When processing big files (both on input and output), the UI is locked.

Both input and output should be done in the background.

There should be some way to at least see a progress indication, maybe with the possibility of cancelling the action.

It would be interesting to be able to setup document metadata, such as author, and document settings, like zoom, password, print/copy permissions, etc.

OCR would be a great feature to have!

Could be through a third-party library or a self-made one, though that last would be quite a challenge (while the first is a supposedly smaller challenge to integrate).

When images are imported to PDF, they are left open, even after clearing the file list. This locks the file for exclusion by the OS, for example.

Thanks for the improvements on image extraction code that is floating around!

I am having some trouble with indexed color spaces for the Flate Decode filter. Specifically, the line:
img.putpalette(lookup.getData())

It fails for color maps that are longer than 768 entries with the error:
ValueError: invalid palette size

For images with a color index that is shorter, it seems like the image isn't being rendered correctly - I see really strange results.

I have attached a pdf with examples of images that have color index length from 368 to 956, so you can see both failure modes. The code does seem to work when the color index is exactly 768.

0198008e-8628-47be-b674-a4e26a419e98.pdf

When resizing the main window, the action buttons also resize, occupying space that is better used by the list widgets.

It might be useful to allow to create a bookmark for each input file.

Some places, specially web services, require a maximum document size in bytes. For PDFs, it's very frustrating to have to extract the images and then optimize the output to fit the size limit.

It would be great to have a feature to optimize the document aiming at reducing the file size by trading image quality.

To be investigated

Long filenames (those that do not fit in the list widget width) get occluded (hidden).

There should be an automatic scrollbar on these cases.

Also, there should be a splitter to allow resizing inside the main window.

No settings are saved from one execution/session to the next.

Settings such as image DPI, "Open files after saving" checkbox and window geometry should be saved for the next session, when the program closes.

Some documents are encrypted.

PyPDFTK should allow them to be decrypted with a password. There should also be some way to change other security settings. And maybe also encryption.