What is the best way to do a flicker-free animated C# custom control?

Question

Hello community,

I am currently creating a custom control that needs to handle animation in a C# project. It is basically a listbox that contains a fixed number of elements that are subject to move. An element (another user control with a background image and a couple of generated labels) can move upwards, downwards or be taken out of the list.

I would like to create animated movement as the elements get moved around within the container custom control but it seems to me that moving controls around using lines such as

myCustomControl.left -= m_iSpeed;

triggered within a timer event is flickery and has a terrible rendering, even with double buffering turned on.

So here's the question : What is the best way to achieve a flicker-free animated C# control? Should I just not create custom controls and handle all of the drawing within a panel's background image that I generate? Is there a super animation method that I have not discovered? :)

Thanks!

Answer 1

A similar discussion took place this morning on this question. visual c# form update results in flickering. so I will be lazy and give the same answer I gave there:

You could try to call this.SuspendLayout(); before you start your move and this.ResumeLayout(false); when you have finished moving all of the controls. In this way all controls should draw at once and you should have less of a flicker.

On a side note I have tried to reproduce this here at work, but seem to be failing. Can you give some more sample code that I can fix maybe?

Answer 2

The normal way to get flicker-free animation is to implement double-buffering. Take a look at this Code Project article

http://www.codeproject.com/KB/GDI-plus/flickerFreeDrawing.aspx

Minimizing calls to paint until you are ready is also a good idea.

Answer 3

your best bet for flicker-free animation is to do the painting yourself (use the Graphics object in the Paint event handler) and use double-buffering. In your custom control you will need code like this in the constructor:

this.SetStyle(ControlStyles.UserPaint | ControlStyles.OptimizedDoubleBuffer | 
    ControlStyles.AllPaintingInWmPaint | ControlStyles.SupportsTransparentBackColor,
    true);

Answer 4

I am using double buffering.. Having the same problem. It would appear as though dumping the buffer at once is still haphazardly done with respect to vertical refresh.

I know there is a better method, becuase my own controls set next to Microsoft Out of the Box controls which do not flicker...

Is there no way to Suspend the Vertical Refresh while rendering the double buffer? Is there a way to delay the buffer copy until a retrace occurs?

It would seem that we lost valuable knowledge of the last 20 years of computing...

Dan -

Answer 5

See How to double buffer .NET controls on a form.