C / C++ / MFC

Communicating dialog boxes

1-Feb-07 12:10

kitty51-Feb-07 7:57

1-Feb-07 7:57

I've created 2 classes each with it's own dialog box in an MDI application
1. commanding class
2. picViewer class

the commanding class has a func load().
where i create a picViewer variable.

<br />
void commanding::load()<br />
{<br />
	UpdateData (TRUE);<br />
<br />
	FILE *pic, *pic1, *pic2;<br />
	picViewer cam1;	<br />
        pic = fopen("C:\\cv\\16bit.jp2", "rb");<br />
	pic1 = fopen("C:\\cv\\nature_50.jp2", "rb");<br />
	pic2 = fopen("C:\\cv\\8_8.jp2", "rb");<br />
	unsigned int numRead;<br />
	<br />
	int i = 0;<br />
	while(i < 3)<br />
	{<br />
		if(i == 0)<br />
			numRead = fread(buff, sizeof(BYTE), 100000, pic);<br />
		else if(i == 1)<br />
			numRead = fread(buff, sizeof(BYTE), 100000, pic1);<br />
		else<br />
			numRead = fread(buff, sizeof(BYTE), 100000, pic2);<br />
		cam1.showPicture(buff,numRead);<br />
		i++;<br />
		Sleep(2000);<br />
	}<br />
<br />
	fclose(pic);<br />
	fclose(pic1);<br />
	fclose(pic2);<br />
	UpdateData (FALSE);<br />
}<br />
<br />

the picViewer class has a func show().

<br />
void picViewer::show(BYTE bfr[], DWORD size)<br />
{<br />
	HBITMAP m_bitmap = NULL;<br />
	CImage image;<br />
	CJpeg2kDecoder imDec;<br />
	<br />
	image = imDec.Open(bfr, size);<br />
	m_bitmap = (HBITMAP)image;<br />
	m_nCam1img.SetBitmap(m_bitmap); <br />
        //m_nCam1img is the var of the picture control in the dialog <br />
        //box to show the bitmap image.<br />
}<br />

whenever I run the application i open up both dialog boxes hit run on the commanding dialog box i get an error when i get to "m_nCam1img.SetBitmap(m_bitmap); " which points to:

<br />
_AFXWIN_INLINE HBITMAP CStatic::SetBitmap(HBITMAP hBitmap)<br />
	{ ASSERT(::IsWindow(m_hWnd)); return (HBITMAP)::SendMessage(m_hWnd, STM_SETIMAGE, IMAGE_BITMAP, (LPARAM)hBitmap); }<br />

in afxwin2.inl
what does that mean? what am i doing wrong? what would i need to do in order to show a picture in a separate dialog box?

thanks!

Kitty5

led mike1-Feb-07 8:19

Re: Communicating dialog boxes [modified]

1-Feb-07 8:19

kitty5 wrote:
picViewer cam1;

If picViewer is a window or dialog it is never being created therefore the CStatic child window is also never created so IsWindow(m_hWnd) returns false and Asserts during debugging.

led mike

kitty51-Feb-07 8:30

1-Feb-07 8:30

led mike wrote:
kitty5 wrote:
picViewer cam1;

If picViewer is a window or dialog it is never being created therefore the CStatic child window is also never created so IsWindow(m_hWnd) returns false and Asserts during debugging.

picViewer is the class that is related to the picViewer dialog.
I added both

<br />
cam1.Create(IDD_PICVIEWER,0); <br />
cam1.EnableWindow(TRUE);<br />

to my commanding::load() function.
this stops the crashing.

however, no picture is shown in the picViewer dialog box even though i call the show().

<br />
cam1.show(buff,numRead);<br />

Thanks!

-- modified at 14:35 Thursday 1st February, 2007

Kitty5

led mike1-Feb-07 8:41

1-Feb-07 8:41

kitty5 wrote:
picViewer is the class that is related to the picViewer dialog.

I don't know that that means.

In the first code you posted:

void commanding::load()
{
UpdateData (TRUE);

FILE *pic, *pic1, *pic2;
picViewer cam1;

that instance of picViewer is local to that function so it is not related to anything else.

led mike

kitty51-Feb-07 8:50

1-Feb-07 8:50

led mike wrote:
In the first code you posted:

void commanding::load(){UpdateData (TRUE);FILE *pic, *pic1, *pic2;picViewer cam1;

that instance of picViewer is local to that function so it is not related to anything else.

oh... really?!
hmmm. ok then ummm... how would i be able to open up an instance of the picViewer dialog box in the commanding class and be able to update the bitmaps?

i've changed my commanding to:

<br />
int commanding::loadCmdGet3CamData()<br />
{<br />
	UpdateData (TRUE);<br />
<br />
	FILE *pic, *pic1, *pic2;<br />
	picViewer cam1;<br />
	pic = fopen("C:\\cv\\16bit.jp2", "rb");<br />
	pic1 = fopen("C:\\cv\\nature_50.jp2", "rb");<br />
	pic2 = fopen("C:\\cv\\8_8.jp2", "rb");<br />
	unsigned int numRead;<br />
	cam1.Create(IDD_IMAGEVIEWER,0);<br />
	cam1.EnableWindow(TRUE);<br />
	int i = 0;<br />
	while(i < 3)<br />
	{<br />
		if(i == 0)<br />
			numRead = fread(buff, sizeof(BYTE), 100000, pic);<br />
		else if(i == 1)<br />
			numRead = fread(buff, sizeof(BYTE), 100000, pic1);<br />
		else<br />
			numRead = fread(buff, sizeof(BYTE), 100000, pic2);<br />
		cam1.showPicture(buff,numRead);<br />
		//ShowPicture(buff,numRead);<br />
		i++;<br />
		Sleep(2000);<br />
	}<br />
<br />
	fclose(pic);<br />
	fclose(pic1);<br />
	fclose(pic2);<br />
}<br />

thanks,

Kitty5

led mike1-Feb-07 9:01

1-Feb-07 9:01

What you have posted so far indicates that you lack the basic knowledge required to achieve your goal on purpose. So changing things and trying it might work eventually if you get lucky. There are several good books, there are also some decent sample applications and tutorials available with Visual Studio and/or on msdn.microsoft.com that might help in regards to the fundamental concepts that you are missing. I don't know that I would be capable of providing adequate coverage in a forum.

led mike

Mark Salsbery1-Feb-07 11:39

Mark Salsbery

1-Feb-07 11:39

I agree with led mike's response.

I see a misunderstanding of variable scope in your code.

Here's my reply to your other related post:

In your picViewer::show() method:

Your CImage object goes out of scope at the end of the function so it probably destroys the
HBITMAP via its destructor.

Instead of

m_bitmap = (HBITMAP)image;

try

m_bitmap = image.Detach();

and remove this line:
if (m_bitmap) DeleteObject(m_bitmap);

Same with code above: All your variables are local so they no longer exist when the function
ends.

Mark

Hamid_RT1-Feb-07 21:20

Hamid_RT

1-Feb-07 21:20

Is m_nCam1img on same dialog and when you run m_nCam1img.SetBitmap(m_bitmap); and Is m_nCam1img valid and aslo if you want to load a jpg file you can use of (CImage)

WhiteSky

kitty52-Feb-07 2:33

2-Feb-07 2:33

Hi everyone.
thanks for responding it's been really helpful.
with much reading i figured it out and it all makes sense now.
I added this to my commanding::load():

<br />
ImageViewer *imgViewDlg;<br />
imgViewDlg = new ImageViewer();<br />
imgViewDlg->Create(IDD_IMAGEVIEWER, NULL);<br />
imgViewDlg->SetWindowPos(NULL, 0, 0, 700, 700,SWP_NOMOVE); <br />
imgViewDlg->ShowWindow(SW_SHOW);<br />

& then I call the showImage()

<br />
imgViewDlg->showPicture(buff,numRead);<br />

and this seems like it is working.
now i'm just looking to see if there's a function for "isWindowActive" or something that i can check if the particular dialog box is inactive because I don't nessesarily want to keep updating the pictures if the window is in the background and someother window is on top of it.

thanks!

Kitty5

Declaration of CSemaphore fails

Hamid_RT2-Feb-07 4:32

Hamid_RT

2-Feb-07 4:32

See GetActiveWindow

WhiteSky

BuckBrown1-Feb-07 7:57

1-Feb-07 7:57

Good Morning Everyone,

I am using Visual C++ 6.0 MFC. I am writing my first multi-threaded application and I need to be able to use semaphores. In examples that I have looked at they say to declare the semaphore class as CSemaphore cph(1, 2) for example. When I try to declare the semaphore in my class header file the compiler returns with the type of error that you would get if you did not #include a needed header file. Is there a header file that CSemaphore requires to be #included?

Thanks,
Buck Confused | :confused:

led mike1-Feb-07 8:06

1-Feb-07 8:06

BuckBrown wrote:
Is there a header file that CSemaphore requires to be #included?

They hide that information in the documentation[^]

led mike

BuckBrown1-Feb-07 8:21

1-Feb-07 8:21

I guess I really don't understand. I read this documentation earlier and thought the idea was something like this -

class CTests : public CWnd
{
// Construction
public:
CTests();

CTemperature* pTemperature;
COutput* pOutput;
CGPIB* pGPIB;
CTabPageSSL* pTabPage;

CSemaphore cph(1, 5);

// Attributes
private:

If I remark out the declaration it compiles fine, if not it does not compile.

Buck

led mike1-Feb-07 8:44

1-Feb-07 8:44

BuckBrown wrote:
I read this documentation earlier

maybe your definition of "reading" is different than mine.

From the documentation:

Requirements

Header: afxmt.h

led mike

BuckBrown1-Feb-07 9:32

1-Feb-07 9:32

Gee, do I feel stupid now. I was so focused on the body of the document that I didn't even notice the little requirements section. My appologies.

Thanks

Zac Howland1-Feb-07 9:31

Zac Howland

1-Feb-07 9:31

BuckBrown wrote:
class CTests : public CWnd
{
// Construction
public:
CTests();

CTemperature* pTemperature;
COutput* pOutput;
CGPIB* pGPIB;
CTabPageSSL* pTabPage;

CSemaphore cph(1, 5);

Doing that in the header file won't compile. The overloaded constructor should be invoked using the constructor of your CTests class:

<code>CTests::CTests() : cph(1, 5) { // do whatever else you want to in the constructor here }

If you decide to become a software engineer, you are signing up to have a 1/2" piece of silicon tell you exactly how stupid you really are for 8 hours a day, 5 days a week

Zac

BuckBrown1-Feb-07 12:19