Resizing window causes black strips

Question

I have a form, which sets these styles in constructor:

this.SetStyle(ControlStyles.AllPaintingInWmPaint, true);
this.SetStyle(ControlStyles.UserPaint, true);         


        

Answer 1

I've found the function which can paint and resize window at the same time - UpdateLayeredWindow.

So now it should be possible to create resizable windows, which do not have any strips while being resized. However, you need to paint the window content yourself, so it is a little inconvenient. But I think that using WPF and UpdateLayeredWindow, there shouldn't be any problem.

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Update

Found problems. :-) When using UpdateLayeredWindow, you must paint the window's border yourself. So, if you want standard window painted using UpdateLayeredWindow with nice glass effect in win7, you are screwed.

On Microsft Connect is even a thread about this problem, where Microsoft says it is a bug by design, and if it ever gets fixed, then probably in Win8 or some newer system. So there isn't much we could do about this.

Answer 2

I found that it is best not to do any custom rendering directly on the Form surface. Instead, put a docked PictureBox on the form, create Bitmap object that will be displayed in the PictureBox, draw everything onto that using the System.Drawing.Graphics.FromImage(Image) method.

I used that method with a game loop to make a simple shooter game (Crimsonland-style) and got pretty good performance (with anti-aliased lines), above 100 FPS.