Note
This is one of 199 standalone projects, maintained as part of the @thi.ng/umbrella monorepo and anti-framework.
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Extensible image dithering w/ various algorithm presets. This is a support package for @thi.ng/pixel.
The package provides the following dithering algorithm presets (can also be very easily extended via definition of custom kernels):
- Atkinson
- Bayes (ordered dithering w/ customizable sizes & levels)
- Burkes
- Diffusion (1D row/column, 2D)
- Floyd-Steinberg
- Jarvis-Judice-Ninke
- Sierra 2-row
- Stucki
- Threshold
STABLE - used in production
Search or submit any issues for this package
yarn add @thi.ng/pixel-dither
ESM import:
import * as pd from "@thi.ng/pixel-dither";
Browser ESM import:
<script type="module" src="https://esm.run/@thi.ng/pixel-dither"></script>
For Node.js REPL:
const pd = await import("@thi.ng/pixel-dither");
Package sizes (brotli'd, pre-treeshake): ESM: 1.06 KB
Three projects in this repo's /examples directory are using this package:
Screenshot | Description | Live demo | Source |
---|---|---|---|
Showcase of various dithering algorithms | Demo | Source | |
Image dithering and remapping using indexed palettes | Demo | Source | |
Multi-layer vectorization & dithering of bitmap images | Demo | Source |
import { imageFromURL, intBufferFromImage, GRAY8 } from "@thi.ng/pixel";
import { ditherWith, ATKINSON } from "@thi.ng/pixel-dither";
// create pixel buffer from HTML image element
const img = intBufferFromImage(await imageFromURL("test.jpg"));
// apply dithering to all channels in given pixel buffer
ditherWith(ATKINSON, img);
// first convert to 8-bit gray before dithering
ditherWith(ATKINSON, img.as(GRAY8));
// ...or apply dithering to select channels only
// use custom threshold & error spillage/bleed factor
ditherWith(ATKINSON, img, { channels: [1, 2, 3], threshold: 0.66, bleed: 0.75 });
All bundled algorithm presets (apart from orderedDither()
) are implemented as
DitherKernel
configurations for, defining how each dithered pixel's error should be
diffused/distributed to neighbors. This approach makes it very easy to define
custom dither configs, like so:
import { ditherWith, type DitherKernel } from "@thi.ng/pixel-dither";
const CUSTOM: DitherKernel = {
// X offsets of neighbor pixels to update
ox: [1],
// Y offsets of neighbor pixels to update
oy: [1],
// error weights for updated pixels
weights: [1],
// bit shift (scale factor)
shift: 1,
};
ditherWith(CUSTOM, img);
The above config will distribute the error to a single pixel @ offset (1,1). However the error will be bit-shifted by 1 bit to the right (aka division-by-2). In code form:
pixels[i + ox + oy * width] += (err * weight) >> shift;
Important: Ensure the offset positions only refer to still unprocessed pixels, i.e. those to the right and/or below the currently processed pixel (in following rows).
You can see the result of this kernel in the pixel-dither demo.
If this project contributes to an academic publication, please cite it as:
@misc{thing-pixel-dither,
title = "@thi.ng/pixel-dither",
author = "Karsten Schmidt",
note = "https://thi.ng/pixel-dither",
year = 2021
}
© 2021 - 2024 Karsten Schmidt // Apache License 2.0