SzTextCompar

Text similarity and comparison analyzer for Windows — a desktop tool that compares two documents (or a whole folder of them) using nine independent similarity methods, highlights matching passages side by side, and visualizes the result as an ECG-style waveform, charts, and an interactive report.

Written in pure Python (Tkinter), with no third-party runtime dependency — the source imports only the Python standard library.

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Features

Two-file comparison

• Open two text/document files side by side, with synchronized scrolling and a line-number gutter.
• Nine independent analysis methods, each giving its own similarity score and a plain-language verdict:
  1. Traditional Diff (character/line level)
  2. Winnowing Fingerprint — robust to reordering and small edits
  3. TF-IDF Weighted Content Analysis (precise cosine similarity, rare words weighted higher)
  4. Sentence Rhythm & Structure — a paraphrase filter based on sentence-length patterns
  5. N-gram Phrase Matching (common 4-word sequences)
  6. Vocabulary (Cosine) Similarity
  7. Jaccard Similarity (set-based)
  8. Simhash Fingerprint (fast, language-independent)
  9. Summary Table & Similarity Index — a weighted overall score combining all of the above, with a table and a chart
• Visual Match View: highlights every matching phrase (configurable minimum word count) in both texts with a color-coded palette, with a clickable match list and next/previous navigation.
• Detailed Visualization: keyword, sentence-rhythm, style, common-n-gram and word-frequency charts, side by side for both texts — exportable as a single, self-contained HTML report (charts included as inline SVG, no external files or internet connection needed to view it).
• Full-Screen Match Waveform ("ECG"): an ECG-style waveform across the whole document — flat where the texts diverge, rising to a full peak for long, sentence-length exact matches. Click or drag on the waveform to jump to that point in both texts at once; zoom horizontally to inspect a section closely. The waveform can be exported as a standalone SVG or PNG image.
• HTML Report: a shareable, standalone HTML summary of the whole comparison.
• Line synchronization (align by diff blocks), timestamp removal (left/right, e.g. for subtitle files), and a "Save As" flow that always lets you choose the output format explicitly (never guesses or silently overwrites your original file).
• Save either side with its highlight colors and underline preserved as .docx, .odt or .html — or as plain text.

Folder Matrix (batch comparison)

• Point the tool at a folder; it compares every file pair in it and shows a sortable similarity matrix.
• Optional result caching and multi-core (multiprocessing) processing for large folders.
• Double-click any pair in the matrix to open it in the two-file view.

File formats

Kept deliberately to formats that need no external library and no extra license:

• Open, read: .txt (auto-detects UTF-8 / UTF-8 BOM / UTF-16 / Windows-1250 / ISO-8859-2), .md, .log, .csv, .tsv, .json, .xml, .tex, .rst, .srt, .py, .vtt, .ass, .ssa, .sbv, .lrc, .html/.htm, .docx, .odt, .epub.
• Save, with highlight colors and underline: plain text, .html, .docx, .odt.
• Every reader/writer above (DOCX, ODT, EPUB, HTML) is original code built directly on the published, open specifications, using only zipfile, xml.etree.ElementTree, html.parser, zlib and struct from the standard library — no PyPI package, so no extra license terms to track.

Interface

• Full Hungarian and English UI, switchable at any time from the Language menu.
• Color menu: freely customize every highlight color used by the Visual Match View, the traditional diff, the selection highlight, and the ECG waveform; settings persist between runs.
• Custom, from-scratch application icon (SzTc.ico / embedded PNGs) — built from geometric shapes, no font or third-party artwork involved.
• About window with the full Apache 2.0 license text and a complete third-party components list (see below).

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Requirements

• Windows 10/11 (built and tested there; the source is plain Tkinter and should also run on Linux/macOS with a standard Python + Tk install).
• No installation of any Python package is required to run the packaged .exe.
• To run from source: Python 3.9+ with Tkinter (the standard python.org installer includes it). No pip install needed — the script only imports the standard library.

Running from source

python SzTextCompar.py

Building the Windows executable

Built with PyInstaller in onedir mode:

pyinstaller --windowed --icon SzTc.ico --name SzTextCompar SzTextCompar.py

Ship the LICENSE, NOTICE and THIRD_PARTY_LICENSES.txt files together with the contents of the dist/SzTextCompar folder.

Before every release: the exact third-party inventory (Python, OpenSSL, Tcl/Tk, zlib, MSVC runtime, … versions) depends on the specific Python/PyInstaller build used. THIRD_PARTY_LICENSES.txt in this repository was generated from a real build's PyInstaller log and an independent file-by-file audit of the finished dist folder (SHA-256 + embedded version resources of all shipped files). If you rebuild with a different Python or PyInstaller version, regenerate that file from a fresh audit of your own dist folder rather than reusing the numbers as-is.

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License

SzTextCompar's own source code is Copyright © 2026 szabiz, licensed under the Apache License, Version 2.0 — see LICENSE

The application source imports only Python standard-library modules (tkinter, difflib, re, json, hashlib, pathlib, collections, math, threading, time, bisect, html, string, os, webbrowser, zipfile, xml.etree.ElementTree, zlib, struct, posixpath, urllib.parse, concurrent.futures) — no PyPI package is required to run it from source, and none is vendored or copied into the repository.

The packaged Windows executable additionally contains the CPython runtime and the native libraries PyInstaller collects for it (OpenSSL, Tcl/Tk, zlib, libffi, libmpdec, Expat, bzip2, XZ/liblzma, the Microsoft Visual C++ Runtime, the IANA time-zone database bundled by Tcl, and the PyInstaller bootloader itself). Every one of those components, with its exact version and license, is listed in THIRD_PARTY_LICENSES.txt — please distribute that file together with any binary release, per each component's own license terms (most require only that their notice be retained, not a specific placement).

The application icon is original artwork (see make_icon.py); no third-party font or image is bundled.

The similarity algorithms used (Simhash, Winnowing, TF-IDF/cosine, Jaccard, suffix-automaton matching) are published, freely implementable methods, implemented independently for this project — no third-party source code was used for them.

The application's results are similarity indicators only, and do not by themselves prove copying, plagiarism, or copyright infringement.