XAML-Map-Control/MBTiles/Shared/MBTileSource.cs

// XAML Map Control - https://github.com/ClemensFischer/XAML-Map-Control
// © 2021 Clemens Fischer
// Licensed under the Microsoft Public License (Ms-PL)

using System;
using System.Diagnostics;
using System.Threading.Tasks;
#if WINUI
using Microsoft.UI.Xaml.Media;
#elif WINDOWS_UWP
using Windows.UI.Xaml.Media;
#else
using System.Windows.Media;
#endif

namespace MapControl.MBTiles
{
    public class MBTileSource : TileSource, IDisposable
    {
        public MBTileData TileData { get; }

        public MBTileSource(MBTileData tiledata)
        {
            var format = tiledata.Metadata["format"];

            if (format == "png" || format == "jpg")
            {
                TileData = tiledata;
            }
            else
            {
                Debug.WriteLine($"MBTileSource: unsupported format '{format}'");
            }
        }

        public void Dispose()
        {
            Dispose(true);
            GC.SuppressFinalize(this);
        }

        protected virtual void Dispose(bool disposing)
        {
            if (disposing && TileData != null)
            {
                TileData.Dispose();
            }
        }

        public override async Task<ImageSource> LoadImageAsync(int x, int y, int zoomLevel)
        {
            ImageSource image = null;

            if (TileData != null)
            {
                var buffer = await TileData.ReadImageBufferAsync(x, y, zoomLevel);

                if (buffer != null)
                {
                    try
                    {
                        image = await ImageLoader.LoadImageAsync(buffer);
                    }
                    catch (Exception ex)
                    {
                        Debug.WriteLine($"MBTileSource : {ex.Message}");
                    }
                }
            }

            return image;
        }
    }
}