Avoid flicker

[Member 2965471]

Hi all, I've a transparent topmost window, I need on mouse move to highlight the window under the cursor I tried so in mouse_move_handler:

...
this.Hide();
hWnd = Win32.WindowFromPoint(p);
this.Show();
...
Win32.GetWindowRect(hWnd, ref rc);
and so on drawing rectangle
...

this code works, but I can't avoid flicker. There is some alternative way to do this?

[Pete OHanlon]

I'm not surprised you've got flickering. You keep showing and hiding a window in there, and it looks as though you are calling this on every mouse move - that's a lot of event updates you're calling this code in. You also haven't shown the code where you're highlighting, this will also be called a lot of times. What is the purpose of the Hide/Show code? What are you changing the visibility of? Are you tracking to see if the window that was last updated matches the one retrieved in WindowFromPoint? If not, that's an obvious optimisation.

Forgive your enemies - it messes with their heads

"Mind bleach! Send me mind bleach!" - Nagy Vilmos

My blog | My articles | MoXAML PowerToys | Mole 2010 - debugging made easier - my favourite utility

[Member 2965471]

The main problem is to get the hwnd of the window immediately under my wpf topmost Window.

[Pete OHanlon]

To be honest, I'm not sure why you're dropping down to GDI to achieve this. There are ways to get the positions of windows that do not rely on dropping down to interop to retrieve these items. You can use the Visual tree and perform your calculations based off that.

Forgive your enemies - it messes with their heads

"Mind bleach! Send me mind bleach!" - Nagy Vilmos

My blog | My articles | MoXAML PowerToys | Mole 2010 - debugging made easier - my favourite utility

[Member 2965471]

because with visual tree I can handle only the windows that own to my application, but under the mouse cursor there may be a window of any application running on desktop.

[Pete OHanlon]

Ah, I see. So you're evaluating ALL windows then. Well, you're going to have to optimise your hit tests then I'm afraid.

Forgive your enemies - it messes with their heads

"Mind bleach! Send me mind bleach!" - Nagy Vilmos

My blog | My articles | MoXAML PowerToys | Mole 2010 - debugging made easier - my favourite utility

[Member 2965471]

I don't know how perform hit test without hiding my window...

[Pete OHanlon]

Probably the easiest way to code this is to enumerate all the windows using EnumDesktopWindows[^]. You can use this to iterate over and do your point in rectangle tests. That way, you aren't relying on showing/hiding windows.

Forgive your enemies - it messes with their heads

"Mind bleach! Send me mind bleach!" - Nagy Vilmos

My blog | My articles | MoXAML PowerToys | Mole 2010 - debugging made easier - my favourite utility

[Member 2965471]

I use EnumWindows, the problem is that more than one windows pass the check(point in rect). How can I determine the right window on which lies the mouse?

[SledgeHammer01]

I would guess the top most window (not counting your own).