C / C++ / MFC Discussion Boards

Re: Reading data of a monochrome BMP file

CPallini11-Feb-09 22:06

11-Feb-09 22:06

Here again you're doing a mistake on computing the memory required.
For a monochrome bitmap, the size required is bit more elaborate than
(Width * Height), since the file holds 8 pixels in each byte, and the horizontal line is padded (if I remember well) to have a 32-bit multiple length. Hence

int bytesPerLine = Width / 8; // eight pixels per byte
if (Width % 8) bytesPerLine++; // take into account the reminder

// pad the line to make it to a 32-bit multiple
if (bytesPerLine % 4 ) bytesPerLine += 4 - (bytesPerLine % 4);

// finally you get the size
int iSize = bytesPerLine * Height;

I hope the above is correct (I haven't tested it). You may verify it comparing the result with the actual size of the file minus the bfOffBits offset.

Two final notes:

If you allocate memory of a given size don't trust any other counter (you're using EOF) while filling it: check always you're not exceeding the allocated size (in your code try to read until the allocated buffer is filled and not until the end of the file: if the file contains more bytes your application crashes).
If you need to read a block, the read it directly, don't read a byte at time.

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke

[My articles]

Re: Reading data of a monochrome BMP file

Member 211673611-Feb-09 22:13

Member 2116736

11-Feb-09 22:13

Thank you very much! I'll check that.

You are very helpful. Smile | :)

Best regards,

Ing LengIeng
Software Developer

Using CDialog::OnOK()

Babu@codeproject10-Feb-09 18:51

Babu@codeproject

10-Feb-09 18:51

Hi all,

Wat is the difference between closing a dialog by using CDIalog::OnOK() or PostQuitMessage(0).

Can I use both at a time?

Regards
Babu

Re: Using CDialog::OnOK()

Eytukan10-Feb-09 19:10

Eytukan

10-Feb-09 19:10

Both have different usage. What do you want to do? To close a dialog, why not use EndDialog()? which is straight forward.

OK,. what country just started work for the day ? The ASP.NET forum is flooded with retarded questions. -Christian Graus

Best wishes to Rexx[^]

Re: Using CDialog::OnOK()

SandipG 10-Feb-09 19:42

SandipG

10-Feb-09 19:42

Babu@codeproject wrote:
Wat is the difference between closing a dialog by using CDIalog::OnOK() or PostQuitMessage(0).

PostQuitMessage will quit your entire application always.

But OnOk will close only the dialog it is called for ( if it is not main dialog)

Also OnOK will call UpdateData().

I hope it helps.

Regards,
Sandip.

[Message Deleted]

Purish Dwivedi10-Feb-09 17:39

Purish Dwivedi

10-Feb-09 17:39

[Message Deleted]

Re: Sample multilingual application with full steps using vc++ in visual studio 2005

Sarath C10-Feb-09 18:51

Sarath C

10-Feb-09 18:51

A google search[^] and taken the first result[^]

-Sarath.
"Great hopes make everything great possible" - Benjamin Franklin

My blog - Sharing My Thoughts

REPOST

_AnsHUMAN_ 10-Feb-09 19:32

_AnsHUMAN_

10-Feb-09 19:32

You need to google first, if you have "It's urgent please" mentioned in your question.
Wink | ;-)

_AnShUmAn_

2nd Repost.. Please Ignore.

SandipG 10-Feb-09 19:49

SandipG

10-Feb-09 19:49

Please Stop posting same question.
You have got answers to previous posts Try and do something based on those answers...

Regards,
Sandip.

[Message Deleted]

Purish Dwivedi10-Feb-09 21:54

Purish Dwivedi

10-Feb-09 21:54

[Message Deleted]

Please don't be rude

CPallini10-Feb-09 22:26

CPallini

10-Feb-09 22:26

Instead, read carefully the posting guidelines (even if they are no more at the top of the forum... Roll eyes | :rolleyes:

) before posting.

No one here will help you if you:

post again and again the same question.
make such stupid and rude replies.

BTW probably *any* idea is a surplus for your brain.
Smile | :)

[Message Deleted]

Purish Dwivedi10-Feb-09 22:58

Purish Dwivedi

10-Feb-09 22:58

[Message Deleted]

Re: Please don't be rude

CPallini10-Feb-09 23:05

CPallini

10-Feb-09 23:05

The good answer is:
"Be polite, study harder, check previous answers (see, for instance [^] ), use profitably Google and CodeProject's article search engine."
Smile | :)

creating app buttons

uzziah010-Feb-09 16:09

uzziah0

10-Feb-09 16:09

I want to add a button to my app, I am thinking, a function call to create an area that when clicked would jump to some callback function. I could use this to change the image in the area just clicked, and perform what ever action I want due to the button press.

I think I need to use CreateWindow() to do this, but I'm not figuring much else about this.

I have not been able to find an example that is simple and straightforward for C on a WM5 device.

If anyone knows of an example or simple explanation that would help, I'd appreciate it.

disable end program notification in console application

Arif Liminto10-Feb-09 14:53

Arif Liminto

10-Feb-09 14:53

Hi, I am still a newbie in MFC

I 've got a problem with my console application program

I use one thread in there , which is I use CWinThread
and it terminates when time is equal to timeout
but I need to handle if the user want to terminate immediately in the console application

so the way I did is

I create this function

BOOL WINAPI ConsoleHandler(DWORD CEVENT)
{
	switch(CEVENT)
	{
		case CTRL_CLOSE_EVENT://if user shutdown immediatelly
		         myClass.CleanUpThread();
			
		break;
	}
	return TRUE;
}

so when the user want to immediatelly, it will go to that function and clean up the thread
however, everytime, I test and debug, I always windows ballon said that "windows cannot end this program, it may need more time to complete an operation"

How to disable that ballon? so i dont want user to see that one, and the program will wait until the thread is cleared.

Thanks so much,

Re: disable end program notification in console application

Eytukan10-Feb-09 16:18

Eytukan

10-Feb-09 16:18

Clean up thread? I think you are trying to clean up a live wire with your wet hands. Are you trying to terminate() your thread by force? if yes never do it. Just come out of the loop with a boolean condition check like.

<br />
while(bRunThread)<br />
{<br />
//run mad <br />
}<br />

When the user wants to come out, just set bRunThread =false.. and you can also use events to make sure the thread has really exited.

OK,. what country just started work for the day ? The ASP.NET forum is flooded with retarded questions. -Christian Graus

Best wishes to Rexx[^]

Re: disable end program notification in console application

Arif Liminto10-Feb-09 16:27

Arif Liminto

10-Feb-09 16:27

thanks I've fixed that one

Re: disable end program notification in console application

Eytukan10-Feb-09 16:30

Eytukan

10-Feb-09 16:30

What was the problem?

OK,. what country just started work for the day ? The ASP.NET forum is flooded with retarded questions. -Christian Graus

Best wishes to Rexx[^]

Re: disable end program notification in console application

Arif Liminto10-Feb-09 17:50

Arif Liminto

10-Feb-09 17:50

I changed the way my program works.
instead, waiting for period of time, then shutdown
I keep it loop until keyboard event occurs or user press close

and I discovered that there were some memory leaks in my program.
I fixed the memory leak, change the program flow and done

Anyway, thanks for your help

Regards,

Arif Liminto

return in catch block

clawton10-Feb-09 11:06

clawton

10-Feb-09 11:06

Are there any rules of thumb, guidelines, issues with, etc... about having a return in a catch block?
For example:

try {
// Some code...
} catch (std::exception &) {
// log error
return -1;
}

Also try this test using VC with VS 2005 SP1 (Microsoft Visual C++ 2005 77626-009-0000007-41138)
1) Create standard MFC dialog based application
2) Add new method with signature: int foo();
3) in foo add the following code:

std::vector<int> v;

try {
v.push_back(1);
} catch (std::exception &;) {
return 1;
}

// Just some code that does something...
if (v.size()) {

}

return 0;
4) Step through the code in debugger. On several systems, I see the debug statement indicator move onto the line with "return 1". The disassembly code is very strange indeed.

Any comments from the guru's out there? Smile | :)

Thanks!

Re: return in catch block

Stuart Dootson10-Feb-09 11:26

Stuart Dootson

10-Feb-09 11:26

clawton wrote:
Are there any rules of thumb, guidelines, issues with, etc... about having a return in a catch block

Should be fine.

clawton wrote:
Step through the code in debugger. On several systems, I see the debug statement indicator move onto the line with "return 1".

Yeah, that happens - it all depends how the debug information's been distributed through the code. Is it in Release or Debug mode? Debugging in Release mode is...interesting.

clawton wrote:
The disassembly code is very strange indeed

In what sense?

Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

Re: return in catch block

clawton10-Feb-09 11:32

clawton

10-Feb-09 11:32

Stuart Dootson wrote:
Is it in Release or Debug mode?

Debug mode.

Stuart Dootson wrote:
clawton wrote:
The disassembly code is very strange indeed

In what sense?

Well, I see the line with "return 1" in there twice... Confused | :confused:

Pasting from the dissassembly output window:

std::vector<int> v;
004131C6 lea ecx,[ebp-34h]
004131C9 call std::vector<int,std::allocator<int> >::vector<int,std::allocator<int> > (4110C3h)
004131CE mov dword ptr [ebp-4],0

try {
004131D5 mov byte ptr [ebp-4],1
v.push_back(1);
004131D9 mov dword ptr [ebp-118h],1
004131E3 lea eax,[ebp-118h]
004131E9 push eax
004131EA lea ecx,[ebp-34h]
004131ED call std::vector<int,std::allocator<int> >::push_back (4119B5h)
004131F2 jmp $LN5 (413211h)
} catch (std::exception &) {
return 1;
004131F4 mov dword ptr [ebp-10Ch],1
004131FE mov dword ptr [ebp-4],0
00413205 mov eax,offset $LN9 (41321Ah)
0041320A ret
void CCatchTestDlg::OnBnClickedOk()
{

Test(1,0);

}

int CCatchTestDlg::Test(int foo, unsigned char * goo)
{
std::vector<int> v;

try {
v.push_back(1);
} catch (std::exception &) {
return 1;
}
0041320B mov eax,offset $LN5 (413211h)
00413210 ret
} catch (std::exception &) {
return 1;
00413211 mov dword ptr [ebp-4],0
00413218 jmp $LN9+17h (413231h)
$LN9:
0041321A mov dword ptr [ebp-4],0FFFFFFFFh
00413221 lea ecx,[ebp-34h]
00413224 call std::vector<int,std::allocator<int> >::~vector<int,std::allocator<int> > (41192Eh)
00413229 mov eax,dword ptr [ebp-10Ch]
0041322F jmp $LN9+54h (41326Eh)

if (v.size()) {
00413231 lea ecx,[ebp-34h]
00413234 call std::vector<int,std::allocator<int> >::size (4115A5h)

Re: return in catch block

Stuart Dootson10-Feb-09 12:10

Stuart Dootson

10-Feb-09 12:10

I think I see 'return 1;' three times...

I think the reason is that there's more code thn you expect round an exception handler (unhandled case, handled case, no exception case) and the disassembler puts in hte source code context for each one.

Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

Re: return in catch block

Stuart Dootson10-Feb-09 12:10

Stuart Dootson

10-Feb-09 12:10

Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

Re: return in catch block

Luc Pattyn10-Feb-09 15:04

Luc Pattyn

10-Feb-09 15:04

Hi,

some people insist on having just one return statement in a function; that makes having it in a
catch block rather hard. If you feel more lenient, go ahead.

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles]

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