npm package: @lyra/image-url
Description: Tools to generate image urls from Lyra content
Author: Vega
Latest version: 0.3.0

# @lyra/image-url

Quickly generate image urls from Lyra image records.

This helper will by default respect any crops/hotspots specified in the Lyra content provided to it. The most typical use case for this is to give it a lyra image and specify a width, height or both and get a nice, cropped and resized image according to the wishes of the content editor and the specifications of the front end developer.

In addition to the core use case, this library provides a handy builder to access the rich selection of processing options available in the Lyra image pipeline.

## Getting started

    npm install --save @lyra/image-url

## Usage

The most common way to use this library in your project is to configure it by passing it your configured lyraClient. That way it will automatically be preconfigured to your current project and dataset:

```js
import React from 'react'
import myConfiguredLyraClient from './lyraClient'
import imageUrlBuilder from '@lyra/image-url'

const builder = imageUrlBuilder(myConfiguredLyraClient)

function urlFor(source) {
  return builder.image(source)
}
```

Then you can use the handy builder syntax to generate your urls:

```js
<img
  src={urlFor(author.image)
    .width(200)
    .url()}
/>
```

This will ensure that the author image is alway 200 pixels wide, automatically applying any crop specified by the editor and cropping towards the hot-spot she drew. You can specify both width and height like this:

```js
  <img src={urlFor(movie.poster).width(500).height(300).url()}>
```

There are a huge number of useful options you can specify, like e.g. blur:

```js
  <img src={urlFor(mysteryPerson.mugshot).width(200).height(200).blur(50).url()}>
```

## Builder methods

### `image(source)`

Specify the image to be rendered. Accepts either a Lyra `image` record, an `asset` record, or just the asset id as a string. In order for hotspot/crop processing to be applied, the `image` record must be supplied.

### `dataset(dataset)`

Usually you should preconfigure your builder with dataset, but even if you do, `.dataset() let you temporarily override the dataset if you need to render assets from other datasets.

### `width(pixels)`

Specify the width of the rendered image in pixels.

### `height(pixels)`

Specify the height of the rendered image in pixels.

### `size(width, height)`

Specify width and height in one go.

### `focalPoint(x, y)`

Specify a center point to focus on when cropping the image. Values from 0.0 to 1.0 in fractions of the image dimensions. When specified, overrides any crop or hotspot in the image record.

### `minWidth(pixels)`, `maxWidth(pixels)`, `minHeight(pixels)`, `maxHeight(pixels)`

Specifies min/max dimensions when cropping

### `blur(amount)`, `sharpen(amount)`, `invert()`

Apply image processing.

### `rect(left, top, width, height)`

Specify the crop in pixels. Overrides any crop/hotspot in the image record.

### `format(name)`

Specify the image format of the image. 'jpg', 'pjpg', 'png', 'webp'

### `orientation(angle)`

Rotation in degrees. Acceptable values: 0, 90, 180, 270

### `quality(value)`

Compression quality, where applicable. 0-100

### `forceDownload(defaultFileName)`

Make this an url to download the image. Specify the file name that will be suggested to the user.

### `flipHorizontal()`, `flipVertical()`

Flips the image.

### `crop(mode)`

Specifies how to crop the image. When specified, overrides any crop or hotspot in the image record. See the [documentation](https://www.vegapublish.com/docs/reference/image-urls#crop-object-object) for details.

### `fit(value)`

Configures the fit mode. See the [documentation](https://www.vegapublish.com/docs/reference/image-urls#fit-object-object) for details.

### `ignoreImageParams()`

Ignore any specifications from the image record (i.e. crop and hotspot).

### `url()`, `toString()`

Return the url as a string.