pdfSetZoom

Change the zoom factor.

void pdfSetZoom(PDFViewerHandle viewer, double zoom)

This function changes the zoom factor. The zoom factor can be any of:

a percentage, where 100 corresponds to 72 dpi, 200 means double size (144 dpi), 50 means half size (36 dpi), etc.
pdfZoomPage, meaning "fit a whole page in the window"
pdfZoomWidth, meaning "fit the page width to the window"
pdfZoomHeight, meaning "fit the page height to the window"

The default zoom value when a new viewer object is created is pdfZoomWidth.

pdfSetZoom(viewer, 150);