compare

Compare two PDFs

Show what changed between two versions of a document, word by word.

Reads: two PDFs — application/pdf, 2 or more
Writes: one file — text files or JSON
Tool page: /compare-pdf

Example

Say what changed between the version you sent and the one that came back.

Given

before.pdf — an ordinary PDF of 2 pages
after.pdf — an ordinary PDF of 3 pages

From code

            import { loadDocument, runOperation } from '@pagecraft/core';

const before = await loadDocument({ bytes, name: 'before.pdf' });
const after = await loadDocument({ bytes, name: 'after.pdf' });

const [output] = await runOperation('compare', [before, after], {
  format: 'text',
  visual: false,
});

From a shell

            pagecraft compare before.pdf after.pdf --no-visual --format text

What comes back

One text file.

This example is run by the test suite. If it stopped being true, the build would fail.

Options

`visual--visual`

boolean

Compare how the pages look

Also draw the pages whose words are identical, to catch a change no words record.

Default: true

`format--format`

string, one of

Default: 'text'

text — A report to read
json — Data for a tool to work with

What it cannot do

The pages are compared in order: page one with page one. A page inserted at the front makes every page after it look changed, because to a reader it is.
A word is compared as it reads, not as it is drawn. A change of font, colour or position that leaves the words alone is a visual difference, and is reported as one.
Comparing how the pages look needs somewhere to draw them. Without it, turn that off and the words are still compared.
A scanned page holds no words to compare. Two scans are compared by how they look and nothing else.