Struct WidgetBase

core/widget.go:145–224

WidgetBase implements the [Widget] interface and provides the core functionality of a widget. You must use WidgetBase as an embedded struct in all higher-level widget types. It renders the standard box model, but does not layout or render any children; see [Frame] for that.

// widget types. It renders the standard box model, but does not layout or render
// any children; see [Frame] for that.
type WidgetBase struct {
	tree.NodeBase

	// Tooltip is the text for the tooltip for this widget,
	// which can use HTML formatting.
	Tooltip string `json:",omitempty"`

	// Parts are a separate tree of sub-widgets that can be used to store
	// orthogonal parts of a widget when necessary to separate them from children.
	// For example, [Tree]s use parts to separate their internal parts from
	// the other child tree nodes. Composite widgets like buttons should
	// NOT use parts to store their components; parts should only be used when
	// absolutely necessary. Use [WidgetBase.newParts] to make the parts.
	Parts *Frame `copier:"-" json:"-" xml:"-" set:"-"`

	// Geom has the full layout geometry for size and position of this widget.
	Geom geomState `edit:"-" copier:"-" json:"-" xml:"-" set:"-"`

	// OverrideStyle, if true, indicates override the computed styles of the widget
	// and allow directly editing [WidgetBase.Styles]. It is typically only set in
	// the inspector.
	OverrideStyle bool `copier:"-" json:"-" xml:"-" set:"-"`

	// Styles are styling settings for this widget. They are set by
	// [WidgetBase.Stylers] in [WidgetBase.Style].
	Styles styles.Style `json:"-" xml:"-" set:"-"`

	// Stylers is a tiered set of functions that are called in sequential
	// ascending order (so the last added styler is called last and
	// thus can override all other stylers) to style the element.
	// These should be set using the [WidgetBase.Styler], [WidgetBase.FirstStyler],
	// and [WidgetBase.FinalStyler] functions.
	Stylers tiered.Tiered[[]func(s *styles.Style)] `copier:"-" json:"-" xml:"-" set:"-" edit:"-" display:"add-fields"`

	// Listeners is a tiered set of event listener functions for processing events on this widget.
	// They are called in sequential descending order (so the last added listener
	// is called first). They should be added using the [WidgetBase.On], [WidgetBase.OnFirst],
	// and [WidgetBase.OnFinal] functions, or any of the various On{EventType} helper functions.
	Listeners tiered.Tiered[events.Listeners] `copier:"-" json:"-" xml:"-" set:"-" edit:"-" display:"add-fields"`

	// ContextMenus is a slice of menu functions to call to construct
	// the widget's context menu on an [events.ContextMenu]. The
	// functions are called in reverse order such that the elements
	// added in the last function are the first in the menu.
	// Context menus should be added through [WidgetBase.AddContextMenu].
	// Separators will be added between each context menu function.
	ContextMenus []func(m *Scene) `copier:"-" json:"-" xml:"-" set:"-" edit:"-"`

	// Scene is the overall Scene to which we belong. It is automatically
	// by widgets whenever they are added to another widget parent.
	Scene *Scene `copier:"-" json:"-" xml:"-" set:"-"`

	// ValueUpdate is a function set by [Bind] that is called in
	// [WidgetBase.UpdateWidget] to update the widget's value from the bound value.
	// It should not be accessed by end users.
	ValueUpdate func() `copier:"-" json:"-" xml:"-" set:"-"`

	// ValueOnChange is a function set by [Bind] that is called when