modifiers

package
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 Go to latest Published: Mar 19, 2026 License: MIT Imports: 8 Imported by: 0

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Overview

Package modifiers provides text modifier implementations for foundation text components.

This package contains the selection controller and related types for handling text selection in compose text components.

Index

Constants

This section is empty.

Variables

This section is empty.

Functions

This section is empty.

Types

type LayoutCoordinates 

type LayoutCoordinates = layout.LayoutCoordinates

LayoutCoordinates provides access to layout coordinates for a composable. Use layout.LayoutCoordinates for new code.

type MouseSelectionObserver 

type MouseSelectionObserver interface {
	// OnExtend is called when the selection should be extended to the given position.
	// Returns true if the extension was successful.
	OnExtend(downPosition geometry.Offset) bool

	// OnExtendDrag is called during a drag to extend the selection.
	// Returns true if the drag should continue.
	OnExtendDrag(dragPosition geometry.Offset) bool

	// OnStart is called when a mouse selection gesture starts.
	// The adjustment determines how the selection should be adjusted (e.g., word on double-click).
	// The clickCount indicates single, double, or triple click.
	// Returns true if the selection was started successfully.
	OnStart(downPosition geometry.Offset, adjustment SelectionAdjustment, clickCount int) bool

	// OnDrag is called during a mouse drag gesture.
	// The adjustment determines how the selection should be adjusted.
	// Returns true if the drag should continue.
	OnDrag(dragPosition geometry.Offset, adjustment SelectionAdjustment) bool

	// OnDragDone is called when the mouse drag gesture ends.
	OnDragDone()
}

MouseSelectionObserver observes mouse selection gestures. This is used for click-and-drag selection with a mouse.

https://cs.android.com/androidx/platform/frameworks/support/+/androidx-main:compose/foundation/foundation/src/commonMain/kotlin/androidx/compose/foundation/text/selection/MouseSelectionObserver.kt

type MultiWidgetSelectionDelegate 

type MultiWidgetSelectionDelegate struct {

	// CoordinatesCallback returns the current layout coordinates.
	CoordinatesCallback func() layout.LayoutCoordinates
	// LayoutResultCallback returns the current text layout result.
	LayoutResultCallback func() *text.TextLayoutResult
	// contains filtered or unexported fields
}

MultiWidgetSelectionDelegate is a selection delegate that coordinates selection across multiple text widgets. It implements the Selectable interface.

https://cs.android.com/androidx/platform/frameworks/support/+/androidx-main:compose/foundation/foundation/src/commonMain/kotlin/androidx/compose/foundation/text/selection/MultiWidgetSelectionDelegate.kt

func NewMultiWidgetSelectionDelegate 

func NewMultiWidgetSelectionDelegate(
	selectableId int64,
	coordinatesCallback func() layout.LayoutCoordinates,
	layoutResultCallback func() *text.TextLayoutResult,
) *MultiWidgetSelectionDelegate

NewMultiWidgetSelectionDelegate creates a new MultiWidgetSelectionDelegate.

func (*MultiWidgetSelectionDelegate) AppendSelectableInfoToBuilder 

func (d *MultiWidgetSelectionDelegate) AppendSelectableInfoToBuilder(builder selection.SelectionLayoutBuilder)

AppendSelectableInfoToBuilder implements Selectable.AppendSelectableInfoToBuilder.

func (*MultiWidgetSelectionDelegate) GetBoundingBox 

func (d *MultiWidgetSelectionDelegate) GetBoundingBox(offset int) geometry.Rect

GetBoundingBox implements Selectable.GetBoundingBox.

func (*MultiWidgetSelectionDelegate) GetCenterYForOffset 

func (d *MultiWidgetSelectionDelegate) GetCenterYForOffset(offset int) float32

GetCenterYForOffset implements Selectable.GetCenterYForOffset.

func (*MultiWidgetSelectionDelegate) GetHandlePosition 

func (d *MultiWidgetSelectionDelegate) GetHandlePosition(sel selection.Selection, isStartHandle bool) geometry.Offset

GetHandlePosition implements Selectable.GetHandlePosition.

func (*MultiWidgetSelectionDelegate) GetLastVisibleOffset 

func (d *MultiWidgetSelectionDelegate) GetLastVisibleOffset() int

GetLastVisibleOffset implements Selectable.GetLastVisibleOffset.

func (*MultiWidgetSelectionDelegate) GetLayoutCoordinates 

func (d *MultiWidgetSelectionDelegate) GetLayoutCoordinates() layout.LayoutCoordinates

GetLayoutCoordinates implements Selectable.GetLayoutCoordinates.

func (*MultiWidgetSelectionDelegate) GetLineHeight 

func (d *MultiWidgetSelectionDelegate) GetLineHeight(offset int) float32

GetLineHeight implements Selectable.GetLineHeight.

func (*MultiWidgetSelectionDelegate) GetLineLeft 

func (d *MultiWidgetSelectionDelegate) GetLineLeft(offset int) float32

GetLineLeft implements Selectable.GetLineLeft.

func (*MultiWidgetSelectionDelegate) GetLineRight 

func (d *MultiWidgetSelectionDelegate) GetLineRight(offset int) float32

GetLineRight implements Selectable.GetLineRight.

func (*MultiWidgetSelectionDelegate) GetRangeOfLineContaining 

func (d *MultiWidgetSelectionDelegate) GetRangeOfLineContaining(offset int) text.TextRange

GetRangeOfLineContaining implements Selectable.GetRangeOfLineContaining.

func (*MultiWidgetSelectionDelegate) GetSelectAllSelection 

func (d *MultiWidgetSelectionDelegate) GetSelectAllSelection() *selection.Selection

GetSelectAllSelection implements Selectable.GetSelectAllSelection.

func (*MultiWidgetSelectionDelegate) GetText 

func (d *MultiWidgetSelectionDelegate) GetText() text.AnnotatedString

GetText implements Selectable.GetText.

func (*MultiWidgetSelectionDelegate) SelectableId 

func (d *MultiWidgetSelectionDelegate) SelectableId() int64

SelectableId implements Selectable.SelectableId.

func (*MultiWidgetSelectionDelegate) TextLayoutResult 

func (d *MultiWidgetSelectionDelegate) TextLayoutResult() *text.TextLayoutResult

TextLayoutResult implements Selectable.TextLayoutResult.

type RememberObserver 

type RememberObserver interface {
	// OnRemembered is called when the object is successfully stored by remember.
	OnRemembered()

	// OnForgotten is called when the object is no longer being remembered.
	OnForgotten()

	// OnAbandoned is called when the remember call was not committed to the composition.
	OnAbandoned()
}

RememberObserver is an interface for objects that need lifecycle callbacks when remembered in composition.

https://cs.android.com/androidx/platform/frameworks/support/+/androidx-main:compose/runtime/runtime/src/commonMain/kotlin/androidx/compose/runtime/RememberObserver.kt

type Selectable 

type Selectable = selection.Selectable

Selectable is an alias to the selection package's Selectable. Use selection.Selectable for new code.

type Selection 

type Selection = selection.Selection

Selection is an alias to the selection package's Selection. Use selection.Selection for new code.

type SelectionAdjustment 

type SelectionAdjustment int

SelectionAdjustment determines how selection should be adjusted during gestures.

https://cs.android.com/androidx/platform/frameworks/support/+/androidx-main:compose/foundation/foundation/src/commonMain/kotlin/androidx/compose/foundation/text/selection/SelectionAdjustment.kt 

const (
	// SelectionAdjustmentNone means no adjustment to selection.
	SelectionAdjustmentNone SelectionAdjustment = iota

	// SelectionAdjustmentCharacter adjusts selection to character boundaries.
	SelectionAdjustmentCharacter

	// SelectionAdjustmentWord adjusts selection to word boundaries.
	SelectionAdjustmentWord

	// SelectionAdjustmentParagraph adjusts selection to paragraph boundaries.
	SelectionAdjustmentParagraph
)

func (SelectionAdjustment) String 

func (s SelectionAdjustment) String() string

String returns the string representation of SelectionAdjustment.

type SelectionController 

type SelectionController struct {
	// contains filtered or unexported fields
}

SelectionController manages text selection for a text composable. It handles registration with the selection system, updates on text/position changes, and drawing of selection highlights.

This is essentially a Modifier.Node moved into remember because we need pointerInput.

https://cs.android.com/androidx/platform/frameworks/support/+/androidx-main:compose/foundation/foundation/src/commonMain/kotlin/androidx/compose/foundation/text/modifiers/SelectionController.kt

func NewSelectionController 

func NewSelectionController(
	selectableId int64,
	selectionRegistrar SelectionRegistrar,
	backgroundSelectionColor graphics.Color,
) *SelectionController

NewSelectionController creates a new SelectionController.

func (*SelectionController) BackgroundSelectionColor 

func (sc *SelectionController) BackgroundSelectionColor() graphics.Color

BackgroundSelectionColor returns the background color used for selection highlights.

func (*SelectionController) Draw 

func (sc *SelectionController) Draw(drawPath func(path graphics.Path, color graphics.Color, shouldClip bool))

Draw draws the selection highlight using the provided draw function. The drawPath function is called with the selection path and background color.

This is a simplified version that takes a draw function instead of DrawScope, as DrawScope depends on platform-specific graphics systems.

func (*SelectionController) Modifier 

func (sc *SelectionController) Modifier() ui.Modifier

Modifier returns the modifier for this selection controller. This modifier should be applied to the text composable to enable selection.

func (*SelectionController) OnAbandoned 

func (sc *SelectionController) OnAbandoned()

OnAbandoned is called when the remember was abandoned before being committed. It unsubscribes from the selection registrar.

func (*SelectionController) OnForgotten 

func (sc *SelectionController) OnForgotten()

OnForgotten is called when the controller is no longer remembered. It unsubscribes from the selection registrar.

func (*SelectionController) OnRemembered 

func (sc *SelectionController) OnRemembered()

OnRemembered is called when the controller is remembered in composition. It subscribes to the selection registrar.

func (*SelectionController) SelectableId 

func (sc *SelectionController) SelectableId() int64

SelectableId returns the unique identifier for this selectable.

func (*SelectionController) UpdateGlobalPosition 

func (sc *SelectionController) UpdateGlobalPosition(coordinates LayoutCoordinates)

UpdateGlobalPosition updates the layout coordinates and notifies the selection registrar.

func (*SelectionController) UpdateTextLayout 

func (sc *SelectionController) UpdateTextLayout(textLayoutResult *text.TextLayoutResult)

UpdateTextLayout updates the text layout result. If the text content has changed, it notifies the selection registrar.

type SelectionRegistrar 

type SelectionRegistrar = selection.SelectionRegistrar

SelectionRegistrar is an alias to the selection package's SelectionRegistrar. Use selection.SelectionRegistrar for new code.

type SelectionRegistrarExtended 

type SelectionRegistrarExtended interface {
	SelectionRegistrar

	// HasSelection returns true if there is an active selection for the given selectableId.
	HasSelection(selectableId int64) bool

	// MakeSelectionModifier creates a modifier for handling selection gestures.
	// This is platform-specific and may return different implementations on different platforms.
	MakeSelectionModifier(
		selectableId int64,
		layoutCoordinates func() LayoutCoordinates,
	) interface{} // Returns Modifier, but typed as interface{} to avoid circular dependencies
}

SelectionRegistrarExtended extends SelectionRegistrar with methods needed for the default selection modifier implementation.

Note: NotifySelectionUpdateStart, NotifySelectionUpdate, and NotifySelectionUpdateEnd are inherited from the embedded SelectionRegistrar interface.

https://cs.android.com/androidx/platform/frameworks/support/+/androidx-main:compose/foundation/foundation/src/commonMain/kotlin/androidx/compose/foundation/text/selection/SelectionRegistrar.kt

type StaticTextSelectionParams 

type StaticTextSelectionParams struct {
	// contains filtered or unexported fields
}

StaticTextSelectionParams holds the parameters needed for static text selection. This is used to track layout coordinates and text layout results for selection handling.

https://cs.android.com/androidx/platform/frameworks/support/+/androidx-main:compose/foundation/foundation/src/commonMain/kotlin/androidx/compose/foundation/text/modifiers/SelectionController.kt

func EmptyStaticTextSelectionParams 

func EmptyStaticTextSelectionParams() StaticTextSelectionParams

EmptyStaticTextSelectionParams returns an empty StaticTextSelectionParams instance.

func NewStaticTextSelectionParams 

func NewStaticTextSelectionParams(
	layoutCoordinates LayoutCoordinates,
	textLayoutResult *text.TextLayoutResult,
) StaticTextSelectionParams

NewStaticTextSelectionParams creates a new StaticTextSelectionParams.

func (StaticTextSelectionParams) Copy 

func (p StaticTextSelectionParams) Copy(
	layoutCoordinates LayoutCoordinates,
	textLayoutResult *text.TextLayoutResult,
) StaticTextSelectionParams

Copy creates a copy of StaticTextSelectionParams with optional overrides.

func (StaticTextSelectionParams) CopyWithLayoutCoordinates 

func (p StaticTextSelectionParams) CopyWithLayoutCoordinates(layoutCoordinates LayoutCoordinates) StaticTextSelectionParams

CopyWithLayoutCoordinates creates a copy with updated layout coordinates.

func (StaticTextSelectionParams) CopyWithTextLayoutResult 

func (p StaticTextSelectionParams) CopyWithTextLayoutResult(textLayoutResult *text.TextLayoutResult) StaticTextSelectionParams

CopyWithTextLayoutResult creates a copy with updated text layout result.

func (StaticTextSelectionParams) GetPathForRange 

func (p StaticTextSelectionParams) GetPathForRange(start, end int) graphics.Path

GetPathForRange returns the path for the given text range, or nil if not available.

func (StaticTextSelectionParams) LayoutCoordinatesValue 

func (p StaticTextSelectionParams) LayoutCoordinatesValue() LayoutCoordinates

LayoutCoordinatesValue returns the layout coordinates.

func (StaticTextSelectionParams) ShouldClip 

func (p StaticTextSelectionParams) ShouldClip() bool

ShouldClip returns true if the selection should be clipped to the layout bounds. This is true when the text has visual overflow and the overflow mode is not Visible.

func (StaticTextSelectionParams) TextLayoutResultValue 

func (p StaticTextSelectionParams) TextLayoutResultValue() *text.TextLayoutResult

TextLayoutResultValue returns the text layout result.

type TextDragObserver 

type TextDragObserver interface {
	// OnDown is called when the pointer first touches down.
	// Not supported for long-press-drag selection.
	OnDown(point geometry.Offset)

	// OnUp is called when the pointer is released.
	OnUp()

	// OnStart is called when a drag gesture starts (after long-press is detected).
	// The selectionAdjustment determines how the selection should be adjusted.
	OnStart(startPoint geometry.Offset, selectionAdjustment SelectionAdjustment)

	// OnDrag is called during a drag gesture with the delta from the previous position.
	OnDrag(delta geometry.Offset)

	// OnStop is called when the drag gesture ends normally.
	OnStop()

	// OnCancel is called when the drag gesture is cancelled.
	OnCancel()
}

TextDragObserver observes text drag gestures for selection. This is used for long-press-drag selection on touch devices.

https://cs.android.com/androidx/platform/frameworks/support/+/androidx-main:compose/foundation/foundation/src/commonMain/kotlin/androidx/compose/foundation/text/TextDragObserver.kt

type TextSubstitutionValue 

type TextSubstitutionValue struct {
	Original              text.AnnotatedString
	Substitution          text.AnnotatedString
	IsShowingSubstitution bool
}

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