How can I set the Transformation-Matrix in Libharu?

Question

I want to use libharu to render my documents to PDF. I would like to set a global scalefactor, which translates my document coordinates to the pdf-page coordinates.

The only function in libharu, which has to do with scaling, is HPDF_Page_GetTransMatrix(page).

HPDF_Page_GetTransMatrix() returns the struct HPDF_TransMatrix as a value, not as a reference, so I cannot change the scaling by setting the elements of that returned matrix.

I miss the Set-Counterpart for the function HPDF_Page_GetTransMatrix()-function.

How can I set a scalefactor?

Answer 1

HPDF_Page_Concat() is the function I looked for. See here