Re: Greyscale image from raw data - C / C++ / MFC Discussion Boards

Re: [Solved] What is the 32-bit form of the _InterlockedIncrement intrinsic?

Skippums22-Sep-09 14:00

22-Sep-09 14:00

If I understand correctly, you are suggesting the following sequence of events:

1) I call my wrapper method in thread1 passing &m_Lock, but somewhere prior to executing the atomic increment, there is a context switch to thread2.
2) Something in thread2 modifies the value of m_Lock, then switches control back to thread1
3) thread1 then increments the new value of m_Lock

Unless I am missing something, the critical section of these operations is still atomic. My method doesn't know what the value of m_Lock is, so whether I increment it before or after thread2 performs the modification is inconsequential. The only thing that could break this would be if &m_Lock is volatile, which could break the code even if calling the intrinsic directly.

Sure, my function won't necessarily be called and return without a context switch, but it doesn't effect (as far as I can tell) the correctness of the code. Is there something else I am still missing? Thanks for your help thus far,

Sounds like somebody's got a case of the Mondays

-Jeff

Greyscale image from raw data

David Ferreira22-Sep-09 4:57

David Ferreira

22-Sep-09 4:57

I'm coding an mfc active x that gets raw data and appends a header so far I've got it displaying the image but there are elements of green in what should be a grey scale image. I'm using a RGB header and assume that the image has shades of grey beyond that allowed in a 256 bit colour image. So how do i get the green to display as shades of grey. I haven't been able to find a method that creates a grey scale image that is y i'm using the RGB. From what i can see there is none and i need to add a palette to the image which i tried to do but can't even get the shades of green to change to a different colour.
Here is my code if anyone can help me out it would be greatly appreciated.

CClientDC dc(this); // device context for painting

BITMAPINFO bmi;//header struc

bmi.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
bmi.bmiHeader.biWidth  = 208;
bmi.bmiHeader.biHeight = 208;
bmi.bmiHeader.biPlanes = 1;
bmi.bmiHeader.biBitCount = 8;
bmi.bmiHeader.biCompression = BI_RGB;
bmi.bmiHeader.biSizeImage = 0;
bmi.bmiHeader.biXPelsPerMeter = 0;
bmi.bmiHeader.biYPelsPerMeter = 0;
bmi.bmiHeader.biClrUsed = 0;
bmi.bmiHeader.biClrImportant = 0;



LPPALETTEENTRY pPalEntry = NULL; // pal palette
RGBQUAD *pRGB = NULL;
BOOL ret = TRUE;
CPalette palette;

int npalColors = palette.GetEntryCount();

pPalEntry = new PALETTEENTRY[npalColors];
pRGB = new RGBQUAD[npalColors];

palette.GetPaletteEntries(0, npalColors, pPalEntry);

for (int i = 0; i < npalColors; i++)
{
    pRGB[i].rgbRed   = pPalEntry[i].peRed;
    pRGB[i].rgbGreen = pPalEntry[i].peRed;//.peGreen;
    pRGB[i].rgbBlue  = pPalEntry[i].peRed;//.peBlue;
    pRGB[i].rgbReserved = 2;
}


CBitmap bitmap;
bitmap.CreateCompatibleBitmap(&dc,208, 208);
::SetDIBits(dc.m_hDC,bitmap,0,208,m_byImg2,&bmi,DIB_RGB_COLORS);//m_byImg2 is the raw data its a pointer to a byte array
CDC dcMemory;
dcMemory.CreateCompatibleDC(&dc);
CBitmap * pOldBitmap = dcMemory.SelectObject(&bitmap);
SetDIBColorTable(dcMemory, 0, npalColors, pRGB);

dc.StretchBlt(0,0, m_nW,m_nH, &dcMemory, 0,0,208,208 , SRCCOPY);//m_nW and m_nH is width and height of the active x when embedded

Re: Greyscale image from raw data

includeh1022-Sep-09 5:20

includeh10

22-Sep-09 5:20

I think you just want to change green color to gray, is it correct?
if yes, you need to change green color in color table to gray, do not need to worry other data.

Re: Greyscale image from raw data

enhzflep22-Sep-09 20:02

enhzflep

22-Sep-09 20:02

Don't have VS installed, so I can't have a poke around with your code, though the immediate thing that springs to mind is:
Why don't you just desaturate the image pixel-by-pixel.

I.e convert the RGB value of each pixel to HSL. Then change the S channel to 0.0 and convert back to RGB - voilla! One monochrome picture.

Re: Greyscale image from raw data

David Ferreira22-Sep-09 21:26

David Ferreira

22-Sep-09 21:26

Firstly thank you for your quick responses I'm new to image processing and although I've done .net c++ programming I've only been working in MFC for a couple of months now so this is proving to be a challenge for me(good thing i enjoy a good challenge).
I'll look into your suggestions now. @includeh10 i'm getting other colours comming through its just that the green is fairly prominent if i can get rid of this it would be good but first prize is getting a complete greyscale image to display. The problem is short of changing the pixel value i'm don't know another way to do this.
@enhzflep The raw data is a finger print coming over USB and I've tried converting this to black and white in...paint...yes the one that comes with windows. Anyway allot of the detail seemed to be lost and would like to shy aways from turning it into a black and white image if possible. I'll give it a go in code and see how it turns out though.
I'll let you know how things turn out thanks again for your responses.

Re: Greyscale image from raw data

enhzflep22-Sep-09 23:15

enhzflep

22-Sep-09 23:15

Just to clarify, I think I've used monochrome incorrectly. With the method I suggest, I take the RGB values that I use to draw some custom controls and adjust the H channel only, giving me the ability to tint color-schemes to any color I want.

If you load your image into Gimp or Photoshop or whatever then desaturate the image, you'll get a perfect grey-scale image.

It's just a matter of understanding and then working in either HSL or HSV colorspace. By changing the S channel to 0 in either model, you effectively remove all color information, leaving only darkness/lightness information remaining.

Here, have a gander if you please: http://en.wikipedia.org/wiki/HSL_and_HSV

Re: Greyscale image from raw data

David Ferreira23-Sep-09 0:58

David Ferreira

23-Sep-09 0:58

I realized what you said after a bit more fiddling it is a good idea and i just need to figure out how to do it ^.^
I'm starting to run out of time though so had to do a bit of a hack. I'll be working on this again when i find the time though i was enjoying it. Here's what i did just in case it helps anyone else.

I get the bytes one byte at a time so this is inside that loop. It could obviously be in a loop of its own just as easily though.

//replace colours with black
		if(data[a] == 208)
		{
			data[a] = 75;
			
		}

What this does is turn any colour that i what to suppress into black.
The black is somewhere between 192 and 208.

This Creates the bitmap once i have the raw pixels in the array

CClientDC dc(this); // device context for painting

BITMAPINFO bmi; //header stuct

bmi.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
bmi.bmiHeader.biWidth  = 208;
bmi.bmiHeader.biHeight = 208;
bmi.bmiHeader.biPlanes = 1;
bmi.bmiHeader.biBitCount = 8;
bmi.bmiHeader.biCompression = BI_RGB;
bmi.bmiHeader.biSizeImage = 0;
bmi.bmiHeader.biXPelsPerMeter = 0;
bmi.bmiHeader.biYPelsPerMeter = 0;
bmi.bmiHeader.biClrUsed = 0;
bmi.bmiHeader.biClrImportant = 0;

CBitmap bitmap;
bitmap.CreateCompatibleBitmap(&amp;dc,208,208); //create 208x208 bitmap
::SetDIBits(dc.m_hDC,bitmap,0,208,rawImageArray,&amp;bmi,DIB_RGB_COLORS);// sets the bits to array
CDC dcMemory;
dcMemory.CreateCompatibleDC(&amp;dc);
CBitmap * pOldBitmap = dcMemory.SelectObject(&amp;bitmap);
dc.StretchBlt(0,0, m_nW,m_nH, &amp;dcMemory, 0,0,208,208 , SRCCOPY);//strechs to size of active x window
dcMemory.SelectObject(pOldBitmap);

Re: Greyscale image from raw data

David Ferreira19-Nov-09 23:30

David Ferreira

19-Nov-09 23:30

This is a really delayed response but a bug caused me to revisit this code and with a little bit more experience in using MFC i approached it with a bit more confidence :P
Solved the problem though, it ended up being a really easy fix and i have "AlexFM" for his post on experts exchange to thank.
I needed to add a palette this solution eluded me because of the need for an array for the bitmap info.
here's my working code i hope it will help someone

CClientDC dc(this); // device context for painting

BITMAPINFO *bmi =  (BITMAPINFO*)new char[sizeof(BITMAPINFO) + sizeof(RGBQUAD)*256];//bitmapinfo struct

bmi->bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
bmi->bmiHeader.biWidth  = 176;
bmi->bmiHeader.biHeight = 176;
bmi->bmiHeader.biPlanes = 1;
bmi->bmiHeader.biBitCount = 8;
bmi->bmiHeader.biCompression = BI_RGB;
bmi->bmiHeader.biSizeImage = 0;
bmi->bmiHeader.biXPelsPerMeter = 0;
bmi->bmiHeader.biYPelsPerMeter = 0;
bmi->bmiHeader.biClrUsed = 0;
bmi->bmiHeader.biClrImportant = 0;

//this defines a grey scale image haven't tried it but i assume you can mod this to change colours
//as this is essentially the palette

for (int i = 0; i < 256; i++ )
{
	bmi->bmiColors[i].rgbBlue = i;
	bmi->bmiColors[i].rgbGreen = i;
	bmi->bmiColors[i].rgbRed = i;
	bmi->bmiColors[i].rgbReserved = 0;
}

//create the bitmap itself
CBitmap bitmap;
//size of bitmap
bitmap.CreateCompatibleBitmap(&dc,176,176); //create 208x208 bitmap
//sets the DIBits and appends header
::SetDIBits(dc.m_hDC,bitmap ,0 ,176 ,rawImageData ,bmi/*The magic header*/ , DIB_RGB_COLORS);

CDC dcMemory;
dcMemory.CreateCompatibleDC(&dc);
CBitmap * pOldBitmap = dcMemory.SelectObject(&bitmap);
//this code was written for an active x and this streachs the image to the original size
//m_nW(which is the width) and m_nH( the height ) are the size of the active x from the ondraw
dc.StretchBlt(0,0, m_nW,m_nH, &dcMemory, 0,0,176,176 , SRCCOPY);
dcMemory.SelectObject(pOldBitmap);

Creation of install shield

shir_k22-Sep-09 3:55

shir_k

22-Sep-09 3:55

Hi To create installer (Install shield) please let me know if following files are sufficient or not

Project related files:

Exe file

*.BSC

Help file

Contents file

DLL’s:

ADVAPI32.DLL

COMCTL32.DLL

COMDLG32.DLL

GDI32.DLL

KERNEL32.DLL

MSVCRT.DLL

NTDLL.DLL

OLE32.DLL

OLEAUT32.DLL

OLEDLG.DLL

OLEPRO32.DLL

RPCRT4.DLL

SECUR32.DLL

SHELL32.DLL

SHLWAPI.DLL

USER32.DLL

WINMM.DLL

WINSPOOL.DRV

(Above DLLs I got from Dependency walker)

Do we need to include MFC runtime and .Net framework while creating installer?

Thanks

Re: Creation of install shield

PJ Arends22-Sep-09 4:55

PJ Arends

22-Sep-09 4:55

For VS 2008 see: http://msdn.microsoft.com/en-us/library/zebw5zk9.aspx[^]

or for VS 2005 see : http://msdn.microsoft.com/en-us/library/zebw5zk9(VS.80).aspx[^]

You may be right
I may be crazy
-- Billy Joel --

Within you lies the power for good - Use it!

Re: Creation of install shield

shir_k4-Oct-09 21:24

shir_k

4-Oct-09 21:24

Thanks for the information. It helped me in identifying the DLLS used by the project.
Do .Net frame work and MFC runtime is required to run the exe developed using Microsoft Visual C++ 6.0.

Thanks
kavitha

how to convert char * to char[100]

prithaa22-Sep-09 3:54

prithaa

22-Sep-09 3:54

Hello,

I want to convert char* to char[100]

how do i go about it
Pritha

Re: how to convert char * to char[100]

C^hris L^osinger22-Sep-09 4:10

C^hris L^osinger

22-Sep-09 4:10

char buf[100];
strncpy(buf, pChar, 99);
buf[99] = 0;

image processing toolkits | batch image processing

Re: how to convert char * to char[100]

Rajesh R Subramanian22-Sep-09 4:30

Rajesh R Subramanian

22-Sep-09 4:30

Why would you ever need such a conversion?! What are you trying to do and did the compiler give you such a conversion error? Give that context here and someone might be able to help you.

It is a crappy thing, but it's life -^ Carlo Pallini

agree!

etkid8422-Sep-09 5:55

etkid84

22-Sep-09 5:55

yea, why would you need to do this?

David

Re: agree!

Rajesh R Subramanian22-Sep-09 6:01

Rajesh R Subramanian

22-Sep-09 6:01

Hi David,

You probably wanted to reply to the OP? Replying to a different message on the thread won't notify the OP about your post. Smile | :)

It is a crappy thing, but it's life -^ Carlo Pallini

oops, my bad

etkid8422-Sep-09 6:10

etkid84

22-Sep-09 6:10

yea .. F'd that up didn't i

David

Re: how to convert char * to char[100]

Skippums22-Sep-09 8:57

Skippums

22-Sep-09 8:57

char *charArray = new char[100];
char (*temp)[100]((char(*)[100])charArray);

Then temp is a pointer to a char[100] array, so *temp is your array of 100 elements. The following should also work:

char (&temp)[100](*((char(*)[100])charArray));

In this case, temp is just an alias to the array, so you don't have to dereference it prior to accessing its members.

As for the reasons to do such a thing, they are many. One is if you have to create the array using a specialized memory allocation function, such as the case where you are using an external memory manager. For example, when coding for Matlab, you have to use mxAlloc to allocate ANY memory that will persist after your function is called. However, it may be more convenient in code to treat allocated memory as an array. As another example, suppose you create a template function that takes a 3D-array that you want to overload to take a 2D array. In this case, you would have to convert a TYPE[][] to a TYPE[1][][], which is a similar operation. For example,

template<size_t height, size_t width>
void doSomething(double (&darray)[height][width]) {
    ...
}

int main() {
    const size_t height = 100;
    const size_t width  = 100;
    // The following line will NOT compile, but is used only for illustrative purposes
    double* memBlock2D = mxAlloc(height * width * sizeof(double));
    double (&memArray2D)[height][width](*((double(*)[height][width])memBlock2D));
    doSomething(memArray2D);
    return 0;
}

Hope this helps,

Sounds like somebody's got a case of the Mondays

-Jeff

modified on Tuesday, September 22, 2009 3:21 PM

How to get cureent url from firefox address bar...

onlyjaypatel22-Sep-09 3:35

onlyjaypatel

22-Sep-09 3:35

Hi all,

I want to get cureent url from address bar of firefox.

Is there any snippet code to do this?

Thanx,
Jay

access to the task manager

einstein.girl22-Sep-09 3:27

einstein.girl

22-Sep-09 3:27

is there any way to get access to the details of the tasks show in the windows "task manager"? by c++.

Re: access to the task manager

David Crow22-Sep-09 3:34

David Crow

22-Sep-09 3:34

Not with C++. Now if you were interested in some Windows API, there probably is. What did you have in mind?

"Old age is like a bank account. You withdraw later in life what you have deposited along the way." - Unknown

"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons

Re: access to the task manager

kilt24-Sep-09 7:10

kilt

24-Sep-09 7:10

See TaskMgr source code (see on Win32 ng[^]

Sleep

VVVimal22-Sep-09 3:24

VVVimal

22-Sep-09 3:24

Hi
I just tried to call Sleep(1000) in a thread function
But when i tried to

Unit threadFun(LPVOID lparam)
{
while(1)
{
Sleep(1000); // When tried to give break point over here appliacation gets terminates
............
}

}

Can any one give me solution to this

Thanks

Re: Sleep

David Crow22-Sep-09 3:35

David Crow

22-Sep-09 3:35

VVVimal wrote:
Can any one give me solution to this

Remove the call to Sleep(). It's almost always unnecessary and usually indicates a design flaw.

Re: Sleep

VVVimal22-Sep-09 4:12

VVVimal

22-Sep-09 4:12

But i need a Sleep() function over there.
Because i need a function to be get called every 1000 milliseconds

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