Show HN: Nano PDF – A CLI Tool to Edit PDFs with Gemini's Nano Banana

Posted by GavCo 10 days ago

The new Gemini 3 Pro Image model (aka Nano Banana) is incredible at generating slides, so I thought it would be fun to build a CLI tool that lets you edit PDF presentations using plain English. The tool converts the page you want to edit into an image, sends it to the model API together with your prompt to generate an edited image, then converts the updated image back and stitches into the original document.

Examples:

- `nano-pdf edit deck.pdf 5 "Update the revenue chart to show Q3 at $2.5M"`

- `nano-pdf add deck.pdf 15 "Create an executive summary slide with 5 bullet points"`

Features:

- Edit multiple pages in parallel

- Add entirely new slides that match your deck's style

- Google Search enabled by default so the model can look up current data

- Preserves text layer for copy/paste and search

It can work with any kind of PDF but I expect it would be most useful for a quick edit to a deck or something similar.

GitHub: https://github.com/gavrielc/Nano-PDF

Comments

Comment by tecoholic 10 days ago

> Converts an image to a single-page PDF with a hidden text layer using Tesseract. This is the 'State Preservation' step.

Does this mean the text only pdf page is transformed into an image that covers the full page, but the text is still under there. So, any machine based extraction would still get the text, but would probably loose all the bounding box information and regular users cannot just use their mouse to select text anymore?

Comment by kumarm 10 days ago

Seems true and really wish the project included some sample PDF output.

My Text to Speech app uses bounding box to display what text in PDF is being read and would not work well PDF's from this project.

Comment by GavCo 10 days ago

OP here, I added a sample PDF output in the project assets and put screenshots in the ReadMe. The text is selectable after rehydration. would this work with your app?

Comment by kumarm 9 days ago

Amazing. Worked really well. Thank you.

Comment by tecoholic 9 days ago

Wait! what? This is incredible. Amazing work.

Comment by lxe 10 days ago

This is nuts and I absolutely love this. So you convert the PDF into image, edit the image, then convert the image back into a PDF.

Comment by thenthenthen 10 days ago

This is the usual workflow dealing with pdfs (unfortunately)

Comment by esafak 9 days ago

No, it's not, unless you are dealing with scans. Lots of apps let you edit PDFs.

Comment by shevis 10 days ago

A side effect of replacing entire pages with images is that the file size will expand dramatically. Most PDFs only contain a couple of images

Comment by falcor84 10 days ago

It might be feasible to have an intermediate AI call take the generated image and slice it into individual text and image elements that it would then render into the pdf page

Comment by moezd 10 days ago

Behold, the might of LLMs! Instead of ushering the age of AGI as advertised 6 months ago, now it cleans your PDFs for you.

Many thanks to humanity for failing to standardise PDF and this project for paying interest on that tech debt with datacenter levels of energy consumption.

Comment by struc_so 8 days ago

Interesting approach. I've spent a lot of time wrangling PDF internals recently, and the issue is usually maintaining the xref table integrity when you inject new content streams.

Does this approach rewrite the entire file structure on save, or are you appending incremental updates to the EOF? Incremental is safer for corruption, but file size bloats quickly with AI-generated diffs.

Comment by treetalker 10 days ago

I'd love to see clearer examples: a video, or original pdf / command / result pdf. Very cool!

Comment by jimmySixDOF 2 days ago

Is Tesseract still considered the go to here for OCR I would have thought lot of other options are out there now

Comment by perfectritone 10 days ago

It's incredible how many hacks there are to make PDFs semi-usable.

Comment by itsmevictor 10 days ago

Very nice! I wonder whether that could be used to get LLMs to annotate pdfs. Say an "agentic" CLI like Claude Code or Gemini-cli reviews a pdf and finds typos, could it use this to annotate the pdf like underlining them in red or something of that sort? That could be nice.

Comment by mentalgear 10 days ago

Nice - but consider adding an animated screengrap like: https://github.com/pythops/oryx

Comment by yoavm 10 days ago

Please don't add an animated gif to your README. Nothing worse than an autoplaying video with no controls, that has 10 frames but takes 5.4MB to download. Github supports normal video files. It allows the user to rewind or pause, and it results in a much smaller file size.

Comment by varenc 10 days ago

Generally agreed! though fun point of info: you can use the .avif format to get something that behaves just like a gif (auto-playing, no sound, no controls) but supports modern features (HDR/transparency channel) and is compressed as well as a modern video is, since its just AV1. And it's supported in most all modern browsers these days: https://caniuse.com/?search=avif

Comment by ornornor 10 days ago

I tend to use webm but I’m curious, is avif better (performance, size) for gif?

Comment by varenc 9 days ago

Webm is better in many ways, but it doesn't give you gif-like behavior I think. As in, you can't just include it in an <img> tag and a get an autoplaying looping video. Though you can simulate it with <video>.

Basically, .avif is an "animated image" format, like .gif, but .webm is only a video format.

edit: just realized .webp i think can be an animated image! So that seems like the alternative

Comment by ornornor 9 days ago

Thanks

Comment by iamflimflam1 10 days ago

The lack of examples makes me very reluctant to commit any time to trying this out - despite it being something that I’m interested in.

Has anyone given any it a go? Does it work?

Comment by stingraycharles 10 days ago

What? There are examples in the repo and even in OP’s post.

I haven’t tried it, but there are plenty of examples.

Comment by albert_e 10 days ago

Do you mean example commands? we see those examples on the githib README, yes,

But people here are probably also looking for example input and output PDFs (or images/screenshots) showing the actual work done to get a sense of what to expect.

Comment by iamflimflam1 10 days ago

Exactly - if these examples work really well, then include some screenshots.

Comment by ThrowawayTestr 10 days ago

I recently tried to change a single word in a PDF and nearly tore my hair out (thank you LibreOffice) I'll definitely keep this in mind for next time, thank you.

Comment by tkfoss 10 days ago

Try photopea next time

Comment by albert_e 10 days ago

Wow - didnt know about this tool for PDF editing - thanks!

https://www.photopea.com/

PS: in my quick test of editing a PDF text -- the output PDF had weirdly added an extra "&" symbol at the end of every existing line of text. will try out more to see if it was something in the input PDF that was causing it.

Comment by fzysingularity 9 days ago

What is photopea built on?

Comment by tkfoss 8 days ago

Author does yearly AMAs on reddit, you should look it up.

Comment by McNulty2 10 days ago

I like the example of updating latest market data. Updating a deck one-off is tedious. Keeping it updated long-term was never going to happen. But now it can

Comment by toddmorey 10 days ago

I thought it was kinda funny that Google Slide’s own built in “beautify this slide” button converts the whole slide into an uneditable image.

Comment by albert_e 10 days ago

AFAIK -- even the "Designer" feature of Microsoft Powerpoint (now folded under Copilot license I believe) gives slide deigns with shapes etc that are not editable. Thankfully the text remains editable. But if we wnat to ever so slightly modify the suggested design my removing or reshaping some if the shapes ... nopes. Feels like they are worried about humans with taste ripping-off the AI output :D

Comment by mlpoknbji 10 days ago

Somewhat unrelated but can anyone recommend a way to edit the text of a PDF using LLM? Something like AI + acrobat pro?

Comment by ohans 7 days ago

Really cool! I reckon a nice UI would be a good addition

Comment by informal007 10 days ago

it will be more excited if i can use this feature in application with GUI, it’s now convenient to check the result after edit the PDF, i need to transfer between CLI and PDF reader

Comment by vood 10 days ago

Congratulations on the release; that's a really good job.

Comment by John7878781 10 days ago

Love this.

After several iterations of edits, would the image quality decrease?

Comment by Zopieux 9 days ago

I am disappointed that this doesn't modify the underlying pdf structure (which is a horror show, I know) but instead relies on fairly lossy OCR back&fourths.

I wish an agent with a validation and rendering tools could instead manipulate the structure to accomplish those edits way less destructively, checking its progress with the tools.

Comment by mertleee 10 days ago

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Comment by sultson 10 days ago

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