leaflet-simple-map-screenshoter/README.md

Leaflet plugin plugin which take screenshot of map

## leaflet-simple-map-screenshoter
[Leaflet](http://www.leafletjs.com) promise based plugin which take screenshot of map.
Used [dom-to-image](https://github.com/tsayen/dom-to-image).

### Install
```
npm install leaflet-simple-map-screenshoter --save
```

### Example
[Open](https://grinat.github.io/leaflet-simple-map-screenshoter/examples/index.html) (see in /examples)

### Usage
Add save screenshot button to leaflet control panel
```javascript
import * as L from 'leaflet'
// import script after leaflet
import {SimpleMapScreenshoter} from 'leaflet-simple-map-screenshoter'

new SimpleMapScreenshoter().addTo(this.map)
```

From cdn
```html
<script src="https://unpkg.com/leaflet"></script>
<script src="https://unpkg.com/leaflet-simple-map-screenshoter"></script>
<script>
L.simpleMapScreenshoter().addTo(map)
</script>
```

For custom usage
```javascript
import 'leaflet'
// import script after leaflet
import 'leaflet-simple-map-screenshoter'

let pluginOptions = {
   cropImageByInnerWH: true, // crop blank opacity from image borders
   hidden: false, // hide screen icon
   preventDownload: false, // prevent download on button click
   domtoimageOptions: {}, // see options for dom-to-image
   position: 'topleft', // position of take screen icon
   screenName: 'screen', // string or function
   iconUrl: ICON_SVG_BASE64, // screen btn icon base64 or url
   hideElementsWithSelectors: ['.leaflet-control-container'], // by default hide map controls All els must be child of _map._container
   mimeType: 'image/png', // used if format == image,
   caption: null, // string or function, added caption to bottom of screen
   captionFontSize: 15,
   captionFont: 'Arial',
   captionColor: 'black',
   captionBgColor: 'white',
   captionOffset: 5,
   // callback for manually edit map if have warn: "May be map size very big on that zoom level, we have error"
   // and screenshot not created
   onPixelDataFail: async function({ node, plugin, error, mapPane, domtoimageOptions }) {
       // Solutions:
       // decrease size of map
       // or decrease zoom level
       // or remove elements with big distanses
       // and after that return image in Promise - plugin._getPixelDataOfNormalMap
       return plugin._getPixelDataOfNormalMap(domtoimageOptions)
   }
}

this.simpleMapScreenshoter = L.simpleMapScreenshoter(pluginOptions).addTo(this.map)
let format = 'blob' // 'image' - return base64, 'canvas' - return canvas
let overridedPluginOptions = {
  mimeType: 'image/jpeg'
}
this.simpleMapScreenshoter.takeScreen(format, overridedPluginOptions).then(blob => {
   alert('done')
   // FileSaver.saveAs(blob, 'screen.png')
}).catch(e => {
   console.error(e)
})
```

### Events

```
simpleMapScreenshoter.click - on leaflet control panel take screen btn click
simpleMapScreenshoter.takeScreen - start build screenshot
simpleMapScreenshoter.done - screenshot build ended
simpleMapScreenshoter.error - on error, return Error instance
```