XAML-Map-Control/MapControl/WinUI/GeoImage.WinUI.cs

using System;
using System.Threading.Tasks;
using Windows.Graphics.Imaging;
using Windows.Storage;
#if UWP
using Windows.UI.Xaml.Media.Imaging;
#else
using Microsoft.UI.Xaml.Media.Imaging;
#endif

namespace MapControl
{
    public static partial class GeoImage
    {
        private static async Task<GeoBitmap> LoadGeoTiff(string sourcePath)
        {
            BitmapSource bitmap;
            Matrix transform;
            MapProjection projection = null;

            var file = await StorageFile.GetFileFromPathAsync(FilePath.GetFullPath(sourcePath));

            using var stream = await file.OpenReadAsync();

            var decoder = await BitmapDecoder.CreateAsync(stream);

            bitmap = await ImageLoader.LoadWriteableBitmapAsync(decoder);

            var geoKeyDirectoryQuery = QueryString(GeoKeyDirectoryTag);
            var pixelScaleQuery = QueryString(ModelPixelScaleTag);
            var tiePointQuery = QueryString(ModelTiePointTag);
            var transformationQuery = QueryString(ModelTransformationTag);
            var metadata = await decoder.BitmapProperties.GetPropertiesAsync(
                new string[]
                {
                    pixelScaleQuery,
                    tiePointQuery,
                    transformationQuery,
                    geoKeyDirectoryQuery
                });

            if (metadata.TryGetValue(pixelScaleQuery, out BitmapTypedValue pixelScaleValue) &&
                pixelScaleValue.Value is double[] pixelScale &&
                pixelScale.Length == 3 &&
                metadata.TryGetValue(tiePointQuery, out BitmapTypedValue tiePointValue) &&
                tiePointValue.Value is double[] tiePoint &&
                tiePoint.Length >= 6)
            {
                transform = new Matrix(pixelScale[0], 0d, 0d, -pixelScale[1], tiePoint[3], tiePoint[4]);
            }
            else if (metadata.TryGetValue(transformationQuery, out BitmapTypedValue transformValue) &&
                        transformValue.Value is double[] transformValues &&
                        transformValues.Length == 16)
            {
                transform = new Matrix(transformValues[0], transformValues[1],
                                       transformValues[4], transformValues[5],
                                       transformValues[3], transformValues[7]);
            }
            else
            {
                throw new ArgumentException("No coordinate transformation found.");
            }

            if (metadata.TryGetValue(geoKeyDirectoryQuery, out BitmapTypedValue geoKeyDirValue) &&
                geoKeyDirValue.Value is short[] geoKeyDirectory)
            {
                projection = GetProjection(geoKeyDirectory);
            }

            return new GeoBitmap(bitmap, transform, projection);
        }
    }
}