zoomWidth

Zoom to fit the page width to the window.
[read-only property] zoomWidth([out, retval] double *zoom)
When the zoom property is set to this value, the zoom factor is set to fit the current page width to the window.

This property is only useful when setting (or reading) zoom.

VB6:
viewer.zoom = viewer.zoomWidth
zoom
zoomPage
zoomHeight