C / C++ / MFC

Re: Need help regarding the slider

25-Jan-09 0:39

Hi David,
I want to create the slider at run time at specified position as that is my requirement.
But even if i create the slider at design time i am facing with the same problem.
whereever i have clicked in the slider the silider poisition is not moved directly to the respected position.
I am explaining my scenario with example below, i hope this will help you for better understanding my question.

I gave the min and max values as 0 and 100. Suppose if i clicked at 33 position, the slider position is not directlt moving to 33 location, instead it is moving to 20th location. every time the tic value is incrementing by 20.

Any help would be appriciated regarding this.

Thanks in advance.

Thanks
Venkatesh. Smile | :)

Mark Salsbery25-Jan-09 7:38

Mark Salsbery

25-Jan-09 7:38

venki502 wrote:
whereever i have clicked in the slider the silider poisition is not moved directly to the respected position.

See here[^].

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Need some help on how to create a Line and how to move that line using mouse options

John50224-Jan-09 4:47

Re: Need some help on how to create a Line and how to move that line using mouse options

24-Jan-09 4:47

Hello,
This is Venkatesh, I am working on VC++ (MFC). Currently i am working on one application which deals with the graphs and lines. i want to create one line and have to move (drag) that line horizotally from one end to other using mouse.

Can any one help me out regarding this...?

Any help would be much appreciated, because as it is very urgent requirement for me..

Thanks
Venkatesh. Smile | :)

Hamid_RT24-Jan-09 5:15

Hamid_RT

24-Jan-09 5:15

You need to declare WM_MOUSEMOVE and WM_LBUTTONUP/DOWN and you need to get current postion of mouse with GetCursorPos and then you can use of LineTo/MoveTo.

Of one Essence is the human race
thus has Creation put the base
One Limb impacted is sufficient
For all Others to feel the Mace
(Saadi )

Re: Need some help on how to create a Line and how to move that line using mouse options

John50224-Jan-09 12:30

Re: Need some help on how to create a Line and how to move that line using mouse options

24-Jan-09 12:30

Thanks Hamid ,thanks for your valuable reply.

PJ Arends24-Jan-09 5:44

PJ Arends

24-Jan-09 5:44

In addition to what Hamid said, you will also have to set the raster operation code to R2_XORPEN when you draw your line. Doing so you will be able to draw the line once to show the line, and then draw it again in the same spot to erase the line. Use CDC::SetROP2(R2_XORPEN) in your drawing code.

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

Within you lies the power for good - Use it!

Re: Need some help on how to create a Line and how to move that line using mouse options

John50224-Jan-09 12:31

Re: Need some help on how to create a Line and how to move that line using mouse options

24-Jan-09 12:31

Thanks Arends ,thanks for your valuable reply.

bob1697224-Jan-09 7:36

bob16972

24-Jan-09 7:36

You can use Rubberbanding[^] to create the line. (Ivor Horton is the best author to reference for sample graphics applications using MFC Smile | :)

)

To interact with it you could simply use CRectTracker with a few modifications if you don't mind a simple rectangular hit test region. This is more than adequate for forms based line manipulations since a good portion or the lines will be vertical or horizontal.

If you need more advanced hit testing that is not restricted to a rectangle, such as for an advanced graphics application, then you will likely need to roll your own tracker class.

Re: Need some help on how to create a Line and how to move that line using mouse options

John50224-Jan-09 12:33

code to analyze bitmap then create predefined palette of colors in bitmap?

24-Jan-09 12:33

Thanks bob,

Thanks for spending your valuable time for getting me to the conclusion page.

Richard Perrine24-Jan-09 4:33

Richard Perrine

24-Jan-09 4:33

I am looking for something that I have not been able to find.

1. example code that analyzes the colors in a bitmap, and
2. code that organizes the colors sampled into a palette of 16x16 or 32x32 or something like that.

can anyone help?

Re: code to analyze bitmap then create predefined palette of colors in bitmap?

Stuart Dootson24-Jan-09 5:01

Re: code to analyze bitmap then create predefined palette of colors in bitmap?

24-Jan-09 5:01

Richard Perrine wrote:
example code that analyzes the colors in a bitmap

Define 'analyze'. To just gather colours, I'd probably go through the bitmap a pixel at a time and store the RGB triplet for each pixel into a std::set. That would make it easy enough to get a list of the unique colours in the bitmap.

To cull the colours to a smaller number (as required if you want to define a fixed palette for the image), you'd use some form of colour quantisation[^].

Richard Perrine wrote:
code that organizes the colors sampled into a palette of 16x16 or 32x32

Maybe you can get some ideas from this color picker control[^]? The source is available.

Richard Perrine24-Jan-09 5:14

Richard Perrine

24-Jan-09 5:14

Thank you, Stuart.

Re: code to analyze bitmap then create predefined palette of colors in bitmap?

Randor 24-Jan-09 6:59

Randor

24-Jan-09 6:59

Richard Perrine wrote:
can anyone help?

These are some excellent color quantization links that you may be interested in.

Floyd-Steinberg implemented in C[^]

Octree Color Quantization[^]

Best Wishes,
-David Delaune

explorer in Windows CE

Miss_F24-Jan-09 2:18

Miss_F

24-Jan-09 2:18

Hi,
I want to use an explorer in my program (it's a C++ program) which is under Windows CE platform. I want to know that is it applicable or not? If yes, does any body know how can I do it?
(If here is not a right forum, Sorry, I don't know under which topic I should write my question)
Thanks a lot
Sincerely Yours
Miss_F

Stuart Dootson24-Jan-09 3:09

24-Jan-09 3:09

Miss_F wrote:
an explorer

What do you mean by 'an explorer'? If you mean manipulating the filesystem/namespace using explorer interfaces like IFolderView[^], then I suspect you're out of luck. If you mean a treeview, then you should be OK[^].

Miss_F24-Jan-09 3:15

Miss_F

24-Jan-09 3:15

I mean adding Internet browsing (using browser) functionality to my application.

Stuart Dootson24-Jan-09 4:43

24-Jan-09 4:43

Looks like you can[^]?

Get TrackBar Value in Form from a Thread

Miss_F24-Jan-09 18:53

Miss_F

24-Jan-09 18:53

Thanks for your help

Member 391913824-Jan-09 1:16

Member 3919138

24-Jan-09 1:16

A trackBar->Value in a form has to be read out from a thread. I read so many articles, but still I got a problem.

I use a delegate which should return me the value of the trackBar position:
delegate int DelegateTrackBarCallBack(System::Object ^object);

I started the Thread by a ParametriziedThreadStart after a Button-Click

Thread^ oThread = gcnew Thread(gcnew ParameterizedThreadStart(&ProcessCANMessage::CAN_Thread::CANThread));

In CANThread I do

target_velocity=Get_TrackBar1_Value(object);

with

int ProcessCANMessage::CAN_Thread::Get_TrackBar1_Value(System::Object^ object)
{
   CAN_Anbindung::Form1^ form;
   form = (CAN_Anbindung::Form1^)object;
   int trackBar_Value;
   if (form->trackBar1->InvokeRequired==false)
   {
	   trackBar_Value=form->trackBar1->Value;
   }
   else
   {
	   CAN_Anbindung::Form1::DelegateTrackBarCallBack ^d = gcnew CAN_Anbindung::Form1::DelegateTrackBarCallBack(Get_TrackBar1_Value);
	   form->Invoke(d, gcnew array<system::object^>{form});
   }
   return (trackBar_Value);
}

During debugging the correct value is assigned to trackBar_Value. But when leaving Get_TrackBar1_Value trackBar_Value is set to "0".

Any ideas what to do?

Stuart Dootson24-Jan-09 1:37

24-Jan-09 1:37

Member 3919138 wrote:
Any ideas what to do?

Post to the C++/CLI[^] forum, as that's what you're using?

From what I can understand of your message, you're expecting trackBar_Value to keep its value in two different invocations of Get_TrackBar1_Value? Nope - local variables don't do that unless they're static. However - doesn't Invoke return the return value of the delegate? So you could do something like this?

trackBar_Value = form->Invoke(d, gcnew array<system::object^>{form});

You might need some casting to convert Invoke's return value from System::Object to int - wouldn't know - I've never really used .NET, never mind C++/CLI.

Member 391913824-Jan-09 1:56

Member 3919138

24-Jan-09 1:56

I tried this befor
I got an error
1>.\ProcessCANMessage.cpp(74) : error C2440: '=': 'System::Object ^' kann nicht in 'int' konvertiert werden

Stuart Dootson24-Jan-09 2:19

24-Jan-09 2:19

Did you convert as shown in this article[^]?

int z = 44;
Object^ o = z; //implicit boxing
int y = *reinterpret_cast<int^>(o); //unboxing

Chris.G.Weber24-Jan-09 6:40

Chris.G.Weber

24-Jan-09 6:40

I will try that. Thanks for your answers and help!

I used a code which shown in one of the articles from this forum which helps to control 4 Progressbars in a Form from 4 Threads.

See: http://www.codeproject.com/KB/mcpp/managedsafethreads.aspx[^]
It works fine, since the delegate function seems to be recalled until the InvokeRequired-property is false. in this case the progressbars can be controlled directly in the thread by "form->progressBar1->PerformStep();"
In my case I want to get the Value (Position) of the trackBar-component. So if the delegate function is called 2 times we have a recursive calling of the same function. I assumed that the return value is then overwritten by the previous call of my function "Get_TrackBar1_Value(object)".

I will let you know about the result.