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fossui.dart

fossui library

fossui: an open-source Flutter UI library.

A single import for the theme system and widgets. Native Flutter theming, golden-tested components.

Classes

FossAlert Feedback
FossAlertDialog Overlays
FossAlertDialogStyle: Visual overrides for a single FossAlertDialog. An alert style is a FossDialogStyle: it carries the same fields and the alert composes a FossDialog, so it passes its style straight through. Every field is optional; a null field falls back to the value the theme resolves. Pass one via style: to tweak a one-off without changing the theme.
FossAlertStyle: Visual overrides for a single FossAlert. Every field is optional; a null field falls back to the value the variant and theme resolve. Pass one via style: to tweak a one-off without changing the theme.
FossAutocomplete Inputs
FossAvatar Layout
FossAvatarStyle: Visual overrides for a single FossAvatar. Every field is optional; a null field falls back to the value the theme resolves. Pass one via style: to tweak a one-off without changing the theme for every other avatar.
FossBadge Feedback
FossBadgeStyle: Visual overrides for a single FossBadge. Every field is optional; a null field falls back to the value the variant and theme resolve. Pass one via style: to tweak a one-off without changing the theme.
FossButton Inputs
FossButtonController: Drives a FossButton imperatively, so loading and disabled can be toggled without rebuilding the button from new parameters. Pass one to a button's controller; you own it and must dispose it.
FossButtonStyle: Visual overrides for a FossButton. Every field is optional; a null field falls back to the value the theme resolves for the button's variant and size. Pass one to a single button via style: to tweak a one-off, without changing the theme for every other button.
FossCard Layout
FossCardStyle: Visual overrides for a single FossCard. Every field is optional; a null field falls back to the value the theme resolves. Pass one via style: to tweak a one-off without changing the theme for every other card.
FossCheckbox Inputs
FossCheckboxGroup<T> Inputs: Lays out a set of FossCheckboxItem options as a multi-select group.
FossCheckboxItem<T>: A single option within a FossCheckboxGroup.
FossCheckboxStyle: Visual overrides for a single checkbox. Every field is optional; a null field falls back to the value the theme resolves. Pass one via style: to tweak a one-off without changing the theme for every other checkbox.
FossColors: Semantic color roles, one field per role. light and dark are baked constant sets; every blend and translucent overlay is resolved to a fixed sRGB color, so no color math runs at runtime.
FossCombobox<T> Inputs
FossComboboxItem<T>: One option in a FossCombobox.
FossComboboxStyle: Visual overrides for a FossAutocomplete or FossCombobox. Every field is optional; a null field falls back to the theme-resolved value.
FossDialog Overlays
FossDialogStyle: Visual overrides for a single FossDialog. Every field is optional; a null field falls back to the value the theme resolves. Pass one via style: to tweak a one-off without changing the theme for every other dialog.
FossDrawer Overlays
FossDrawerStyle: Visual overrides for a single FossDrawer. Every field is optional; a null field falls back to the value the theme resolves. Pass one via style: to tweak a one-off without changing the theme for every other drawer.
FossMotion: Animation durations. Gate any token-driven animation on MediaQuery.disableAnimations so reduced-motion users get no motion.
FossMultiCombobox<T> Inputs
FossMultiSelect<T> Inputs: A pick-several-from-list control with no typing.
FossProgress Feedback
FossProgressStyle: Visual overrides for a single FossProgress. Every field is optional; a null field falls back to the value the theme resolves. Pass one via style: to tweak a one-off without changing the theme for every other bar.
FossRadii: Corner radii in logical pixels. standard is the default scale; full is a pill sentinel, clamped to half the height at the use site.
FossRadio<T> Inputs
FossRadioGroup<T> Inputs: Lays out a set of FossRadio options as a single-choice group.
FossRadioStyle: Visual overrides for a single FossRadio. Every field is optional; a null field falls back to the value the theme resolves. Pass one via style: to tweak a one-off without changing the theme for every other radio.
FossSelect<T> Inputs
FossSelectItem<T>: One option in a FossSelect or FossMultiSelect.
FossSelectStyle: Visual overrides for a single FossSelect or FossMultiSelect. Every field is optional; a null field falls back to the value the theme resolves. Pass one via style: to tweak a one-off without changing the theme for every other select.
FossSeparator Layout
FossShadows: Layered drop shadows per elevation step. Each is a baked List<BoxShadow> (black at low alpha); none is an empty list. Resolved at author time, no shadow math at runtime.
FossSince: Records the fossui version a public API was introduced in.
FossSlider Inputs
FossSliderStyle: Visual overrides for a single FossSlider. Every field is optional; a null field falls back to the value the theme resolves. Pass one via style: to tweak a one-off without changing the theme for every other slider.
FossSpacing: Spacing scale built from one unit (4 px). Call the instance to scale the unit (call) or build an inset (all); every step is unit * n.
FossSpinner Feedback
FossSwitch Inputs
FossSwitchStyle: Visual overrides for a single switch. Every field is optional; a null field falls back to the value the theme resolves. Pass one via style: to tweak a one-off without changing the theme for every other switch.
FossTab<T>: One tab: its value, label, optional leading icon and content panel, and whether it is enabled.
FossTabs<T> Layout
FossTabsStyle: Visual overrides for a single FossTabs. Every field is optional; a null field falls back to the value the theme resolves for the chosen variant. Pass one via style: to tweak a one-off without changing the theme for every other tab set.
FossTextField Inputs
FossTextFieldStyle: Visual overrides for a FossTextField. Every field is optional; a null field falls back to the value the theme resolves for the size and state. Pass one to a single field via style: to tweak a one-off, without changing the theme for every other field.
FossTheme: Provides a FossThemeData to its subtree for non-Material apps. Material apps can instead register the theme in ThemeData.extensions; either way context.fossTheme resolves it.
FossThemeData: The root token bundle: the six leaf bundles in one object. Register it once, then read everything through context.fossTheme. FossThemeData.light and FossThemeData.dark are the defaults; build your own to retheme the app.
FossThemeSpec: A compact override layer for retheming a FossThemeData in one call.
FossToast Overlays
FossToastController: Owns the queue of live toasts and their auto-dismiss timers. Shared by a FossToaster and read with FossToastScope.of. Notifies on every change.
FossToastEntry: A live toast in a FossToastController's queue.
FossToaster Overlays: Hosts transient toasts over its child. Mount it once near the app root, above everything that needs to raise a toast.
FossToastHandle: A handle to a raised toast, returned by showFossToast. Holds the toast's id and its toaster so the caller can dismiss it early or update its message without threading a BuildContext back in.
FossToastScope: Shares a FossToastController with the subtree. Read it with FossToastScope.of; provided by a FossToaster.
FossToastStyle: Visual overrides for a single FossToast. Every field is optional; a null field falls back to the value the theme resolves.
FossTooltip Overlays
FossTooltipStyle: Visual overrides for a single FossTooltip. Every field is optional; a null field falls back to the value the theme resolves. Pass one via style: to tweak a one-off without changing the theme for every other tooltip.
FossTypography: Text styles per size step. Each carries family, size, line height, and letter spacing; set weight with the FossTextStyleWeight getters (.medium for labels and buttons, .semibold for headings, .bold for emphasis).

Enums

FossAlertVariant: The status of a FossAlert, driving its border, fill, and leading glyph.
FossAvatarSize: The size axis of a FossAvatar. Selects the square box edge and the fallback text step; md (32) is the default.
FossBadgeSize: The size axis of a FossBadge: the pill height, minimum width, horizontal padding, and type step. md is the default.
FossBadgeVariant: The color axis of a FossBadge. primary is the default solid pill; secondary, outline, and destructive complete the solid set; info, success, warning, and error are soft, tinting the role at low alpha.
FossButtonSize: The size of a FossButton.
FossButtonStatus: The interactive status a FossButtonController holds. The three states are mutually exclusive: idle is the normal, enabled state.
FossButtonVariant: The visual treatment of a FossButton.
FossCheckboxGroupVariant: The visual treatment of a FossCheckboxGroup.
FossDialogFooterVariant: The footer treatment shared by the dialog and the alert dialog.
FossDialogPresentation: How a modal presents: a centered card or a bottom-stuck sheet.
FossDrawerFooterVariant: The footer treatment of a FossDrawer.
FossDrawerSide: The edge a FossDrawer anchors to and slides in from.
FossDrawerVariant: The corner treatment of a FossDrawer surface.
FossRadioGroupVariant: The visual treatment of a FossRadioGroup.
FossSelectSize: The height and type scale of a FossSelect or FossMultiSelect trigger.
FossSeparatorOrientation: The axis a FossSeparator runs along.
FossTabsOrientation: The axis the tab strip runs along.
FossTabsVariant: The two tab looks.
FossTextFieldSize: The size of a FossTextField.
FossToastVariant: The kind of a FossToast: drives the leading glyph, its tint, and whether the toast auto-dismisses.
FossTooltipSide: The side of the anchor a FossTooltip prefers to open on. The popup flips to the opposite side when it would overflow the viewport.

Extensions

FossTextStyleWeight on TextStyle: Weight conveniences on a TextStyle, for use on the FossTypography scale.
FossThemeContext on BuildContext: The single way to read fossui tokens.

Functions

fieldMetrics(FossThemeData theme, FossTextFieldSize size) → ({Color fill, double minHeight, double padX, double radius}): The size-driven field geometry: resting fill, corner radius, minimum height, and horizontal inset. Shared so every field surface (single-line input, chips input) resolves the same box from the same size.
showFossAlertDialog<T>({required BuildContext context, required WidgetBuilder builder, FossDialogPresentation presentation = FossDialogPresentation.bottomSheet, String? barrierLabel, bool useRootNavigator = true}) → Future<T?>: Opens a non-dismissible alert dialog and resolves to the value passed to Navigator.pop.
showFossDialog<T>({required BuildContext context, required WidgetBuilder builder, FossDialogPresentation presentation = FossDialogPresentation.bottomSheet, bool barrierDismissible = true, String? barrierLabel, bool useRootNavigator = true}) → Future<T?>: Opens a modal dialog and resolves to the value passed to Navigator.pop.
showFossDrawer<T>({required BuildContext context, required WidgetBuilder builder, FossDrawerSide side = FossDrawerSide.bottom, bool barrierDismissible = true, String? barrierLabel, bool useRootNavigator = true}) → Future<T?>: Opens an edge FossDrawer and resolves to the value passed to Navigator.pop.
showFossToast(BuildContext context, FossToast toast) → FossToastHandle: Raises toast on the nearest FossToaster and returns a FossToastHandle to dismiss or update it.