Re: Basic GDI question - C / C++ / MFC Discussion Boards

Nish Nishant2-Jun-02 19:10

2-Jun-02 19:10

How do I draw a pixel into a CView?
What's the API call to draw a pixel?

I guess I put all the code in the OnDraw of the CView derived class!

Regards
Nish

Regards,
Nish
Native CPian.
Born and brought up on CP.
With the CP blood in him.

Re: Basic GDI question [found it]

Nish Nishant2-Jun-02 19:15

Nish Nishant

2-Jun-02 19:15

CDC::SetPixel

Thanks

Nish

Regards,
Nish
Native CPian.
Born and brought up on CP.
With the CP blood in him.

Re: Basic GDI question [found it]

Paul M Watt2-Jun-02 19:42

Paul M Watt

2-Jun-02 19:42

How many SetPixel operations will you be performing?
If you are doing a lot, you may want to consider creating a bitmap and accessing the bits directly becuase set pixel will slow your program down by orders of magnitude.

Build a man a fire, and he will be warm for a day
Light a man on fire, and he will be warm for the rest of his life!

Re: Basic GDI question [found it]

Nish Nishant2-Jun-02 19:56

Nish Nishant

2-Jun-02 19:56

kilowatt wrote:
How many SetPixel operations will you be performing?
If you are doing a lot, you may want to consider creating a bitmap and accessing the bits directly becuase set pixel will slow your program down by orders of magnitude.

I am trying to decrypt an unknown image format! I wanted to try out different combinations and reproduce the image. We have a hard copy of the image and the image file [some kinda custom format from the mid 80s]

Nish

Regards,
Nish
Native CPian.
Born and brought up on CP.
With the CP blood in him.

Re: Basic GDI question [found it]

Paul M Watt2-Jun-02 20:16

Paul M Watt

2-Jun-02 20:16

Sounds interesting?

Are you doing that for fun, or have you tried to find the decoder and it is not available?

Build a man a fire, and he will be warm for a day
Light a man on fire, and he will be warm for the rest of his life!

Re: Basic GDI question [found it]

Nish Nishant2-Jun-02 20:23

Nish Nishant

2-Jun-02 20:23

kilowatt wrote:
Are you doing that for fun, or have you tried to find the decoder and it is not available?

Part fun, part serious. We have a client who's been using this image format for almost 20 years. The main program is in GWBASIC and they have this external program [written with assembler]. Partial sources available. Long assembler listings Frown | :-(

I understand that the first 32 bytes is some kinda header. The rest of it has a lot of 0xFFs in them. I am assuming the 0xFFs are the black spaces and am making guessed at what the other bytes mean.

One problem is I don't know the width of the image in pixels!!!

Nish

Regards,
Nish
Native CPian.
Born and brought up on CP.
With the CP blood in him.

Re: Basic GDI question

Mike Nordell3-Jun-02 23:04

Mike Nordell

3-Jun-02 23:04

Nish wrote:
How do I draw a pixel into a CView?

Don't, it will be dog slow. Create a DIB section instead and get direct access to the bits, then blit that bitmap to the view. It will be both much faster and easier to handle.

Re: Basic GDI question

Nish Nishant3-Jun-02 23:18

Nish Nishant

3-Jun-02 23:18

Mike Nordell wrote:
Don't, it will be dog slow

Yeah it sure was slow Frown | :-(

So slow it looked like some kinda animation where I could see it drawing it on screen Frown | :-(

Nish

Regards,
Nish
Native CPian.
Born and brought up on CP.
With the CP blood in him.

How telling Windows I'm idle in message loop?

2-Jun-02 18:38

Hi,
I have pure Win32 based project with own message loop, something like:

CreateWindow();
for (;; )
{
	EngineMain();		//render stuff
	if(!PumpMessage()) break;	//handle all window messages
				//...until OpenGL window should be closed
}
DestroyWindow();

When there is nothing todo (e.g. dialog is miminized) I would like to tell Windows that I'm idle. Currently the CPU consumption is allways 100%, because the message loop is running like crazy, hehe. Well, I'd like to avoid that.

thx, Moak Smile | :)

Re: How telling Windows I'm idle in message loop?

Michael Dunn2-Jun-02 18:39

Michael Dunn

2-Jun-02 18:39

You code never blocks, like GetMessage() normally does. You need some mechanism to make your thread block (and thus receive no CPU time) when the queue is empty, then unblock when a message arrives in the queue.

--Mike--
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Re: How telling Windows I'm idle in message loop?

2-Jun-02 18:46

thx, i did without PeekMessage and it blocks + CPU consumption is low!

Re: How telling Windows I'm idle in message loop?

Paul M Watt2-Jun-02 19:49

Paul M Watt

2-Jun-02 19:49

I am just curious, how did you end up doing it?

Build a man a fire, and he will be warm for a day
Light a man on fire, and he will be warm for the rest of his life!

Re: How telling Windows I'm idle in message loop?

3-Jun-02 5:34

kilowatt wrote:
I am just curious, how did you end up doing it?

I'll block with WaitMessage() when there is no window visible. Member variable m_data.bVisible is set in my WindowProc callback handler (have a look on WM_SIZE).

BOOL CBlueSharkEngineWindow::PumpMessage()
{
	assert(m_data.bCreated);
	assert(m_pInterface);

	MSG msg;
	while (::PeekMessage (&msg,NULL,0,0,PM_NOREMOVE))	
	{
		if (!::GetMessage (&msg, NULL, 0, 0)) 
		{
			m_pInterface->pConsole->Logfile(SHARKENGINE_LOG_DEBUG3, "Quit message received");
			return FALSE;			
		}

		::TranslateMessage (&msg);
		::DispatchMessage (&msg);
	}

	if(!m_data.bVisible) WaitMessage();
	
	return TRUE;
}

Greets, Moak

Re: How telling Windows I'm idle in message loop?

Alexandru Savescu2-Jun-02 21:47

Alexandru Savescu

2-Jun-02 21:47

I think you should create a worker thread that does whatever your EngineMain funtion is doing. Thus, you can still handle all other Windows messages

Best regards,
Alexandru Savescu

redirecting mouse button ??

Alek2-Jun-02 18:01

Alek

2-Jun-02 18:01

I used SetWindowsHookEx(WH_MOUSE,....) to get mouse message.
After get mouse message(like WM_RBUTTONUP...)I need to redirect it.
For example, when user clicks right button, I want call 'Run...' dialog.
I know that I need to disable popup menu and then to do what I want it to do.

Below is my code:

HHOOK glhHook = NULL;
HINSTANCE glhInstance = NULL;
glhook = SetWindowsHookEx(WH_MOUSE, MouseProc, glhInstance, 0);
.
.
.
LRESULT WINAPI CALLBACK MouseProc(int nCode, WPARAM wp, LPARAM lp)
{
if(wp == WM_RBUTTONUP)
{
// do something....

((MOUSEHOOKSTRUCT*)lp->hwnd = NULL;
((MOUSEHOOKSTRUCT*)lp->wHitTestCode = NULL;
((MOUSEHOOKSTRUCT*)lp->dwExtraInfo = NULL;
return false;
}
}

but it still show the popup menu and ignore the action I want to do
why???
Is anybody can give me some suggestion?

Re: redirecting mouse button ??

Paul M Watt2-Jun-02 18:29

Paul M Watt

2-Jun-02 18:29

First, make sure that your code is in a DLL, message hook procs need to be placed in a DLL.

Second, is your code not being called at all, or it is being called, but what you want to happen is not happening?

When you do get your code to happen, you will not want to send the message on to the other hooks in the chain. If you want to prevent whatever app that should receive the mouse message from displaying the context menu, the only way to do this is to make sure that they do not receive the message.

Build a man a fire, and he will be warm for a day
Light a man on fire, and he will be warm for the rest of his life!

whats this macro do?

2-Jun-02 16:56

hi, does any body know what this macro does??

#ifdef __cplusplus
extern "C" {
#endif

#ifdef __cplusplus
}
#endif

i found it in a headfile and i have no clue Frown | :(

Re: whats this macro do?

Paul M Watt2-Jun-02 17:45

Paul M Watt

2-Jun-02 17:45

It will turn off name mangling for your program symbols. Which means that programs that are written in a different language besides C++ or even different C++ compilers will be able to use your code. THis also means that you will not be able to take advantage of certain C++ features like function overloading.

Build a man a fire, and he will be warm for a day
Light a man on fire, and he will be warm for the rest of his life!

Re: whats this macro do?

2-Jun-02 18:04

well i created a dll which exports this function:

#define dllEngineExport __declspec( dllexport )
dllEngineExport inline HRESULT setAppGUID( GUID g_guidApp );

but when i come to use the dll in other apps the function works fine. but if i include that macro. ill get this error:

error LNK2001: unresolved external symbol _setAppGUID

dunno whats wrong. Confused | :confused:

hide a button?

2-Jun-02 13:19

Im trying to create a background for my application using BitBlt()
Works fine. The image includes butten (I drew some buttons on the image)

And I want them to be clickable.

How can I add a clickable zone? e.g a simple butten, but will not be visable but clickable.

thanks

Re: hide a button?

Nish Nishant2-Jun-02 15:01

Nish Nishant

2-Jun-02 15:01

Instead of a button use a static control. Remember to set the SS_NOTIFY style to get mouse clicks.

Nish

Regards,
Nish
Native CPian.
Born and brought up on CP.
With the CP blood in him.

Re: hide a button?

Paul M Watt2-Jun-02 18:00

Paul M Watt

2-Jun-02 18:00

You could monitor the LBUTTONDOWN and LBUTTONUP combinations to determine if the user clicked the mouse. You would then determine the rectangle where the buttons are on your image, and you could check to see which button should be clicked (if a buttons should be clicked) by testing the point that was clicked in the function PtInRect.

Build a man a fire, and he will be warm for a day
Light a man on fire, and he will be warm for the rest of his life!

Can't get rid of error

2-Jun-02 13:17

fatal error RC1004: unexpected end of file found

File of interest is a header file as follows:

// define for the application icon
#define ICON_T3DX 100

// define for the application cursor
#define CURSOR_CROSSHAIR 200

// define for the application music
#define SOUND_ID_MUSIC 1

// defines for the top level menu OPTIONS
#define MENU_OPTIONS_ID_PRINT 1000
#define MENU_OPTIONS_ID_EXIT 1001

// defines for the top level menu HELP
#define MENU_HELP_ABOUT 2000
#define MENU_HELP_INSTRUCTIONS 2001

Tried including stdafx.h but it didn't fix it.

Help!

Re: Can't get rid of error

Rama Krishna Vavilala2-Jun-02 15:13

Rama Krishna Vavilala

2-Jun-02 15:13

How does your CPP file look like. The oroblem may be because of header files included before or after. How do you know that this is the file that causes the error.

Message Closed

2-Jun-02 15:18

User 38746

2-Jun-02 15:18

Message Closed

modified 21-May-21 21:01pm.

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