Engine

The <KritzelEngine> is the low-level headless canvas primitive. It handles rendering, viewport management, pointer events, undo/redo, and workspace management with no built-in controls.

Object

Props

No object-specific props.

Events

Event	Payload Type	Description
objectsAdded	ObjectsAddedEvent	Emitted when one or more objects are added to the canvas.
objectsChange	KritzelBaseObject[]	Emitted when objects on the canvas are added, removed, or modified.
objectsRemoved	ObjectsRemovedEvent	Emitted when one or more objects are removed from the canvas.
objectsUpdated	ObjectsUpdatedEvent	Emitted when one or more objects are updated on the canvas.

Methods

addObject

Adds a new object to the canvas. The object is automatically assigned an ID, core reference, and z-index.

addObject<T extends KritzelBaseObject>(object: T): Promise<T | null>

addObjects

Adds multiple objects to the canvas in a single batch operation within one undo step and render cycle.

addObjects<T extends KritzelBaseObject>(objects: T[]): Promise<T[]>

removeObject

Removes an object from the canvas.

removeObject<T extends KritzelBaseObject>(object: T): Promise<T | null>

removeObjects

Removes multiple objects from the canvas in a single batch operation.

removeObjects<T extends KritzelBaseObject>(objects: T[]): Promise<T[]>

updateObject

Updates properties of an existing canvas object.

updateObject<T extends KritzelBaseObject>(object: T, updatedProperties: Partial<T>): Promise<T | null>

getObjectById

Retrieves a canvas object by its unique ID.

getObjectById<T extends KritzelBaseObject>(id: string): Promise<T | null>

getAllObjects

Returns all objects on the canvas across all layers.

getAllObjects<T extends KritzelBaseObject>(): Promise<T[]>

findObjects

Returns all objects matching the given predicate. Excludes internal selection-related objects.

findObjects<T extends KritzelBaseObject>(predicate: (obj: KritzelBaseObject) => boolean): Promise<T[]>

getObjectsTotalCount

Returns the total number of objects on the canvas.

getObjectsTotalCount(): Promise<number>

getObjectsInViewport

Returns all objects currently visible within the viewport bounds.

getObjectsInViewport(): Promise<KritzelBaseObject[]>

---

Selection

Props

No selection-specific props.

Events

Event	Payload Type	Description
objectsSelectionChange	void	Emitted when the set of selected objects changes.

Methods

getSelectedObjects

Returns the currently selected objects. Returns an empty array if nothing is selected.

getSelectedObjects(): Promise<KritzelBaseObject[]>

selectObjects

Programmatically selects the given objects. Switches to the selection tool automatically.

selectObjects(objects: KritzelBaseObject[]): Promise<void>

selectAllObjectsInViewport

Selects all objects currently visible in the viewport. Switches to the selection tool automatically.

selectAllObjectsInViewport(): Promise<void>

clearSelection

Deselects all currently selected objects.

clearSelection(): Promise<void>

triggerSelectionChange

Manually triggers the objectsSelectionChange event.

triggerSelectionChange(): Promise<void>

---

Viewport & Navigation

Props

Property	Type	Description
isPanningEnabled	boolean	Enable or disable viewport panning via regular wheel input.
isZoomingEnabled	boolean	Enable or disable viewport zooming via Ctrl+wheel.
scaleMax	number	Maximum zoom scale allowed.
scaleMin	number	Minimum zoom scale allowed.
viewportBoundaryBottom	number	Bottom pan boundary in world coordinates.
viewportBoundaryLeft	number	Left pan boundary in world coordinates.
viewportBoundaryRight	number	Right pan boundary in world coordinates.
viewportBoundaryTop	number	Top pan boundary in world coordinates.

Events

Event	Payload Type	Description
viewportChange	KritzelViewportState	Emitted on viewport pan, zoom, or resize.
objectsInViewportChange	KritzelBaseObject[]	Emitted when the set of objects visible in the current viewport changes.

Methods

getViewport

Returns the current viewport state including position, scale, and dimensions.

getViewport(): Promise<KritzelViewportState>

setViewport

Sets the viewport to center on the given world coordinates at the specified scale.

setViewport(x: number, y: number, scale: number): Promise<void>

panTo

Pans the viewport to center on the given world coordinates without changing the scale.

panTo(x: number, y: number): Promise<void>

panToObject

Pans the viewport to center on the specified object without changing the scale.

panToObject(object: KritzelBaseObject): Promise<void>

zoomTo

Zooms the viewport to the given scale. Optionally centers on a world point; if omitted, zooms around the viewport center.

zoomTo(scale: number, worldX?: number, worldY?: number): Promise<void>

zoomIn

Zooms into the viewport by a specified factor over an optional duration.

zoomIn(factor?: number, duration?: number): Promise<void>

zoomOut

Zooms out of the viewport by a specified factor over an optional duration.

zoomOut(factor?: number, duration?: number): Promise<void>

centerObjectInViewport

Moves the given object to the center of the current viewport and returns the updated object. Use panToObject or centerObjects when you want to move the camera instead.

centerObjectInViewport(object: KritzelBaseObject): Promise<KritzelBaseObject>

centerObjects

Pans and zooms the viewport to fit the provided objects.

centerObjects(objects: KritzelBaseObject[], animate?: boolean): Promise<boolean>

centerAllObjects

Pans and zooms the viewport to fit all objects on the canvas, including those not currently rendered.

centerAllObjects(animate?: boolean): Promise<boolean>

backToContent

Pans and zooms the viewport to fit the nearest content, with padding. Useful when the user has panned away from all objects.

backToContent(): Promise<boolean>

screenToWorld

Converts screen-relative pixel coordinates to world coordinates.

screenToWorld(x: number, y: number): Promise<{ x: number; y: number }>

worldToScreen

Converts world coordinates to screen-relative pixel coordinates.

worldToScreen(x: number, y: number): Promise<{ x: number; y: number }>

---

Workspace

Props

Property	Type	Description
activeWorkspaceId	string	Optional workspace ID to load.
workspaces	KritzelWorkspace[]	Optional authoritative workspace catalog for this engine instance.
syncConfig	KritzelSyncConfig	Configuration for synchronization providers.
user	IKritzelUser	Current user for awareness broadcasting.
isLoading	boolean	External loading state merged with internal workspace loading state.

Events

Event	Payload Type	Description
activeWorkspaceChange	KritzelWorkspace	Emitted when the active workspace changes.
workspacesChange	KritzelWorkspace[]	Emitted when workspaces are created, updated, or deleted.
awarenessChange	AwarenessStateMap	Emitted when awareness state changes.
syncingChange	boolean	Emitted when remote workspace synchronization status changes.
loadingChange	boolean	Emitted when the combined loading state changes.

Methods

setActiveWorkspace

Switches the active workspace shown in the engine by ID.

setActiveWorkspace(id: string): Promise<void>

createWorkspace

Creates a new workspace and emits a workspacesChange event. Accepts a KritzelWorkspace instance.

createWorkspace(workspace: KritzelWorkspace): Promise<KritzelWorkspace | null>

updateWorkspace

Applies a workspace as declared and emits a workspacesChange event. Metadata and viewport are always applied. When workspace.objects is set it is treated as the complete desired object set: objects are matched by ID, unknown IDs are added, known IDs are updated, and objects missing from the list are removed. Leave objects undefined to keep the current objects, or pass [] to remove them all. Updating the objects of a workspace that is not currently active requires a configured sync provider.

updateWorkspace(workspace: KritzelWorkspace): Promise<void>

deleteWorkspace

Deletes a workspace and emits a workspacesChange event.

deleteWorkspace(workspace: KritzelWorkspace): Promise<void>

getWorkspaces

Returns all available workspaces.

getWorkspaces(): Promise<KritzelWorkspace[]>

getActiveWorkspace

Returns the currently active workspace.

getActiveWorkspace(): Promise<KritzelWorkspace>

getIsPublic

Gets whether the active workspace is publicly accessible.

getIsPublic(): Promise<boolean>

loadSharedWorkspace

Loads a workspace shared externally using a secure access token.

loadSharedWorkspace(token: string): Promise<void>

reinitSync

Reinitializes the active synchronization provider connection.

reinitSync(): Promise<void>

---

Tool Management

Props

No tool-specific props.

Events

Event	Payload Type	Description
activeToolChange	KritzelBaseTool	Emitted when the active drawing tool changes.

Methods

registerTool

Registers a new drawing tool with the engine.

registerTool(
  toolName: string,
  toolClass: any,
  toolConfig?: KritzelBrushToolConfig | KritzelLineToolConfig | KritzelTextToolConfig | KritzelShapeToolConfig
): Promise<KritzelBaseTool | null>

setActiveTool

Switches the active drawing tool. Deactivates the current tool and clears any selection.

setActiveTool(toolName: string): Promise<void>

disable

Disables all user interaction with the engine (pointer, keyboard, etc.).

disable(): Promise<void>

enable

Re-enables user interaction after a call to disable.

enable(): Promise<void>

---

Clipboard & Editing

Props

No clipboard/editing-specific props.

Events

No clipboard/editing-specific events.

Methods

copy

Copies the currently selected objects to the internal clipboard.

copy(): Promise<void>

cut

Cuts the currently selected objects to the internal clipboard and removes them from the canvas.

cut(): Promise<void>

paste

Pastes previously copied objects at the specified world coordinates.

paste(x: number, y: number): Promise<void>

delete

Deletes the currently selected objects from the canvas.

delete(): Promise<void>

---

Ordering

Props

No ordering-specific props.

Events

No ordering-specific events.

Methods

bringForward

Moves an object one layer forward in the z-order. If omitted, applies to the current selection.

bringForward(object?: KritzelBaseObject): Promise<void>

sendBackward

Moves an object one layer backward in the z-order. If omitted, applies to the current selection.

sendBackward(object?: KritzelBaseObject): Promise<void>

bringToFront

Moves an object to the very front of the z-order. If omitted, applies to the current selection.

bringToFront(object?: KritzelBaseObject): Promise<void>

sendToBack

Moves an object to the very back of the z-order. If omitted, applies to the current selection.

sendToBack(object?: KritzelBaseObject): Promise<void>

---

Alignment

Props

No alignment-specific props.

Events

No alignment-specific events.

Methods

alignObjects

Aligns the currently selected objects according to the specified alignment.

alignObjects(alignment: KritzelAlignment): Promise<void>

Alignment values: StartHorizontal, CenterHorizontal, EndHorizontal, StartVertical, CenterVertical, EndVertical.

---

Grouping

Props

No grouping-specific props.

Events

No grouping-specific events.

Methods

group

Groups the currently selected objects into a single group.

group(): Promise<void>

ungroup

Ungroups the currently selected group back into individual objects.

ungroup(): Promise<void>

---

Undo & Redo

Props

No undo/redo-specific props.

Events

Event	Payload Type	Description
undoStateChange	KritzelUndoState	Emitted when undo/redo availability changes.

Methods

undo

Undoes the last action.

undo(): Promise<void>

redo

Redoes the last undone action.

redo(): Promise<void>

---

Export & Import

Props

No export/import-specific props.

Events

No export/import-specific events.

Methods

getScreenshot

Captures a screenshot of the current viewport as a data URL.

getScreenshot(format?: "png" | "svg"): Promise<string | null>

exportViewportAsPng

Exports the current viewport as a PNG file and triggers a browser download.

exportViewportAsPng(): Promise<void>

exportViewportAsSvg

Exports the current viewport as an SVG file and triggers a browser download.

exportViewportAsSvg(): Promise<void>

canExportSelectedObjectAs

Checks whether the currently selected object supports a specific export format.

canExportSelectedObjectAs(format: KritzelObjectExportFormat): Promise<boolean>

exportSelectedObject

Exports the currently selected object in the specified format.

exportSelectedObject(format: KritzelObjectExportFormat): Promise<void>

getSelectedObjectSupportedExportFormats

Returns the export formats supported by the currently selected object.

getSelectedObjectSupportedExportFormats(): Promise<KritzelObjectExportFormat[]>

exportAsJson

Exports the current workspace and all its objects as a JSON string.

exportAsJson(): Promise<string>

importFromJson

Imports a workspace from a JSON string into a new workspace.

importFromJson(json: string): Promise<void>

loadObjectsFromJson

Loads objects from workspace JSON into the current workspace.

loadObjectsFromJson(json: string): Promise<number>

downloadAsJson

Downloads the current workspace as JSON.

downloadAsJson(filename?: string): Promise<void>

importFromFile

Opens a file picker and imports the selected JSON file.

importFromFile(): Promise<void>

---

Localization & Settings

Props

Property	Type	Description
fallbackLocale	LocaleCode	Locale used to resolve terms missing from the active locale.
locale	LocaleCode	Current locale code.
locales	KritzelLocale[]	Available locale definitions.
theme	ThemeCode	Current theme.
themes	KritzelTheme[]	Available themes.

Events

No localization/settings-specific events.

Methods

registerLocales

registerLocales(locales: KritzelLocale[]): Promise<void>

setLocale

setLocale(code: LocaleCode): Promise<void>

getLocale

getLocale(): Promise<LocaleCode>

getAvailableLocales

getAvailableLocales(): Promise<LocaleCode[]>

getAvailableLocaleOptions

getAvailableLocaleOptions(): Promise<{ code: LocaleCode; label: string }[]>

t

t(key: KritzelTermKey, vars?: KritzelTermVars): Promise<string>

getResolvedTerms

getResolvedTerms(): Promise<Partial<Record<KritzelTermKey, string>>>

saveSettings

saveSettings(settings: KritzelSettingsConfig): Promise<void>

loadSettings

loadSettings(): Promise<Partial<KritzelSettingsConfig> | null>

---

Context Menu & Lifecycle

Props

Property	Type	Description
assetStorageConfig	KritzelAssetStorageConfig	Binary asset storage provider configuration.
cursorTarget	HTMLElement	Element to apply cursor styles to.
debugInfo	KritzelDebugInfo	Debug overlay configuration.
editorId	string	Identifier for namespacing storage keys.
globalContextMenuItems	ContextMenuItem[]	Canvas background menu items.
licenseKey	string	Valid key removes the watermark.
lockDrawingScale	boolean	Keeps objects at a fixed visual size across zoom.
objectContextMenuItems	ContextMenuItem[]	Selected-object menu items.

Events

Event	Payload Type	Description
contextMenuStateChange	KritzelContextMenuState	Emitted when context-menu state changes.
isEngineReady	KritzelEngineState	Emitted when the engine is ready.
longpress	PointerEvent	Emitted on touch or pen long-press.
notificationsChange	KritzelNotification	Emitted when notifications change.

Methods

openContextMenu

openContextMenu(options: { x: number; y: number; objectId?: string }): Promise<void>

hideContextMenu

Hides the context menu and resets any associated selection state.

hideContextMenu(): Promise<void>

getDisplayableShortcuts

Returns all registered keyboard shortcuts (without action/condition) for display in a help UI.

getDisplayableShortcuts(): Promise<Omit<KritzelShortcut, "action" | "condition">[]>

beginSceneBootstrap

beginSceneBootstrap(): Promise<void>

endSceneBootstrap

endSceneBootstrap(): Promise<void>