Using mapbox-gl-native in Node.js I need to find out the actual bounds of a map after rendering. I'm rendering a map as outlined in the project's README.md:
var fs = require('fs');
var path = require('path');
var mbgl = require('mapbox-gl-native');
var sharp = require('sharp');
var options = {
request: function(req, callback) {
fs.readFile(path.join(__dirname, 'test', req.url), function(err, data) {
callback(err, { data: data });
});
},
ratio: 1
};
var map = new mbgl.Map(options);
map.load(require('./test/fixtures/style.json'));
map.render({zoom: 12.25, center: [-122.67, 45.52]}, function(err, buffer) {
if (err) throw err;
// TODO: get map extent
// var extent = map.extent();
// extent is {minX: ..., maxX: ..., minY: ..., maxY: ...} or similar...
map.release();
var image = sharp(buffer, {
raw: {
width: 512,
height: 512,
channels: 4
}
});
// Convert raw image buffer to PNG
image.toFile('image.png', function(err) {
if (err) throw err;
});
});
After the map is rendered, I would like to find out what the bounds of the rendered map are. Does anyone know if this is possible with mapbox-gl-native or if this is something that could be added to the API in a future version? Or is there another way to calculate the actual bounds of a map simply from the zoom level, the map's center and the map's dimensions?
I used and slightly adjusted the excellent answer by @JohnS to a similar question to calculate the zoom level from a given extent. Maybe there is a way to revert this calculation to obtain the actual extent?