14 GUI Utilities

(require framework/gui-utils)

(gui-utils:trim-string str size)

→   (and/c string?        (λ (str)          ((string-length str) . <= . size)))

str : string?

size : (and/c number? positive?)

Constructs a string whose size is less than size by trimming the str and inserting an ellispses into it.

(gui-utils:quote-literal-label str)

→   (and/c string?        (lambda (str)          ((string-length str) . <= . 200)))

str : string?

Constructs a string whose ampersand characters are escaped; the label is also trimmed to <= 200 characters.

(gui-utils:format-literal-label   str       rest ...)

→   (and/c string?        (lambda (str)          ((string-length str) . <= . 200)))

str : string?

rest : (listof any/c)

Formats a string whose ampersand characters are escaped; the label is also trimmed to <= 200 characters.

(gui-utils:cancel-on-right?) → boolean?

Returns #t if cancel should be on the right-hand side (or below) in a dialog and #f otherwise.

See also gui-utils:ok/cancel-buttons.

(gui-utils:ok/cancel-buttons   parent       confirm-callback       cancel-callback      [ confirm-label       cancel-label])

→   (is-a?/c button%)   (is-a?/c button%)

parent : (is-a?/c area-container<%>)

confirm-callback : ((is-a?/c button%) (is-a?/c event%) . -> . any)

cancel-callback : ((is-a?/c button%) (is-a?/c event%) . -> . any)

confirm-label : string? = (string-constant ok)

cancel-label : string? = (string-constant cancel)

Adds an Ok and a cancel button to a panel, changing the order to suit the platform. Under Mac OS X and unix, the confirmation action is on the right (or bottom) and under Windows, the canceling action is on the right (or bottom). The confirmation action button has the '(border) style. The buttons are also sized to be the same width.

The first result is be the OK button and the second is the cancel button.

See also gui-utils:cancel-on-right?.

(gui-utils:next-untitled-name) → string?

Returns a name for the next opened untitled frame. The first name is “Untitled”, the second is “Untitled 2”, the third is “Untitled 3”, and so forth.

(gui-utils:cursor-delay) → real?

(gui-utils:cursor-delay new-delay) → void?

new-delay : real?

This function is not a parameter. Instead, the state is just stored in the closure.

The first case in the case lambda returns the current delay in seconds before a watch cursor is shown, when either gui-utils:local-busy-cursor or gui-utils:show-busy-cursor is called.

The second case in the case lambda Sets the delay, in seconds, before a watch cursor is shown, when either gui-utils:local-busy-cursor or gui-utils:show-busy-cursor is called.

(gui-utils:show-busy-cursor thunk [delay]) → any/c

thunk : (-> any/c)

delay : integer? = (gui-utils:cursor-delay)

Evaluates (thunk) with a watch cursor. The argument delay specifies the amount of time before the watch cursor is opened. Use gui-utils:cursor-delay to set this value to all calls.

This function returns the result of thunk.

(gui-utils:delay-action   delay-time             open             close)   →   void?

delay-time : real?

open : (-> void?)

close : (-> void?)

Use this function to delay an action for some period of time. It also supports cancelling the action before the time period elapses. For example, if you want to display a watch cursor, but you only want it to appear after 2 seconds and the action may or may not take more than two seconds, use this pattern:

(let ((close-down

(gui-utils:delay-action

2

(λ () .. init watch cursor ...)

(λ () .. close watch cursor ...))))

(close-down))

Creates a thread that waits delay-time. After delay-time has elapsed, if the result thunk has not been called, call open. Then, when the result thunk is called, call close. The function close will only be called if open has been called.

(gui-utils:local-busy-cursor   window             thunk            [ delay])   →   any/c

window : (is-a?/c window<%>)

thunk : (-> any/c)

delay : integer? = (gui-utils:cursor-delay)

Evaluates (thunk) with a watch cursor in window. If window is #f, the watch cursor is turned on globally. The argument delay specifies the amount of time before the watch cursor is opened. Use gui-utils:cursor-delay to set this value for all uses of this function.

The result of this function is the result of thunk.

(gui-utils:unsaved-warning   filename       action      [ can-save-now?       parent])

→ (symbols 'continue 'save 'cancel)

filename : string?

action : string?

can-save-now? : boolean? = #f

parent   :   (or/c false/c       (is-a?/c frame%)       (is-a?/c dialog%))   =   #f

This displays a dialog that warns the user of a unsaved file.

The string, action, indicates what action is about to take place, without saving. For example, if the application is about to close a file, a good action is "Close" "Anyway". The result symbol indicates the user’s choice. If can-save-now? is #f, this function does not give the user the “Save” option and thus will not return 'save.

(gui-utils:get-choice   message             true-choice             false-choice            [ title             default-result             parent             style             checkbox-proc             checkbox-label])   →   any/c

message : string?

true-choice : string?

false-choice : string?

title : string? = (string-constant warning)

default-result : any/c = 'disallow-close

parent   :   (or/c false/c (is-a?/c frame%) (is-a?/c dialog%))       =   #f

style : (symbols 'app 'caution 'stop) = 'app

checkbox-proc   :   (or/c false/c (case-> (boolean? . -> . void?)                       (-> boolean?)))       =   #f

checkbox-label : string? = (string-constant dont-ask-again)

Opens a dialog that presents a binary choice to the user. The user is forced to choose between these two options, ie cancelling or closing the dialog opens a message box asking the user to actually choose one of the two options.

The dialog will contain the string message and two buttons, labeled with the true-choice and the false-choice. If the user clicks on true-choice #t is returned. If the user clicks on false-choice, #f is returned.

The argument default-result determines how closing the window is treated. If the argument is 'disallow-close, closing the window is not allowed. If it is anything else, that value is returned when the user closes the window.

If gui-utils:cancel-on-right? returns #t, the false choice is on the right. Otherwise, the true choice is on the right.

The style parameter is (eventually) passed to message as an icon in the dialog.

If checkbox-proc is given, it should be a procedure that behaves like a parameter for getting/setting a boolean value. The intention for this value is that it can be used to disable the dialog. When it is given, a checkbox will appear with a checkbox-label label (defaults to the dont-ask-again string constant), and that checkbox value will be sent to the checkbox-proc when the dialog is closed. Note that the dialog will always pop-up – it is the caller’s responsibility to avoid the dialog if not needed.

(gui-utils:get-clicked-clickback-delta [white-on-black?])

→ (is-a?/c style-delta%)

white-on-black? : boolean? = #f

This delta is designed for use with set-clickback. Use it as one of the style-delta% argument to set-clickback.

If white-on-black? is true, the function returns a delta suitable for use on a black background.

See also gui-utils:get-clickback-delta.

(gui-utils:get-clickback-delta [white-on-black?])

→ (is-a?/c style-delta%)

white-on-black? : boolean? = #f

This delta is designed for use with set-clickback. Use the result of this function as the style for the region text where the clickback is set.

If white-on-black? is true, the function returns a delta suitable for use on a black background.

See also gui-utils:get-clicked-clickback-delta.