gpui: Use DWM API for backdrop effects and add Mica/Mica Alt support (#41842)

This PR updates window background rendering to use the **official DWM
backdrop API** (`DwmSetWindowAttribute`) instead of the legacy
`SetWindowCompositionAttribute`.
It also adds **Mica** and **Mica Alt** options to
`WindowBackgroundAppearance` for native Windows 11 effects.

### Motivation

Enables modern, stable, and GPU-accelerated backdrops consistent with
Windows 11’s Fluent Design.
Removes reliance on undocumented APIs while maintaining backward
compatibility with older Windows versions.

### Changes

* Added `MicaBackdrop` and `MicaAltBackdrop` variants.
* Switched to DWM API for applying backdrop effects.
* Verified fallback behavior on Windows 10.

### Release Notes:

- Added `WindowBackgroundAppearance::MicaBackdrop` and
`WindowBackgroundAppearance::MicaAltBackdrop` for Windows 11 Mica and
Mica Alt window backdrops.

### Screenshots

- `WindowBackgroundAppearance::Blurred`
<img width="553" height="354" alt="image"
src="https://github.com/user-attachments/assets/57c9c25d-9412-4141-94b5-00000cc0b1ec"
/>

- `WindowBackgroundAppearance::MicaBackdrop`
<img width="553" height="354" alt="image"
src="https://github.com/user-attachments/assets/019f541c-3335-4c9e-b026-71f5a1786534"
/>

- `WindowBackgroundAppearance::MicaAltBackdrop`
<img width="553" height="354" alt="image"
src="https://github.com/user-attachments/assets/5128d600-c94d-4c89-b81a-8b842fe1337a"
/>

---------

Co-authored-by: John Tur <john-tur@outlook.com>

This commit is contained in:

Barani S

2025-11-18 18:20:32 -05:00

committed by

GitHub

co-authored by

John Tur

parent 951132fc13

commit 917148c5ce

2 changed files with 40 additions and 4 deletions

									
										crates/gpui/src/platform.rs
									
		+4
		
												View File
												
				@@ -1389,6 +1389,10 @@ pub enum WindowBackgroundAppearance {

				    ///

				    /// Not always supported.

				    Blurred,

				    /// The Mica backdrop material, supported on Windows 11.

				    MicaBackdrop,

				    /// The Mica Alt backdrop material, supported on Windows 11.

				    MicaAltBackdrop,

				}

				/// The options that can be configured for a file dialog prompt