If I create a PDF from scratch using Pdfium.Net, I see that each new object saves and restores the graphics state with the q and Q operators wrapped around its content. Therefore, if I am working with my own documents, I can treat the Matrix property for each new PdfPageObject I add as an absolute transformation for that object.

However, if I load a PDF that originates from some other source that I do not control, the graphics state (or Current Transformation Matrix) after the existing page objects have been loaded could be anything. Therefore, the matrix I apply to my first new object is concatenated with the CTM, and may appear with unintended transformations applied.

Is there a straightforward way to wrap a q and Q operator around the existing PdfPageObject collection using Pdfium.Net? This would probably have the same effect as clearing the CTM.

Alternately, is it possible to determine the current transformation matrix that results from the existing collection of PdfPageObjects? For example, is there a way to detect or count the q and Q operators that have been issued already, in order to calculate the CTM by concatenating the matrices of those objects that were generated on the current graphics state stack? Then I could calculate the inverse of that matrix and use that as a starting point before adding new objects.