// JavaScript

// converts lat/lon to pixel x/y at zoom level 0 for 256*256 tile size , inverts y coord
function latLonToPixels(lat, lon) { // lat, lon: epsg:4326
    var sinLat = Math.sin(lat * Math.PI / 180.0);
    var pixelX = ((lon + 180) / 360) * 256;
    var pixelY = (0.5 - Math.log((1 + sinLat) / (1 - sinLat)) / (Math.PI * 4)) * 256;
    return { x: pixelX, y: pixelY }; // object with .x and .y
}