Halftone generator

This tool generates halftone from a given image (amazing video about halftone). The output is in a from of an svg file. The tool was created to generate halftone images that can be printed with a pen plotter. This guided the choice of the parameters and the output format.

Installation

Python

I used Python 3.12. For installation, I recommend using miniconda (quick command line installation guide).

After installing miniconda, create a new environment by running:

conda create --name halftone python=3.12

Activate the environment by running:

conda activate halftone

Requirements

After cloning or downloading the repository, install the required packages by running:

pip install -r requirements.txt

Usage

Function generate_halftone from src/halftone.py splits the given image is split into four layers (C, M, Y, K). Each layer consists of points on a grid. The size of the points is proportional to the average color intensity of the area covered by the circle. Grids are rotated to a given angle to mitigate the Moiré pattern.

The function has the following parameters:

Parameter	Description	Default
image_path	path to the image
save_path	path to save the svg
paper_w	width of the paper in meters
paper_h	height of the paper in meters
max_dot_size	maximum size of the dots in meters
colors	list of hex color codes for each layer	["#00ffff", "#ff00ff", "#ffff00", "#000000"]
angles	list of angles in degrees for each layer	[15, 75, 0, 45]
alphas	list of opacities for each layer	[1, 1, 1, 1]
lws	list of line widths in millimeters for each layer	[1, 1, 1, 1]
pad	padding in meters	0
use_black	whether to plot the black layer or not	False
fit_how	how to fit the image to the paper (options: "fit", "fit-width", "fit-height")	"fit"
dot_fill_how	how to fill the dot. This is done because the plotter software does not support filled circles. (options: "circles", "lines")	"circles"

Command line

After installing and activating the environment, you can run python in the command line:

python

Then you can import the function and run it with your parameters:

import src.halftone as ht
ht.generate_halftone("example/tatry.jpeg","./example", 0.141, 0.1, 0.003, lws=[0.4,0.4,0.4,0.4], alphas=[0.8, 0.8, 0.8, 0.8], pad=0.005)

Jupyter notebook

Please see the example for a detailed guide on how to use the tool in a jupyter notebook.

Contribution

You can contribute to this project by creating a pull request or submitting an issue.

License

This project is licensed under the MIT License (see the LICENSE file for details).