widgetkit🔗ℹ

3.1 status-bar%🔗ℹ

A compact bottom-of-window bar: a status message plus an optional determinate progress gauge. Core gui ships message% and gauge% but no combined status bar, so this is boilerplate every app rewrites. It subclasses horizontal-panel%, so extra children (e.g. a Cancel button) can be appended.

Constructor:

(new status-bar% [parent parent]

[initial-message ""]

[show-progress #f])

Methods: (send bar set-message text), (send bar set-progress percentage) (0–100, ignored if the bar has no gauge), (send bar get-message), (send bar clear).

(define bar (new status-bar% [parent f] [show-progress #t]

[initial-message "Ready."]))

(send bar set-message "Working...")

(send bar set-progress 75)

3.2 spinner%🔗ℹ

An indeterminate circular activity indicator. Core gui only ships the determinate gauge%; there is no “busy, unknown duration” control. spinner% draws a rotating arc on a canvas driven by a timer.

Constructor:

(new spinner% [parent parent]

[diameter 24] [color "dodgerblue"]

[track-color "lightgray"] [interval 60])

Methods: (send sp start), (send sp stop), (send sp spinning?).

(define sp (new spinner% [parent f] [diameter 36]))

(send sp start)

(send sp stop)

3.3 stepper%🔗ℹ

A compact [-] value [+]  numeric stepper. Core gui has slider% for picking from a range but no small +/- control for numeric tweaks.

Constructor:

(new stepper% [parent parent]

[min-value 0] [max-value 100] [step 1] [initial 0]

[callback (λ (self) (void))] [show-value #t])

Methods: (send st get-value), (send st set-value v), (send st increment), (send st decrement). Values are clamped to [min-value ,max-value] using the exported clamp helper.

(new stepper% [parent f] [min-value 0] [max-value 12] [initial 1]

[callback (λ (self) (printf "qty: ~a\n" (send self get-value)))])

3.4 disclosure%🔗ℹ

A collapsible section: a header button toggles the visibility of a content panel. Add the collapsible children to the panel returned by get-content.

(define d (new disclosure% [parent f] [label "Advanced options"] [expanded? #f]))

(new check-box% [parent (send d get-content)] [label "Verbose logging"])

Methods: (send d get-content), (send d is-expanded?), (send d set-expanded! bool).

3.5 image-view%🔗ℹ

A canvas that displays a bitmap%, centered and scaled to fit (or at a fixed numeric scale). core gui has canvas% but no ready-made widget to just show an image.

(new image-view% [parent f] [bitmap some-bitmap%] [scale 'fit])

(define iv (new image-view% [parent f]))

(send iv load-file "photo.png")

Methods: (send iv set-bitmap b), (send iv load-file path), (send iv get-bitmap).

3.6 progress-dialog%🔗ℹ

A modal dialog showing a message and a determinate gauge, with an optional Cancel button. Drive it from a worker thread while (send pd show #t) runs the modal event loop; update the UI via queue-callback and close with (send pd show #f). See "examples/progress-dialog-demo.rkt" for the full pattern.

(define pd (new progress-dialog% [parent f] [label "Working..."]))

(void (thread

(λ ()

... (queue-callback (λ () (send pd set-progress n))) ...

(queue-callback (λ () (send pd show #f))))))

(send pd show #t)

Methods: (send pd set-progress n), (send pd set-message s), (send pd cancelled?).

3.7 notification-banner%🔗ℹ

A transient, dismissible message strip (a “toast”/banner) with a severity (info/success/warning/error), pinned to the top of a window. It collapses when dismissed (click near its right edge) or after an auto-dismiss timeout. Use it instead of a modal message-box when you just want to flash a non-blocking result.

(define nb (new notification-banner% [parent f]))

(send nb show-message "Saved." 'success 3000)

(send nb show-message "Check input." 'warning #f)

Methods: (send nb show-message text severity auto-dismiss-ms) (pass #f for auto-dismiss-ms to keep it up), (send nb hide), (send nb current-message).

3.8 log-view%🔗ℹ

A scrolling, read-only, monospace log/console output that stretches to fill its parent, auto-scrolls to the newest line, accepts append-line while staying read-only, and trims old lines past max-lines. Building this from raw editor-canvas% + text% is where most people get stuck (the canvas does not stretch inside a pane%; auto-scroll and read-only-with-programmatic-appends both need care).

(define log (new log-view% [parent f] [max-lines 5000]))

(send log append-line "[boot] ready")

Methods: (send log append-line s), (send log clear), (send log get-text), (send log scroll-to-bottom).

3.9 split-view%🔗ℹ

Two panes separated by a draggable divider (Qt’s QSplitter / GTK’s GtkPaned). Add children to (send sv get-first) and (send sv get-second); the divider is mouse-draggable; set-fraction sets the first pane’s share in 0..1.

(new split-view% [parent f] [orientation 'horizontal] [fraction 0.4])

3.10 toolbar%🔗ℹ

A fixed-height row of action buttons with separators. Callbacks are no-argument thunks; add-button returns the created button% and add-separator the separator canvas. Any other widget can be added with [parent tb].

(send tb add-button "Open" (λ () ...))

(send tb add-separator)

3.11 search-field%🔗ℹ

A “Search…” box firing a one-argument (λ (query) ...) callback on every keystroke and on clear.

(new search-field% [parent f] [callback (λ (q) (filter-items q))])

3.12 stack%🔗ℹ

Shows one of several pages at a time (QStackedWidget). Pair it with a choice% or tab-panel% for working switched content; this sidesteps the tab-panel%-has-no-callback trap.

(define pages (new stack% [parent f]))

(define p0 (send pages add-page))

(send pages show-page 0)

4.1 Tooltips & cue text🔗ℹ

From the gui-widget-mixins package (Apache-2.0 OR MIT). Core gui has no tooltips and no placeholder text for text-field%.

(new (cue-mixin "" (tooltip-mixin text-field%))

[parent f] [label "Name:"]

[cue "Enter your name"]

[tooltip "Your full name"])

cue-mixin takes a default cue string and a base class; tooltip-mixin takes a base class. validate-mixin adds a validation callback. decorate-mixin / decorate-with compose several enhancements.

4.2 table-panel%🔗ℹ

From the table-panel package (LGPL-2.1). A panel that aligns its children to a grid — core gui has only horizontal/vertical panels.

(define g (new table-panel% [parent f] [dimensions '(4 2)]))

(for ([l '("Name:" "Value:" "Unit:" "Note:")])

(new message% [parent g] [label l])

(new text-field% [parent g] [label #f]))

4.3 canvas-list%🔗ℹ

From the canvas-list package (MIT). A fast, single-selection, virtualized list that renders only the visible rows and supports custom per-item drawing. Core list-box% cannot virtualize very large lists or custom-draw items.

(new canvas-list%

[parent f]

[items (for/vector ([i (in-range 1 2000)]) (format "Item ~a" i))]

[item-height 22]

[action-callback (λ (canvas item event) (printf "picked ~a\n" item))])

4.4 date-text-field%🔗ℹ

From the text-date package (MIT). A text-field% for entering dates (dd.mm.yyyy): shows today’s date as faded cue text when empty and filters input to digits and dots. Core gui has no date entry widget.

(new date-text-field% [parent f] [label "Date:"])

5.1 labeled-field%🔗ℹ

A text-field% with cue (placeholder) and tooltip already mixed in, so you do not have to remember that cue-mixin takes two arguments and must be composed with tooltip-mixin.

(new labeled-field% [parent f] [label "Name:"]

[cue "Enter your name"] [tooltip "Your full name"])

5.2 text-list%🔗ℹ

A canvas-list% for a list of items rendered as text, with a one-argument action callback instead of the underlying three-argument one.

(new text-list% [parent f]

[items (vector "a" "b" "c")]

[action (λ (item) (printf "picked ~a\n" item))])