From c5b343fbb89515f49a56a2de7122068c2862fef7 Mon Sep 17 00:00:00 2001
From: Tim Broddin <tim@wannabes.be>
Date: Wed, 22 Feb 2023 16:09:08 +0100
Subject: [PATCH] Add util functions to convert from/between Mapbox zoom levels
 & Mapkit camera distance (#29092)

* Add helper functions to convert from & to zoom level

* Add helper functions to convert from & to zoom level

* Simplified convertCameraDistanceToZoomLevel
---
 .../add-map-block-mapkit-zoom-conversion        |  4 ++++
 .../extensions/blocks/map/mapkit-utils/index.js | 17 +++++++++++++++++
 2 files changed, 21 insertions(+)
 create mode 100644 projects/plugins/jetpack/changelog/add-map-block-mapkit-zoom-conversion
 create mode 100644 projects/plugins/jetpack/extensions/blocks/map/mapkit-utils/index.js

diff --git a/projects/plugins/jetpack/changelog/add-map-block-mapkit-zoom-conversion b/projects/plugins/jetpack/changelog/add-map-block-mapkit-zoom-conversion
new file mode 100644
index 0000000000000..955697ec9630a
--- /dev/null
+++ b/projects/plugins/jetpack/changelog/add-map-block-mapkit-zoom-conversion
@@ -0,0 +1,4 @@
+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
new file mode 100644
index 0000000000000..96db0dd7b3a10
--- /dev/null
+++ b/projects/plugins/jetpack/extensions/blocks/map/mapkit-utils/index.js
@@ -0,0 +1,17 @@
+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 };