Drawing

[makaveliuk]

Hi,

I am new to drawing in C++ and have written an app with a processing screen which updates a status line quite rapidly, and when I run it it flickers a lot.

On another screen I have a progress bar drawn in code which also flickers quite badly.

I am refreshing the window by using the Invalidate() function and drawing the window in the Paint() event.

Is there a way to just refresh the small part of the window that changes? Or stop it flickering?

Thanks in advance,
Dan.

 

[Cagliostro]

1. If you whish to reduce fliker then you should paint at the first on a bitmap and after that to transfer the bit block on the window.
2. If you wish do draw something you should not invalidate any rect, just get the window DC and use drawing functions.
3. If you whish to refresh a small part of a window you whould use InvalidateRect(..SmallRect..) where instead of SmallRect you will specify that small window area. In this case this rect will be updated when window will receive WM_PAINT. To force receiving of that message you should sent the message WM_PAINT or to call UpdateWindow

Ion Filipski

 

[makaveliuk]

Thanks for the reply, I have just worked out how to create a DC in memory and double buffer the drawing functions as you mentioned and it draws perfectly with no flickering!

Cheers!