Enumerate the objects on a page

Returns a list of pdfium_obj handles - one per drawing primitive on the page, in PDFium's z-order (back to front). Each element carries its type ("path", "text", "image", "form", "shading", "unknown"), a 1-based index within the page, and an internal pointer suitable for passing to downstream object queries.

Usage

pdf_page_objects(page, page_num = 1L, recursive = FALSE)

Arguments

page

A pdfium_page from pdf_page_load(), or a pdfium_doc (in which case the first page is loaded and closed automatically).

page_num

One-based page index. Only used when page is a pdfium_doc. Ignored otherwise.

recursive

Logical. When TRUE, descend into every "form" page object via pdf_form_objects() and return the flattened depth-first traversal: top-level objects first, then each form's nested objects immediately after the form, then any forms nested inside those, and so on. Nested objects carry the same parent_form slot that pdf_form_objects() would set, so callers can reconstruct the tree from the flat list. Default FALSE.

Value

A list (possibly empty) of pdfium_obj objects.

Details

Page objects do not own their own lifetime - they remain valid only as long as the parent pdfium_page is open. The handle's internal parent reference keeps the page (and transitively the document) alive for as long as you hold the object, but calling pdf_page_close() explicitly invalidates all returned objects.

See also

pdf_obj_type(), pdf_form_objects()

Examples

fixture <- system.file("extdata", "fixtures", "shapes.pdf",
  package = "pdfium"
)
if (nzchar(fixture)) {
  doc <- pdf_doc_open(fixture)
  p <- pdf_page_load(doc, 1)
  objs <- pdf_page_objects(p)
  length(objs)
  vapply(objs, pdf_obj_type, character(1))
  pdf_page_close(p)
  pdf_doc_close(doc)
}