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sharp/docs/api-output.md

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<!-- Generated by documentation.js. Update this documentation by updating the source code. -->
## toFile
Write output image data to a file.
If an explicit output format is not selected, it will be inferred from the extension,
with JPEG, PNG, WebP, TIFF, DZI, and libvips' V format supported.
Note that raw pixel data is only supported for buffer output.
A `Promise` is returned when `callback` is not provided.
### Parameters
- `fileOut` **[String][1]** the path to write the image data to.
- `callback` **[Function][2]?** called on completion with two arguments `(err, info)`.
`info` contains the output image `format`, `size` (bytes), `width`, `height`,
`channels` and `premultiplied` (indicating if premultiplication was used).
When using a crop strategy also contains `cropOffsetLeft` and `cropOffsetTop`.
### Examples
```javascript
sharp(input)
.toFile('output.png', (err, info) => { ... });
```
```javascript
sharp(input)
.toFile('output.png')
.then(info => { ... })
.catch(err => { ... });
```
- Throws **[Error][3]** Invalid parameters
Returns **[Promise][4]&lt;[Object][5]>** when no callback is provided
## toBuffer
Write output to a Buffer.
JPEG, PNG, WebP, TIFF and RAW output are supported.
By default, the format will match the input image, except GIF and SVG input which become PNG output.
`callback`, if present, gets three arguments `(err, data, info)` where:
- `err` is an error, if any.
- `data` is the output image data.
- `info` contains the output image `format`, `size` (bytes), `width`, `height`,
`channels` and `premultiplied` (indicating if premultiplication was used).
When using a crop strategy also contains `cropOffsetLeft` and `cropOffsetTop`.
A `Promise` is returned when `callback` is not provided.
### Parameters
- `options` **[Object][5]?**
- `options.resolveWithObject` **[Boolean][6]?** Resolve the Promise with an Object containing `data` and `info` properties instead of resolving only with `data`.
- `callback` **[Function][2]?**
### Examples
```javascript
sharp(input)
.toBuffer((err, data, info) => { ... });
```
```javascript
sharp(input)
.toBuffer()
.then(data => { ... })
.catch(err => { ... });
```
```javascript
sharp(input)
.toBuffer({ resolveWithObject: true })
.then(({ data, info }) => { ... })
.catch(err => { ... });
```
Returns **[Promise][4]&lt;[Buffer][7]>** when no callback is provided
## withMetadata
Include all metadata (EXIF, XMP, IPTC) from the input image in the output image.
The default behaviour, when `withMetadata` is not used, is to strip all metadata and convert to the device-independent sRGB colour space.
This will also convert to and add a web-friendly sRGB ICC profile.
### Parameters
- `withMetadata` **[Object][5]?**
- `withMetadata.orientation` **[Number][8]?** value between 1 and 8, used to update the EXIF `Orientation` tag.
### Examples
```javascript
sharp('input.jpg')
.withMetadata()
.toFile('output-with-metadata.jpg')
.then(info => { ... });
```
- Throws **[Error][3]** Invalid parameters
Returns **Sharp**
## jpeg
Use these JPEG options for output image.
### Parameters
- `options` **[Object][5]?** output options
- `options.quality` **[Number][8]** quality, integer 1-100 (optional, default `80`)
- `options.progressive` **[Boolean][6]** use progressive (interlace) scan (optional, default `false`)
- `options.chromaSubsampling` **[String][1]** set to '4:4:4' to prevent chroma subsampling when quality &lt;= 90 (optional, default `'4:2:0'`)
- `options.trellisQuantisation` **[Boolean][6]** apply trellis quantisation, requires mozjpeg (optional, default `false`)
- `options.overshootDeringing` **[Boolean][6]** apply overshoot deringing, requires mozjpeg (optional, default `false`)
- `options.optimiseScans` **[Boolean][6]** optimise progressive scans, forces progressive, requires mozjpeg (optional, default `false`)
- `options.optimizeScans` **[Boolean][6]** alternative spelling of optimiseScans (optional, default `false`)
- `options.optimiseCoding` **[Boolean][6]** optimise Huffman coding tables (optional, default `true`)
- `options.optimizeCoding` **[Boolean][6]** alternative spelling of optimiseCoding (optional, default `true`)
- `options.quantisationTable` **[Number][8]** quantization table to use, integer 0-8, requires mozjpeg (optional, default `0`)
- `options.quantizationTable` **[Number][8]** alternative spelling of quantisationTable (optional, default `0`)
- `options.force` **[Boolean][6]** force JPEG output, otherwise attempt to use input format (optional, default `true`)
### Examples
```javascript
// Convert any input to very high quality JPEG output
const data = await sharp(input)
.jpeg({
quality: 100,
chromaSubsampling: '4:4:4'
})
.toBuffer();
```
- Throws **[Error][3]** Invalid options
Returns **Sharp**
## png
Use these PNG options for output image.
PNG output is always full colour at 8 or 16 bits per pixel.
Indexed PNG input at 1, 2 or 4 bits per pixel is converted to 8 bits per pixel.
### Parameters
- `options` **[Object][5]?**
- `options.progressive` **[Boolean][6]** use progressive (interlace) scan (optional, default `false`)
- `options.compressionLevel` **[Number][8]** zlib compression level, 0-9 (optional, default `9`)
- `options.adaptiveFiltering` **[Boolean][6]** use adaptive row filtering (optional, default `false`)
- `options.palette` **[Boolean][6]** quantise to a palette-based image with alpha transparency support, requires libimagequant (optional, default `false`)
- `options.quality` **[Number][8]** use the lowest number of colours needed to achieve given quality, requires libimagequant (optional, default `100`)
- `options.colours` **[Number][8]** maximum number of palette entries, requires libimagequant (optional, default `256`)
- `options.colors` **[Number][8]** alternative spelling of `options.colours`, requires libimagequant (optional, default `256`)
- `options.dither` **[Number][8]** level of Floyd-Steinberg error diffusion, requires libimagequant (optional, default `1.0`)
- `options.force` **[Boolean][6]** force PNG output, otherwise attempt to use input format (optional, default `true`)
### Examples
```javascript
// Convert any input to PNG output
const data = await sharp(input)
.png()
.toBuffer();
```
- Throws **[Error][3]** Invalid options
Returns **Sharp**
## webp
Use these WebP options for output image.
### Parameters
- `options` **[Object][5]?** output options
- `options.quality` **[Number][8]** quality, integer 1-100 (optional, default `80`)
- `options.alphaQuality` **[Number][8]** quality of alpha layer, integer 0-100 (optional, default `100`)
- `options.lossless` **[Boolean][6]** use lossless compression mode (optional, default `false`)
- `options.nearLossless` **[Boolean][6]** use near_lossless compression mode (optional, default `false`)
- `options.force` **[Boolean][6]** force WebP output, otherwise attempt to use input format (optional, default `true`)
### Examples
```javascript
// Convert any input to lossless WebP output
const data = await sharp(input)
.webp({ lossless: true })
.toBuffer();
```
- Throws **[Error][3]** Invalid options
Returns **Sharp**
## tiff
Use these TIFF options for output image.
### Parameters
- `options` **[Object][5]?** output options
- `options.quality` **[Number][8]** quality, integer 1-100 (optional, default `80`)
- `options.force` **[Boolean][6]** force TIFF output, otherwise attempt to use input format (optional, default `true`)
- `options.compression` **[Boolean][6]** compression options: lzw, deflate, jpeg, ccittfax4 (optional, default `'jpeg'`)
- `options.predictor` **[Boolean][6]** compression predictor options: none, horizontal, float (optional, default `'horizontal'`)
- `options.pyramid` **[Boolean][6]** write an image pyramid (optional, default `false`)
- `options.tile` **[Boolean][6]** write a tiled tiff (optional, default `false`)
- `options.tileWidth` **[Boolean][6]** horizontal tile size (optional, default `256`)
- `options.tileHeight` **[Boolean][6]** vertical tile size (optional, default `256`)
- `options.xres` **[Number][8]** horizontal resolution in pixels/mm (optional, default `1.0`)
- `options.yres` **[Number][8]** vertical resolution in pixels/mm (optional, default `1.0`)
- `options.squash` **[Boolean][6]** squash 8-bit images down to 1 bit (optional, default `false`)
### Examples
```javascript
// Convert SVG input to LZW-compressed, 1 bit per pixel TIFF output
sharp('input.svg')
.tiff({
compression: 'lzw',
squash: true
})
.toFile('1-bpp-output.tiff')
.then(info => { ... });
```
- Throws **[Error][3]** Invalid options
Returns **Sharp**
## raw
Force output to be raw, uncompressed uint8 pixel data.
### Examples
```javascript
// Extract raw RGB pixel data from JPEG input
const { data, info } = await sharp('input.jpg')
.raw()
.toBuffer({ resolveWithObject: true });
```
Returns **Sharp**
## toFormat
Force output to a given format.
### Parameters
- `format` **([String][1] \| [Object][5])** as a String or an Object with an 'id' attribute
- `options` **[Object][5]** output options
### Examples
```javascript
// Convert any input to PNG output
const data = await sharp(input)
.toFormat('png')
.toBuffer();
```
- Throws **[Error][3]** unsupported format or options
Returns **Sharp**
## tile
Use tile-based deep zoom (image pyramid) output.
Set the format and options for tile images via the `toFormat`, `jpeg`, `png` or `webp` functions.
Use a `.zip` or `.szi` file extension with `toFile` to write to a compressed archive file format.
Warning: multiple sharp instances concurrently producing tile output can expose a possible race condition in some versions of libgsf.
### Parameters
- `tile` **[Object][5]?**
- `tile.size` **[Number][8]** tile size in pixels, a value between 1 and 8192. (optional, default `256`)
- `tile.overlap` **[Number][8]** tile overlap in pixels, a value between 0 and 8192. (optional, default `0`)
- `tile.angle` **[Number][8]** tile angle of rotation, must be a multiple of 90. (optional, default `0`)
- `tile.depth` **[String][1]?** how deep to make the pyramid, possible values are `onepixel`, `onetile` or `one`, default based on layout.
- `tile.container` **[String][1]** tile container, with value `fs` (filesystem) or `zip` (compressed file). (optional, default `'fs'`)
- `tile.layout` **[String][1]** filesystem layout, possible values are `dz`, `zoomify` or `google`. (optional, default `'dz'`)
### Examples
```javascript
sharp('input.tiff')
.png()
.tile({
size: 512
})
.toFile('output.dz', function(err, info) {
// output.dzi is the Deep Zoom XML definition
// output_files contains 512x512 tiles grouped by zoom level
});
```
- Throws **[Error][3]** Invalid parameters
Returns **Sharp**
[1]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String
[2]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Statements/function
[3]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error
[4]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Promise
[5]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object
[6]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean
[7]: https://nodejs.org/api/buffer.html
[8]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number
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