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Rust · Win32/GDI · Tray daemon

isolmaSS

A screenshot and annotation utility built in Rust with direct Win32/GDI access, running as a background tray daemon.

  • Windows
  • Rust
  • Utility
Role
Design and build
Platform
Windows · tray daemon
Flow
PrintScreen → drag → annotate in place → copy or save
Budget
≤2.5 MiB executable · ≤3 MiB installer

What it does

Pressing PrintScreen freezes the screen, you drag a selection, and annotation happens directly on the frozen screen; the result is copied or saved.

Window snap: a plain click inside a window selects it by Z-order and DWMWA_EXTENDED_FRAME_BOUNDS, leaving out cloaked modern apps, utility tool windows and the desktop shell.

Highlights

01

Triple-trigger hotkey

RegisterHotKey, a WH_KEYBOARD_LL hook and a state poll work together, so PrintScreen keeps working even when Windows silently drops low-level hooks.

02

In-place annotation

Move, pen, line, arrow, rectangle, marker, text, blur and eraser, with undo/redo and a 20-colour palette. The native build keeps rectangle, arrow, pen, text and blur/mosaic with a 50-command undo stack.

03

Output

Ctrl+C flattens the screenshot and annotations into a 32-bit CF_DIB on the clipboard; the native build saves PNG or JPEG through GDI+.

04

Quiet operation

A tray menu with Capture Now, Settings, Check for Updates and the last five captures; a left click captures instantly.

Technology

  • Rust
  • Win32/GDI
  • windows-rs
  • Tauri v2
  • WebView2
  • React

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