sharp
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High performance Node.js image processing, the fastest module to resize JPEG, PNG, WebP and TIFF images
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## composite
Composite image(s) over the processed (resized, extracted etc.) image.
The images to composite must be the same size or smaller than the processed image.
If both `top` and `left` options are provided, they take precedence over `gravity`.
The `blend` option can be one of `clear`, `source`, `over`, `in`, `out`, `atop`,
`dest`, `dest-over`, `dest-in`, `dest-out`, `dest-atop`,
`xor`, `add`, `saturate`, `multiply`, `screen`, `overlay`, `darken`, `lighten`,
`colour-dodge`, `color-dodge`, `colour-burn`,`color-burn`,
`hard-light`, `soft-light`, `difference`, `exclusion`.
More information about blend modes can be found at
[https://libvips.github.io/libvips/API/current/libvips-conversion.html#VipsBlendMode][1]
and [https://www.cairographics.org/operators/][2]
### Parameters
- `images` **[Array][3]<[Object][4]>** Ordered list of images to composite
- `images[].input` **([Buffer][5] \| [String][6])?** Buffer containing image data, String containing the path to an image file, or Create object (see bellow)
- `images[].input.create` **[Object][4]?** describes a blank overlay to be created.
- `images[].input.create.width` **[Number][7]?**
- `images[].input.create.height` **[Number][7]?**
- `images[].input.create.channels` **[Number][7]?** 3-4
- `images[].input.create.background` **([String][6] \| [Object][4])?** parsed by the [color][8] module to extract values for red, green, blue and alpha.
- `images[].blend` **[String][6]** how to blend this image with the image below. (optional, default `'over'`)
- `images[].gravity` **[String][6]** gravity at which to place the overlay. (optional, default `'centre'`)
- `images[].top` **[Number][7]?** the pixel offset from the top edge.
- `images[].left` **[Number][7]?** the pixel offset from the left edge.
- `images[].tile` **[Boolean][9]** set to true to repeat the overlay image across the entire image with the given `gravity`. (optional, default `false`)
- `images[].premultiplied` **[Boolean][9]** set to true to avoid premultipling the image below. Equivalent to the `--premultiplied` vips option. (optional, default `false`)
- `images[].density` **[Number][7]** number representing the DPI for vector overlay image. (optional, default `72`)
- `images[].raw` **[Object][4]?** describes overlay when using raw pixel data.
- `images[].raw.width` **[Number][7]?**
- `images[].raw.height` **[Number][7]?**
- `images[].raw.channels` **[Number][7]?**
### Examples
```javascript
sharp('input.png')
.rotate(180)
.resize(300)
.flatten( { background: '#ff6600' } )
.composite([{ input: 'overlay.png', gravity: 'southeast' }])
.sharpen()
.withMetadata()
.webp( { quality: 90 } )
.toBuffer()
.then(function(outputBuffer) {
// outputBuffer contains upside down, 300px wide, alpha channel flattened
// onto orange background, composited with overlay.png with SE gravity,
// sharpened, with metadata, 90% quality WebP image data. Phew!
});
```
- Throws **[Error][10]** Invalid parameters
Returns **Sharp**
[1]: https://libvips.github.io/libvips/API/current/libvips-conversion.html#VipsBlendMode
[2]: https://www.cairographics.org/operators/
[3]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Array
[4]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object
[5]: https://nodejs.org/api/buffer.html
[6]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String
[7]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number
[8]: https://www.npmjs.org/package/color
[9]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean
[10]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Error