normcap

OCR powered screen-capture tool to capture information instead of images.

Links: Releases | Changelog | Roadmap | Repo

Content: Introduction | Installation | Usage | Contribute | Credits

Introduction

Basic usage:

1. Launch normcap
2. Select a region on the screen
3. Retrieve recognized text in clipboard

Installation

On Linux

1. Install dependencies:

## on Ubuntu/Debian:
sudo apt-get install tesseract-ocr xclip python3-tk python3-pil.imagetk libleptonica-dev libtesseract-dev

# on Arch:
sudo pacman -S tesseract tesseract-data-eng leptonica xclip tk python-pillow

# on Fedora
sudo dnf install tesseract tesseract-devel leptonica-devel xclip python3-tkinter

2. Install normcap:

## on Ubuntu/Debian:
pip3 install normcap

# on Arch:
pip install normcap

(OR download and extract binary package from the latest release)

3. Execute normcap

On Windows (recommended method)

1. Download and extract the binary package from the latest release (no installation required)

2. Execute normcap-v{version}.exe

On Windows (alternative method)

1. Install "Tesseract", e.g. by using the installer provided by UB Mannheim

2. Set the environment variable TESSDATA_PREFIX to Tesseract's data folder, e.g.:

setx TESSDATA_PREFIX "C:\Program Files\Tesseract-OCR\tessdata"

3. Install tesserocr, e.g. by using the Windows specific wheel:

pip install https://github.com/simonflueckiger/tesserocr-windows_build/releases/download/tesserocr-v2.4.0-tesseract-4.0.0/tesserocr-2.4.0-cp37-cp37m-win_amd64.whl

4. Run

pip install normcap

5. Execute normcap

On Mac

Attention! On Mac, not everything works. Help needed!

1. Install dependencies:

brew install tesseract tesseract-lang

2. Install normcap:

pip install normcap

(OR download and extract binary package from the latest release)

3. Execute normcap-v{version}.app

Usage

General

• After launching normcap press <esc> to abort and quit.

• Before letting the mouse button go, press the <space>-key to switch mode, as indicated by a symbol:

  • ☰ (raw): Copy detected text line by line, without further modification
  • ☶ (parse): Try to auto-detect the type of text using magics and format the text accordingly, then copy

• To download additional languages for Mac and Linux, check the official repository of your distribution for tesseract-languages. Packages' names might vary.

• The Windows release of normcap supports English and German out of the box. If you need additional languages, download the appropriate files from the tesseract repo and place them into the /normcap/tessdata/ folder.

• normcap is intended to be executed on demand via a keybinding or desktop shortcut. Therefore it doesn't occupy resources by running in the background, but its startup is a bit slower.

• By default normcap is "stateless": it copies recognized text to the system's clipboard but doesn't save images or text on the disk. However, you can use the --path switch to store the images in any folder.

Command line options

normcap has no settings, just a set of command line arguments:

(normcap)dynobo@cioran:~$ normcap --help
usage: normcap [-h] [-v] [-m MODE] [-l LANG] [-c COLOR] [-p PATH]

OCR-powered screen-capture tool to capture information instead of images.

optional arguments:
  -h, --help               show this help message and exit
  -v, --verbose            print debug information to console (default: False)
  -m MODE, --mode MODE     startup mode [raw,parse] (default: parse)
  -l LANG, --lang LANG     languages for ocr, e.g. eng+deu (default: eng)
  -c COLOR, --color COLOR  set primary color for UI (default: #FF0000)
  -p PATH, --path PATH     set a path for storing images (default: None)

Magics

"Magics" are like add-ons providing automated functionality to intelligently detect and format the captured input.

First, every "magic" calculates a "score" to determine the likelihood of being responsible for this type of text. Second, the "magic" which achieved the highest "score" takes the necessary actions to "transform" the input text according to its type.

Currently implemented Magics:

Magic	Score	Transform
Single line	Only single line is detected	Trim unnecessary whitespace
Multi line	Multi lines, but single Paragraph	Separated by line breaks and trim each lined
Paragraph	Multiple blocks of lines or multiple paragraphs	Join every paragraph into a single line, separate different paragraphs by empty line
E-Mail	Number of chars in email addresses vs. overall chars	Transform to a comma-separated list of email addresses
URL	Number of chars in URLs vs. overall chars	Transform to line-break separated URLs

Why "normcap"?

See XKCD:

Contribute

Setup Environment

Prerequisites are Python, Tesseract (incl. language data) and on Linux also XClip.

# Clone repository
git clone https://github.com/dynobo/normcap.git

# Change into project directory
cd normcap

# Create and activate virtual env
python -m venv .venv
source .venv/bin/activate

# Install project development incl. dependencies
pip install -r requirements.txt
# or depending on your OS:
#    pip install -r requirements-macos.txt
#    pip install -r requirements-win.txt

# Register pre-commit hook
pre-commit install -t pre-commit

# Run normcap in pipenv environment
python -m normcap

Design Principles

• Multi-Platform
  Should work on Linux, Mac & Windows.
• Don't run as service
  As normcap is (hopefully) not used too often, it shouldn't consume resources in the background, even if it leads to slower start-up time.
• No network connection
  Everything should run locally without any network communication.
• Avoid text in UI
  This just avoids translations ;-) And I think it is feasible in such a simple application.
• Avoid configuration file or settings UI
  Focus on simplicity and core functionality.
• Dependencies
  The fewer dependencies, the better. Of course, I have to compromise, but I'm always open to suggestions on how to further reduce dependencies.
• Chain of Responsibility as main design pattern
  See description on refactoring.guru
• Multi-Monitors
  Supports setups with two or more displays

Credits

This project uses the following non-standard libraries:

• mss - taking screenshots
• pillow - manipulating images
• tesserocr - wrapper for tesseract's API
• pyperclip - accessing clipboard
• pyinstaller - packaging for platforms
• notify-py - system notifications

And it depends on external software

• tesseract - OCR engine

Thanks to the maintainers of those nice libraries!

Certification