sharp/docs/api-composite.md
Lovell Fuller 8717ecc429 Modularise JS source in 'lib' subdirectory.
Generate public API documention via jsdoc comments.
2016-11-02 09:25:20 +00:00

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<!-- Generated by documentation.js. Update this documentation by updating the source code. -->
# overlayWith
Overlay (composite) an image over the processed (resized, extracted etc.) image.
The overlay image must be the same size or smaller than the processed image.
If both `top` and `left` options are provided, they take precedence over `gravity`.
**Parameters**
- `overlay` **([Buffer](https://nodejs.org/api/buffer.html) \| [String](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String))** Buffer containing image data or String containing the path to an image file.
- `options` **\[[Object](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object)]**
- `options.gravity` **\[[String](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String)]** gravity at which to place the overlay. (optional, default `'centre'`)
- `options.top` **\[[Number](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number)]** the pixel offset from the top edge.
- `options.left` **\[[Number](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number)]** the pixel offset from the left edge.
- `options.tile` **\[[Boolean](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Boolean)]** set to true to repeat the overlay image across the entire image with the given `gravity`. (optional, default `false`)
- `options.cutout` **\[[Boolean](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Boolean)]** set to true to apply only the alpha channel of the overlay image to the input image, giving the appearance of one image being cut out of another. (optional, default `false`)
- `options.raw` **\[[Object](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object)]** describes overlay when using raw pixel data.
- `options.raw.width` **\[[Number](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number)]**
- `options.raw.height` **\[[Number](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number)]**
- `options.raw.channels` **\[[Number](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number)]**
**Examples**
```javascript
sharp('input.png')
.rotate(180)
.resize(300)
.flatten()
.background('#ff6600')
.overlayWith('overlay.png', { gravity: sharp.gravity.southeast } )
.sharpen()
.withMetadata()
.quality(90)
.webp()
.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](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error)** Invalid parameters
Returns **Sharp**