Pdfa 1a

[jjelosua]

Hi @galkahana,

First of all, thank you for your wok in this library and glad to see you have come back to it.

While using PDFWriter for a project we have detected that if the original document is pdfa-1a compliant simply recreating it or modifying it using some new IUs broke the standard validation (tested with: Verapdf and Avepdf).

As you can see the modifications are minimal but effective.

• The DocumentContext.cpp one comes straight from the ISO19005-1 standard clause 6.1.2, just added a new >127 byte
• The PDFWriter.cpp one is caused when we try to modify a PDF file using IUs, the first oject was added in the same line as the %%EOF of the original document causing an error in the validation. Just added a new line separator in ModifyPDFForStream in the same way that it was done in the ModifyPDF function above.

Attached you can see a screenshot of the xml report that avepdf provided with the error and a screenshot the chunk of the PDF where we have highlighted where the error that avepdf is complaining about is made:

[galkahana]

Thanks man!
looks good. im gonna take it.