sharp/docs/api-constructor.md

Sharp

Emits: Sharp#event:info, Sharp#event:warning

new

Constructor factory to create an instance of sharp, to which further methods are chained.

JPEG, PNG, WebP, GIF, AVIF or TIFF format image data can be streamed out from this object. When using Stream based output, derived attributes are available from the info event.

Non-critical problems encountered during processing are emitted as warning events.

Implements the stream.Duplex class.

Throws:

• Error Invalid parameters

Param	Type	Default	Description
[input]	Buffer | ArrayBuffer | Uint8Array | Uint8ClampedArray | Int8Array | Uint16Array | Int16Array | Uint32Array | Int32Array | Float32Array | Float64Array | string		if present, can be a Buffer / ArrayBuffer / Uint8Array / Uint8ClampedArray containing JPEG, PNG, WebP, AVIF, GIF, SVG or TIFF image data, or a TypedArray containing raw pixel image data, or a String containing the filesystem path to an JPEG, PNG, WebP, AVIF, GIF, SVG or TIFF image file. JPEG, PNG, WebP, AVIF, GIF, SVG, TIFF or raw pixel image data can be streamed into the object when not present.
[options]	Object		if present, is an Object with optional attributes.
[options.failOn]	string	"'warning'"	when to abort processing of invalid pixel data, one of (in order of sensitivity): 'none' (least), 'truncated', 'error' or 'warning' (most), highers level imply lower levels, invalid metadata will always abort.
[options.limitInputPixels]	number | boolean	268402689	Do not process input images where the number of pixels (width x height) exceeds this limit. Assumes image dimensions contained in the input metadata can be trusted. An integral Number of pixels, zero or false to remove limit, true to use default limit of 268402689 (0x3FFF x 0x3FFF).
[options.unlimited]	boolean	false	Set this to true to remove safety features that help prevent memory exhaustion (JPEG, PNG, SVG, HEIF).
[options.sequentialRead]	boolean	true	Set this to false to use random access rather than sequential read. Some operations will do this automatically.
[options.density]	number	72	number representing the DPI for vector images in the range 1 to 100000.
[options.ignoreIcc]	number	false	should the embedded ICC profile, if any, be ignored.
[options.pages]	number	1	Number of pages to extract for multi-page input (GIF, WebP, TIFF), use -1 for all pages.
[options.page]	number	0	Page number to start extracting from for multi-page input (GIF, WebP, TIFF), zero based.
[options.subifd]	number	-1	subIFD (Sub Image File Directory) to extract for OME-TIFF, defaults to main image.
[options.level]	number	0	level to extract from a multi-level input (OpenSlide), zero based.
[options.animated]	boolean	false	Set to true to read all frames/pages of an animated image (GIF, WebP, TIFF), equivalent of setting pages to -1.
[options.raw]	Object		describes raw pixel input image data. See raw() for pixel ordering.
[options.raw.width]	number		integral number of pixels wide.
[options.raw.height]	number		integral number of pixels high.
[options.raw.channels]	number		integral number of channels, between 1 and 4.
[options.raw.premultiplied]	boolean		specifies that the raw input has already been premultiplied, set to true to avoid sharp premultiplying the image. (optional, default false)
[options.create]	Object		describes a new image to be created.
[options.create.width]	number		integral number of pixels wide.
[options.create.height]	number		integral number of pixels high.
[options.create.channels]	number		integral number of channels, either 3 (RGB) or 4 (RGBA).
[options.create.background]	string | Object		parsed by the color module to extract values for red, green, blue and alpha.
[options.create.noise]	Object		describes a noise to be created.
[options.create.noise.type]	string		type of generated noise, currently only gaussian is supported.
[options.create.noise.mean]	number		mean of pixels in generated noise.
[options.create.noise.sigma]	number		standard deviation of pixels in generated noise.
[options.text]	Object		describes a new text image to be created.
[options.text.text]	string		text to render as a UTF-8 string. It can contain Pango markup, for example <i>Le</i>Monde.
[options.text.font]	string		font name to render with.
[options.text.fontfile]	string		absolute filesystem path to a font file that can be used by font.
[options.text.width]	number	0	integral number of pixels to word-wrap at. Lines of text wider than this will be broken at word boundaries.
[options.text.height]	number	0	integral number of pixels high. When defined, dpi will be ignored and the text will automatically fit the pixel resolution defined by width and height. Will be ignored if width is not specified or set to 0.
[options.text.align]	string	"'left'"	text alignment ('left', 'centre', 'center', 'right').
[options.text.justify]	boolean	false	set this to true to apply justification to the text.
[options.text.dpi]	number	72	the resolution (size) at which to render the text. Does not take effect if height is specified.
[options.text.rgba]	boolean	false	set this to true to enable RGBA output. This is useful for colour emoji rendering, or support for pango markup features like <span foreground="red">Red!</span>.
[options.text.spacing]	number	0	text line height in points. Will use the font line height if none is specified.
[options.text.wrap]	string	"'word'"	word wrapping style when width is provided, one of: 'word', 'char', 'charWord' (prefer char, fallback to word) or 'none'.

Example

sharp('input.jpg')
  .resize(300, 200)
  .toFile('output.jpg', function(err) {
    // output.jpg is a 300 pixels wide and 200 pixels high image
    // containing a scaled and cropped version of input.jpg
  });

Example

// Read image data from readableStream,
// resize to 300 pixels wide,
// emit an 'info' event with calculated dimensions
// and finally write image data to writableStream
var transformer = sharp()
  .resize(300)
  .on('info', function(info) {
    console.log('Image height is ' + info.height);
  });
readableStream.pipe(transformer).pipe(writableStream);

Example

// Create a blank 300x200 PNG image of semi-transluent red pixels
sharp({
  create: {
    width: 300,
    height: 200,
    channels: 4,
    background: { r: 255, g: 0, b: 0, alpha: 0.5 }
  }
})
.png()
.toBuffer()
.then( ... );

Example

// Convert an animated GIF to an animated WebP
await sharp('in.gif', { animated: true }).toFile('out.webp');

Example

// Read a raw array of pixels and save it to a png
const input = Uint8Array.from([255, 255, 255, 0, 0, 0]); // or Uint8ClampedArray
const image = sharp(input, {
  // because the input does not contain its dimensions or how many channels it has
  // we need to specify it in the constructor options
  raw: {
    width: 2,
    height: 1,
    channels: 3
  }
});
await image.toFile('my-two-pixels.png');

Example

// Generate RGB Gaussian noise
await sharp({
  create: {
    width: 300,
    height: 200,
    channels: 3,
    noise: {
      type: 'gaussian',
      mean: 128,
      sigma: 30
    }
 }
}).toFile('noise.png');

Example

// Generate an image from text
await sharp({
  text: {
    text: 'Hello, world!',
    width: 400, // max width
    height: 300 // max height
  }
}).toFile('text_bw.png');

Example

// Generate an rgba image from text using pango markup and font
await sharp({
  text: {
    text: '<span foreground="red">Red!</span><span background="cyan">blue</span>',
    font: 'sans',
    rgba: true,
    dpi: 300
  }
}).toFile('text_rgba.png');

clone

Take a "snapshot" of the Sharp instance, returning a new instance. Cloned instances inherit the input of their parent instance. This allows multiple output Streams and therefore multiple processing pipelines to share a single input Stream.

Example

const pipeline = sharp().rotate();
pipeline.clone().resize(800, 600).pipe(firstWritableStream);
pipeline.clone().extract({ left: 20, top: 20, width: 100, height: 100 }).pipe(secondWritableStream);
readableStream.pipe(pipeline);
// firstWritableStream receives auto-rotated, resized readableStream
// secondWritableStream receives auto-rotated, extracted region of readableStream

Example

// Create a pipeline that will download an image, resize it and format it to different files
// Using Promises to know when the pipeline is complete
const fs = require("fs");
const got = require("got");
const sharpStream = sharp({ failOn: 'none' });

const promises = [];

promises.push(
  sharpStream
    .clone()
    .jpeg({ quality: 100 })
    .toFile("originalFile.jpg")
);

promises.push(
  sharpStream
    .clone()
    .resize({ width: 500 })
    .jpeg({ quality: 80 })
    .toFile("optimized-500.jpg")
);

promises.push(
  sharpStream
    .clone()
    .resize({ width: 500 })
    .webp({ quality: 80 })
    .toFile("optimized-500.webp")
);

// https://github.com/sindresorhus/got/blob/main/documentation/3-streams.md
got.stream("https://www.example.com/some-file.jpg").pipe(sharpStream);

Promise.all(promises)
  .then(res => { console.log("Done!", res); })
  .catch(err => {
    console.error("Error processing files, let's clean it up", err);
    try {
      fs.unlinkSync("originalFile.jpg");
      fs.unlinkSync("optimized-500.jpg");
      fs.unlinkSync("optimized-500.webp");
    } catch (e) {}
  });