Wraps FPDFPage_InsertClipPath. After insertion the clip path is
owned by the page; the R-side pdfium_clip_box handle's
externalptr is cleared automatically so subsequent operations on
it error cleanly via is_open().
Arguments
- page
A
pdfium_pagefrompdf_page_load()orpdf_page_new(). Parent doc must be readwrite.- clip_path
A
pdfium_clip_boxfrompdf_clip_path_new().