C# Streams.InMemoryRandomAccessStream类代码示例

 async Task<WriteableBitmap> ResizeImage(WriteableBitmap baseWriteBitmap, uint width, uint height)
 {
     Stream stream = baseWriteBitmap.PixelBuffer.AsStream();
     byte[] pixels = new byte[(uint)stream.Length];
     await stream.ReadAsync(pixels, 0, pixels.Length);
     var inMemoryRandomStream = new InMemoryRandomAccessStream();
     var encoder = await BitmapEncoder.CreateAsync(BitmapEncoder.JpegEncoderId, inMemoryRandomStream);
     encoder.SetPixelData(BitmapPixelFormat.Bgra8, BitmapAlphaMode.Ignore, (uint)baseWriteBitmap.PixelWidth, (uint)baseWriteBitmap.PixelHeight, 96, 96, pixels);
     await encoder.FlushAsync();
     var transform = new BitmapTransform
     {
         ScaledWidth = width,
         ScaledHeight = height
     };
     inMemoryRandomStream.Seek(0);
     var decoder = await BitmapDecoder.CreateAsync(inMemoryRandomStream);
     var pixelData = await decoder.GetPixelDataAsync(
                     BitmapPixelFormat.Bgra8,
                     BitmapAlphaMode.Straight,
                     transform,
                     ExifOrientationMode.IgnoreExifOrientation,
                     ColorManagementMode.DoNotColorManage);
     var sourceDecodedPixels = pixelData.DetachPixelData();
     var inMemoryRandomStream2 = new InMemoryRandomAccessStream();
     var encoder2 = await BitmapEncoder.CreateAsync(BitmapEncoder.JpegEncoderId, inMemoryRandomStream2);
     encoder2.SetPixelData(BitmapPixelFormat.Bgra8, BitmapAlphaMode.Ignore, width, height, 96, 96, sourceDecodedPixels);
     await encoder2.FlushAsync();
     inMemoryRandomStream2.Seek(0);
     var bitmap = new WriteableBitmap((int)width, (int)height);
     await bitmap.SetSourceAsync(inMemoryRandomStream2);
     return bitmap;
 }

		public byte[] DrawStrokeOnImageBackground(IReadOnlyList<InkStroke> strokes, byte[] backgroundImageBuffer)
		{

			var stmbuffer = new InMemoryRandomAccessStream();
			stmbuffer.AsStreamForWrite().AsOutputStream().WriteAsync(backgroundImageBuffer.AsBuffer()).AsTask().Wait();

			CanvasDevice device = CanvasDevice.GetSharedDevice();
			var canbit = CanvasBitmap.LoadAsync(device, stmbuffer, 96).AsTask().Result;


			CanvasRenderTarget renderTarget = new CanvasRenderTarget(device, canbit.SizeInPixels.Width, canbit.SizeInPixels.Height, 96);

			using (var ds = renderTarget.CreateDrawingSession())
			{
				ds.Clear(Colors.Transparent);

				if (backgroundImageBuffer != null)
				{

					ds.DrawImage(canbit);
				}

				ds.DrawInk(strokes);
			}
			var stm = new InMemoryRandomAccessStream();
			renderTarget.SaveAsync(stm, CanvasBitmapFileFormat.Png).AsTask().Wait();
			var readfrom = stm.GetInputStreamAt(0).AsStreamForRead();
			var ms = new MemoryStream();
			readfrom.CopyTo(ms);
			var outputBuffer = ms.ToArray();
			return outputBuffer;
		}

        private async Task<byte[]> ImageToBytes(IRandomAccessStream sourceStream)
        {
            byte[] imageArray;

            BitmapDecoder decoder = await BitmapDecoder.CreateAsync(sourceStream);

            var transform = new BitmapTransform { ScaledWidth = decoder.PixelWidth, ScaledHeight = decoder.PixelHeight };
            PixelDataProvider pixelData = await decoder.GetPixelDataAsync(
                BitmapPixelFormat.Rgba8,
                BitmapAlphaMode.Straight,
                transform,
                ExifOrientationMode.RespectExifOrientation,
                ColorManagementMode.DoNotColorManage);

            using (var destinationStream = new InMemoryRandomAccessStream())
            {
                BitmapEncoder encoder = await BitmapEncoder.CreateAsync(BitmapEncoder.PngEncoderId, destinationStream);
                encoder.SetPixelData(BitmapPixelFormat.Rgba8, BitmapAlphaMode.Premultiplied, decoder.PixelWidth,
                    decoder.PixelHeight, 96, 96, pixelData.DetachPixelData());
                await encoder.FlushAsync();

                BitmapDecoder outputDecoder = await BitmapDecoder.CreateAsync(destinationStream);
                await destinationStream.FlushAsync();
                imageArray = (await outputDecoder.GetPixelDataAsync()).DetachPixelData();
            }
            return imageArray;
        }

        private async void OnDeferredImageRequestedHandler(DataProviderRequest request)
        {
            // In this delegate we provide updated Bitmap data using delayed rendering.

            if (_imageFile != null)
            {
                // If the delegate is calling any asynchronous operations it needs to acquire
                // the deferral first. This lets the system know that you are performing some
                // operations that might take a little longer and that the call to SetData 
                // could happen after the delegate returns. Once you acquired the deferral object 
                // you must call Complete on it after your final call to SetData.
                DataProviderDeferral deferral = request.GetDeferral();
                InMemoryRandomAccessStream inMemoryStream = new InMemoryRandomAccessStream();

                // Make sure to always call Complete when finished with the deferral.
                try
                {
                    // Decode the image and re-encode it at 50% width and height.
                    IRandomAccessStream imageStream = await _imageFile.OpenAsync(FileAccessMode.Read);
                    BitmapDecoder imageDecoder = await BitmapDecoder.CreateAsync(imageStream);
                    BitmapEncoder imageEncoder = await BitmapEncoder.CreateForTranscodingAsync(inMemoryStream, imageDecoder);
                    imageEncoder.BitmapTransform.ScaledWidth = (uint)(imageDecoder.OrientedPixelWidth * 0.5);
                    imageEncoder.BitmapTransform.ScaledHeight = (uint)(imageDecoder.OrientedPixelHeight * 0.5);
                    await imageEncoder.FlushAsync();

                    request.SetData(RandomAccessStreamReference.CreateFromStream(inMemoryStream));
                }
                finally
                {
                    deferral.Complete();
                }
            }
        }

        private async Task RenderUIElement(FrameworkElement elm, string fileName, int width, int height) {
            
            await System.Threading.Tasks.Task.Delay(TimeSpan.FromSeconds(1));

            using (InMemoryRandomAccessStream ms = new InMemoryRandomAccessStream())
            {
                var renderTargetBitmap = new RenderTargetBitmap();
                await renderTargetBitmap.RenderAsync(elm);

                var pixels = await renderTargetBitmap.GetPixelsAsync();

                var logicalDpi = DisplayInformation.GetForCurrentView().LogicalDpi;
                var encoder = await BitmapEncoder.CreateAsync(BitmapEncoder.PngEncoderId, ms);
                encoder.SetPixelData(
                    BitmapPixelFormat.Bgra8,
                    BitmapAlphaMode.Ignore,
                    (uint)renderTargetBitmap.PixelWidth,
                    (uint)renderTargetBitmap.PixelHeight,
                    logicalDpi,
                    logicalDpi,
                    pixels.ToArray());

                await encoder.FlushAsync();

                await X.Services.Image.Service.Instance.GenerateResizedImageAsync(width, elm.ActualWidth, elm.ActualHeight, ms, fileName + ".png", Services.Image.Service.location.TileFolder, height);
            }

        }

        /// <summary>
        /// Asynchronously saves the <paramref name="photo" /> given to the camera roll album.
        /// </summary>
        /// <param name="photo">Photo to save.</param>
        /// <returns>Image with thumbnail.</returns>
        /// <exception cref="ArgumentNullException"><paramref name="photo"/> is <see langword="null"/>.</exception>
        public async Task<IThumbnailedImage> SaveResultToCameraRollAsync(ICapturedPhoto photo)
        {
            if (photo == null)
            {
                throw new ArgumentNullException("photo");
            }

            Tracing.Trace("StorageService: Trying to save picture to the Camera Roll.");

            Picture cameraRollPicture;
            string name = this.GeneratePhotoName();

            using (InMemoryRandomAccessStream stream = new InMemoryRandomAccessStream())
            {
                // Convert image to JPEG format and rotate in accordance with the original photo orientation.
                Tracing.Trace("StorageService: Converting photo to JPEG format. Size: {0}x{1}, Rotation: {2}", photo.Width, photo.Height, photo.Rotation);
                byte[] pixelData = await photo.DetachPixelDataAsync();

                BitmapEncoder encoder = await BitmapEncoder.CreateAsync(BitmapEncoder.JpegEncoderId, stream);
                encoder.BitmapTransform.Rotation = photo.Rotation;
                encoder.BitmapTransform.Flip     = photo.Flip;
                encoder.IsThumbnailGenerated     = true;

                encoder.SetPixelData(BitmapPixelFormat.Bgra8, BitmapAlphaMode.Ignore, photo.Width, photo.Height, Constants.DefaultDpiX, Constants.DefaultDpiY, pixelData);
                await encoder.FlushAsync();

                cameraRollPicture = this.lazyMediaLibrary.Value.SavePictureToCameraRoll(name, stream.AsStream());
            }

            Tracing.Trace("StorageService: Saved to Camera Roll as {0}", name);

            return new MediaLibraryThumbnailedImage(cameraRollPicture);
        }

        public async Task<BitmapImage> GetBijinPicture(string Path)
        {
            var date = DateTime.Now;
            var url = "http://www.bijint.com/" + Path + "/tokei_images/" + date.ToString("HHmm") + ".jpg";

            HttpClient client = new HttpClient();
            client.DefaultRequestHeaders.Referrer = new Uri("http://www.bijint.com/" + Path);
            BitmapImage bitmap;
            using (var strm = await client.GetStreamAsync(new Uri(url)))
            {
                // BitmapImageインスタンスへはStream型をそのまま読み込ませることができないため、
                // InMemoryRandomAccessStreamへソースストリームをコピーする
                InMemoryRandomAccessStream ims = new InMemoryRandomAccessStream();
                var output = ims.GetOutputStreamAt(0);
                await RandomAccessStream.CopyAsync(strm.AsInputStream(), output);

                // BitmapImageへソースを設定し、Imageコントロールで表示させる
                bitmap = new BitmapImage();
                bitmap.SetSource(ims);
            }
            return bitmap;

            //var html = await client.GetStringAsync("http://www.bijint.com/kobe/cache/" + date.ToString("HHmm") + ".html");
            //this.html.NavigateToString(html);
        }

        /// <summary>
        /// This is the click handler for the 'Solution' button.
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private async void bookmarkBtn_Click(object sender, RoutedEventArgs e)
        {
            InMemoryRandomAccessStream ms = new InMemoryRandomAccessStream();
            await webView8.CapturePreviewToStreamAsync(ms);
            
            //Create a small thumbnail
            int longlength = 180, width = 0, height = 0;
            double srcwidth = webView8.ActualWidth, srcheight = webView8.ActualHeight;
            double factor = srcwidth / srcheight;
            if (factor < 1)
            {
                height = longlength;
                width = (int)(longlength * factor);
            }
            else
            {
                width = longlength;
                height = (int)(longlength / factor);
            }
            BitmapSource small = await resize(width, height, ms);
            
            BookmarkItem item = new BookmarkItem();
            item.Title = webView8.DocumentTitle;
            item.PageUrl = webView8.Source;
            item.Preview = small;

            bookmarks.Add(item);
        }

		/// <summary>
		/// Continuously look for a QR code
		/// NOTE: this method won't work if recording is enabled ('hey Cortana, start recording' thing).
		/// </summary>
		public static async Task<string> ReadAsync(CancellationToken token = default(CancellationToken))
		{
			var mediaCapture = new MediaCapture();
			await mediaCapture.InitializeAsync();
			await mediaCapture.AddVideoEffectAsync(new MrcVideoEffectDefinition(), MediaStreamType.Photo);

			var reader = new BarcodeReader();
			reader.Options.TryHarder = false;

			while (!token.IsCancellationRequested)
			{
				var imgFormat = ImageEncodingProperties.CreateJpeg();
				using (var ras = new InMemoryRandomAccessStream())
				{
					await mediaCapture.CapturePhotoToStreamAsync(imgFormat, ras);
					var decoder = await BitmapDecoder.CreateAsync(ras);
					using (var bmp = await decoder.GetSoftwareBitmapAsync())
					{
						Result result = await Task.Run(() =>
							{
								var source = new SoftwareBitmapLuminanceSource(bmp);
								return reader.Decode(source);
							});
						if (!string.IsNullOrEmpty(result?.Text))
							return result.Text;
					}
				}
				await Task.Delay(DelayBetweenScans);
			}
			return null;
		}

        private async void GetBijinPicture()
        {
            var date = DateTime.Now;
            var url = "http://www.bijint.com/jp/tokei_images/" + date.ToString("HHmm") + ".jpg";

            HttpClient client = new HttpClient();
            client.DefaultRequestHeaders.Referrer = new Uri("http://www.bijint.com/jp/");
            using (var strm = await client.GetStreamAsync(new Uri(url)))
            {
                // BitmapImageインスタンスへはStream型をそのまま読み込ませることができないため、
                // InMemoryRandomAccessStreamへソースストリームをコピーする
                InMemoryRandomAccessStream ims = new InMemoryRandomAccessStream();
                var output = ims.GetOutputStreamAt(0);
                await RandomAccessStream.CopyAsync(strm.AsInputStream(), output);

                // BitmapImageへソースを設定し、Imageコントロールで表示させる
                var bitmap = new BitmapImage();
                bitmap.SetSource(ims);
                image.Source = bitmap;

                // Save用にbyte配列に保存
                ims.Seek(0);
                imageBuffer = new byte[ims.Size];
                IBuffer ibuffer = imageBuffer.AsBuffer();
                await ims.ReadAsync(ibuffer, (uint)ims.Size, InputStreamOptions.None);
            }
        }

        public static async Task<IRandomAccessStream> RenderToRandomAccessStream(this UIElement element) {
            var rtb = new RenderTargetBitmap();
            await rtb.RenderAsync(element);

            IBuffer pixelBuffer = await rtb.GetPixelsAsync();
            byte[] pixels = pixelBuffer.ToArray();

            // Useful for rendering in the correct DPI
            DisplayInformation displayInformation = DisplayInformation.GetForCurrentView();

            var stream = new InMemoryRandomAccessStream();
            BitmapEncoder encoder = await BitmapEncoder.CreateAsync(BitmapEncoder.PngEncoderId, stream);
            encoder.SetPixelData(BitmapPixelFormat.Bgra8,
                                 BitmapAlphaMode.Premultiplied,
                                 (uint)rtb.PixelWidth,
                                 (uint)rtb.PixelHeight,
                                 displayInformation.RawDpiX,
                                 displayInformation.RawDpiY,
                                 pixels);

            await encoder.FlushAsync();
            stream.Seek(0);

            return stream;
        }

        public static async Task<IRandomAccessStream> ConvertToRandomAccessStream(Stream source)
        {
            Stream streamToConvert = null;
            
            if (!source.CanRead)
                throw new Exception("The source cannot be read.");

            if (!source.CanSeek)
            {
                var memStream = new MemoryStream();
                await source.CopyToAsync(memStream);
                streamToConvert = memStream;
            }
            else
            {
                streamToConvert = source;
            }

            var reader = new DataReader(streamToConvert.AsInputStream());
            streamToConvert.Position = 0;
            await reader.LoadAsync((uint) streamToConvert.Length);
            var buffer = reader.ReadBuffer((uint) streamToConvert.Length);

            var randomAccessStream = new InMemoryRandomAccessStream();
            var outputStream = randomAccessStream.GetOutputStreamAt(0);
            await outputStream.WriteAsync(buffer);
            await outputStream.FlushAsync();

            return randomAccessStream;
        }

		internal static Bitmap FromStream(Stream stream)
		{
		    Bitmap bitmap = null;

		    Task.Run(async () =>
		    {
		        using (var raStream = new InMemoryRandomAccessStream())
		        {
		            await stream.CopyToAsync(raStream.AsStream());
		            var decoder = await BitmapDecoder.CreateAsync(raStream);
		            var pixelData = await decoder.GetPixelDataAsync();

		            var width = (int)decoder.OrientedPixelWidth;
		            var height = (int)decoder.OrientedPixelHeight;
		            const PixelFormat format = PixelFormat.Format32bppArgb;
		            var bytes = pixelData.DetachPixelData();

                    bitmap = new Bitmap(width, height, format);
                    var data = bitmap.LockBits(new Rectangle(0, 0, width, height), ImageLockMode.ReadWrite, format);
                    Marshal.Copy(bytes, 0, data.Scan0, bytes.Length);
                    bitmap.UnlockBits(data);
                }
		    }).Wait();

		    return bitmap;
		}

       async  void BeginReadCCTV()
        {
            
            IsBeginRead = true;
            ISExit = false;
            tblCCTV cctvinfo=null;
            await Dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Normal,
                   () =>
                   {
                       cctvinfo = this.DataContext as tblCCTV;
                   });

             
           // client=new HttpClient();
            while (!ISExit)
            {
                try
                {
                    Uri uri = new Uri("http://192.192.161.3/" + cctvinfo.REF_CCTV_ID.Trim() + ".jpg?" + rnd.Next(), UriKind.Absolute);

                    using (httpClient = new HttpClient())
                    {
                        httpClient.Timeout = TimeSpan.FromSeconds(0.5);
                        var contentBytes = await httpClient.GetByteArrayAsync(uri);

                   
                        var ims =  new InMemoryRandomAccessStream();

                        var dataWriter = new DataWriter(ims);
                        dataWriter.WriteBytes(contentBytes);
                        await dataWriter.StoreAsync();
                       //ims.seak 0
                     ims.Seek(0 );
                       
                       await Dispatcher.RunAsync( Windows.UI.Core.CoreDispatcherPriority.Normal,()=>
                            {
                        BitmapImage bitmap = new BitmapImage();
                        bitmap.SetSource(ims );
                       

                        this.imgCCTV.Source = bitmap;
                        imginx = (imginx + 1) % 90000;
                        this.RunFrameRate.Text = imginx.ToString();
                            });
                    }
                    
                }
                catch (Exception ex)
                {
                 //   this.textBlock1.Text = ex.Message;
                }
                // BitmapImage img = new BitmapImage();
                // img.SetSource(stream);

              

               
            }
        
        }

        public async Task<string> RenderToBase64(UIElement element)
        {
            RenderTargetBitmap rtb = new RenderTargetBitmap();
            await rtb.RenderAsync(element);

            var pixelBuffer = await rtb.GetPixelsAsync();
            var pixels = pixelBuffer.ToArray();

            // Useful for rendering in the correct DPI
            var displayInformation = DisplayInformation.GetForCurrentView();

            var stream = new InMemoryRandomAccessStream();
            var encoder = await BitmapEncoder.CreateAsync(BitmapEncoder.PngEncoderId, stream);
            encoder.SetPixelData(BitmapPixelFormat.Bgra8,
                                 BitmapAlphaMode.Premultiplied,
                                 (uint)rtb.PixelWidth,
                                 (uint)rtb.PixelHeight,
                                 displayInformation.RawDpiX,
                                 displayInformation.RawDpiY,
                                 pixels);

            await encoder.FlushAsync();
            stream.Seek(0);

            // read bytes
            var bytes = new byte[stream.Size];
            await stream.AsStream().ReadAsync(bytes, 0, bytes.Length);

            // create base64
            return Convert.ToBase64String(bytes);
        }