Maybe a bug rep, and plz give me some suggestions for my project, thanks

[wangsongpower]

I am using Avalonia 12.0.3+Net10, I want to achieve a style:

• no titlebar
• all area have titlebar function (drag, right click menu)
• background with mica/AcrylicBlur/etc, or I draw a solid color with gradient animation

Now I knew, there is a bug fixed but not release yet. When ExtendClientAreaToDecorationsHint sets to true, TransparencyLevelHint will not work.

I tried to set ExtendClientAreaTitleBarHeightHint to 100 (finally set to full window), then I found the system buttons right top side go verticalalignment center. So is this on purpose or bug? Or I can set by myself?

And maybe another bug, when pressing system button and move cursor out of window, the IsPressed keeps even though move back to window.

My opinion is that:

• ExtendClientAreaTitleBarHeightHint=0, ExtendClientAreaToDecorationsHint=true
• set a rootGrid, and put window contents, my overlays (mask) in it
• WindowDecorationProperties.SetElementRole of rootGrid to titlebar when window state is not fullscreen, set to none when it is full screen

Btw, how to hide the fullscreen button next system buttons?

Is any better idea? Thanks a lot

[torum]

no titlebar
background with mica/AcrylicBlur/etc
Now I knew, there is a bug fixed but not release yet. When ExtendClientAreaToDecorationsHint sets to true, TransparencyLevelHint will not work.

You can take a look at the comment I posted a few weeks ago.
#21170 (comment)
and sample project Example.zip.

all area have titlebar function (drag, right click menu)

Drag

    private void Window_PointerPressed(object? sender, PointerPressedEventArgs e)
    {
        if (e.GetCurrentPoint(this).Properties.IsLeftButtonPressed)
        {
            if (this.WindowState == WindowState.Normal)
            {
                // Call BeginMoveDrag to enable window dragging
                BeginMoveDrag(e);
            }
        }
    }

Use MenuFlyout for right click menu.

Btw, how to hide the fullscreen button next system buttons?

You can use WindowDrawnDecorations.xaml to customize it. (See the sample project above to see how)
<Button x:Name="PART_FullScreenButton" IsVisible="False" ..

[wangsongpower]

@torum Really thanks for the example project.
One more question, is this a temporary solution before the new release? Or just an example shows how to custom?
As for the "maybe bug", I should customize it by myself, right?
That "IsPressed keeping", I think it is a bug.

[torum]

is this a temporary solution before the new release?

If you want to hide the fullscreen button, you keep it, otherwise it is temp until the fix is released.

As for the "maybe bug", I should customize it by myself, right?

I'm not sure what "maybe bug" is...

You don't need to change the value of ExtendClientAreaTitleBarHeightHint at all.

[torum]

all area have titlebar function (drag, right click menu)

Did you mean "the system window menu (aka the Control Menu)" by "right click menu"?

In that case,

// KeyUp.                    
if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
{
	if (GetTopLevel(this)?.TryGetPlatformHandle() is not { } handle) return;
	NativeMethods.ShowSystemWindowMenu(handle.Handle);
}

 // Helper method to show the system window menu (aka the Control Menu) for a given window handle
public static partial class NativeMethods
{
    private const int WM_SYSCOMMAND = 0x0112;
    private const int SC_KEYMENU = 0xF100;

    [LibraryImport("user32.dll", EntryPoint = "DefWindowProcW")]
    private static partial IntPtr DefWindowProc(IntPtr hWnd, uint msg, IntPtr wParam, IntPtr lParam);

    public static void ShowSystemWindowMenu(IntPtr hWnd)
    {
        DefWindowProc(hWnd, WM_SYSCOMMAND, (IntPtr)SC_KEYMENU, (IntPtr)32);
    }
}

[wangsongpower]

@torum Really appreciate, thanks

[torum]

The code above is for the Alt+Space to show the system window menu. If you want to show the same menu by right click, you need another code.

Something like,

        [DllImport("user32.dll", SetLastError = true)]
        private static extern IntPtr GetSystemMenu(IntPtr hWnd, bool bRevert);

        [DllImport("user32.dll", SetLastError = true)]
        private static extern int TrackPopupMenu(IntPtr hMenu, uint uFlags, int x, int y, int nReserved, IntPtr hWnd, IntPtr prcRect);

        [DllImport("user32.dll", SetLastError = true)]
        private static extern bool PostMessage(IntPtr hWnd, uint Msg, IntPtr wParam, IntPtr lParam);

        private const uint TPM_RETURNCMD = 0x0100;
        private const uint WM_SYSCOMMAND = 0x0112;

        private void Window_PointerReleased(object? sender, Avalonia.Input.PointerReleasedEventArgs e)
        {
            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
            {
               ShowNativeSystemMenu(e);
               e.Handled = true;
            }
        }

        private void ShowNativeSystemMenu(PointerReleasedEventArgs e)
        {
            // 1. Obtain the raw Win32 HWND handle safely from Avalonia
            var platformHandle = this.TryGetPlatformHandle();
            if (platformHandle == null) return;
            IntPtr hwnd = platformHandle.Handle;

            // 2. Convert the Avalonia pointer position to global Screen Coordinates
            var screenPoint = this.PointToScreen(e.GetPosition(this));

            // 3. Fetch the window's live System Menu handle
            IntPtr sysMenu = GetSystemMenu(hwnd, false);
            if (sysMenu != IntPtr.Zero)
            {
                // 4. Display the native menu at the cursor context.
                // TPM_RETURNCMD forces TrackPopupMenu to return the ID of the clicked menu item.
                int command = TrackPopupMenu(sysMenu, TPM_RETURNCMD, screenPoint.X, screenPoint.Y, 0, hwnd, IntPtr.Zero);

                if (command > 0)
                {
                    // 5. Post the selected command back to the window loop so Windows handles it (Minimize, Maximize, Close, Move, etc.)
                    PostMessage(hwnd, WM_SYSCOMMAND, (IntPtr)command, IntPtr.Zero);
                }

                e.Handled = true;
            }
        }

[torum]

I tried to set ExtendClientAreaTitleBarHeightHint to 100 (finally set to full window)

Turns out,

<Window xmlns="https://github.com/avaloniaui"
...
  WindowDecorationProperties.ElementRole="TitleBar">

Works

[torum]

I think I got what you want.

no titlebar

Use ExtendClientAreaToDecorationsHint="True"

all area have titlebar function (drag, right click menu)

Use BeginMoveDrag for drag the window and call Win32Api for the system window menu (aka the Control Menu) in the code behind (Window_PointerPressed).

I tried to set ExtendClientAreaTitleBarHeightHint to 100 (finally set to full window)

I wouldn't recommend that route because it might have unexpected side effects especially on other platforms like linux and mac.

background with mica/AcrylicBlur/etc, or I draw a solid color with gradient animation
Now I knew, there is a bug fixed but not release yet. When ExtendClientAreaToDecorationsHint sets to true, TransparencyLevelHint will not work.

Customize the template for temp fix.

Btw, how to hide the fullscreen button next system buttons?

Customize the template.

Sample project file.
WindowFullTitlebar.zip

Note: For some reason, the close menu in the system window menu is disabled. Fixed.

[wangsongpower]

Really appreciate! I works perfect.
Sry, I have another questions.
1, if I set ExtendClientAreaToDecorationsHint = true, then the shadow around frame are gone. How can I fix it?
2, If I want to remove all the system buttons right top side (for messagebox), for example,
Styles.Add(new Style(x => x .OfType<Avalonia.Controls.Chrome.WindowDrawnDecorations>() .Template() .OfType<Panel>().Name("PART_OverlayWrapper")) { Setters = { new Setter(IsVisibleProperty, VisibleCaptionButtons) } });
Buttons are disappeared, but why that area cant be drag move?
Thanks

[wangsongpower]

So, if set ExtendClientAreaToDecorationsHint = true, it means, windows/macos original style are gone. Instead, for example, window no border and apply the WindowDrawnDecorations? All the original style (animation, shadow and so on) are done by avalonia?

[wangsongpower]

I tested, ExtendClientAreaToDecorationsHint = true

• win11, whatever TransparencyLevelHint set, shadow and round corner appear
• win10, whatever TransparencyLevelHint set, shadow not appear

[torum]

win10, whatever TransparencyLevelHint set, shadow not appear

I can't repro it since I don't have Win10s anymore, but the fix may be coming. #21412