C / C++ / MFC

Re: Cannot get the correct cursor position in picture control

4-Feb-09 4:53

See the documentation of GetCursorPos[^], it tells you:
Retrieves the cursor's position, in screen coordinates.

z01e wrote:
GetCursorPos(&p1);
ClientToScreen(&p1);

With this you are getting the cursor position in screen coordinates and then you are converting it to screen cordinates.

> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> Life: great graphics, but the gameplay sux. <

z01e4-Feb-09 5:03

Re: Cannot get the correct cursor position in picture control

4-Feb-09 5:03

so what function should i use to get coordinate in picture control?

p.s. sorry ,i'm very newbie for mfc. It would be kind if you could explain clearly.
Thank you

Code-o-mat4-Feb-09 5:36

Re: Cannot get the correct cursor position in picture control

4-Feb-09 5:36

Well, you can either try this (using GetMessagePos()[^] as DavidCrow already suggested):

CPoint Pt(GetMessagePos());

POINT Pt;
GetCursorPos(&Pt);
picture_control.ScreenToClient(&Pt);

> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> Life: great graphics, but the gameplay sux. <

z01e4-Feb-09 5:56

Re: Cannot get the correct cursor position in picture control

4-Feb-09 5:56

thank you very much Code-o-mat.

and how can i keep these lines after i draw because in just a few second
all lines are disappear.

Code-o-mat4-Feb-09 6:10

Re: Cannot get the correct cursor position in picture control

4-Feb-09 6:10

I'm not sure what you mean, but if my guess is correct, you are drawing onto the picture control with the mouse. In this case, you will either have to remember what lines you have drawn, this aproach is more complicated, or simply, draw ONTO the bitmap in memory also, not just the window, this is probably easier done. Create a memory DC, select the bitmap into it and use MoveTo/LineTo to draw your lines. Don't forget to clean up after you are done drawing.

> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> Life: great graphics, but the gameplay sux. <

z01e4-Feb-09 6:25

Re: Cannot get the correct cursor position in picture control

4-Feb-09 6:25

i try to search MemDC but i don't understand. T_T

can i have example of MemDC and where do i put these function in if i want to show these lines on the image(old) until i load new image, these lines will gone?

thanks for your help

Code-o-mat4-Feb-09 6:43

Re: Cannot get the correct cursor position in picture control

4-Feb-09 6:43

Well, if you load a new bitmap into your picture control then yes, the lines will be gone. And for the memdc, you can do something like this:

CDC MemDC;
MemDC.CreateCompatibleDC(dc_of_picture_control);
CBitmap *origBitmap = MemDC.SelectObject(pointer_to_bitmap_you_want_to_draw_to);
MemDC.MoveTo(0, 0);
MemDC.LineTo(line_to_x, line_to_y);
MemDC.SelectObject(origBitmap);
MemDC.DeleteDC();

> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> Life: great graphics, but the gameplay sux. <

z01e4-Feb-09 7:11

Re: Cannot get the correct cursor position in picture control

4-Feb-09 7:11

void CMyGUIDlg::OnStnClickedPic1()
{
CWnd* prnt = GetDlgItem(IDC_PIC1);
CDC *pdc = prnt->GetDC();
CDC MemDC;
MemDC.CreateCompatibleDC(pdc);
CBitmap *origBitmap = (CBitmap*)MemDC.SelectObject(&m_pic1); //m_pic1.SetBitmap("LenaRGB.BMP");
MemDC.MoveTo(0, 0);
MemDC.LineTo(100,100 );
MemDC.SelectObject(origBitmap);
MemDC.DeleteDC();
}

T_T still can't do it. i try what you said but it is still no line after i minimize it.

hope you not bored me yet i'm sorry but thank you very much

Code-o-mat4-Feb-09 7:59

Re: Cannot get the correct cursor position in picture control

4-Feb-09 7:59

What is m_pic1? Isn't it a CStatic that shows your bitmap? If it is, don't select THAT into the DC (you shouldn't be able to do that i think), ask it for its bitmap and select that. So if it is a CStatic or derivative, try using GetBitmap[^] like:

...
CBitmap TempBmp;
TempBmp.Attach(m_pic1.GetBitmap());
CBitmap *origBitmap = MemDC.SelectObject(&TempBmp);
...
MemDC.SelectObject(origBitmap);
TempBmp.Detach();
...

> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> Life: great graphics, but the gameplay sux. <

z01e4-Feb-09 8:42

Re: Cannot get the correct cursor position in picture control

4-Feb-09 8:42

still doesnt work - -
but thank you very much

i load image by using this.

void CPictureBox::ShowBitmap(CPaintDC *pdc)
{
//Create a device context to load the bitmap into
CDC dcMem;
dcMem.CreateCompatibleDC(pdc);

//Get the Display area available
CRect lRect;
GetClientRect(lRect);
lRect.NormalizeRect();

//select the bitmap into compatible device context
CBitmap* pOldBitmap = (CBitmap*)dcMem.SelectObject(&m_bmpBitmap);
//m_bmpBitmap.SetBitmapDimension(lRect.Width(),lRect.Height());

//copy & resize the window to the dialog window
pdc->StretchBlt(0,0,lRect.Width(),lRect.Height(),&dcMem,0,0,bm.bmWidth,bm.bmHeight,SRCCOPY);
}
void CPictureBox::OnPaint()
{
CPaintDC dc(this); // device context for painting

RECT rect;
GetClientRect(&rect);
dc.FillSolidRect(&rect, RGB(255,255,255));

if(m_sBitmap!="")
ShowBitmap(&dc);
}
void CPictureBox::SetBitmap(CString strBitmap)
{
m_sBitmap = strBitmap;

HBITMAP hBitmap = (HBITMAP) ::LoadImage(AfxGetInstanceHandle(),
m_sBitmap, IMAGE_BITMAP, 0, 0,
LR_LOADFROMFILE | LR_CREATEDIBSECTION);

// Do we have a valid handle for the loaded image?
if (hBitmap)
{
// Delete the current bitmap
if (m_bmpBitmap.DeleteObject())
m_bmpBitmap.Detach(); // If there was a bitmap, detach it
// Attach the currently loaded bitmap to the bitmap object
m_bmpBitmap.Attach(hBitmap);
}
m_bmpBitmap.GetBitmap(&bm); //Get Bitmap Structure
Invalidate();
}

maybe this is why it doesn't work.and i dont know what should i do with it to make this work. T_T

anyway thanks to you.

Code-o-mat4-Feb-09 10:12

Re: Cannot get the correct cursor position in picture control

4-Feb-09 10:12

I believe -according to what i see in the code you gave- you have to select m_bmpBitmap into the memory-dc when you draw the lines.
Btw i see you are using StretchBlt, that will cause problems with drawing those lines, but first try to get it to keep the lines first.

> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> Life: great graphics, but the gameplay sux. <

z01e4-Feb-09 23:05

4-Feb-09 23:05

thank you for all your help.

Memory Leak

rr_ramesh714-Feb-09 1:37

rr_ramesh71

4-Feb-09 1:37

I have a static function in that I have some array members, that function will be called from so many places, I want to know that when ever the process of the function is over means all the member variables will be get released from memory or will Occupy the space.

prasad_som4-Feb-09 1:42

prasad_som

4-Feb-09 1:42

rr_ramesh71 wrote:
I have some array member

What kind of array it is ?

rr_ramesh714-Feb-09 2:18

rr_ramesh71

4-Feb-09 2:18

char lbuffer[5000]; // will this array get released after the function over
sprintf(lbuffer,"Stock in List [%s] Quantiry %d",  SymbolList,qty);

but according to me memory is keeps on increasing when ever we call the function it is not reducing after it is completed

Cedric Moonen4-Feb-09 2:37

Cedric Moonen

4-Feb-09 2:37

Yes the buffer will be released.

rr_ramesh71 wrote:
but according to me memory is keeps on increasing when ever we call the function it is not reducing after it is completed

How do you check that ? Are you using some tools to verify that information ?

Cédric Moonen
Software developer

Charting control [v1.5]
OpenGL game tutorial in C++

prasad_som4-Feb-09 3:32

prasad_som

4-Feb-09 3:32

rr_ramesh71 wrote:
// will this array get released after the function over

Yes, You don't need to worry about memory, as its been allocated on stack.

Stuart Dootson4-Feb-09 1:43

Stuart Dootson

4-Feb-09 1:43

How are the arrays declared?

If they're declared as local variables (as shown with localArray below), they will definitely be cleared up, as they're allocated space on the stack, which is tidied up when the function exits.

double SomeFunction(int x)
{
   double localArray[] = { 1.0, 2.0, 3.0, 4.0 };
   const size_t localArraySize = sizeof localArray / sizeof localArray[0];
   return x<localArraySize?localArray[x]:-1.0;
}

Cedric Moonen4-Feb-09 1:46

Cedric Moonen

4-Feb-09 1:46

The only thing you have to take care in this case, is that if you are allocating memory with new (or new[]), then you should delete it with delete (or delete[]). For the rest, the memory will be automatically released.

Cédric Moonen
Software developer

Charting control [v1.5]
OpenGL game tutorial in C++

Code-o-mat4-Feb-09 2:25