On Feb 13, 9:49 pm, Joseph M. Newcomer <newco...@flounder.com> wrote:
Several problems, see below...
On Wed, 13 Feb 2008 07:14:15 -0800 (PST), MC Felon <paec....@gmail.com> wrote:
Hello
I wish to make a small program (MFC win32 app) which displays text and
clears screen, pauses and repeats all over again. In short, the screen
must display "something" and make it blink. How do i do this? I tried
this:
[code]
#include <afxwin.h>
#include "Messagebox.h"
#include <windows.h>
cm d;
BOOL cm::InitInstance()
{
m_pMainWnd = new wnd;
***
blink = FALSE; // or TRUE, doesn't matter much
// BOOL blink; is in your class wnd as a protected member
****> m_pMainWnd -> ShowWindow(m_nCmdShow);
m_pMainWnd -> UpdateWindow();
return TRUE;
}
wnd :: wnd()
{
Create(NULL,_T("app"));
****
#define IDT_BLINK 1 // or some suitable integer of your choice
SetTimer(IDT_BLINK, time, NULL);
where 'time' is some suitable blink time. You might use
SetTimer(IDT_BLINK, ::GetCaretBlinkTime(), NULL);
as a first cut at the time
Then add a WM_TIMER handler:
void wnd::OnTimer(UINT id)
{
switch(id)
{ /* id */
case IDT_BLINK:
blink = !blink;
Invalidate();
break;
} /* id */
superclass_of_wnd::OnTimer(id); // whatever superclass_of_wnd is
}
****
}
void wnd :: OnPaint()
{
CPaintDC dc(this);
CRect r;
GetClientRect(&r);
while(1)
{
Sleep(1000);
dc.DrawText(_T("hey"), -1, &r, DT_VCENTER | DT_CENTER |
DT_SINGLELINE);
Sleep(200);
Invalidate();
}
[\code]
****
First, putting a Sleep in a GUI thread should be thought of as *always* an error (if there
is the extremely rare exception where this makes sense, it might be recognizable, but here
it is just wrong). Because the program does nothing but lock up in the OnPaint handler,
it locks up.
What you would want to do is as shown above. Then replace that entire while-loop with the
following code:
if(blink)
dc.DrawText(....etc...);
and it is done. Much simpler, much easier, no effort, no loops, no sleep, etc.
joe
****
Messagebox.h contains derived classes of CWinApp and CFrameWnd. What's
wrong? My screen freezes, it's damn busy and the program discontinues
response!
****
Well, your screen freezes and the program fails to repond because that's exactly what you
asked it to do!
****>Thanks a lot in advance.
Joseph M. Newcomer [MVP]
email: newco...@flounder.com
Web:http://www.flounder.com
MVP Tips:http://www.flounder.com/mvp_tips.htm
Thanks for the prompt replies. I'll try it out and let you know if it