Hypobat

Hypobat

BETA 0.4.20-beta

Cross-platform PDF viewer & annotator

Open a hundred-megabyte, thousand-page drawing and be reading it a second later. Mark it up with highlights and notes that every other PDF reader understands. Save it without ever putting the file you started with at risk.

Choose a download See what it does

Windows 10/11 x64 installer · Linux x86-64 and ARM64, .deb or AppImage · Android in progress · ChromeOS later

Measured, not asserted

  • ~1 sA hundred-megabyte drawing of a thousand pages, open and readable. The page count, outline and thumbnails fill in while you read.
  • ~90 msThe window is there before you have let go of the mouse — in the app's own colour, with its icon in place. Measured on Linux.
  • 112,000A drawing carrying that many form fields opens in about a second, with every field ready to fill in.
  • GigabytesA multi-gigabyte scan stays smooth to scroll, not merely possible to open.

What it does

A reader that also edits, and does not lose your file doing it

Your highlights and notes open correctly in Acrobat, Preview and Okular — they are ordinary PDF annotations, not a private format. And a save that is interrupted cannot damage the original.

Viewing and navigation

Zoom in, fit the page, fit the width. Long scanned documents stay smooth to scroll, and a page you have just marked up redraws without flickering.

  • Single page, facing pages, or facing pages with the cover alone
  • Continuous scrolling or page-at-a-time, independent of the layout
  • Rotate the view a quarter turn without changing the file — a 90° chip says so
  • Night mode and page-colour inversion as separate switches; full screen on F11
  • Tabs, one per file, and Alt+← / → to retrace jumps
  • Sidebar with thumbnails, outline, your own bookmarks and a comments list

Annotating and markup

Highlight, underline, strikethrough and squiggly on a selection; freehand ink; rectangles, ellipses, lines and arrows.

  • Sticky notes with author and timestamp, listed in the sidebar with jump-to
  • Text boxes with a font size and a frame — editable afterwards, and re-wrapping rather than stretching when resized
  • Signatures and initials: a drawing pad with a pen, a stroke eraser and four inks, or import a PNG
  • Select, move, resize and delete anything already on the page
  • Undo and redo across 19 steps, with the buttons naming the step — "Undo highlight"

Text and search

Select by drag, word by double-click, line by triple-click — a drag may start in the margin and anchors at the nearest character.

  • Three syntaxes: plain text, wildcards, and regular expressions
  • Starts while you type; a pattern that will not parse is reported in the bar
  • A 1094-page document searches in about 1.8 s the first time, a fraction of a second after that
  • F3 and Shift+F3 go on finding with the bar closed
  • A jump waits for its destination to be drawn, so the page arrives sharp instead of resolving in front of you

Forms and page tools

Fill in forms — text fields, checkboxes, radio buttons, dropdowns — and the values are saved with the document.

  • No limit on how big a form may be: a drawing with six figures worth of fields opens ready to fill in
  • Rotate a page or every page, insert an empty page before or after, delete one
  • Insert pages from another PDF with a range picker
  • The thumbnail menu and the page menu offer the same entries in the same order

Saving and exporting

A save that is interrupted cannot damage the original — not even a Save As onto the file you already have open.

  • Save As can set the PDF version, 1.4 to 2.0
  • Flatten annotations into the page, including the marks that other tools quietly lose when they flatten
  • PDF/A export for archiving, with anything it cannot make conformant reported rather than hidden
  • Password-protect a copy, opened again with the password before it is kept — so it can never be written unreadable
  • Autosave of unsaved work, offered back after a crash
  • Edit the title, author, subject and keywords; the properties show the change at once

Printing

What reaches the printer is the document as it stands, unsaved annotations included. The document you are working on is not touched.

  • Printer, copies and page ranges (2-5, 8); a range naming pages that do not exist is refused in place
  • Pages are fitted to the paper and centred, never stretched
  • A password-protected document prints like any other
  • macOS cannot print yet, and the dialog says so

And the rest of it

An offline manual on F1 that opens at the topic of whatever has the keyboard, with its own search. Document properties on Ctrl+D, down to which page sizes a mixed document actually contains. Bookmarks of your own that never touch the document, so they work even on files you cannot write to. A window whose tab strip is its title bar, remembering its size and position. Password-protected documents opened, annotated, printed and saved like any other. Keyboard shortcuts for effectively all of it — and, in the search box, every shortcut a text caret has no use for keeps working.

And, beside the PDFs, it reads Markdown: the README next to the drawings opens in a tab of its own, rendered in the app's theme, with its headings as the sidebar, find, text size, a copy button on every code block and the same context menu. Windows ships no viewer for .md files at all, so the installer offers Hypobat as one. Displayed, never edited: closing a Markdown file never asks.

Downloads

Two platforms have something to download. The other three say so.

Windows Installer

One file to download and run. It asks whether to install for everyone on the computer — which needs an administrator — or only for you, which needs nothing at all. It removes again from Settings ▸ Apps like any other program. It registers for PDF files, and for Markdown files as well.

Windows 10/11, x64
hypobat-0.4.20-beta-setup.exe · 17 MB

Download the installer

Linux Download

Two downloads, one application. On Debian, Ubuntu and their relatives the package installs Hypobat like any other program — a menu entry, the icon, PDFs (and Markdown files) opening in it — and removes like one. Everywhere else the AppImage is a single file: nothing is installed, and removing it is deleting the file. This is the platform everything lands on first.

Both are built for 64-bit ARM as well — a Raspberry Pi, an ARM laptop. That build is the newest thing on this page: it has been seen opening documents on a Raspberry Pi 4, and has not yet done real work there.

x86-64 · Ubuntu 22.04 and later, Debian 12+, Fedora 35+, RHEL 9+

Debian, Ubuntu, Linux Mint and other Debian-based systems: the package. Install it from the folder it was saved in with sudo apt install ./hypobat_0.4.20~beta-1_amd64.deb
hypobat_0.4.20~beta-1_amd64.deb · 12 MB

Download the package

Every other distribution: the AppImage. A browser saves it without permission to run, so make it executable first — in the file's Properties, or with chmod +x hypobat-0.4.20-beta-linux-x64.AppImage
hypobat-0.4.20-beta-linux-x64.AppImage · 14 MB

Download the AppImage

or the same build as a folder: hypobat-0.4.20-beta-linux-x64.tar.gz · 14 MB

64-bit ARM — a Raspberry Pi 4 or 5 on the 64-bit Raspberry Pi OS, an ARM laptop or board: the same three, built for arm64, for the same systems, and installed or made executable the same way.
hypobat_0.4.20~beta-1_arm64.deb · 11 MB
hypobat-0.4.20-beta-linux-arm64.AppImage · 14 MB
hypobat-0.4.20-beta-linux-arm64.tar.gz · 14 MB

Android In progress

It runs, and it does real work. Documents open through the system's own chooser and are written back where they came from; one finger scrolls, two zoom, a long press opens the page menu; the back gesture closes a document rather than the app, and Hypobat appears in Android's “Open with”. What is missing is the packaging: there is no signed build, so there is nothing here to install yet.

No build published

Not yet available

ChromeOS For the future

Chromebooks run Linux applications in a container, and the Debian package under Linux installs there and puts Hypobat in the launcher — that much has been done on a real ChromeOS machine. What has not been confirmed is that it then draws its window: the only machine available to test on is a virtual one, where the graphics are emulated twice over and nothing is rendered. Until a Chromebook settles that, ChromeOS is not offered here as a platform of its own. An ARM Chromebook would want the ARM package, which no Chromebook has been near either.

Not offered yet

Not yet available

macOS and iOS Planned

Targets from the first day and nothing more than that so far: neither has been built, and macOS cannot print even in principle yet. They are on the list, without a date attached to them.

Not built

Not yet available

Version 0.4.20-beta

What beta means here

It means the version number starts with a zero and the app says BETA beside its own name, on the startup screen and in About. It does not mean a demo: this is the build its author uses every day on real documents, which is also the reason the save path gets more attention than the icons do.

What works

  • Everything described above, on Linux and on Windows
  • Saving, flattening, PDF/A export, password protection and printing, each checked by opening the result again
  • Large and awkward documents — multi-gigabyte scans, drawings with six-figure field counts, password-protected files

What is still moving

  • Versions advance in small steps, often several in a day; behaviour can change under you between them
  • Android is being adapted from a desktop application and is not finished
  • The interface is English only; other languages are prepared for but not written

Not there yet

  • Cryptographic signing — today you can place a signature you have drawn, which is not the same thing
  • PDF/A output checked against an independent validator, and embedded fonts for it
  • Presentation mode
  • No support organisation and no ticket queue — there is one author, and no pretence otherwise