Task ITileSource.InitAsync()
{
// Configuration values priority:
// 1. Default values for MBTiles.
// 2. Actual values (MBTiles metadata).
// 3. Values from configuration file - overrides given above, if provided.
this.repository = new MBTiles.Repository(configuration.Location, false);
var metadata = new MBTiles.Metadata(this.repository.ReadMetadata());
var title = String.IsNullOrEmpty(this.configuration.Title) ?
(!String.IsNullOrEmpty(metadata.Name) ? metadata.Name : this.configuration.Id) :
this.configuration.Title;
var format = String.IsNullOrEmpty(this.configuration.Format) ?
(!String.IsNullOrEmpty(metadata.Format) ? metadata.Format : "png") :
this.configuration.Format;
// Re-create configuration
this.configuration = new TileSourceConfiguration
{
Id = this.configuration.Id,
Type = this.configuration.Type,
Format = format,
Title = title,
Tms = this.configuration.Tms ?? true, // Default true for the MBTiles, following the Tile Map Service Specification.
Location = this.configuration.Location,
ContentType = Utils.TileFormatToContentType(format),
MinZoom = this.configuration.MinZoom ?? metadata.MinZoom ?? 0, // TODO: ? Check actual SELECT MIN/MAX(zoom_level) ?
MaxZoom = this.configuration.MaxZoom ?? metadata.MaxZoom ?? 24,
};
return(Task.CompletedTask);
}
Task ITileSource.InitAsync()
{
// Configuration values priority:
// 1. Default values for MBTiles source type.
// 2. Actual values (MBTiles metadata table values).
// 3. Values from configuration file - overrides given above, if provided.
if (String.IsNullOrEmpty(this.configuration.Location))
{
throw new InvalidOperationException("configuration.Location is null or empty");
}
this.repository = new MBTiles.Repository(configuration.Location, false);
var metadata = new MBTiles.Metadata(this.repository.ReadMetadata());
var title = String.IsNullOrEmpty(this.configuration.Title) ?
(!String.IsNullOrEmpty(metadata.Name) ? metadata.Name : this.configuration.Id) :
this.configuration.Title;
var format = String.IsNullOrEmpty(this.configuration.Format) ?
(!String.IsNullOrEmpty(metadata.Format) ? metadata.Format : ImageFormats.Png) :
this.configuration.Format;
// Get tile width and height from first tile, for raster formats
var tileWidth = Utils.WebMercator.DefaultTileWidth;
var tileHeight = Utils.WebMercator.DefaultTileHeight;
var firstTile = this.repository.ReadFirstTile();
if (firstTile != null && (format == ImageFormats.Png || format == ImageFormats.Jpeg))
{
var size = Utils.ImageHelper.GetImageSize(firstTile);
if (size.HasValue)
{
tileWidth = size.Value.Width;
tileHeight = size.Value.Height;
}
}
var minZoom = this.configuration.MinZoom ?? metadata.MinZoom ?? null;
var maxZoom = this.configuration.MaxZoom ?? metadata.MaxZoom ?? null;
if (minZoom == null || maxZoom == null)
{
var zoomRange = this.repository.GetZoomLevelRange();
if (zoomRange.HasValue)
{
minZoom = zoomRange.Value.Min;
maxZoom = zoomRange.Value.Max;
}
else
{
minZoom = 0;
maxZoom = 20;
}
}
// Re-create configuration
this.configuration = new SourceConfiguration
{
Id = this.configuration.Id,
Type = this.configuration.Type,
Format = format,
Title = title,
Abstract = this.configuration.Abstract,
Tms = this.configuration.Tms ?? true, // Default true for the MBTiles, following the Tile Map Service Specification.
Srs = Utils.SrsCodes.EPSG3857, // MBTiles supports only Spherical Mercator tile grid
Location = this.configuration.Location,
ContentType = Utils.EntitiesConverter.TileFormatToContentType(format),
MinZoom = minZoom,
MaxZoom = maxZoom,
GeographicalBounds = metadata.Bounds, // Can be null, if no corresponding record in 'metadata' table
TileWidth = tileWidth,
TileHeight = tileHeight,
Cache = null, // Not used for MBTiles source
};
return(Task.CompletedTask);
}
