Set the horizontal scale factor.
[read/write property] xScale([out, retval] double *scale) xScale([in] double scale)
This property sets the horizontal scale factor, where 1.0 means actual size, 0.5 means half-size, 2.0 means double-size, etc.

Similarly, the yScale property sets the vertical scale factor.

resetParams resets these to their default values, which means to print at actual size (xScale = yScale = 1) if the PDF page fits on the paper, and to shrink larger pages to fit (xScale = yScale < 1).

pdf.xScale = 0.75 pdf.yScale = 0.75