# racket-tray

A small system tray API for Racket.

Version 0.1.1 implements Windows directly through the Win32 API. It uses the
native `HWND` of an existing Racket `frame%` or `dialog%`, `Shell_NotifyIconW`,
and `SetWindowSubclass`. No additional native DLL is required.

```racket
#lang racket/gui

(require racket-tray)

(define tray-frame%
  (class frame%
    (super-new [label "Tray example"]
               [width 400]
               [height 250])

    ;; Close [X] to the tray instead of destroying the frame.
    (define/override (on-close)
      (send this show #f))))

(define frame (new tray-frame%))

(define (show-frame)
  (send frame show #t)
  (when (send frame is-iconized?)
    (send frame iconize #f)))

(define tray
  (mk-tray frame
           "example.png"
           show-frame
           #:hide-on-minimize? #t))

(tray-set-menu!
 tray
 (list
  (list "Open" show-frame)
  'separator
  (list "Exit"
        (λ ()
          (tray-close tray)
          (exit)))))

(send frame show #t)
```

`mk-tray` and `tray-set-icon!` accept both Windows `.ico` files and `.png`
files. PNG transparency is preserved when the image is converted to a native
Windows tray icon.

With `#:hide-on-minimize? #t`, minimizing the associated window hides it from
the taskbar while keeping its native window handle alive. Closing a window to
the tray does not need a separate tray API: override `frame%`'s `on-close` and
call `(send this show #f)`.

`tray-set-menu!` accepts a `popup-menu%` object directly, a simple menu list,
or `#f` to remove the context menu.

At the moment non-Windows platforms report that the operation is unsupported.