Always on top: Add transparent support for on topped window

[vanzue]

Summary of the Pull Request

Transparency support (best-effort)

Not every window can be made transparent. Transparency is applied on a best-effort basis and depends on how the target app/window is built and rendered.

When it may not work

• Windows with special rendering pipelines (e.g., certain hardware-accelerated / compositor-managed surfaces).
• Some tool/popup/owned windows where the foreground window isn’t the actual surface being drawn.

How it works (high-level)

• Resolve the best target window (preferring the top-level/root window over transient children).
• Apply Windows’ standard layered-window alpha mechanism (per-window opacity) to adjust transparency.
• When unpinned, Restore the original opacity/state when possible.

If transparency doesn’t change, it means the window doesn’t support this mechanism in its current configuration.

PR Checklist

• Closes:
  add window opacity to Always On Top #43278
  Always on top window transparency #42929
  Controle de opacidade #28773

• Communication: I've discussed this with core contributors already. If the work hasn't been agreed, this work might be rejected
• Tests: Added/updated and all pass
• Localization: All end-user-facing strings can be localized
• Dev docs: Added/updated
• New binaries: Added on the required places
  • JSON for signing for new binaries
  • WXS for installer for new binaries and localization folder
  • YML for CI pipeline for new test projects
  • YML for signed pipeline
• Documentation updated: If checked, please file a pull request on our docs repo and link it here: #xxx

Detailed Description of the Pull Request / Additional comments

Validation Steps Performed

always.on.top.transparency.support.for.window.mp4

[Copilot]

Pull request overview

This pull request adds transparency adjustment support to the Always on Top module, allowing users to dynamically adjust the opacity of pinned windows using keyboard shortcuts (modifier keys + '+' or '-'). The implementation includes shared transparency utilities in common/utils/window.h that are reused by both AlwaysOnTop and FancyZones modules.

Changes:

• Added transparency adjustment hotkeys (modifier + '+' for increase, modifier + '-' for decrease) with 20%-100% opacity range
• Created shared window transparency utilities in common/utils/window.h for applying and restoring transparency
• Refactored FancyZones (WindowDrag and WindowMouseSnap) to use the new shared transparency utilities
• Added UI documentation and sound effects for transparency adjustments

Reviewed changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated 13 comments.

Show a summary per file

File	Description
src/settings-ui/Settings.UI/Strings/en-us/Resources.resw	Updated activation shortcut description and added transparency adjustment documentation
src/settings-ui/Settings.UI/SettingsXAML/Views/AlwaysOnTopPage.xaml	Added transparency info card to settings UI
src/modules/alwaysontop/AlwaysOnTopModuleInterface/dllmain.cpp	Extended hotkey registration to support 3 hotkeys (pin, increase/decrease opacity) and added event handles
src/modules/alwaysontop/AlwaysOnTop/Sound.h	Added new sound types for opacity changes and removed unused member
src/modules/alwaysontop/AlwaysOnTop/SettingsConstants.h	Added trailing comma to enum (style change)
src/modules/alwaysontop/AlwaysOnTop/Settings.h	Added transparency range constants (min 20%, max 100%, step 10%)
src/modules/alwaysontop/AlwaysOnTop/AlwaysOnTop.h	Added transparency methods and window state tracking structures
src/modules/alwaysontop/AlwaysOnTop/AlwaysOnTop.cpp	Implemented transparency adjustment logic, window resolution, and state management
src/common/utils/window.h	Added shared transparency utilities (MakeWindowTransparent, RestoreWindowTransparency)
src/common/interop/shared_constants.h	Added event name constants for opacity increase/decrease events
src/modules/fancyzones/FancyZonesLib/WindowMouseSnap.h	Refactored to use WindowTransparencyProperties structure
src/modules/fancyzones/FancyZonesLib/WindowMouseSnap.cpp	Simplified to use shared transparency utilities
src/modules/fancyzones/FancyZonesLib/WindowDrag.h	Refactored to use WindowTransparencyProperties structure
src/modules/fancyzones/FancyZonesLib/WindowDrag.cpp	Simplified to use shared transparency utilities

[github-actions]

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