racket/collects/scribblings/gui/system-menu-funcs.scrbl
Matthew Flatt 2bdcdbb197 racket/draw, racket/gui: modernize contracts, mostly in documentation
Use `or/c' instead of `one-of/c', `#f' instead of `false/c'.
2012-04-06 18:51:10 -06:00

156 lines
6.2 KiB
Racket

#lang scribble/doc
@(require "common.rkt")
@title{System Menus}
@defproc[(current-eventspace-has-standard-menus?)
boolean?]{
Returns @racket[#t] for Mac OS X when the current eventspace is the
initial one, since that eventspace is the target for the standard
application menus. For any other system or eventspace, the result is
@racket[#f].
This procedure is intended for use in deciding whether to include a
@onscreen{Quit}, @onscreen{About}, and @onscreen{Preferences} menu
item in a frame's menu. On Mac OS X, the application
@onscreen{Quit} menu triggers a call to a frame's
@method[top-level-window<%> on-exit] method, the @onscreen{About} menu item is controlled by
@racket[application-about-handler], and the
@onscreen{Preferences} menu item is controlled by
@racket[application-preferences-handler].
}
@defproc[(current-eventspace-has-menu-root?)
boolean?]{
Returns @racket[#t] for Mac OS X when the current eventspace is the
initial one, since that eventspace can supply a menu bar to be active
when no frame is visible. For any other system or eventspace, the
result is @racket[#f].
This procedure is intended for use in deciding whether to create a
@racket[menu-bar%] instance with @racket['root] as its parent.
}
@defproc*[([(application-about-handler)
(-> any)]
[(application-about-handler [handler-thunk (-> any)])
void?])]{
When the current eventspace is the initial eventspace, this
procedure retrieves or installs a thunk that is called when the
user selects the application @onscreen{About} menu item on Mac OS
X. The thunk is always called in the initial eventspace's
handler thread (as a callback).
The default handler displays a generic Racket dialog.
If the current eventspace is not the initial eventspace, this
procedure returns @racket[void] (when called with zero arguments)
or has no effect (when called with a handler).
}
@defproc*[([(application-file-handler)
(path? . -> . any)]
[(application-file-handler [handler-proc (path? . -> . any)])
void?])]{
When the current eventspace is the initial eventspace, this procedure
retrieves or installs a procedure that is called on Mac OS X
and Windows when the application is running and user double-clicks an
application-handled file or drags a file onto the application's
icon. The procedure is always called in the initial eventspace's
handler thread (as a callback), and the argument is a filename.
The default handler queues a callback to the
@method[window<%> on-drop-file] method of the most-recently activated frame in the main eventspace (see
@racket[get-top-level-edit-target-window]), if
drag-and-drop is enabled for that frame. Otherwise, it saves
the filename and re-queues the handler event when the application
file handler is later changed.
On Windows, when the application is @italic{not} running and user double-clicks an
application-handled file or drags a file onto the application's icon,
the filename is provided as a command-line argument to the
application.
On Mac OS X, if an application is started @emph{without} files, then
the @racket[application-start-empty-handler] procedure is called.
If the current eventspace is not the initial eventspace, this
procedure returns @racket[void] (when called with zero arguments)
or has no effect (when called with a handler).
}
@defproc*[([(application-preferences-handler)
(or/c (-> any) #f)]
[(application-preferences-handler [handler-thunk (or/c (-> any) #f)])
void?])]{
When the current eventspace is the initial eventspace, this procedure
retrieves or installs a thunk that is called when the user selects
the application @onscreen{Preferences} menu item on Mac OS X. The
thunk is always called in the initial eventspace's handler thread (as
a callback). If the handler is set to @racket[#f], the
@onscreen{Preferences} item is disabled.
The default handler is @racket[#f].
If the current eventspace is not the initial eventspace, this
procedure returns @racket[void] (when called with zero arguments)
or has no effect (when called with a handler).
}
@defproc*[([(application-quit-handler)
(-> any)]
[(application-quit-handler [handler-thunk (-> any)])
void?])]{
When the current eventspace is the initial eventspace, this procedure
retrieves or installs a thunk that is called when the user requests
that the application quit (e.g., through the @onscreen{Quit} menu
item on Mac OS X, or when shutting down the machine in Windows). The
thunk is always called in the initial eventspace's handler thread (as
a callback). If the result of the thunk is @racket[#f], then the
operating system is explicitly notified that the application does not
intend to quit (on Windows).
The default handler queues a call to the
@method[top-level-window<%> can-exit?] method of the most
recently active frame in the initial eventspace (and then calls the
frame's @method[top-level-window<%> on-exit] method if the
result is true). The result is @racket[#t] if the eventspace is
left with no open frames after
@method[top-level-window<%> on-exit] returns, @racket[#f]
otherwise.
If the current eventspace is not the initial eventspace, this
procedure returns @racket[void] (when called with zero arguments)
or has no effect (when called with a handler).
}
@defproc*[([(application-start-empty-handler)
(-> any)]
[(application-start-empty-handler [handler-thunk (-> any)])
void?])]{
When the current eventspace is the initial eventspace, this procedure
retrieves or installs a thunk that is called when the user starts
the application on Mac OS X without supplying any initial files (e.g.,
by double-clicking the application icon instead of double-clicking
files that are handled by the application).
The default handler re-queues the handler event when the application
start-empty handler is later changed. As a result, if an application
sets both @racket[application-start-empty-handler] and
@racket[application-file-handler], then one or the other is
eventually called.
If the current eventspace is not the initial eventspace, this
procedure returns @racket[void] (when called with zero arguments)
or has no effect (when called with a handler).
}