If the window is just sitting there, you shouldn't be getting random
WM_ERASEBKGND messages.

Note that any WM_ERASEBKGND handler should return non-zero if
background erasing was handled.

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

WM_DESTROY message does not appear to post on VK_ESCAPE [modified]

Sauce!4-Oct-07 3:06

Sauce!

4-Oct-07 3:06

I'm following along with tutorials from www.directxtutorial.com[^] and have succesfully gotten a d3d window up and running. The next section of the tutorial covers running the app in fullscreen, without a title bar or an exit button, requiring changes to be made. One of these changes is the inclusion of a KEY_DOWN and KEY_UP macro, allowing me to check the state of any key. This is implemented so that there is a means of closing the app, using the escape key, however upon pressing the escape key, nothing happens. If I change the line if(KEY_DOWN(VK_ESCAPE)) to if(KEY_UP(VK_ESCAPE)) then the app will exit instantly. Can anybody explain what is happening or what might be causing it?

#define KEY_DOWN(vk_code) ((GetAsyncKeyState(vk_code) & 0x8000) ? 1 : 0)<br />
#define KEY_UP(vk_code) ((GetAsyncKeyState(vk_code) & 0x8000) ? 0 : 1)<br />
<br />
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~<br />
                                  SNIP!<br />
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~<br />
<br />
LRESULT CALLBACK WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam)<br />
{<br />
	switch(msg)<br />
		{<br />
		case WM_CLOSE:<br />
			DestroyWindow(hWnd);<br />
		break;<br />
		case WM_DESTROY:<br />
			Cleanup();<br />
			PostQuitMessage(0);<br />
			return 0;<br />
		case WM_PAINT:<br />
			Render();<br />
			ValidateRect(hWnd, NULL);<br />
<br />
			// check the 'escape' key<br />
			if(KEY_DOWN(VK_ESCAPE))<br />
			PostMessage(hWnd, WM_DESTROY, 0, 0);<br />
			return 0;<br />
		}<br />
	return DefWindowProc(hWnd, msg, wParam, lParam);<br />
}

-- modified at 10:02 Thursday 4th October, 2007

Re: WM_DESTROY message does not appear to post on VK_ESCAPE

led mike4-Oct-07 4:36

led mike

4-Oct-07 4:36

Sauce! wrote:
Can anybody explain what is happening or what might be causing it?

Yes, you can by debugging it and checking the value returned from GetAsyncKeyState()

Re: WM_DESTROY message does not appear to post on VK_ESCAPE

Sauce!4-Oct-07 4:52

Sauce!

4-Oct-07 4:52

unfortunately, I cannot compile in debug as I get errors. I will post these tomorrow. I have been searching about for an article I had a while back that details some of the errors that can occur between a debug or release build and how to fix them, but I've had no luck with that.

Re: WM_DESTROY message does not appear to post on VK_ESCAPE

David Crow4-Oct-07 4:59

David Crow

4-Oct-07 4:59

Sauce! wrote:
I have been searching about for an article I had a while back that details some of the errors that can occur between a debug or release build and how to fix them, but I've had no luck with that.

Perhaps it was this one.

"A good athlete is the result of a good and worthy opponent." - David Crow

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

Re: WM_DESTROY message does not appear to post on VK_ESCAPE

Sauce!4-Oct-07 5:29

Sauce!

4-Oct-07 5:29

YES! Thankyou! Big Grin | :-D

<3 <3 <3 <3 <3

Function Pointer? [modified]

kiranin4-Oct-07 3:01

kiranin

4-Oct-07 3:01

If we declare a function pointer as

typedef void (*myPtr)(void);
myptr NewPtr;

This means that NewPtr is a function pointer of type myptr, where myptr is inturn a function pointer to a function which returns void and takes no function parameters.. then what does the below piece of code mean?

Can somebody please interpret this piece of code for me?

typedef NTSTATUS (NTAPI *pfnNtQueryInformationProcess)(
IN HANDLE ProcessHandle,
IN PROCESSINFOCLASS ProcessInformationClass,
OUT PVOID ProcessInformation,
IN ULONG ProcessInformationLength,
OUT PULONG ReturnLength OPTIONAL
);

pfnNtQueryInformationProcess gNtQueryInformationProcess;

Thanx

-- modified at 9:07 Thursday 4th October, 2007

Re: Function Pointer?

toxcct4-Oct-07 3:15

toxcct

4-Oct-07 3:15

exactly the same as your code, at the difference that the pfnNtQueryInformationProcess is a typedef to a function pointer to a function which returns a NTSTATUS and gets as parameters a HANDLE, a PROCESSINFOCLASS, a PVOID, an ULONG, and a PULONG...

then you declare a variable gNtQueryInformationProcess of that type so defined...

what don't you understand in this ?

[VisualCalc][Binary Guide][CommDialogs] | [Forums Guidelines]

Re: Function Pointer?

kiranin4-Oct-07 3:25

kiranin

4-Oct-07 3:25

Then it should have been declared as

typedef NTSTATUS (*pfnNtQueryInformationProcess)(
IN HANDLE ProcessHandle,
IN PROCESSINFOCLASS ProcessInformationClass,
OUT PVOID ProcessInformation,
IN ULONG ProcessInformationLength,
OUT PULONG ReturnLength OPTIONAL
);

pfnNtQueryInformationProcess gNtQueryInformationProcess;

What is this NTAPI in between? What is its signifance?

Thanx

Re: Function Pointer?

toxcct4-Oct-07 3:27

toxcct

4-Oct-07 3:27

kiranin wrote:
What is this NTAPI in between

it is the calling convention... see how it's defined if that interrest you, but it's probably one of these : __stdcall, __fastcall, __cdecl, __thiscall...

[VisualCalc][Binary Guide][CommDialogs] | [Forums Guidelines]

Re: Function Pointer?

kiranin4-Oct-07 3:37

kiranin

4-Oct-07 3:37

hm.. yeah dats rite.. its a calling convention.. herez the piece of code frm winnt.h

#if ((_MSC_VER >= 800) || defined(_STDCALL_SUPPORTED)) && !defined(_M_AMD64)
#define NTAPI __stdcall
#else
#define _cdecl
#define NTAPI
#endif

Thanx Smile | :)

Re: Function Pointer?

David Crow4-Oct-07 3:22

David Crow

4-Oct-07 3:22

pfnNtQueryInformationProcess is a function pointer to a function that returns NTSTATUS, has an NTAPI calling convention, and takes five arguments.

"A good athlete is the result of a good and worthy opponent." - David Crow

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

Build binary with debugging information

Programm3r4-Oct-07 2:17

Programm3r

4-Oct-07 2:17

Hi all,

I am busy testing the use of minidumps, but I received this messge

Debugging information for @project 1.exe' cannot be found or does not match.
Binary was not built with debug information.

I am well aware of how to do it in Visual Studio

You can use the following options:
Compiler: /Zi (/Z7 and /ZI can also be used in some cases - see their documentation for more information)
Linker: /debug (in release builds also use /opt:ref option)
All these options can be set in the IDE.

My question is, how can I do it in Borland Developer Studio 2006 ??

Can anyone please help me ??

Many thanks
Regards,

The only programmers that are better that C programmers are those who code in 1's and 0's Green Alien | [Alien]

Programm3r
My Blog: ^_^

How to identify click event of Tab control?

Atul234-Oct-07 1:49

Atul23

4-Oct-07 1:49

Hi All,

I am doing project in VC++ 6.0 in which i am displaying tabs on the window area.I want to load a particular page whenever user click on particular tab.These tabs are created at run time.So how can I identify which tab is clicked by user.If anybody know the solution of this, then please forward it me.

Thanks in Advance

Atul

Re: How to identify click event of Tab control?

Naveen4-Oct-07 1:52

Naveen

4-Oct-07 1:52

you wil recieve a TCN_SELCHANGE message when user changes the tab item.

nave

[OpenedFileFinder]

Re: How to identify click event of Tab control?

David Crow4-Oct-07 3:24

David Crow

4-Oct-07 3:24

Atulmahajan wrote:
So how can I identify which tab is clicked by user.

Check out the PSN_SETACTIVE notification.

"A good athlete is the result of a good and worthy opponent." - David Crow

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

using, namespace and enum: VS2003 Compiler Bug?

Russell^'4-Oct-07 1:35

Russell^'

4-Oct-07 1:35

Does anyone knows if

in file.h

namespace MyNamespace{
...
  enum MyEnum{
  ...
  EnumItem,
  ....
  };
...
};

then in file.cpp

using namespace MyNamespace;
...
foo(MyNamespace::MyEnum::EnumItem, ..);
or
foo(MyEnum::EnumItem, ..);
...

gives error C2825 and error C2275 in the first case
and
gives error C2039 in the second case
Cry | :((

It doesn't work also if I remove the line using (of course then using extended variable usage)

can it be related to a bug of the compiler in VS2003? I'm quite sure that I'm not wronging the code sintax.

Russell

Re: using, namespace and enum: VS2003 Compiler Bug?

jhwurmbach4-Oct-07 2:12

jhwurmbach

4-Oct-07 2:12

Hmm. This

namespace MyNamespace{
  enum MyEnum{ EnumItem,SecondItem	  };
};

int _tmain(int argc, _TCHAR* argv[])
{
  MyNamespace::MyEnum firstItem = MyNamespace::MyEnum::EnumItem;
  MyNamespace::MyEnum secondItem = MyNamespace::MyEnum::SecondItem;

  return system("pause");
}

gives a warning C4482: nonstandard extension used: enum 'MyNamespace::MyEnum' used in qualified name with VC 2005.

That is meaning that enums are second class citizens and the correct way of refering them would be:

MyNamespace::MyEnum firstItem = MyNamespace::EnumItem;
MyNamespace::MyEnum secondItem = MyNamespace::SecondItem;

Though I speak with the tongues of men and of angels, and have not money, I am become as a sounding brass, or a tinkling cymbal.
George Orwell, "Keep the Aspidistra Flying", Opening words

Re: using, namespace and enum: VS2003 Compiler Bug?

Russell^'4-Oct-07 2:22

Russell^'

4-Oct-07 2:22

yes!
you are right.
I found only now your same conclusion.
thank you

Russell

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