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.

All methods are async and return Promises. The <KritzelEditor> exposes all the same methods.

Common props

Property	Type	Default	Description
cursorTarget	HTMLElement	document.body	Element to apply cursor styles to
globalContextMenuItems	ContextMenuItem[]	undefined	Context menu items for canvas background
objectContextMenuItems	ContextMenuItem[]	undefined	Context menu items for selected objects
lockDrawingScale	boolean	true	Fixed visual size for drawn objects regardless of zoom
scaleMax	number	ABSOLUTE_SCALE_MAX	Maximum zoom scale
scaleMin	number	ABSOLUTE_SCALE_MIN	Minimum zoom scale
syncConfig	KritzelSyncConfig	undefined	Sync provider configuration
theme	'light' | 'dark'	'light'	Active theme
viewportBoundaryLeft	number	-Infinity	Left pan boundary
viewportBoundaryRight	number	Infinity	Right pan boundary
viewportBoundaryTop	number	-Infinity	Top pan boundary
viewportBoundaryBottom	number	Infinity	Bottom pan boundary
workspaces	KritzelWorkspace[]	undefined	Optional authoritative workspace catalog for this engine instance. Provider-only workspaces are hidden but not deleted.

Common events

Event	Payload Type	Description
isEngineReady	KritzelEngineState	Emitted when the engine is fully initialized
activeToolChange	KritzelBaseTool	Emitted when the active tool changes
longpress	PointerEvent	Emitted on long-press (useful for mobile context menus)
objectsChange	KritzelBaseObject[]	Emitted when objects are added, removed, or modified
objectsAdded	ObjectsAddedEvent	Emitted when objects are added
objectsRemoved	ObjectsRemovedEvent	Emitted when objects are removed
objectsUpdated	ObjectsUpdatedEvent	Emitted when objects are updated
objectsInViewportChange	KritzelBaseObject[]	Emitted when visible objects change (after pan/zoom)
objectsSelectionChange	void	Emitted when selected objects change
undoStateChange	KritzelUndoState	Emitted when undo/redo availability changes
viewportChange	KritzelViewportState	Emitted on pan, zoom, or resize
workspacesChange	KritzelWorkspace[]	Emitted when workspaces are created, updated, or deleted

---

Object

Props

Property	Type	Description
objectConfig	KritzelObjectConfig	Configures how objects behave, in one place for all objects: which objects get a titlebar, and which can be rotated or resized. Each option is a boolean or a function of the object. See Configuring Objects.

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 in 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 in one 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

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>

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Viewport & Navigation

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 to an object without changing 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 in by one configured step: zoomIn(): Promise<void>.

zoomOut

Zooms out by one configured step: zoomOut(): Promise<void>.

centerObjectInViewport

Pans and zooms the viewport to center on the given object.

centerObjectInViewport(object: KritzelBaseObject): Promise<KritzelBaseObject>

centerObjects

Centers the combined bounds of supplied objects: centerObjects(objects: KritzelBaseObject[]): Promise<void>.

centerAllObjects

Centers the combined bounds of all objects: centerAllObjects(): Promise<void>.

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>

Returns true if content was found and the viewport was adjusted, false otherwise.

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

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

Returns whether the active workspace is public: getIsPublic(): Promise<boolean>.

loadSharedWorkspace

Loads a shared workspace: loadSharedWorkspace(workspaceId: string): Promise<void>.

reinitSync

Reinitializes the active synchronization provider: reinitSync(): Promise<void>.

---

Tool Management

registerTool

Registers a new drawing tool with the engine.

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

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>

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Clipboard & Editing

copy

Copies the currently selected objects to the internal clipboard.

copy: Promise<void>

cut

Cuts selected objects to the clipboard.

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>

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Ordering

bringForward

Moves an object one layer forward in the z-order, past the next layer above it. If omitted, applies to the current selection and moves each selected layer. A group is one layer, so all of its children move together; a grouped object moves within its group.

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

sendBackward

Moves an object one layer backward in the z-order, past the next layer below it. If omitted, applies to the current selection and moves each selected layer. A group is one layer, so all of its children move together; a grouped object moves within its group.

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

bringToFront

Moves an object to the very front of the z-order. If omitted, applies to the current selection, keeping the relative order of the selected layers. A group moves together with all of its children; a grouped object moves to the front of its group.

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

sendToBack

Moves an object to the very back of the z-order. If omitted, applies to the current selection, keeping the relative order of the selected layers. A group moves together with all of its children; a grouped object moves to the back of its group.

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

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Alignment

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

group

Creates a group (KritzelGroup) from the given objects. Requires at least two objects. They become one layer at the position of the topmost object, in a single undoable step. Objects are resolved by id, so stale references work; objects that are not in the active workspace are skipped with a console warning. Objects inside a common group are grouped within it; objects from different groups are grouped at the level that contains all of them. Selected objects that end up in the group are replaced by the group in the selection. Resolves to the created group, or null (with a console warning) when fewer than two objects could be grouped. To group the current selection, pass await getSelectedObjects().

group(objects: KritzelBaseObject[]): Promise<KritzelGroup | null>

ungroup

Ungroups the given groups. Their children become individual objects again and keep their stacking order; the children of a nested group stay in its parent group. All groups are dissolved in a single undoable step. Groups are resolved by id, so stale references work; entries that are not a KritzelGroup or not in the active workspace are skipped with a console warning. Dissolved groups in the selection are replaced by their children. Resolves to the extracted children. To ungroup the current selection, pass the KritzelGroup objects from await getSelectedObjects().

ungroup(groups: KritzelGroup[]): Promise<KritzelBaseObject[]>

---

Undo & Redo

undo

Undoes the last action.

undo: Promise<void>

redo

Redoes the last undone action.

redo: Promise<void>

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Export & Import

getScreenshot

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

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

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 selected object supports a format: canExportSelectedObjectAs(format: KritzelExportFormat): Promise<boolean>.

exportSelectedObject

Exports the selected object: exportSelectedObject(format: KritzelExportFormat): Promise<void>.

getSelectedObjectSupportedExportFormats

Returns supported selected-object formats: getSelectedObjectSupportedExportFormats(): Promise<KritzelExportFormat[]>.

exportAsJson

Serializes the current workspace: exportAsJson(): Promise<string>.

importFromJson

Imports a serialized workspace: importFromJson(json: string): Promise<void>.

loadObjectsFromJson

Loads serialized objects: loadObjectsFromJson(json: string): Promise<number>.

downloadAsJson

Downloads the current workspace: downloadAsJson(filename?: string): Promise<void>.

importFromFile

Opens a file picker and imports a workspace: importFromFile(): Promise<void>.

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Localization & Settings

Props

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

Methods

registerLocales

Registers locale definitions: registerLocales(locales: KritzelLocale[]): Promise<void>.

setLocale

Sets the active locale: setLocale(code: LocaleCode): Promise<void>.

getLocale

Returns the active locale: getLocale(): Promise<LocaleCode>.

getAvailableLocales

Returns available locale codes: getAvailableLocales(): Promise<LocaleCode[]>.

getAvailableLocaleOptions

Returns available code/label options: getAvailableLocaleOptions(): Promise<{ code: LocaleCode; label: string }[]>.

t

Resolves a localized term: t(key: KritzelTermKey, vars?: KritzelTermVars): Promise<string>.

getResolvedTerms

Returns all resolved terms: getResolvedTerms(): Promise<Partial<Record<KritzelTermKey, string>>>.

saveSettings

Persists settings: saveSettings(settings: KritzelSettingsConfig): Promise<void>.

loadSettings

Loads persisted settings: loadSettings(): Promise<Partial<KritzelSettingsConfig> | null>.

Context Menu & Lifecycle

Props

Property	Type	Description
assetStorageConfig	KritzelAssetStorageConfig	Configuration for binary asset storage providers.
cursorTarget	HTMLElement	Element to apply cursor styles to.
debugInfo	KritzelDebugInfo	Controls visible debug overlays.
editorId	string	Identifier for namespacing storage keys across engine instances.
globalContextMenuItems	ContextMenuItem[]	Items shown on the canvas background context menu.
isWatermarkVisible	boolean	Show or hide the "Powered by Kritzel" watermark (default true). Keeping it visible helps support the project.
lockDrawingScale	boolean	Keeps drawn objects at a fixed visual size across zoom levels.
objectContextMenuItems	ContextMenuItem[]	Items shown for selected objects.

Events

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

Methods

openContextMenu

Opens a context menu: openContextMenu(options: { x: number; y: number; objectId?: string }): Promise<void>.

hideContextMenu

Hides the context menu: hideContextMenu(): Promise<void>.

getDisplayableShortcuts

Returns shortcuts without actions or conditions: getDisplayableShortcuts(): Promise<Omit<KritzelShortcut, "action" | "condition">[]>.

beginSceneBootstrap

Starts scene bootstrap and hides the scene: beginSceneBootstrap(): Promise<void>.

endSceneBootstrap

Ends scene bootstrap: endSceneBootstrap(): Promise<void>.

Agentic Cursors

Props

No agentic-cursor-specific props.

Events

Event	Payload Type	Description
agenticCursorDetached	KritzelAgenticCursorDetachedEvent	Emitted when an agentic cursor is detached from an object, either manually or because the object was removed.

Methods

addAgenticCursor

Adds a programmatically controlled cursor. Agentic cursors are rendered locally only.

addAgenticCursor(options?: KritzelAgenticCursorOptions): Promise<KritzelAgenticCursor>

updateAgenticCursor

Updates the name, color, status or visibility of an agentic cursor. Pass status: null to clear the status.

updateAgenticCursor(id: string, patch: KritzelAgenticCursorPatch): Promise<KritzelAgenticCursor>

moveAgenticCursor

Smoothly moves an agentic cursor to world coordinates or to an anchor on an object. Object targets attach the cursor by default. Resolves when the animation ends; completed is false if the move was interrupted.

moveAgenticCursor(id: string, target: KritzelAgenticCursorTarget, options?: KritzelAgenticCursorMoveOptions): Promise<KritzelAgenticCursorMoveResult>

detachAgenticCursor

Detaches an agentic cursor from its object. The cursor stays at its current position.

detachAgenticCursor(id: string): Promise<void>

removeAgenticCursor

Removes an agentic cursor. A running move resolves with completed: false.

removeAgenticCursor(id: string): Promise<boolean>

clearAgenticCursors

Removes all agentic cursors.

clearAgenticCursors(): Promise<void>

getAgenticCursor

Returns a snapshot of an agentic cursor, or null if it doesn't exist.

getAgenticCursor(id: string): Promise<KritzelAgenticCursor | null>

getAgenticCursors

Returns snapshots of all agentic cursors.

getAgenticCursors(): Promise<KritzelAgenticCursor[]>

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Object Titlebar

Props

Property	Type	Description
objectTitlebar	KritzelObjectTitlebarConfig	Content of the titlebar rendered above every object for which objectConfig.hasTitlebar is true. The same configuration applies to all objects. Leave unset to disable titlebars. See Object Titlebar.

Events

Event	Payload Type	Description
objectTitlebarAction	KritzelObjectTitlebarActionEvent	Emitted when a button in an object titlebar is clicked or a menu item of a titlebar menu is selected, in addition to calling the optional action callback of the button or menu item.
objectTitlebarMenuStateChange	KritzelObjectTitlebarMenuState	Emitted when a titlebar menu opens or closes. Contains the resolved menu items and the menu button as anchor, so that a host can render the menu. <KritzelEditor> renders titlebar menus itself and does not re-emit this event.

Methods

closeObjectTitlebarMenu

Closes the open titlebar menu, if any.

closeObjectTitlebarMenu(): Promise<void>

selectObjectTitlebarMenuItem

Selects a menu item of the open titlebar menu. Closes the menu, calls the menu item's action, and emits objectTitlebarAction with the id of the menu as elementId and menuItemId. Does nothing if no menu is open or the menu item is hidden or disabled.

selectObjectTitlebarMenuItem(menuItemId: string): Promise<void>

Use updateObject to change the name of an existing object.