tiff/README.md

TIFF image decoder written entirely in JavaScript

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# tiff

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TIFF image decoder written entirely in JavaScript.

## Installation

```console
npm install tiff
```

## Compatibility

### [TIFF standard](./TIFF6.pdf)

The library can currently decode greyscale and RGB images (8, 16 or 32 bits).
It supports LZW compression and images with an additional alpha channel.

### Extensions

Images compressed with Zlib/deflate algorithm are also supported.

## API

### [Complete API documentation](https://image-js.github.io/tiff/)

### `tiff.decode(data[, options])`

Decodes the file and returns TIFF IFDs.

#### IFD object

Each decoded image is stored in an `IFD`.

##### IFD#data

The `data` property is a Typed Array containing the pixel data. It is a
`Uint8Array` for 8bit images, a `Uint16Array` for 16bit images and a
`Float32Array` for 32bit images.

##### Other properties of IFD

- `size` - number of pixels
- `width` - number of columns
- `height` - number of rows
- `bitsPerSample` - bit depth
- `alpha` - `true` if the image has an additional alpha channel
- `xResolution`
- `yResolution`
- `resolutionUnit`

### `tiff.pageCount(data)`

Returns the number of IFDs (pages) in the file.

### `tiff.isMultiPage(data)`

Returns true if the file has 2 or more IFDs (pages) and false if it has 1.
This is slightly more efficient than calling `pageCount()` if all you need to
know is whether the file has multiple pages or not.

## License

[MIT](./LICENSE)