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Hi,
I am able to draw vertical line on dialog, line will move from left to right for the period of time. while moving i am erasing the previous line with previous pixels and drawing new line with new pixels...
but while the line is moving, if i have opened any other application on dialog box, the prevois line is not erasing and it is continue with the new line..
can any one help me why it is happening like this...?
Thanks in advance..
Any advice will be appriciated..
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What are you doing exactly in the OnPaint handler ?
What you have to think is that windows doesn't remember the drawings for your window. So it means that whenever it needs to repaint the window (for instance because you have another window on top), then it will ask your window to repaint itself (by sending a WM_PAINT message). If you don't redraw your window properly, then you will loose some data.
Also, the ebest way to erase a previous line your example is to simply request a new repainting of your window and draw the line at the new position (as everything is cleared, your previous line won't be visible anymore).
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Hi cedric,
Thanks for your reply.. actually i am drawing line along with the slider positions on dialog, i mean slider will move from left to right, that time along with slider positions the line will also move.
I have written the below code in one thread..
m_pDlg->GetClientRect( &deflatedClientRect );
deflatedClientRect.DeflateRect( TB_WIDTH, TB_WIDTH );
m_pDlg->m_slider_bar1.SetPos(slide_pos);
m_pDlg->m_slider_bar2.SetPos(slide_pos);
m_pDlg->m_slider_bar1.GetThumbRect( &thumbRect );
m_pDlg->m_slider_bar1.ClientToScreen( &thumbRect );
m_pDlg->ScreenToClient( &thumbRect );
ptStart.x = thumbRect.CenterPoint().x;
ptStart.y = TB_WIDTH;
//ptEnd.x = ptStart.x;
//ptEnd.y = deflatedClientRect.bottom;
m_pDlg->x1 = ptStart.x;
m_pDlg->x2 = ptStart.x;
//m_pDlg->x2 = ptEnd.x;
//m_pDlg->y2 = 280;
m_pDlg->InvalidateRect(deflatedClientRect,TRUE);
using this code i will get sliders pixels information, and i am calling InavalidateRect from here.
In Onpaint i am using below code snippet..
int nOldmode=dc.SetROP2(R2_NOTXORPEN);
dc.MoveTo(old_x1,old_y1);
dc.LineTo(old_x2,old_y2);
dc.MoveTo(x1,y1);
dc.LineTo(x2,y2);
old_x1 = x1;
old_y1 = y1;
old_x2 = x2;
old_y2 = y2;
plase check the code and let me know that is the problem..>
thnaks in advance..
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Did you read my previous message ?
Why are you repainting the old line ?
venki502 wrote: I have written the below code in one thread..
You are doing that in a separate thread ? 
I wouldn't do that: instead simply handle the slider moved event and update the position of your line at that point. Why do you need a thread for that ?
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Hi,
Actualli i am setting the slider position in OnTimer function, Okay can you please tell me the event fired at silder movement, so that i will try with that..
Thanks.
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This is getting painful to read.
1/ In your thumbtrack handler, just call InvalidateRect () to cause the window to redraw.
2/ In the OnPaint routine, get the thumb positions, calculate your two end points for the line. Draw the line.
Go home and sleep.
It's not a complex problem. I have no idea why you're bringing in threads, etc.
If you want, you could be clever and use R2_NOT to undraw a line, and draw it in the new position, but that seems a little over complex at the moment.
Good luck,
Iain.
Codeproject MVP for C++, I can't believe it's for my lounge posts...
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Hello,
i need help with this onMouseMove function... what i am doing here is drawing a line on the left and right side. On the left it;s all OpenGL AVI on the right i am calling my own function to draw the same lines as i move a mouse... however my problem is with MakeCurrent and clear screen here... because when i draw a line and rotate it ... there are bunch of lines all around. I don't know what i am doing wrong and where i need this swap buffer.... can someone please tell me how to get rid of those multiple lines when i move my mouse:
void CtestopenglView::OnMouseMove(UINT nFlags, CPoint point)
{
wglMakeCurrent(m_hDC,m_hRC);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glClear(GL_COLOR_BUFFER_BIT);
::SwapBuffers(m_hDC);
if(m_drawenabled)
{
m_start = point;
glPushMatrix();
glColor3f(0.0,0.0,0.0);
DrawLine(m_start.x+300, m_start.y, m_end.x+300, m_end.y);
glBegin(GL_LINES);
glVertex3d(m_start.x, m_start.y,0);
glVertex3d(m_end.x, m_end.y,0);
glEnd();
glPopMatrix();
m_start = point;
glPushMatrix();
glColor3f(1.0,1.0,1.0);
DrawLine(m_start.x+300, m_start.y, m_end.x+300, m_end.y);
glBegin(GL_LINES);
glVertex3d(m_start.x, m_start.y,0);
glVertex3d(m_end.x, m_end.y,0);
glEnd();
glPopMatrix();
}
CView::OnMouseMove(nFlags, point);
wglMakeCurrent(m_hDC,NULL);
wglMakeCurrent(m_hDC,m_hRC);
glFlush();
::SwapBuffers(m_hDC);
}
thanks
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What happens if you get rid of the first SwapBuffers call? I have a feeling that the glClear won't be clearing the buffer you're drawing on, and also that you only need one SwapBuffer call per iteration (you'll be drawing on the back buffer and swapping it to the front once it's drawn on?, then doing the same thing with the other buffer at the next iteration)
Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p
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hey,
if i take out the first swap only i do get one line on the screen ... however it does not stay on the screen when i try to draw another... it dissapears...
i need to keep on drawing the lines and keep on the screen...so that i could write something like WE right now after taking that swap out and trying to draw second line of the W first line is no longer on the screen...
what should i do
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For msg based painting you should only draw in the paint handler.
In the mouse handler save any mouse specific state that's important then invalidate the area that needs to be redrawn.
...cmk
The idea that I can be presented with a problem, set out to logically solve it with the tools at hand, and wind up with a program that could not be legally used because someone else followed the same logical steps some years ago and filed for a patent on it is horrifying.
- John Carmack
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how to access webcam using VC++
S K Dhruw
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do you have the SDK for webcams?
see here[^]
You need to google first, if you have "It's urgent please" mentioned in your question.
 _AnShUmAn_
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Now I am writing a project ,i need to protect my process from being closed by users who may be using ctrl+alt+del or something like this.what is the simplest way to do this?pls help me ,thanks.
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You can't. And why would you do such a thing ? The only real 'application' for which it would make sense is a virus.
So, what happens if you have a small bug in your application which makes it hang ? People will need to reboot their PC in order to get rid of it ? That's completely crazy...
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I suppose he actually can. I think that a 'standard user' cannot close a process having administrator privileges (It's a guess, however).
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]
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Well, (I suppose that) if you run you application as administrator, the noone (except another user with administrator, or higher, privileges) will be able to kill it.
Why don't you make a test?
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]
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What i am making is not a virus but a monitor of system ,and i don't want normal user to close it without a password which is a function in my project.
So how can i do this ? any solution?
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Hello all,
I am creating PROJECT in vc++ 2005.
I got this error while running the program:
Error:
Unhandled exception at 0x7849affe (mfc80ud.dll) APP.exe: 0xC0000005: Access violation reading location 0xcccccccc.
At afxsock.inl file:
Line where error is coming:
AFXSOCK_INLINE int CAsyncSocket::SendTo(const void* lpBuf, int nBufLen, const SOCKADDR* lpSockAddr, int nSockAddrLen, int nFlags)
{ return SendToHelper(lpBuf, nBufLen, lpSockAddr, nSockAddrLen, nFlags);
My code is:
m_sSocket->SendTo(&msg, sizeof(char),MAINW_R_PORT,IP,0);
CAN ANYONE HELP ME IN RECTIFYING THE ERROR.
THANKS
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I think your problem of first parameter of SendTo(const void*,how did you se msg?
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 )
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i even tried type casting as msg is char datatype but its not working.
Thanks
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What is msg ? Are you only sending 1 byte of data (sizeof(char) will have 1 as a result) ?
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yes i am sending one byte of data as char msg='v',but its not working.
Thanks
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Hi,Even i faced the same problem,you must have created some array with new and either forgot to delete it or deleting it after the value is changed.
Thanks A Ton
Ash_VCPP
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i hav nt created any array as such only one character i am sending with msg='v'.can u please tell me how you solved your problem,i will try to do that
Thanks
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