C / C++ / MFC Discussion Boards

Danzy8327-Oct-10 1:52

27-Oct-10 1:52

Hi everyone. I have a program that plays audio files. I have a control that I want to use to control the volume. I have declared a HANDLE for the waveOut as

HWAVEOUT hWo;

that I use to write the audio samples. Now I want to control the volume. I used

waveOutSetVolume()

and this affects the wave output volume of the system. How do I control the volume from my application without affecting the volume of the system, or what function is used for this task. Thanks in advance.

Re: controlling wave output volume

David Crow27-Oct-10 3:03

David Crow

27-Oct-10 3:03

Dan_K wrote:
How do I control the volume from my application without affecting the volume of the system...

I believe you'll need Vista for per-application volume control.

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Re: controlling wave output volume

Chris Meech27-Oct-10 3:25

Chris Meech

27-Oct-10 3:25

As David mentioned you might be looking for an OS specific type function. You might try the following, though and that is to obtain the current volume setting when your program starts up, then allow the user to change volume at will, and when the user closes your program you restore the volume back. It won't work quite like you are looking for, but it might be a nice addition. Smile | :)

Chris Meech
I am Canadian. [heard in a local bar]

In theory there is no difference between theory and practice. In practice there is. [Yogi Berra]

Re: controlling wave output volume

Danzy8327-Oct-10 3:44

Danzy83

27-Oct-10 3:44

Windows Media Player 9 on Windows XP for instance works without changing the system volume so I thought there could be a way out.

Re: controlling wave output volume

Sauro Viti27-Oct-10 3:53

Sauro Viti

27-Oct-10 3:53

There are two ways to change the intensity of your output:

Change the volume: on Xp and earlier systems you have only a general setting for it, starting on Vista has been provided a per-application setting
Scaling the audio samples: in this case you have to get the audio data from your stream, modify them and send the modified one to the audio output

Re: controlling wave output volume

Danzy8327-Oct-10 3:58

Danzy83

27-Oct-10 3:58

Can you please give me a brief idea about scaling the samples? I don't know much about digital sound processing but I learnt it has to do with the amplitude. I don't know if the amplitude is the value of a sample. If this is right, then I think if you give me a brief idea, I would be able to do it.

Re: controlling wave output volume

Code-o-mat27-Oct-10 4:25

Code-o-mat

27-Oct-10 4:25

Windows Media Player -as far as i know- user DirectX/DirectShow to play sounds, not the waveOut API (i am not sure how it works with DirectShow, am just mentioning...)

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How can i use tab inside edit control

learningvisualc27-Oct-10 0:33

learningvisualc

27-Oct-10 0:33

Hi all,

I have made a multiline edit control but the problem is when i try to use tab in it the focus shifts to next control. Is there any way to use tab inside edit control.

Thanks in advance

Re: How can i use tab inside edit control

Sauro Viti27-Oct-10 0:48

Sauro Viti

27-Oct-10 0:48

See the following pages; they speak about your problem and there are some trick on how to do:

http://www.eggheadcafe.com/software/aspnet/29955165/capturing-tab-keypress-in-cedit.aspx[^]
http://stackoverflow.com/questions/1230260/mfc-cedit-ctrl-question[^]

Print Preview in applications

msr_codeproject27-Oct-10 0:01

msr_codeproject

27-Oct-10 0:01

Hi I want to know how Print Preview from applications (like MS-Paint,
Windows Photo Gallery etc.,) works?

Will the properties of the preview (like qulaity, size, orientation etc.,)
depends on the printer driver or the application?

Can anybody share some writeup on this?

Regards
msr

Re: Print Preview in applications

Richard MacCutchan27-Oct-10 2:40

Richard MacCutchan

27-Oct-10 2:40

This[^] should get you started.

Just say 'NO' to evaluated arguments for diadic functions! Ash

How to print only the current folder name in powershell

melwyn26-Oct-10 23:43

melwyn

26-Oct-10 23:43

Hi,
Sorry for asking a powershell question. This should be easy for an expert.

Suppose I'm in the folder C:\Windows\System32 . I want to print out only "System32".

I have found commands that give the entire path, but I want only the last bit Smile | :)

Thanks,
Mel

Re: How to print only the current folder name in powershell

Sauro Viti27-Oct-10 0:16

Sauro Viti

27-Oct-10 0:16

You have posted the same question on 4 different forums; please, don't do it!
The best when asking something is to choose the forum that better matches your subject, and post a unique question explaining as better as possible what is your problem.

Thank you!

How to convert PDF to image file? example:jpg etc.

illfar26-Oct-10 22:00

illfar

26-Oct-10 22:00

How to convert PDF to image file?
example:jpg file

Thank you

i want to use C language to do.
where is the conference code.

Re: How to convert PDF to image file? example:jpg etc.

CPallini26-Oct-10 22:36

CPallini

26-Oct-10 22:36

You probably need a library for the purpose (the other route would be reading the PDF specifications for implementing the decoding algorithm).
Smile | :)

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]

CFileDialog

MsmVc26-Oct-10 21:36

MsmVc

26-Oct-10 21:36

Hi all

How can i use FilterIndex in CFileDialog?
Please help me

Re: CFileDialog

CPallini26-Oct-10 21:55

CPallini

26-Oct-10 21:55

MsmVc wrote:
How can i use FilterIndex in CFileDialog?

As specified by the documentation. MSDN gives even this sample code.
Smile | :)

How to reset the Combo Box to previous selection [modified]

msr_codeproject26-Oct-10 19:36

msr_codeproject

26-Oct-10 19:36

Hi, I have a combo box in my application.

Whenever there is CB_SELCHANGE occurs, I need to perform some operation.
If the operation fails I need to reset the combo box to previous value.

My Trail:

Whenever there is a change in selection I am copying that item to a string variable (say str).
Now I am using CB_FINDSTRING to get the index using str by calling SendMessage. But it was not working.

I have confusion with LPARAM and WPARAM in SendMessage. Please give me the syntax of SendMessage
using CB_FINDSTRING.

Can you people throw me some idea?

Thanks in advance
msr

modified on Wednesday, October 27, 2010 1:43 AM

Re: How to reset the Combo Box to previous selection

CPallini26-Oct-10 21:50

CPallini

26-Oct-10 21:50

A bit of book-keeping would avoid the SendMessage stuff.
Anyway you probably have to write something like (assuming your str is a char*):

LRESULT result = SendMessage(hWnd, CB_FINDSTRING, (WPARAM)-1, (LPARAM)str);

Re: How to reset the Combo Box to previous selection

msr_codeproject26-Oct-10 22:09

msr_codeproject

26-Oct-10 22:09

Thank you. Now it is working. I have interchanged LPARAM and WPARAM parameters. Here is my code.

DWORD GetComboBoxIndex = 0;
GetComboBoxIndex = SendMessage(hWnd, CB_FINDSTRINGEXACT, -1, (LPARAM)str);
SendMessage(hWnd, CB_SETCURSEL, GetComboBoxIndex, NULL);

Regards
msr

Re: How to reset the Combo Box to previous selection

CPallini26-Oct-10 22:18

CPallini

26-Oct-10 22:18

You are welcome.
Smile | :)

Error Heap in allocate modeless .

HTT9026-Oct-10 7:32

HTT90

26-Oct-10 7:32

I have the code about create many modeless dialog .

for(int i=0;i < 5;++i)
    {   
        pRegionDlg[i] = new CRegionDlg ( this );
        pRegionDlg[i]->Create( IDD_DIALOG , this );
        pRegionDlg[i]->ShowWindow( SW_SHOW ) ;
    }

this code is error heap . but I don't understand why it's error . while this code can run good on other program .

Thanks for reading and helping .

Re: Error Heap in allocate modeless .

David Crow26-Oct-10 7:51

David Crow

26-Oct-10 7:51

HTT90 wrote:
this code is error heap . but I don't understand why it's error . while this code can run good on other program .

What is this supposed to mean? What error? Where? How was pRegionDlg declared? Please clarify.

Re: Error Heap in allocate modeless .

CPallini26-Oct-10 9:30

CPallini

26-Oct-10 9:30

Maybe 'the other program' properly allocates the pRegionDlg array.
Smile | :)

Re: Error Heap in allocate modeless .

HTT9026-Oct-10 16:21

HTT90

26-Oct-10 16:21

I did :

in header file :

CRegionDlg *pRegionDlg[8] ;

and when I debug , I receive a message , it's inform me no loaded from dll . and heap is error .

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