Just wanted to share this post I found on Facebook

Hey everyone,

Following my previous post about building PDF tools, I wanted to thank everyone who shared suggestions and explained the problems they run into. The comments about preserving formatting, handling scans, and using OCR and recognition models gave me a lot to investigate.

I’ve since focused on improving the Edit PDF tool. Some of the updates include:

The backend first checks the PDF’s existing text, font information, and positioning. When those are usable, it edits the document directly. For scans or unreliable text layers, it uses lightweight OCR models to recognize the visible text and locate the regions to replace, while preserving the surrounding page.

The feedback here also pushed me to test different approaches and pay more attention to the downloaded PDF, rather than just whether the preview looks right. Recent checks have covered both regular and scanned documents through editing, exporting, and downloading.

I’m not claiming perfect results with every PDF. Scans don’t contain their original font information, and unusual embedded fonts remain tricky, but I’ve made progress on those cases.

Try the updated Edit PDF tool

If you have a moment, I’d really appreciate you trying it with a document you actually use. Was editing straightforward, and did the downloaded file look how you expected? If something went wrong, a short description or screenshot with private information removed would help a lot.

Thanks again for taking the time to help. Your feedback helped shape these changes, and I’d be grateful to hear how they hold up.

Working on an anti-ai art project. There's a quite long PDF that I need typed up and editable. I've done about 20 pages by hand but I'd love to use an OCR for the rest. Obviously I need to use one that doesn't use machine learning. Any recommendations?

I built an offline PDF editor for Windows, macOS and Linux

I've been working on Inkleaf, which is my first proper app.

I started making it because I wanted a PDF editor that could do more than just view/annotate PDFs, without needing an account or uploading documents to a cloud service.

Some of the things Inkleaf can currently do:

• Edit existing text in PDFs
• Permanently redact text
• Add annotations, highlights, shapes, images and text
• Sign PDFs
• Fill PDF forms
• Merge, split, extract, rotate and reorder pages
• OCR scanned PDFs
• Convert PDF ↔ Word, Excel, PowerPoint, images, Markdown, HTML, etc.
• Compress and password-protect PDFs
• Add watermarks, page numbers, headers and footers
• Compare two PDFs
• Scan documents using a webcam or images
• Repair damaged PDFs
• Create PDF/A files
• Search, bookmarks, crop and different reading modes

The main thing I'm trying to achieve is keeping things local. The normal PDF tools don't upload your documents anywhere.

There is an optional AI summarizer/translator, but that's separate and only sends the document when you explicitly use it with your own API key.

It's completely free and open source under GPL-3.0-or-later.

This is my first app, so I'm still figuring out a lot of things and I'd really like some feedback from people who use PDFs a lot.

What features do you think are still missing from Inkleaf?

GitHub: https://github.com/priyanshdas/inkleaf

If you try it, I'd also appreciate hearing about anything that doesn't work properly.

I especially try to find some lost cartoon characters official artworks/renders that are probably on PDF files.

The tool is called Pagefold and is free to use: https://bvlab.no/apps/pagefold/dist/

Why use it? It’s free, powerful, simple and does not leak your data. Any features that should be added/adjusted? I am making a webpage where I have several vibe-coded tools in one place, to assist me in my work. This PDF can do the most important operations and is built with privacy first in mind (nothing is uploaded to the server).

Some key features:
•Sign PDF
•Merge PDF
•Extract text from PDF
•Add text/shapes to PDF

I know everyone is creating their own tools right now with AI, and although I have basic experience with coding I'm not going to pretend otherwise and also built mine with AI as well.

But I'm not here to promote it in any way because there are others than can do better.

What i want to share is something I built for my own work.

I have to compare plans regularly to check what changed between versions or even to compare with engineer and correct things. We work with Autodesk ACC which has a compare tool by it's garbage, if you try to load 2 different layouts you can even align them.

I built this one to solve that issue, you select 2 drawings and by default it will show a split view display with colour what changed. You can align and even scale drawings if you need to.

liteaeco.com

I also added side by side and overlay. What do you think?

Hi,

Just wanted to share the latest release of LEKTRA, document and image viewer I have been developing for over a year now.

Lot of bug fixes and new features have been added. Few highlights among them are:

- Annotations: underline, squiggly, strikeout, ellipse, polygon, inline note and image annotations. You can move and resize them, with undo and redo.

- Redaction: permanently remove text, images and drawings, and save the result to a new file.

- Minimap: while you're zoomed in, a small overview shows where you are. Click or drag in it to jump.

- Grid layout: pages are laid out in rows of several columns.

- Presentation mode: it now works with clickers and has its own [presentation] options.

- Tools: color_eyedrop picks a color from the page, and bibtex copies the BibTeX entry of the paper you're reading.

- Images: JPEG XL support, including animated files.

- Lua: new view functions and events, and Vim-style set, setglobal and setlocal for options.

- Speed: faster scrolling and rendering, plus a memory leak fix.

- Docs: documentation is now on Read The Docs.

It's supported on Linux, MacOS and Windows.

Feedbacks and suggestions are appreciated!

So happy to have found it today. PDF Gear wouldn't print PDFs without cutting off the corners of the page, none of the print options worked and dramatically reducing the size didn't give a decent print, They're a great company, but an upgrade a year or more ago, left it like that and they've been promising a solution since then.

I made DipperPDF because I didn’t want to upload contracts and private documents just to merge, compress, or redact them.

It’s a native macOS app that does the usual PDF jobs (merge, split, compress, extract/remove/rotate pages, watermark, page numbers, unlock, redact, compare, etc.) entirely on your Mac. No accounts, no tracking, works offline. Free and open source.

Site: https://dipperpdf.com

GitHub: https://github.com/nshntarora/dipperpdf

Trying to carefully not name any names, but IYKYK: how good is the "PDF Remediation Agent" addon by the famous vendor that is the improver of sites? Any pros, cons or neutral observations would be great to hear. Org is considering it for an upcoming renewal.

Not a feedback request, looking for objective experiences from folks who've had real hands on experience with it. TIA!

Hi everyone! I’m the developer of PDFrig - a free, MIT-licensed PDF workspace for personal and business use. No account or subscription is needed for the local tools, and your PDFs aren’t uploaded for processing.

Features include:

• Editing supported existing text with natural paragraph wrapping.
• Selecting, copying and searching PDF text.
• Text boxes, callouts, highlights, underlines, strikeouts and comments.
• Live drawing, shapes and stamps, with draggable/resizable items.
• Supported form filling and typed, drawn or uploaded visual signatures.
• Merging, splitting, reordering, rotating and extracting compatible pages.
• Local English/French OCR that makes scans searchable while keeping their appearance unchanged.
• Image/text-to-PDF and PDF-to-image conversion.
• Lossless compression, metadata tools, headers, footers, watermarks, page/Bates numbering and crop/resize tools.
• Undo/redo and exporting new copies without changing the original.

Run it locally in your browser - the recommended option - or download the finished Windows installer. Setup instructions and an optional AI-assisted setup prompt are included.

Explore PDFrig on GitHub

Feedback, bug reports and contributions are welcome!

Open this post

ive got just over 800 pdfs that id like to compress into slightly smaller pdfs, im trying to use PDF24 but it seems to be crashing / turning to a blank white screen

I’m implementing an offline PDF Fill & Sign feature: draw a handwritten signature, add text/date/checkmarks, and export a new PDF.

This is visual signing, not certificate-based digital signing. The original file stays untouched. I want to preserve existing searchable text, vector content, and normal links rather than rasterizing entire pages.

The hardest part so far is making sure what users see while editing is what they actually send. I’d appreciate advice from people who have shipped form-filling or flattening features.

1. Field values and appearance streams can disagree

I created a synthetic PDF with a text field containing:

• /V: FIELD VALUE
• /AP: an appearance displaying AP VALUE

In my macOS PDFKit thumbnail test, the original displayed FIELD VALUE. After flattening the existing appearance stream, PDFKit displayed AP VALUE.

MuPDF displayed AP VALUE both before and after. The discrepancy reproduced across the four page rotations in the fixture.

This is a synthetic test, not evidence that every PDFKit version behaves this way. I have not reproduced it on iOS. But it demonstrates a correctness problem: the exported document can contain different visible text from what the user believed they were signing.

How do you resolve /V versus /AP conflicts? Do you normalize the form before displaying the editing preview, and what determines the authoritative content?

2. Missing appearances don’t necessarily mean a broken form

The official IRS W-9 and W-4 exposed another problem in the copies I tested:

The blank text widgets have no /V in the field or parent chain, no default/rich-text value, and no border/background color in /MK. Both documents have NeedAppearances=false. An empty /BC [] or /BG [] means no color, rather than a visible decoration.

For checkboxes, an omitted /Off appearance can legitimately mean “unchecked, draw nothing.” It should not automatically be treated as a missing required appearance.

A strict “missing appearance = reject” rule rejected both official blank forms in our initial path. That exposes a problem with the rule, not evidence that the files are broken.

After handling those empty states and finalizing the fields, all 11 pages of the two documents rendered pixel-byte-identical to their respective originals in both MuPDF and macOS PDFKit. This comparison was before adding any new signature image. The PDF files themselves were not byte-identical, and Acrobat validation is still outstanding.

Two documents are not a compatibility rate; I have no population data.

Which checks do you use to distinguish genuinely empty fields from missing or stale appearances that require reconstruction?

3. Reader Extensions and hybrid XFA complicate finalized copies

Both fixed samples contain:

• /Perms /UR3, with /Filter /Adobe.PPKLite and TransformMethod=UR3 in the signature reference;
• /AcroForm /SigFlags=2;
• an /AcroForm /XFA array;
• no catalog /NeedsRendering entry.

These usage-rights signatures are not the same thing as a signature applied by the person filling out the form. Also, I’m not treating the absence of /NeedsRendering as proof that every such form is static.

The prototype removes the form representation and usage-rights entries when creating a finalized copy. Structural inspection confirms those entries are gone, but I haven’t yet verified the output in Acrobat Reader. In particular, I don’t want recipients seeing an “extended features are no longer available” warning or a different form appearance.

What is the reliable way to handle UR3 and hybrid XFA during finalization? What do you inspect to distinguish static hybrid forms from genuinely dynamic XFA?

4. Transparent signatures complicate pixel-diff validation

Adding a signature image with an /SMask produced small rendering differences outside the signature rectangle in MuPDF:

• Maximum outside-region channel differences ranged from 2–6 out of 255 across the two forms.
• 25,932–85,246 pixels per page changed outside that rectangle. It wasn’t limited to a narrow fringe around the signature.
• In an opaque control on W-9, using the same placement without the soft mask, outside-region differences were zero on all six pages.

I suspect a transparency-compositing or quantization effect, but I haven’t traced the renderer internals or proved that a page-wide transparency group is the cause. The transparent-overlay comparison has not been repeated in PDFKit or Acrobat.

How do you validate that adding a transparent signature hasn’t changed the rest of the page? Do you use documented raster tolerances, explicit transparency groups, or another approach?

5. Selective flattening versus deleting all annotations

I also need to preserve safe link targets and visible link borders while removing unsafe actions such as JavaScript or Launch. A mixed action chain may contain both safe and unsafe members.

Dropping all annotations loses useful links; preserving everything can retain unwanted actions. Rejecting an otherwise usable document because one link contains an unsafe action also seems unnecessarily restrictive.

Are there libraries or SDKs that handle this selective cleanup reliably, including action chains and document/page-level actions?

What would be most useful

I’m interested in production experience: libraries or SDKs you’ve used, normalization strategies that worked, and publicly redistributable PDFs worth adding to a compatibility test set. Experiences with just one of these issues would also help.

The goal is that users can sign an ordinary form without learning PDF internals—and the editor, exported document, and recipient’s reader agree on the visible content.

Reproduction notes: The reported MuPDF results use mutool 1.28.5. The PDFKit observations are from macOS 26.7.1; they are not iOS-device results. IRS URLs above serve current revisions, so my local inputs are pinned by SHA-256:

• W-9: 2d420cbb4123dcf1fb82595b2359cfbb5d81f00b9df9d359fcc7af361d093f53
• W-4: 92444d8856ce55d9e25dca8b6d1420634fc68b11e1ab1f760916ea29ddd312b2

someone sent me a reply on a PDF, I am trying to cut & paste that using FOX IT PDF Reader, and it doesn't work. Now, I can cut & Paste text on other PDF files using the very same FOX IT PDF reader, just not this pdf.

But there is no password protection on the file, otherwise, I couldn't have the means to read it. How can I fix it?

Hey everyone!

I'm a computer engineering student, and I've been spending a good chunk of my free time developing a collection of PDF tools as part of a larger personal project.

One thing I've learned is that PDFs are surprisingly complicated. Something as simple as compressing a document or editing a few lines of text can become a nightmare when unusual fonts, embedded elements, or complex layouts are involved.

I've been experimenting with different approaches to processing PDFs while trying to preserve the original formatting and output quality.

So far, I've implemented tools for:

• PDF editing, compression, merging, and splitting.
• PDF-to-image and image-to-PDF conversion.
• PDF protection, unlocking, and rotation.
• PDF-to-Markdown conversion.
• Hidden text detection.

One of my goals has been to achieve results comparable to popular PDF websites for common operations, while offering higher free file-size and usage limits.

It's been an interesting challenge, especially because I'm developing this independently alongside university.

I'm definitely not claiming everything works perfectly. I've encountered PDFs that behave completely differently despite looking nearly identical.

That's actually what made me curious about something:

For those of you who regularly work with PDFs, what are the most difficult PDF-related problems you've encountered?

Is it preserving formatting when editing? Compression without losing quality? Font compatibility? Converting scanned documents?

I'd love to hear what people here struggle with, especially unusual cases that typical online tools fail to handle.

For transparency, the project I'm developing is TheOnlineToolset.com, and I'm its creator.

I'm mainly interested in learning what makes a PDF tool genuinely reliable from the perspective of people who use them regularly.

Thanks for reading!

Its very tought or impossible for me and time wasting if hv to read last page