react-map-gl/docs/user-guide/transitions.md
2017-11-29 10:38:06 -08:00

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# Transitions
`react-map-gl` does not expose the transition API from `mapbox-gl-js` since it is designed to be a stateless component, and needs to synchronize with separate overlay systems such as deck.gl.
Instead, transitions can be defined using [InteractiveMap](/docs/components/interactive-map.md)'s transition props. For example:
```jsx
import ReactMapGL, {LinearInterpolator, FlyToInterpolator} from 'react-map-gl';
// 3rd-party easing functions
import d3 from 'd3-ease';
<ReactMapGL
{...viewport}
transitionDuration={1000}
transitionInterpolator={new FlyToInterpolator()}
transitionEasing={d3.easeCubic}
onTransitionEnd={() => {
// do something
}} >
```
See [viewport transition](#examples/viewport-transition) for a complete example.
## InteractiveMap's Transition Props
See properties of [InteractiveMap](/docs/components/interactive-map.md).
- `transitionDuration` {Number}
- `transitionInterpolator` {Object}
- `transitionEasing` {Function}
- `transitionInterruption` {Number}
- `onTransitionStart` {Function}
- `onTransitionInterrupt` {Function}
- `onTransitionEnd` {Function}
## Transition Interpolators
A `TransitionInterpolator` instance must be supplied to the `transitionInterpolator` prop. It contains the following methods:
- `arePropsEqual(currentProps, nextProps)` - called to determine if transition should be triggered when viewport props update.
- `initiateProps(startProps, endProps)` - called before transition starts to pre-process the start and end viewport props.
- `interpolateProps(startProps, endProps, t)` - called to get viewport props in transition. `t` is a time factor between `[0, 1]`.
### `LinearInterpolator`
Interpolates all viewport props linearly. This interpolator offers similar behavior to Mapbox's `easeTo` when combined with a `transitionEasing` function. You may optionally limit the transition to selected viewport props, for example `new LinearInterpolator(['pitch', 'bearing'])` animates pitch and bearing while the user is still allowed to pan and zoom.
##### constructor
`new LinearInterpolator([transitionProps])`
Parameters:
- `transitionProps` {Array} (optional) - list of prop names to interpolate. Default: `['longitude', 'latitude', 'zoom', 'pitch', 'bearing']`.
### `FlyToInterpolator`
This interpolator offers similar behavior to Mapbox's `flyTo` method.
##### constructor
`new FlyToInterpolator()`