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Resize

Change an image’s width and/or height — by exact pixels or by percent — with control over how the aspect ratio is handled and which resampling filter is used.

Function

Section titled “Function”
resize_image(input, &ResizeOptions) -> Vec<u8>
Language Name
Rust resize_image
JavaScript resizeImage
Python resize_image
CLI dusrelimage resize <input> --width 800 -o out.jpg

Options

Section titled “Options”
Field Type Default Meaning
width u32 or null null Target width in pixels.
height u32 or null null Target height in pixels.
percent f32 or null null Scale by percent, e.g. 50 = half size.
fit FitMode Fit Fit / Fill / Stretch / Crop (see below).
filter Filter Lanczos3 Nearest / Triangle / CatmullRom / Gaussian / Lanczos3.
background Colour white Fill colour used by Fill mode.

Give width, height, or percent — at least one is required. Giving only one of width/height keeps the aspect ratio (aspect lock). Giving neither is INVALID_DIMENSIONS.

Fit modes

Section titled “Fit modes”
Mode Behaviour
Fit Scale to fit inside the width × height box, keeping aspect ratio. The output may be smaller than the box on one side.
Fill Scale to fit inside the box, then centre on a background canvas of exactly the target size (letterbox).
Stretch Scale to exactly width × height, ignoring aspect ratio (image may look squashed).
Crop Scale then centre-crop to exactly width × height.

Filters

Section titled “Filters”
Filter Best for
Lanczos3 (default) Downscaling photos — sharpest result.
CatmullRom General-purpose, good balance.
Triangle Fast, decent quality.
Gaussian Softer, smooth result.
Nearest Pixel art / upscaling without blur — fastest and blockiest.

Examples

Section titled “Examples”
import { resizeImage } from 'dusrelimage';


const thumb = resizeImage(input, { width: 400 });            // aspect locked
const half = resizeImage(input, { percent: 50 });             // half size
const exact = resizeImage(input, { width: 800, height: 800, fit: 'Crop' }); // square
Terminal window
dusrelimage resize photo.jpg --width 800 -o photo-800.jpg
dusrelimage resize photo.jpg --percent 50 -o photo-half.jpg
dusrelimage resize photo.jpg --width 800 --height 800 --fit crop -o square.jpg

Errors

Section titled “Errors”
Code When
INVALID_IMAGE Input is not a decodable image.
INVALID_DIMENSIONS No width, height or percent given; a dimension is zero.
IMAGE_TOO_LARGE Over max_pixels (default 120,000,000), or a side exceeds max_dimension (default 16000).
EMPTY_INPUT Empty input bytes.