@localnerve/imagemin-optipng NPM

imagemin-optipng

Imagemin plugin for OptiPNG

A published ESM fork of imagemin/imagemin-optipng

Install

$ npm install imagemin-optipng

Silicon ARM

imagemin-optipng uses neon chipset optimizations that are incompatible with Apple Silicon.
To compile on newer M1/M2/M3/M4+ Macs, set the environment variable to disable neon optimizations CPPFLAGS=-DPNG_ARM_NEON_OPT=0 Since npm doesn't allow one to hook the install event (only the install script), this is not fully automatable. The npm lifecycle hooks do not currently provide any mechanism to run scripts prior to dependency build/install, such as setting variables for arm64.

The following package.json script in a parent project will build imagemin-optipng for arm64 architectures:

"install-arm": "CPPFLAGS=-DPNG_ARM_NEON_OPT=0 npm i",

Usage

import imagemin from 'imagemin';
import imageminOptipng from 'imagemin-optipng';

(async () => {
	await imagemin(['images/*.png'], {
		destination: 'build/images',
		plugins: [
			imageminOptipng()
		]
	});

	console.log('Images optimized!');
})();

API

imageminOptipng(options?)(buffer)

Returns a Promise<Buffer>.

options

Type: object

optimizationLevel

Type: number\ Default: 3

Select an optimization level between 0 and 7.

The optimization level 0 enables a set of optimization operations that require minimal effort. There will be no changes to image attributes like bit depth or color type, and no recompression of existing IDAT datastreams. The optimization level 1 enables a single IDAT compression trial. The trial chosen is what. OptiPNG thinks it’s probably the most effective. The optimization levels 2 and higher enable multiple IDAT compression trials; the higher the level, the more trials.

Level and trials:

1 trial
8 trials
16 trials
24 trials
48 trials
120 trials
240 trials

bitDepthReduction

Type: boolean\ Default: true

Apply bit depth reduction.

colorTypeReduction

Type: boolean\ Default: true

Apply color type reduction.

paletteReduction

Type: boolean\ Default: true

Apply palette reduction.

interlaced

Type: boolean | undefined | null\ Default: false

Enable Adam7 PNG interlacing on any images that are processed. Interlaced images look better when they're loaded partially, but usually interlace makes compression less efficient. Set to undefined or null to keep the same interlacing as the input image.

errorRecovery

Type: boolean\ Default: true

A reasonable amount of effort will be spent to try to recover as much data as possible of a broken image, but the success cannot generally be guaranteed.