Re: find pixel colour on screen - C / C++ / MFC Discussion Boards

Question

Hamid_RT18-Feb-06 20:28

Hamid_RT

18-Feb-06 20:28

Hello All,
I have 2 question

1-How to convert cm to pixel
2-How to convert inch to cm
Thank you

Re: Question

mbue18-Feb-06 20:56

mbue

18-Feb-06 20:56

1 inch == 2,54 cm
number of pixels per inch depends on DPI (dots per inch)
96 DPI = 37,795275590551 pixel per cm

Re: Question

Divyang Mithaiwala18-Feb-06 21:19

Divyang Mithaiwala

18-Feb-06 21:19

Hello Visible_Info,

To get value of picxel per inch use this function

GetDeviceCaps(hdc, LOGPIXELSX);

Number of pixels per logical inch along the screen width. In a system with multiple display monitors, this value is the same for all monitors.

GetDeviceCaps(hdc, LOGPIXELSY);

Number of pixels per logical inch along the screen height. In a system with multiple display monitors, this value is the same for all monitors.

For getting more help click here[^]

find pixel colour on screen

OnTilt18-Feb-06 18:51

OnTilt

18-Feb-06 18:51

Hello. I was just wondering if anyone knew a simple way to find the colour of a specific pixel displayed on the screen by ANY program.
I used this program called "Macro Scheduler" which had a very simple GPC (Get Pixel Colour) command to use which returned the colour in a number of a specific pixel displayed on screen regardless of which program displayed it. Is their something similar in C++?
I'm very new to C++ but if I could get around this problem I could start on my project and learn along the way.
I also don't really care about the specific colour, like if 256 colours or whatever, I just need to find a value to distinguish between pixels displayed on MY screen.
Any help is greatly appeciated.

-- modified at 0:54 Sunday 19th February, 2006

Re: find pixel colour on screen

Divyang Mithaiwala18-Feb-06 20:57

Divyang Mithaiwala

18-Feb-06 20:57

Hello OnTilt

I specify one of the way but i am not sure that this is a proper or not.

First make on dailog form which has two property you have o set.
1) Full screen mode
2) Transperent display mode

Now by calling any function which can return pixel value of form will return pixel value of screen. And one more thing this dailog form will not affect operation of any other application.

If this is not usefull to then i am sorry.

Regards,
Divyang Mithaiwala

Re: find pixel colour on screen

Gavin Taylor19-Feb-06 2:17

Gavin Taylor

19-Feb-06 2:17

Take a look at the GetWindowDC[^] API, if you pass NULL as it's window handle it will return a device context back for the current desktop. After that you can use GetPixel[^] to retrieve the color for any pixel. You'll need something like:

COLORREF GetDesktopPixel( int x, int y )
{
	COLORREF cl = 0;
	HDC hDC = NULL;
	
	hDC  = GetWindowDC( NULL ); // Get DC for Desktop
	cl = GetPixel( hDC, x, y );
	DeleteDC( hDC ); // Close the DC
	
	return cl;
}

Gavin Taylor
w: http://www.gavspace.com

Re: find pixel colour on screen

Divyang Mithaiwala19-Feb-06 17:26

Divyang Mithaiwala

19-Feb-06 17:26

Hey thanx Gavin.

It's realy nice. I don't know about this. Thanx again.

Reagards,
Divyang Mithaiwala

Re: find pixel colour on screen

Gavin Taylor19-Feb-06 2:19

Gavin Taylor

19-Feb-06 2:19

COLORREF GetDesktopPixel( int x, int y )
{
	COLORREF cl = 0;
	HDC hDC = NULL;
	
	hDC  = GetWindowDC( NULL ); // Get DC for Desktop
	cl = GetPixel( hDC, x, y );
	DeleteDC( hDC ); // Close the DC
	
	return cl;
}

Gavin Taylor
w: http://www.gavspace.com

Re: find pixel colour on screen

OnTilt19-Feb-06 9:47

OnTilt

19-Feb-06 9:47

Exactly what I was looking for Gavin. Thanks guys.

Re: find pixel colour on screen

Owner drawn19-Feb-06 18:15

Owner drawn

19-Feb-06 18:15

http://www.codeproject.com/miscctrl/ColorFindercp1.asp[^]

Owner drawn
Jesus Loves

Trapping Interrupts in Windows

Rane18-Feb-06 17:40

Rane

18-Feb-06 17:40

How to trap the interrupts produced in Windows Environment,by establishing a system wide monitor/hook.

What is the core API to be used?
(_dos_getvect & _dos_setvect cannot be used in MS VC++ programs)

Any one having any intresting Idea??

-Rane
Rose | [Rose]

Rane

Re: Trapping Interrupts in Windows

Gary R. Wheeler19-Feb-06 4:11

Gary R. Wheeler

19-Feb-06 4:11

Under Windows NT, 2000, XP, and Server 2003, applications can not handle interrupts. Interrupt handling is reserved for device drivers. Typically, a device driver will handle an interrupt and then signal an event. An application will have a worker thread waiting on that event. It isn't real-time, but it is safer than allowing applications direct access to hardware.

Software Zen: delete this;

Fold With Us![^]

Re: Trapping Interrupts in Windows

Rane19-Feb-06 18:50

Rane

19-Feb-06 18:50

Is it possible to write a universal driver to trap the software interrupts alone.
(Any class/API supporting it?)

Rose | [Rose]

Rane

Simple Win32 Console App question...

jc0dex18-Feb-06 15:36

jc0dex

18-Feb-06 15:36

Hey Guys ..

I'm running a Win32 Console UDP Server/Client application. I want to run my server update function inside my main loop while also checking for key input. All I need to check for is if a single key has been pressed.

The kicker is I need a way to continue on with the update without pausing for user input. When the user hits 't' for toggle it calls a function that closes the socket and reopens it as a server or client.

Here's what I have now, but as I said I need something that doesn't wait for user input.

Update()
{
char toggle;

toggle = cin.get()

if(toggle == 't')
{
ToggleMode();
}

// get all the packets we can
while(ReceiveData());

// Send all the data to the clients
SendData();

return true;
}

Thanks in advance!

Re: Simple Win32 Console App question...

PJ Arends18-Feb-06 16:58

PJ Arends

18-Feb-06 16:58

Have a look at _kbhit()

You may be right
I may be crazy
But it just may be a lunatic you’re looking for
-- Billy Joel --

Within you lies the power for good - Use it!

Re: Simple Win32 Console App question...

jc0dex18-Feb-06 17:27

jc0dex

18-Feb-06 17:27

Do I have to be using the CRT libraries for this?

I tried including <conio.h> but when I do:

if(_kbhit())
{ToggleMode()}

It never gets into the true condition hen I press any key on the key board.

Any help?

Re: Simple Win32 Console App question...

PJ Arends18-Feb-06 17:32

PJ Arends

18-Feb-06 17:32

jc0dex wrote:
Do I have to be using the CRT libraries for this?

Yes. _kbhit is a C run-time function. Look it up in MSDN for some sample code.

You may be right
I may be crazy
But it just may be a lunatic you’re looking for
-- Billy Joel --

Within you lies the power for good - Use it!

Re: Simple Win32 Console App question...

jc0dex18-Feb-06 17:57

jc0dex

18-Feb-06 17:57

I found that GetAsyncKeyState does exactly what I was needing.

Thanks guys!

How to use CreateProcessAsUser?!

PPatrickFFM18-Feb-06 13:20

PPatrickFFM

18-Feb-06 13:20

Hi!

I've had some trouble with the CreateProcessAsUser function. I want to start a process with Admin privileges - respectevily which requires Admin privileges - within an application lunched by an account without having any rights.
So far so good. In using the LogonUser function I was able to get a hadle to the previously specified user which could be used for the CreateProcessAsUser function. But it won't work!!! Everytime I try to start a process I get the same error (1314). I've set out to do a search in the www and it seems there are a lot more people having the same problem. As I understand it the user account creating the new process must have a set of special privileges enabled. But how to assign those, since I still haven't any rights for it. I just want to implement a kind of the "RunAs" offered by Windows.
Is there a simple way of doing such a thing?

Thanks in advance

PIT

Re: How to use CreateProcessAsUser?!

oshah18-Feb-06 13:40

oshah

18-Feb-06 13:40

To enable a privilege, you can use code from this SDK article[^].

However, I think your trouble is that you need privileges that even an administrator does not have. The closest account that does have the privilege you're going to get is the service account. If you can create a service, use that.

That said, you should strongly consider using CreateProcessWithLogonW instead. It was specifically created to overcome the troubles with CreateProcessAsUser. It works by delegating to the "Secondary Logon" service.

What operating system are you using? CreateProcessAsUser was changed in WinXP so that SeTcbPrivilege is no longer required.

rich edit box

Sam 200618-Feb-06 13:11

Sam 2006

18-Feb-06 13:11

hi,

i'm trying to teach myself c++ (using mfc), i've just got a quick question. i'm not new to the vs enviorment, i've used it for c# programs.

i am running windows xp sp2 (home edition) with the newest version of the .net framework. i am using visual studio 2002.

when i place a 'rich edit 2.0 control' onto my form, the program won't run. when i remove the control, it runs.

when i run the program with a rich edit box, it looks like everything ran fine and i closed it, however i never even see the program's dialog. does anyone have suggestions to get this thing running?

this is what is in the output window:

'SomeProgram.exe': Loaded 'F:\Programming\SomeProgram\Release\SomeProgram.exe', Symbols loaded.
'SomeProgram.exe': Loaded 'C:\WINDOWS\system32\ntdll.dll', No symbols loaded.
'SomeProgram.exe': Loaded 'C:\WINDOWS\system32\kernel32.dll', No symbols loaded.
'SomeProgram.exe': Loaded 'C:\WINDOWS\system32\user32.dll', No symbols loaded.
'SomeProgram.exe': Loaded 'C:\WINDOWS\system32\gdi32.dll', No symbols loaded.
'SomeProgram.exe': Loaded 'C:\WINDOWS\system32\comdlg32.dll', No symbols loaded.
'SomeProgram.exe': Loaded 'C:\WINDOWS\system32\shlwapi.dll', No symbols loaded.
'SomeProgram.exe': Loaded 'C:\WINDOWS\system32\advapi32.dll', No symbols loaded.
'SomeProgram.exe': Loaded 'C:\WINDOWS\system32\rpcrt4.dll', No symbols loaded.
'SomeProgram.exe': Loaded 'C:\WINDOWS\system32\msvcrt.dll', No symbols loaded.
'SomeProgram.exe': Loaded 'C:\WINDOWS\WinSxS\x86_Microsoft.Windows.Common-Controls_6595b64144ccf1df_6.0.2600.2180_x-ww_a84f1ff9\comctl32.dll', No symbols loaded.
'SomeProgram.exe': Loaded 'C:\WINDOWS\system32\shell32.dll', No symbols loaded.
'SomeProgram.exe': Loaded 'C:\WINDOWS\system32\winspool.drv', No symbols loaded.
'SomeProgram.exe': Loaded 'C:\WINDOWS\system32\ole32.dll', No symbols loaded.
'SomeProgram.exe': Loaded 'C:\WINDOWS\system32\oleaut32.dll', No symbols loaded.
'SomeProgram.exe': Loaded 'C:\WINDOWS\system32\oleacc.dll', No symbols loaded.
'SomeProgram.exe': Loaded 'C:\WINDOWS\system32\msvcp60.dll', No symbols loaded.
'SomeProgram.exe': Loaded 'C:\Program Files\Google\Google Desktop Search\GoogleDesktopNetwork3.dll', No symbols loaded.
'SomeProgram.exe': Loaded 'C:\WINDOWS\system32\ws2_32.dll', No symbols loaded.
'SomeProgram.exe': Loaded 'C:\WINDOWS\system32\ws2help.dll', No symbols loaded.
'SomeProgram.exe': Unloaded 'C:\Program Files\Google\Google Desktop Search\GoogleDesktopNetwork3.dll'
'SomeProgram.exe': Unloaded 'C:\WINDOWS\system32\ws2_32.dll'
'SomeProgram.exe': Unloaded 'C:\WINDOWS\system32\ws2help.dll'
'SomeProgram.exe': Loaded 'C:\WINDOWS\system32\MsgPlusLoader.dll', No symbols loaded.
'SomeProgram.exe': Loaded 'C:\WINDOWS\system32\uxtheme.dll', No symbols loaded.
'SomeProgram.exe': Loaded 'C:\WINDOWS\system32\PGPhk.dll', No symbols loaded.
'SomeProgram.exe': Loaded 'C:\Program Files\Xfire\xfire_toucan_17902.dll', No symbols loaded.
'SomeProgram.exe': Loaded 'C:\WINDOWS\system32\wsock32.dll', No symbols loaded.
'SomeProgram.exe': Loaded 'C:\WINDOWS\system32\ws2_32.dll', No symbols loaded.
'SomeProgram.exe': Loaded 'C:\WINDOWS\system32\ws2help.dll', No symbols loaded.
'SomeProgram.exe': Loaded 'C:\WINDOWS\system32\msvcr71.dll', No symbols loaded.
The thread 'Win32 Thread' (0xb74) has exited with code 0 (0x0).
The program '[2808] SomeProgram.exe: Native' has exited with code 0 (0x0).

thanks in advance,
sam kline

-- modified at 19:13 Saturday 18th February, 2006

Re: rich edit box

Michael Dunn18-Feb-06 13:21

Michael Dunn

18-Feb-06 13:21

As with all common controls, you have to call the right init function to get them loaded and their window classes registered.
MFC has AfxInitRichEdit() which is the function to call in your situation.

--Mike--
Visual C++ MVP Cool | :cool:

LINKS~! Ericahist | NEW!! PimpFish | CP SearchBar v3.0 | C++ Forum FAQ

Re: rich edit box

Sam 200618-Feb-06 14:10

Sam 2006

18-Feb-06 14:10

ok, but where do i put that? Big Grin | :-D

thanks, sam kline

Re: rich edit box

Sam 200618-Feb-06 16:25

Sam 2006

18-Feb-06 16:25

oh, found it.
AfxInitRichEdit2();

thanks!

Printing Combinations

RockyJames18-Feb-06 9:50

RockyJames

18-Feb-06 9:50

Hi,
Let me explain using a very simple example: finding all combinations of 2
from a set of 6 letters {A, B, C, D, E, F}. The first combination is AB and the
last is EF
The total number of possible combinations is: n!/(r!(n-r)!)=6!/(2!(6-2)!)=15
combinations
Let me show you all the combinations first:
AB
AC
AD
AE
AF
BC
BD
BE
BF
CD
CE
CF
DE
DF
EF

I want to print all the comibinations..........

Regards
James

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