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输出

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.

参数

fileOut String the path to write the image data to.
callback Function? 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.
Throws Error Invalid parameters

返回 Promise<Object> 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.

参数

options Object?
- options.resolveWithObject Boolean? Resolve the Promise with an Object containing data and info properties instead of resolving only with data.
callback Function?

返回 Promise<Buffer> 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.

参数

withMetadata Object?
- withMetadata.orientation Number? value between 1 and 8, used to update the EXIF Orientation tag.
Throws Error Invalid parameters

返回 Sharp

jpeg¶

Use these JPEG options for output image.

参数

options Object? output options
- options.quality Number quality, integer 1-100 (optional, default 80)
- options.progressive Boolean use progressive (interlace) scan (optional, default false)
- options.chromaSubsampling String set to '4:4:4' to prevent chroma subsampling when quality <= 90 (optional, default '4:2:0')
- options.trellisQuantisation Boolean apply trellis quantisation, requires mozjpeg (optional, default false)
- options.overshootDeringing Boolean apply overshoot deringing, requires mozjpeg (optional, default false)
- options.optimiseScans Boolean optimise progressive scans, forces progressive, requires mozjpeg (optional, default false)
- options.optimizeScans Boolean alternative spelling of optimiseScans (optional, default false)
- options.force Boolean force JPEG output, otherwise attempt to use input format (optional, default true)
Throws Error Invalid options

返回 Sharp

png¶

Use these PNG options for output image.

参数

options Object?
- options.progressive Boolean use progressive (interlace) scan (optional, default false)
- options.compressionLevel Number zlib compression level, 0-9 (optional, default 9)
- options.adaptiveFiltering Boolean use adaptive row filtering (optional, default false)
- options.force Boolean force PNG output, otherwise attempt to use input format (optional, default true)
Throws Error Invalid options

返回 Sharp

webp¶

Use these WebP options for output image.

参数

options Object? output options
- options.quality Number quality, integer 1-100 (optional, default 80)
- options.alphaQuality Number quality of alpha layer, integer 0-100 (optional, default 100)
- options.lossless Boolean use lossless compression mode (optional, default false)
- options.nearLossless Boolean use near_lossless compression mode (optional, default false)
- options.force Boolean force WebP output, otherwise attempt to use input format (optional, default true)
Throws Error Invalid options

返回 Sharp

tiff¶

Use these TIFF options for output image.

参数

options Object? output options
- options.quality Number quality, integer 1-100 (optional, default 80)
- options.force Boolean force TIFF output, otherwise attempt to use input format (optional, default true)
- options.compression Boolean compression options: lzw, deflate, jpeg (optional, default 'jpeg')
- options.predictor Boolean compression predictor options: none, horizontal, float (optional, default 'horizontal')
- options.xres Number horizontal resolution in pixels/mm (optional, default 1.0)
- options.yres Number vertical resolution in pixels/mm (optional, default 1.0)
- options.squash Boolean squash 8-bit images down to 1 bit (optional, default false)
Throws Error Invalid options

返回 Sharp

raw¶

Force output to be raw, uncompressed uint8 pixel data.

返回 Sharp

toFormat¶

Force output to a given format.

参数

format (String | Object) as a String or an Object with an 'id' attribute
options Object output options
Throws Error unsupported format or options

返回 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.

参数

tile Object?
- tile.size Number tile size in pixels, a value between 1 and 8192. (optional, default 256)
- tile.overlap Number tile overlap in pixels, a value between 0 and 8192. (optional, default 0)
- tile.container String tile container, with value fs (filesystem) or zip (compressed file). (optional, default 'fs')
- tile.layout String filesystem layout, possible values are dz, zoomify or google. (optional, default 'dz')

Examples

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 Invalid parameters

返回 Sharp