public byte[] Render(Envelope envelope, string format, int tileWidth, int tileHeight)
{
// Lock map object for rendering
// TO DO: better strategy is to create a pool of map objects
lock (mapLock)
{
_map.Width = Convert.ToUInt32(tileWidth);
_map.Height = Convert.ToUInt32(tileHeight);
_map.ZoomToBox(envelope.Minx, envelope.Miny, envelope.Maxx, envelope.Maxy);
format = format.ToLower();
// Render Image
if (format == "png" || format == "jpg")
{
Image img = new Image(Convert.ToInt32(_map.Width), Convert.ToInt32(_map.Height));
_map.Render(img);
if (format == "png")
{
format = this._pngOptions;
}
if (format == "jpg")
{
format = this._jpegOptions;
}
return img.Encode(format);
}
// Render UTFGrid
else if (format == "json")
{
NETMapnik.Grid grd = new NETMapnik.Grid(_map.Width, _map.Height);
_map.Render(grd, Convert.ToUInt32(this._gridLayerIndex), this._gridFields);
string json = JsonConvert.SerializeObject(grd.Encode("utf", true, Convert.ToUInt32(this._gridResolution)));
return Encoding.UTF8.GetBytes(json);
}
// Render vector tile
else if (format == "pbf")
{
//tile coord (i.e., 0/0/0 not needed for pbf rendering
VectorTile vTile = new VectorTile(0,0,0, _map.Width,_map.Height);
_map.Render(vTile);
byte[] bytes = vTile.GetBytes();
//compress vector tile bytes
if (bytes.Length > 0)
{
bytes = Compress(bytes);
}
return bytes;
}
// Format not expected so throw exception
throw new InvalidTileFormatException(
string.Format("Invalid tile FORMAT {0}", format)
);
}
}