Pixelate

Mosaic-blur a rectangle of an image — the standard way to hide a face, a number plate, or any private detail.

Function

pixelate_image(input, &PixelateOptions) -> Vec<u8>

Language	Name
Rust	pixelate_image
JavaScript	pixelateImage
Python	pixelate_image
CLI	dusrelimage pixelate <input> --x 100 --y 80 --width 120 --height 120 --block-size 16 -o out.jpg

Options

Field	Type	Default	Meaning
x, y	u32	0	Top-left of the rectangle, in pixels.
width, height	u32	0 = to edge	Size of the rectangle; 0 means to the image edge.
block_size	u32	10	Mosaic block size in pixels, 2–100. Outside 2–100 → INVALID_ARGUMENT.

Only the rectangle is pixelated — the rest of the image is untouched.

How it works

The rectangle is downscaled with a Nearest filter to one pixel per block, then upscaled with Nearest back to its original size. That gives the classic mosaic look, and it is fully reversible in the sense that the same input + options always give the same output.

Examples

import { pixelateImage } from 'dusrelimage';

// Hide a face
const out = pixelateImage(input, { x: 100, y: 80, width: 120, height: 120, blockSize: 16 });

// Coarser mosaic for a number plate
const plate = pixelateImage(input, { x: 400, y: 300, width: 200, height: 50, blockSize: 24 });

dusrelimage pixelate photo.jpg --x 100 --y 80 --width 120 --height 120 \
  --block-size 16 -o private.jpg

Pixelation is not encryption

Pixelation hides a detail from a casual viewer, but a coarse mosaic can sometimes be partially reversed by upscaling tools. For truly sensitive material, crop the region out instead — see Crop.

Errors

Code	When
INVALID_IMAGE	Input is not a decodable image.
INVALID_ARGUMENT	Block size outside 2–100.
INVALID_ARGUMENT	Block size outside 2–100, or the rectangle is outside the image. (Width/height 0 means to the image edge, not an error.)
IMAGE_TOO_LARGE	Over max_pixels (default 120,000,000).
EMPTY_INPUT	Empty input bytes.