Add util functions to convert from/between Mapbox zoom levels & Mapki…

…t camera distance (#29092) * Add helper functions to convert from & to zoom level * Add helper functions to convert from & to zoom level * Simplified convertCameraDistanceToZoomLevel
Automattic · Feb 22, 2023 · c5b343f · c5b343f
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diff --git a/projects/plugins/jetpack/changelog/add-map-block-mapkit-zoom-conversion b/projects/plugins/jetpack/changelog/add-map-block-mapkit-zoom-conversion
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+Significance: minor
+Type: other
+
+Adds util functions for mapkit that allow converting zoom levels to camera distance, and back
diff --git a/projects/plugins/jetpack/extensions/blocks/map/mapkit-utils/index.js b/projects/plugins/jetpack/extensions/blocks/map/mapkit-utils/index.js
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+const earthRadius = 6.371e6;
+
+function getMetersPerPixel( latitude ) {
+	return Math.abs( ( earthRadius * Math.cos( ( latitude * Math.PI ) / 180 ) * 2 * Math.PI ) / 256 );
+}
+
+function convertZoomLevelToCameraDistance( zoomLevel, latitude ) {
+	const altitude = ( 512 / Math.pow( 2, zoomLevel ) ) * 0.5; // altitude in pixels
+	return altitude * getMetersPerPixel( latitude );
+}
+
+function convertCameraDistanceToZoomLevel( cameraDistance, latitude ) {
+	const altitude = cameraDistance / getMetersPerPixel( latitude );
+	return Math.log2( 512 / ( altitude / 0.5 ) );
+}
+
+export { convertZoomLevelToCameraDistance, convertCameraDistanceToZoomLevel };