Creating Non-Rectangular Forms - C / C++ / MFC Discussion Boards

econy7-Jan-13 5:22

7-Jan-13 5:22

Hi, I am a novice in programming on RTOS.

I have a question about the task function design. For example, the system tick is 10ms,

if one task can't finish a loop within 10 ms (do one function in one loop), then how can I guanrantee the funciton's run time?

I mean, the time it start, and the time it stop?

Re: The task runtime question of RTOS.

jeron17-Jan-13 5:35

jeron1

7-Jan-13 5:35

Your question is pretty valgue as there are a lot of RTOS's out there. A guess, is to put the function in its own thread and make the thread a higher priority than all others so it would not be preempted. Prioritization can be a tricky business though.

Re: The task runtime question of RTOS.

Joe Woodbury7-Jan-13 10:28

Joe Woodbury

7-Jan-13 10:28

Not being sarcastic, but check out this article on Wikipedia: http://en.wikipedia.org/wiki/Real-time_operating_system[^]

HOW the RTOS you are using schedules threads is very important. Many (most?) RTOSs can't actually guarantee a function's run time; they simply run fast enough that with proper programming you can get close enough. Something that takes over 10ms will almost always fall into this latter category since writing a function to use such an exact amount of time is essentially impossible (hardware interrupts alone on embedded system will add enough variance to cause a measurable difference in timings.)

(Here's a good article on RTOS interrupt scheduling: http://rtos.com/articles/18835[^])

modified 7-Jan-13 16:37pm.

Treeview After Select Event

Varun Pandey7-Jan-13 2:49

Varun Pandey

7-Jan-13 2:49

Hey guys, quick question...

I am working with treeview in win32 (VC++).

I want to remove selection facility provided for treeview. Can anyone tell what window message is posted onAfterSelect Event of tree view.

PS:- List also has checkboxes. So disabling mouse click isn't an option...

Thanks in advance...

-
Varun

Re: Treeview After Select Event

jeron17-Jan-13 5:08

jeron1

7-Jan-13 5:08

TVN_SELCHANGED[^]

how to hide a column of a listctrl

haha_c7-Jan-13 0:55

haha_c

7-Jan-13 0:55

Hi,I want to hide a column of my listctrl,and In my program never show,like delete,but It should not be delete,how to do with it,I set it's column width 0,but when I drag the column,It will show.

Re: how to hide a column of a listctrl

Pete O'Hanlon7-Jan-13 1:16

Pete O'Hanlon

7-Jan-13 1:16

You should be able to get what you want from this[^] sample.

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Creating Non-Rectangular Forms

Luca D'Amico6-Jan-13 11:38

Luca D'Amico

6-Jan-13 11:38

Hello,
I'd like to create a Non-Rectangular Form based on an image.

In short: I need to do this http://www.codeguru.com/csharp/csharp/cs_misc/designtechniques/article.php/c10083/Creating-NonRectangular-Forms.htm[^]
but in C++ (not c#)

I hope that somebody can point me to the right direction.

Thanks Smile | :)

Re: Creating Non-Rectangular Forms

David Crow6-Jan-13 17:25

David Crow

6-Jan-13 17:25

Luca D'Amico wrote:

I hope that somebody can point me to the right direction.

The only thing I can think of is this.

"One man's wage rise is another man's price increase." - Harold Wilson

"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

"Show me a community that obeys the Ten Commandments and I'll show you a less crowded prison system." - Anonymous

Re: Creating Non-Rectangular Forms

«_Superman_»6-Jan-13 17:56

«_Superman_»

6-Jan-13 17:56

The basics of this is to create a region of whatever shape you want.
There are several region function available in the Windows API - Region Functions[^]

Here are some good article on CP about region creation -
Simple way to create non-rectangular shaped dialogs[^]
CreateRegionFromFile[^]
Transparent digital clock[^]
Burn the Edges of Your Windows to Give Them Character[^]

«_Superman_»
I love work. It gives me something to do between weekends.

Microsoft MVP (Visual C++) (October 2009 - September 2013)

Polymorphism in C

Re: Creating Non-Rectangular Forms

Richard MacCutchan6-Jan-13 22:13

Richard MacCutchan

6-Jan-13 22:13

Take a look at http://www.flipcode.com/archives/Win32_Window_Skinning.shtml[^], it explains exactly how to do it.

One of these days I'm going to think of a really clever signature.

Re: Creating Non-Rectangular Forms

Luca D'Amico7-Jan-13 13:05

Luca D'Amico

7-Jan-13 13:05

Thanks a lot mates Smile | :)

std::vector problem

Super Lloyd6-Jan-13 1:21

Super Lloyd

6-Jan-13 1:21

I have a function which return an std::vector<T>
it is quite big and moved around a lot and kept for a long time, so I put it into a
std::shared_ptr<std::vector<T>>

Now I need to access the vector as an array
with
std::vector<T> a;
I can write
T* pa = &a[0];

But this doesn't work with a std::shared_ptr<std::vector<T>>

What can I do?

Remark
Why don't I just pass it by reference around?
Well, it is created in a function, and then it is captured by a lambda that is spawn regularly into a task (i.e. in another thread) which would be the only reference left.
And I want to avoid copying the vector (it is big) and destructing when it goes out of scope, I want to create it only once and reuse it / keep it alive!...

A train station is where the train stops. A bus station is where the bus stops. On my desk, I have a work station....
_________________________________________________________
My programs never have bugs, they just develop random features.

Re: std::vector problem

CPallini6-Jan-13 7:14

CPallini

6-Jan-13 7:14

Super Lloyd wrote:
Now I need to access the vector as an array

What's wrong with it?
e.g.

C++

shared_prt<vector<int>> p(new vector<int>{1,2,3,4});
cout << (*p)[2] << endl;

Veni, vidi, vici.

Re: std::vector problem

Super Lloyd6-Jan-13 11:53

Super Lloyd

6-Jan-13 11:53

Nothing, just me struggling with the syntax...
But thanks for your tip, it works indeed!!! Smile | :)

So simple! Could I add in hindsight! ^^

Static link to ATL alwayas fail

Falconapollo4-Jan-13 23:19

Falconapollo

4-Jan-13 23:19

I use some ATL functions to create a Media control. But, it seems that I can only use Dynamic link to ATL option, when I switch to Static link to ATL. I just can't create the control successfully.

I'm so confused. Anyone can help me?

C++

//related headers
#include <wmp.h>
#include <atlbase.h>
#include <atlcom.h>
#include <atlhost.h>
#include <atlctl.h>

//related vars
CAxWindow  m_wndView;  // ActiveX host window class.    CComPtr<IWMPPlayer>  
m_spWMPPlayer;  // Smart pointer to IWMPPlayer interface.

//related function code:
CComPtr<IAxWinHostWindow>  spHost;
HRESULT  hr;
m_wndView.Create(m_hWnd, rect, NULL, WS_CHILD | WS_VISIBLE | WS_CLIPCHILDREN, WS_EX_CLIENTEDGE);
hr = m_wndView.QueryHost(&spHost);
/*
when I switch to "Static Link to ATL" option, I will fail here
E_FAIL == hr;//the failure flag
*/
if(!SUCCEEDED(hr)) return FALSE;

hr = spHost->CreateControl(CComBSTR(_T("{6BF52A52-394A-11d3-B153-00C04F79FAA6}")), m_wndView, 0);
if(!SUCCEEDED(hr)) return FALSE;

hr = m_wndView.QueryControl(&m_spWMPPlayer);
if(!SUCCEEDED(hr)) return FALSE;

Re: Static link to ATL alwayas fail

Richard MacCutchan5-Jan-13 1:28

Richard MacCutchan

5-Jan-13 1:28

You need to look at the actual error code value when you get a FAIL result, in order to see why it has failed.

One of these days I'm going to think of a really clever signature.

how to use a work thread write file and the main thread show a carton

haha_c4-Jan-13 22:12

haha_c

4-Jan-13 22:12

Hi,when I Write files ,I want a carton show to let user know a data is performing.
I want to use a work thread in background to writing file,when the file finish ,it may be send a message to main window destroy the carton,but I dont't know how to do it ,please help me

Re: how to use a work thread write file and the main thread show a carton

David Crow5-Jan-13 11:41

David Crow

5-Jan-13 11:41

Use an event. With MFC, check out CEvent. I talk about this briefly in this article.

Re: how to use a work thread write file and the main thread show a carton

Albert Holguin6-Jan-13 6:14

Albert Holguin

6-Jan-13 6:14

Use PostMessage()[^].... make sure you know how to catch the message on your receiving window as well. MSDN usually has good tutorials. It's easier if you're using MFC since the message map is easily defined.

Re: how to use a work thread write file and the main thread show a carton

haha_c6-Jan-13 14:58

haha_c

6-Jan-13 14:58

Thanks

Re: how to use a work thread write file and the main thread show a carton

Randor 6-Jan-13 17:39

Randor

6-Jan-13 17:39

Hi,

cherry729 wrote:
I want to use a work thread in background to writing file,when the file finish ,it may be send a message to main window destroy the carton,but I dont't know how to do it ,please help me

If you want to save some time and avoid re-inventing the wheel then you might be interested in using the old Animation Window class[^]. If you are using the MFC library... this basic window class is represented in the CAnimateCtrl Class[^]. You can open, start, stop and pause the animation by simply sending window messages from any thread in your application.

Best Wishes,
-David Delaune

capDriverConnect displays captured frame in CView

Vaclav_4-Jan-13 16:15

Vaclav_

4-Jan-13 16:15

I am running into annoying problem using capDriverConnect API in an ancient VFW library.
I have a simple two step code using capCreateCaptureWindow and capDriverConnect.
The "problem " is that capDriverConnect randomly copies the captured data into the CView derived class.
It appears that when the code is run in debug the data is blank ( black ) about 50 % of the time and when run (.exe - still in debug mode) it fills the data ( single frame from USB camera ) about 80% of the time.
<b>I cannot find anywhere ( I did Google for it) if capDriverConnect suppose to do that and / or how to stop it. </b>
I need to capture frames for further processing and that code is working correctly.

Please - no commentary about how obsolete or crappy VFW is. It is used in OpenCV and that library does ton of video processing which I need.

I am not trying to be a moron, but if you do not have a clue why capDriverConnect
behave this way save your and mine time and do not reply. OK?

Cheers Vaclav

What is the merit to rewrite memcpy?

econy4-Jan-13 7:31

econy

4-Jan-13 7:31

One embedded program has a MemCpy(), like:

void MemCpy(unsigned byte *pTg, unsigned byte *pSc, size_t slen)
{
  volatile unsigned byte *ps, *pt;
  for (pt=pTg, ps=pSc; ps<(pSc+slen); pt++,ps++)
    *pt = *ps;
}

I wonder why the coder didnot use standard C memcpy function, what is the merit to rewrite a memcpy function like the above?

modified 4-Jan-13 14:46pm.

Re: What is the merit to rewrite memcpy?

Richard MacCutchan4-Jan-13 9:19

Richard MacCutchan

4-Jan-13 9:19

If this is connected to your question below, it is possible that the system available on the embedded device did not include a full standard C library. Alternatively this could just save using the library and thus reduce memory requirements.

One of these days I'm going to think of a really clever signature.

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