/// <summary>
/// gets image from tile server
/// </summary>
/// <param name="provider"></param>
/// <param name="pos"></param>
/// <param name="zoom"></param>
/// <returns></returns>
public PureImage GetImageFrom(IMapProvider provider, GPoint pos, int zoom, out Exception result)
{
PureImage ret = null;
result = null;
try
{
var rtile = new RawTile(provider.MapId, pos, zoom);
// let't check memmory first
if (UseMemoryCache)
{
var m = MemoryCache.GetTileFromMemoryCache(rtile);
if (m != null)
{
if (IMapProvider.TileImageProxy != null)
{
ret = IMapProvider.TileImageProxy.FromArray(m);
if (ret == null)
{
#if DEBUG
Debug.WriteLine("Image disposed in MemoryCache o.O, should never happen ;} " + new RawTile(provider.MapId, pos, zoom));
if (Debugger.IsAttached)
{
Debugger.Break();
}
#endif
m = null;
}
}
}
}
if (ret == null)
{
if (Mode != AccessMode.ServerOnly)
{
if (PrimaryCache != null)
{
// hold writer for 5s
if (CacheOnIdleRead)
{
Interlocked.Exchange(ref readingCache, 5);
}
ret = PrimaryCache.GetImageFromCache(provider.MapId, pos, zoom);
if (ret != null)
{
if (UseMemoryCache)
{
MemoryCache.AddTileToMemoryCache(rtile, ret.Data.GetBuffer());
}
return(ret);
}
}
}
if (Mode != AccessMode.CacheOnly)
{
ret = provider.GetTileImage(pos, zoom);
{
// Enqueue Cache
if (ret != null)
{
if (UseMemoryCache)
{
MemoryCache.AddTileToMemoryCache(rtile, ret.Data.GetBuffer());
}
if (Mode != AccessMode.ServerOnly)
{
EnqueueCacheTask(new CacheQueueItem(rtile, ret.Data.GetBuffer(), CacheUsage.Both));
}
}
}
}
else
{
result = noDataException;
}
}
}
catch (Exception ex)
{
result = ex;
ret = null;
Debug.WriteLine("GetImageFrom: " + ex.ToString());
}
return(ret);
}
abstract public bool Save(Stream stream, PureImage image);
