API Reference

The public API is exposed on window.instance after the viewer initializes:

window.instance = {
  docViewer,                  // underlying ComPDFKitViewer (instance 1)
  Core: { /* engine bridge (~120 functions) */ },
  UI:   { /* UI APIs (~62 functions + Header/Panel/Popup classes) */ },
};

This page lists the instance.UI surface grouped by category. For the engine (instance.Core) surface, see Core Bridge.

Each apis/*.js module is a factory (stores...) => (...args) => result; apis/index.js injects the Pinia stores at registration time. Three deprecated aliases are also exposed: setThemeMode, setActiveToolMode, setActiceToolMode.

Header & Toolbar

UI.setHeaderItems(headerCallback)

Customize the header / toolbar groups inside a callback. The callback receives a UI.Header instance — a mutable working copy of all header arrays.

UI.Header methods: get(dataElement), getItems(), getHeader(group), insertBefore(item), insertAfter(item), delete(id?), shift(), unshift(...items), push(...items), pop(), update(items) — all chainable, return Header.

UI.setHeaderItems(header => {
  header.getHeader('default').push({ type: 'actionButton', dataElement: 'myBtn', onClick: () => {} });
});

UI.setToolbarGroup(groupDataElement)

Switch the active toolbar group. Groups: toolbarGroup-View, -Annotation, -Form, -Measurement, -Sign, -Security, -Redaction, -Compare, -Editor, -Document, -Separation.

Elements (open / close / enable / disable)

API	Signature	Notes
openElement	(dataElement: string) => void	Opens element; closes sibling panels on the same side.
closeElement	(dataElement: string) => void
openElements	(dataElements: string[]) => void
closeElements	(dataElements: string[]) => void
isElementOpen	(dataElement: string) => boolean
disableElements	(dataElements: string[] | string) => void	Unmounts from DOM (does not disable the feature).
enableElements	(dataElements: string[] | string) => void
setActiveElementTab	(dataElement: string, tab: string|number) => void	Switches the active sub-tab.

Panels

UI.addPanel(panel)

Add a custom panel. panel = { dataElement, location: 'left'|'right', render: string | () => HTMLElement }.

UI.setPanels(panelList)

Replace the entire panel list.

UI.getPanels() → Array<UI.Components.Panel>

Returns deep-cloned entries wrapped in Panel instances.

UI.Components.Panel: dataElement (get/set), render (get/set), location (get/set, invalid → 'right'), setLocation(location), delete().

Tools

API	Signature	Notes
setActiveTool	(dataElement: string, options?: { continueAdding?: boolean }) => void	Activate a tool by its data-element. continueAdding currently keeps only the signatureFields creation tool active after an item is created.
getActiveTool	() => object
getTool	(tool: string) => object	Shallow copy of the tool style preset.
getToolColor	(tool: string) => string
registerTool	(tool: object, options: object) => boolean	Register a custom annotation tool.

Themes & Styles

API	Signature	Notes
setTheme	(value: string|object) => void	'light' / 'dark'.
setCustomStyle	(style: string) => void	Injects a <style> into <head>.

Localization

API	Signature	Notes
setLanguage	(language: string) => Promise<void>	en, zh-CN, zh-TW, fr, th, ja. Persists to localStorage.
addLanguage	(language: object) => void
removeLanguage	(language: string) => void
setLanguages	(languages: Array|object) => void

Signatures

API	Signature	Notes
setAutoJumpNextSign	(value: boolean) => void
setSignatureDialogTabs	(value: Array) => void
setSignatureDialogProperties	(type: string, properties: object, replace?: boolean = false) => void
setEnableSignatureTemplates	(value: boolean) => void
enableSignatureTool	() => void
disableSignatureTool	() => void

Stamps

API	Signature	Notes
setStampPanelTabs	(tabs: Array) => void
setImportStamps	(images: Array) => void
addCustomStamps	(images: Array) => void	Persists to localStorage.
setCustomStamps	(stamps: Array) => void
getCustomStamps	() => Array

Forms

API	Signature	Notes
setFormBoardFold	(fold: boolean) => void
setFormBoardPosition	(position: string|number) => void
setHighlightForm	(value: boolean) => void	Pushes into core.

Content Editor

API	Signature	Notes
disableDocumentEditorSave	() => void
disableDocumentEditorSaveAs	() => void
enableDocumentEditorSave	() => void
enableDocumentEditorSaveAs	() => void
saveDocumentEditor	() => Promise<void>	Saves edits and reloads the document.

Modals

UI.addCustomModal(options)

Register a custom modal. options = { dataElement, disableBackdropClick?, disableEscapeKeyDown?, render?, header, body, footer } where each section is { title, className, style, children }. Same dataElement replaces the prior modal. Controlled via openElement / closeElement / disableElements.

Popups

Four properties, each implementing UI.Popup (add(items, dataElement?), update(items?), getItems()):

• UI.textPopup
• UI.annotationPopup
• UI.contentEditorPopup
• UI.cropPagePopup

Remove items via UI.disableElements.

User / Author

API	Signature	Notes
setCurrentUser	(user: string) => void	Falls back to 'Guest'.
setAnnotator	(user: string) => void	Same action as setCurrentUser.
setAuthor	(value: string) => void	Empty string if falsy.
setHighlightLink	(value: boolean) => void
getPassword	() => string	Password for the current document.

Fonts

API	Signature	Notes
setCustomFonts	(fonts: Array) => void	Errors if not an array.
getCustomFonts	() => Array
setFontSizes	(fontSizes: Array) => void
getFontSizes	() => Array

Loading

API	Signature	Notes
setCustomLoading	(value: boolean) => void

Annotation Import / Export

API	Signature	Notes
disableAnnotationExport	() => void
enableAnnotationExport	() => void
disableAnnotationImport	() => void
enableAnnotationImport	() => void

Deprecated aliases

Alias	Replaces
setThemeMode	setTheme
setActiveToolMode	setToolbarGroup
setActiceToolMode (typo)	setToolbarGroup

Each emits [ComPDF] "<name>" is deprecated and will be removed in a future version. Please use "<replacement>" instead. and forwards all arguments.

instance.Core (engine bridge)

The full instance.Core surface (~120 functions) is documented in Core Bridge. Commonly used entries:

• Document: loadDocument, getPagesCount, getCurrentPage, getDocumentName, download, saveDocumentEdit, compare.
• Navigation: nextPage, previousPage, rotateClockwise, rotateCounterclockwise, zoomIn, zoomOut, scaleChanged, getScale, switchScrollMode, switchSpreadMode, requestFullScreenMode, toggleSidebar, pageToWindow, windowToPage.
• Search: search, setActiveSearchResult, clearSearchResults, getSelectedText.
• Annotations: getAnnotationsList, getAnnotationManager, getAnnotationHistoryManager, importAnnotations, exportAnnotations, exportXfdf, selectAnnotation, jumpToAnnotation, setAnnotationStyles, addAnnotationImage, handleReplyAnnotation.
• Tools: setTool, switchTool, setToolMode, getToolMode, getToolStyles, setToolStyles, registerTool.
• Content editor: setContentEditorProperty, getContentEditManager, getContentEditHistoryManager, saveDocumentEdit.
• Forms: handleField, enableSkipNoRequired, disableSkipNoRequired, setAutoJumpNextSign, getRequiredFormSign.
• Signatures: handleSign, getSignature, deleteSignature, verifySignature, getVerificationResult, loadCertificates, addToTrustedCertificateLists, checkCertificateIsTrusted.
• Security: checkPermissionPassword, getPermission, setPassword, removePassword, checkPassword.
• Redaction/flatten: applyRedactions, flattenPdf, flattenPdfDownload.
• Events: eventBus, addEvent, removeEvent.
• Users: setCurrentUser, getCurrentUser, isUserAdmin, isReadOnlyModeEnabled.

Related

• Core Bridge — full engine surface.
• UI Customization — task-oriented entry points.
• Architecture — how UI / Core / docViewer are assembled.