70 lines
2.2 KiB
Markdown
70 lines
2.2 KiB
Markdown
# fast-png
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PNG image decoder and encoder written entirely in JavaScript.
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<h3 align="center">
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<a href="https://www.zakodium.com">
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<img src="https://www.zakodium.com/brand/zakodium-logo-white.svg" width="50" alt="Zakodium logo" />
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</a>
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<p>
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Maintained by <a href="https://www.zakodium.com">Zakodium</a>
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</p>
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[![NPM version][npm-image]][npm-url]
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[![build status][ci-image]][ci-url]
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[![npm download][download-image]][download-url]
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</h3>
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## Installation
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`$ npm install --save fast-png`
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## Usage
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### `decode(png[, options])`
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#### Arguments
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- `png` - A TypedArray or Buffer that contains the PNG data.
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- `options` - An object of options
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#### Options
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- `checkCrc` - If set to `true`, the CRC will be checked for each chunk and an error will be thrown in case it's wrong (default: false).
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### `encode(image)`
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#### Arguments
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- `png` - An object representing the image. You can pass an ImageData from the Canvas API or an object with the following properties:
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- `width` - The width of the image
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- `height` - The height of the image
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- `data` - An array or TypedArray with the image data
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- `depth` - A number indicating the color depth (only 8 and 16 are supported now). Default: `8`.
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- `channels` - Number of channels, including alpha (1, 2, 3 and 4 are supported). Default: `4`.
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- `text` - An object with key-value pairs representing `tEXt` chunks. The keys must have less than 80 characters.
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The keys and values must have only characters in the latin1 charset (maximum code point of 255).
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Default: `undefined`.
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### `hasPngSignature(array)`
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Returns whether the array starts with the PNG signature (magic bytes).
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## PNG standard
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Spec can be found at: https://www.w3.org/TR/PNG/
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## License
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[MIT](./LICENSE)
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[npm-image]: https://img.shields.io/npm/v/fast-png.svg?style=flat-square
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[npm-url]: https://www.npmjs.com/package/fast-png
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[ci-image]: https://github.com/image-js/fast-png/workflows/Node.js%20CI/badge.svg?branch=main
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[ci-url]: https://github.com/image-js/fast-png/actions?query=workflow%3A%22Node.js+CI%22
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[download-image]: https://img.shields.io/npm/dm/fast-png.svg?style=flat-square
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[download-url]: https://www.npmjs.com/package/fast-png
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