cartodb/lib/assets/javascripts/cdb/doc/static_maps.md

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2020-06-15 10:58:47 +08:00
# Static Maps
Static views of CARTO maps can be generated using the [Static Maps API](https://carto.com/docs/carto-engine/maps-api/static-maps-api/) within CARTO.js. The map's style, including the zoom and bounding box, follows from what was set in the `viz.json` file, but you can change the zoom, center, and size of your image with a few lines of code. You can also change your basemap Images can be placed in specified DOM elements on your page, or you can generate a URL for the image.
## Quick Start
The easiest way to generate an image is by using the following piece of code, which generates is replaced by an `img` tag once run in an HTML file:
```javascript
<script>
var vizjson_url = 'https://documentation.carto.com/api/v2/viz/008b3ec6-02c3-11e4-b687-0edbca4b5057/viz.json';
cartodb.Image(vizjson_url)
.size(600, 400)
.center([-3.4, 44.2])
.zoom(4)
.write({ class: "thumb", id: "AwesomeMap" });
</script>
```
#### Result
```html
<img id="AwesomeMap" src="https://cartocdn-ashbu.global.ssl.fastly.net/documentation/api/v1/map/static/center/04430594691ff84a3fdac56259e5180b:1419270587670/4/-3.4/44.2/600/400.png" class="thumb">
```
### cartodb.Image(_layerSource[, options]_)
#### Arguments
Name |Description
--- | ---
layerSource | can be either a `viz.json` object or a [MapConfig object](https://carto.com/docs/carto-engine/maps-api/mapconfig#mapnik-layer-options).<br/><br/>**Note:** If defining an image through the MapConfig layer definition, you must set the `tiler_domain`, `tiler_port`, and `tiler_protocol`, as displayed in this [example](https://github.com/CartoDB/cartodb.js/blob/4ba5148638091fd2c194f48b2fa3ed6ac4ecdb23/examples/layer_definition.html). Otherwise the Static Image API tries to use your localhost to source the tiles and an error appears.
options |
--- | ---
&#124;_ basemap | change the basemap specified in the layer definition. Type: Object defining base map properties (see example below).
&#124;_ no_cdn | Disable CDN usage. Type: Boolean. Default: `false` (use CDN)
&#124;_ override_bbox | Override default of using the bounding box of the visualization. This is needed to use `Image.center` and `Image.zoom`. Type: Boolean. Default: `false` (use bounding box)
#### Returns
An `Image` object
#### Example
```javascript
<script>
var vizjson_url = 'https://documentation.carto.com/api/v2/viz/008b3ec6-02c3-11e4-b687-0edbca4b5057/viz.json';
var basemap = {
type: "http",
options: {
urlTemplate: "http://{s}.basemaps.cartocdn.com/dark_all/{z}/{x}/{y}.png",
subdomains: ["a", "b", "c"]
}
};
cartodb.Image(vizjson_url, {basemap: basemap})
.size(600, 400)
.center([0,0])
.write({ class: "thumb", id: "AwesomeMap" });
</script>
```
---
## cartodb.Image
### Image.size(_width, height_)
Sets the size of the image.
#### Arguments
Name |Description
--- | ---
width | the width of the resulting image in pixels
height | the height of the resulting image in pixels
#### Returns
An `Image` object
### Image.center(_latLng_)
Sets the center of the map.
#### Arguments
Name |Description
--- | ---
latLng | an array of the latitude and longitude of the center of the map. Example: `[40.4378271, -3.6795367]`
#### Returns
An `Image` object
### Image.zoom(_zoomLevel_)
Sets the zoom level of the static map. Must be used with the option `override_bbox: true` if not using `Image.center` or `Image.bbox`.
#### Arguments
Name |Description
--- | ---
zoomLevel | the zoom of the resulting static map. `zoomLevel` must be an integer in the range [0,24].
#### Returns
An `Image` object
### Image.bbox(_boundingBox_)
If you set `bbox`, `center` and `zoom` will be overridden.
#### Arguments
Name |Description
--- | ---
boundingBox | an array of coordinates making up the bounding box for your map. `boundingBox` takes the form: `[sw_lat, sw_lon, ne_lat, ne_lon]`.
#### Returns
An `Image` object
### Image.into(_HTMLImageElement_)
Inserts the image into the HTML DOM element specified.
#### Arguments
Name |Description
--- | ---
HTMLImageElement | the DOM element where your image is to be located.
#### Returns
An `Image` object
#### Example
```javascript
cartodb.Image(vizjson_url).into(document.getElementById('map_preview'))
```
### Image.write(_attributes_)
Adds an `img` tag in the same place script is executed. It's possible to specify a class name (`class`) and/or an id attribute (`id`) for the resulting image:
#### Arguments
Name |Description
--- | ---
class | the DOM class applied to the resulting `img` tag.
id | the DOM id applied to the resulting `img` tag.
src | path to a temporary image that acts as a placeholder while the static map is retrieved.
#### Returns
An `Image` object
#### Example
```javascript
<script>
cartodb.Image(vizjson_url)
.size(600, 400)
.center([-3.4, 44.2])
.zoom(10)
.write({ class: "thumb", id: "ImageHeader", src: 'spinner.gif' });
</script>
```
### Image.getUrl(_callback(err, url)_)
Gets the URL for the image requested.
#### Callback Arguments
Name |Description
--- | ---
err | error associated with the image request, if any.
url | URL of the generated image.
#### Returns
An `Image` object
#### Example
```javascript
<script>
cartodb.Image(vizjson_url)
.size(600, 400)
.getUrl(function(err, url) {
console.log('image url',url);
})
</script>
```
### Image.format(_format_)
Gets the URL for the image requested.
#### Arguments
Name |Description
--- | ---
format | image format of resulting image. One of `png` (default) or `jpg` (which have a quality of 85 dpi)
#### Returns
An `Image` object