VUISO MERGE PDF — how to use
============================

Combine PDFs into one, in the order you choose. Everything happens inside your
browser. Nothing is uploaded, there is no account, and it works with the
network switched off.

This tool works with WHOLE FILES. To drop individual pages use Vuiso Split PDF;
to turn pages that came in sideways use Vuiso Rotate PDF.


OPENING IT

  Double-click "Vuiso Merge PDF.html". It opens in your browser like a normal
  page. There is nothing to install. Chrome or Edge is recommended; Firefox and
  Safari work too.


THE SHORT VERSION

  1. Add PDF          (or drag the files onto the page area)
  2. Drag the cards until the order is right
  3. Merge & Download


ADDING FILES

  "Add PDF" accepts several files at once, and you can keep adding more later.
  Dragging files onto the grey area does the same thing.

  Each file becomes one card, showing its first page, its name, how many pages
  it has and how big it is. Only the first page is ever drawn - never every
  page - which is what keeps this tool light even on very large sets.

  The same file can be added twice. It counts as two separate cards.

  A password-protected or damaged file is reported and skipped; the rest still
  load.


SETTING THE ORDER

  The number in the top-left corner of each card is its position in the output.
  Files are merged left to right, then down.

  Drag       Grab a card and move it. A blue marker shows where it will land.
             Let go and it drops there.

  Arrows     The < and > buttons in a card's corner move it one place at a
             time. Easier than dragging when you only need a small change.

  Undo       Ctrl+Z. Every move is undoable, so trying an order costs nothing.

  The X button takes a file out of the merge. That one asks first, because
  undo does not cover it - a file is heavy, and bringing it back would mean
  reading it off the disk again.


MERGING

  "Merge & Download" shows a summary first: how many files, how many pages, the
  order they will be written in, and the output file name. Nothing is written
  until you press the button in that window.

  Your original files are never modified. They are not even opened for writing.


KEYBOARD SHORTCUTS

  Ctrl+O              Add PDF
  Ctrl+Z / Ctrl+Y     Undo / Redo
  Ctrl+E              Merge & Download


NOTES

  - Page content is copied across untouched. Text stays text, vectors stay
    vectors, and nothing is re-encoded, so nothing loses quality and a
    searchable PDF stays searchable.

  - Memory: source files are opened one at a time while the output is built,
    and released before the next is read. A merge of about 300MB was measured
    at roughly 2.4GB of memory at its peak and produced a correct file. As a
    rough guide, allow about 300MB plus seven or eight times the total size of
    what you are merging. Under 50MB it is comfortable anywhere.

  - Forms and signatures: page content is preserved, but interactive form
    fields and digital signatures do not survive being copied into a new
    document. That is a limit of merging PDFs in general, not of this tool. If
    a signature matters, merge before signing.

  - Nothing is stored. No cookies, no local storage, no database - closing the
    tab loses the arrangement, which is why there is a warning before you do.


PRIVACY

  The file contains a Content-Security-Policy that forbids network connections
  entirely. That is enforced by the browser, not promised by us: open DevTools,
  watch the Network tab, and it stays empty. You can also disconnect from the
  internet and the tool still works.

  Verify the copy you hold matches the one published:

      Windows      Get-FileHash "Vuiso Merge PDF.html" -Algorithm SHA256
      macOS/Linux  shasum -a 256 "Vuiso Merge PDF.html"

  Compare the result with the SHA-256 printed on the download page and in the
  .sha256.txt file next to this one.


LICENCE

  See LICENSES.txt, which must stay alongside the tool.