diff --git a/index.d.ts b/index.d.ts
index a57d545d33b2798024b9762d3d3513e58a38e19d..83ace9fc85b7354e128948402a50e00083eacd8c 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -256,7 +256,11 @@ export function zoom(value: Value, SVGPointX: number, SVGPointY: number, scaleFa
 export function fitSelection(
     value: Value, selectionSVGPointX: number, selectionSVGPointY: number, selectionWidth: number, selectionHeight: number): Value;
 
-export function fitToViewer(value: Value): Value;
+export function fitToViewer(
+    value: Value,
+    SVGAlignX?: typeof ALIGN_CENTER | typeof ALIGN_LEFT | typeof ALIGN_RIGHT | undefined,
+    SVGAlignY?: typeof ALIGN_CENTER | typeof ALIGN_TOP | typeof ALIGN_BOTTOM | undefined
+): Value;
 
 export function zoomOnViewerCenter(value: Value, scaleFactor: number): Value;