diff options
Diffstat (limited to 'TODO')
| -rw-r--r-- | TODO | 131 |
1 files changed, 37 insertions, 94 deletions
@@ -28,76 +28,54 @@ Next can only be used by one thread at a time, but multiple threads can simultaneously use separate objects. + * Write some documentation about the design of copyForeignObject. -Soon -==== + * copyForeignObject still to do: - * Provide an option to copy encryption parameters from another file. - This would make it possible to decrypt a file, manually work with - it, and then re-encrypt it using the original encryption parameters - including a possibly unknown owner password. + - qpdf command - * See if I can support the new encryption formats mentioned in the - open bug on sourceforge. Check other sourceforge bugs. + Command line could be something like - * Splitting/merging concepts + --pages [ --new ] { file [password] numeric-range ... } ... -- - newPDF() could create a PDF with just a trailer, no pages, and a - minimal info. Then the page routines could be used to add pages to - it. + The first file referenced would be the one whose other data would + be preserved (like trailer, info, encryption, outlines, etc.). + --new as first file would just use an empty file as the starting + point. Be explicit about whether outlines, etc., are handled. + They are not handled initially. - Starting with any pdf, you should be able to copy objects from - another pdf. The copy should be smart about never traversing into - a /Page or /Pages. + Example: to grab pages 1-5 from file1 and 11-15 from file2 - We could provide a method of copying objects from one PDF into - another. This would do whatever optimization is necessary (maybe - just optimizePagesTree) and then traverse the set of objects - specified to find all objects referenced by the set. Each of those - would be copied over with a table mapping old ID to new ID. This - would be done from bottom up most likely disallowing cycles or - handling them sanely. + --pages file1.pdf 1-5 file2.pdf 11-15 -- - Command line could be something like + To implement this, we would remove all pages from file1 except + pages 1 through 5. Then we would take pages 11 through 15 from + file2, copy them to the file, and add them as pages. - --pages [ --new ] { file [password] numeric-range ... } ... -- + - document that makeIndirectObject doesn't handle foreign objects + automatically because copying a foreign object is a big enough + deal that it should be explicit. However addPages* does handle + foreign page objects automatically. - The first file referenced would be the one whose other data would - be preserved (like trailer, info, encryption, outlines, etc.). - --new as first file would just use an empty file as the starting - point. + - Test /Outlines and see whether there's any point in handling + them in the API. Maybe just copying them over works. What + about command line tool? Also think about page labels. - Example: to grab pages 1-5 from file1 and 11-15 from file2 + - Tests through qpdf command line: copy pages from multiple PDFs + starting with one PDF and also starting with empty. - --pages file1.pdf 1-5 file2.pdf 11-15 -- + * (Hopefully) Provide an option to copy encryption parameters from + another file. This would make it possible to decrypt a file, + manually work with it, and then re-encrypt it using the original + encryption parameters including a possibly unknown owner password. - To implement this, we would remove all pages from file1 except - pages 1 through 5. Then we would take pages 11 through 15 from - file2 and add them to a set for transfer. This would end up - generating a list of indirect objects. We would copy those objects - shallowly to the new PDF keeping track of the mapping and replacing - any indirect object keys as appropriate, much like QPDFWriter does. - When all the objects are registered, we would add those pages to - the result. - - This approach could work for both splitting and merging. It's - possible it could be implemented now without any new APIs, but most - of the work should be doable by the library with only a small set - of additions. +Soon +==== - newPDF() - QPDFObjectCopier c(qpdf1, qpdf2) - QPDFObjectHandle obj = c.copyObject(<object from qpdf1>) - Without traversing pages, copies all indirect objects referenced - by <object from qpdf1> preserving referential integrity and - returns an object handle in qpdf2 of the same object. If called - multiple times on the same object, retraverses in case there were - changes. + * See if I can support the new encryption formats mentioned in the + open bug on sourceforge. Check other sourceforge bugs. - QPDFObjectHandle obj = c.getMapping(<object from qpdf1>) - find the object in qpdf2 corresponding to the object from qpdf1. - Return the null object if none. General ======= @@ -110,23 +88,11 @@ General * Update qpdf docs about non-ascii passwords. See thread from 2010-12-07,08 for details. - * Look at page splitting. Subramanyam provided a test file; see - ../misc/article-threads.pdf. Email Q-Count: 431864 from - 2009-11-03. See also "Splitting by Pages" below. - - * Consider writing a PDF merge utility. With 2.2, it would be - possible to have a StreamDataProvider that would allow stream data - to be directly copied from one PDF file to another. One possible - strategy would be to have a program that adds all the pages of one - file to the end of another file. The basic - strategy would be to create a table that adds new streams to the - original file, mapping the new streams' obj/gen to a stream in the - file whose pages are being appended. The StreamDataProvider, when - asked, could simply pipe the streams of the file being appended to - the provided pipeline and could copy the filter and decode - parameters from the original file. Being able to do this requires - a lot of the same logic as being able to do splitting, so a general - split/merge program would be a great addition. + * Consider impact of article threads on page splitting/merging. + Subramanyam provided a test file; see ../misc/article-threads.pdf. + Email Q-Count: 431864 from 2009-11-03. Other things to consider: + outlines, page labels, thumbnails, zones. There are probably + others. * See whether it's possible to remove the call to flattenScalarReferences. I can't easily figure out why I do it, @@ -279,26 +245,3 @@ Index: QPDFWriter.cc * From a suggestion in bug 3152169, consisder having an option to re-encode inline images with an ASCII encoding. - - -Splitting by Pages -================== - -Although qpdf does not currently support splitting a file into pages, -the work done for linearization covers almost all the work. To do -page splitting. If this functionality is needed, study -obj_user_to_objects and object_to_obj_users created in -QPDF_optimization for ideas. It's quite possible that the information -computed by calculateLinearizationData is actually sufficient to do -page splitting in many circumstances. That code knows which objects -are used by which pages, though it doesn't do anything page-specific -with outlines, thumbnails, page labels, or anything else. - -Another approach would be to traverse only pages that are being output -taking care not to traverse into the pages tree, and then to fabricate -a new pages tree. - -Either way, care must be taken to handle other things such as -outlines, page labels, thumbnails, threads, zones, etc. in a sensible -way. This may include simply omitting information other than page -content. |