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POReading and Writing Images to Isolated Storage
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copied!<p>I have come across a couple of different ways to write images to isolated storage on some Windows Phone sites, however I am unsure which is the best to use for a camera app or if there are some that are better than others:</p> <p>The first is from this post on a basic camera application: <a href="http://msdn.microsoft.com/en-us/library/hh202956(v=VS.92).aspx" rel="nofollow">http://msdn.microsoft.com/en-us/library/hh202956(v=VS.92).aspx</a> It takes the jpeg from the camera and writes it to isolated storage directly.</p> <pre><code> void cam_CaptureImageAvailable(object sender, Microsoft.Devices.ContentReadyEventArgs e) { string fileName = savedCounter + ".jpg"; try { // Write message to the UI thread. Deployment.Current.Dispatcher.BeginInvoke(delegate() { txtDebug.Text = "Captured image available, saving picture."; }); // Save picture to the library camera roll. library.SavePictureToCameraRoll(fileName, e.ImageStream); // Write message to the UI thread. Deployment.Current.Dispatcher.BeginInvoke(delegate() { txtDebug.Text = "Picture has been saved to camera roll."; }); // Set the position of the stream back to start e.ImageStream.Seek(0, SeekOrigin.Begin); // Save picture as JPEG to isolated storage. using (IsolatedStorageFile isStore = IsolatedStorageFile.GetUserStoreForApplication()) { using (IsolatedStorageFileStream targetStream = isStore.OpenFile(fileName, FileMode.Create, FileAccess.Write)) { // Initialize the buffer for 4KB disk pages. byte[] readBuffer = new byte[4096]; int bytesRead = -1; // Copy the image to isolated storage. while ((bytesRead = e.ImageStream.Read(readBuffer, 0, readBuffer.Length)) > 0) { targetStream.Write(readBuffer, 0, bytesRead); } } } // Write message to the UI thread. Deployment.Current.Dispatcher.BeginInvoke(delegate() { txtDebug.Text = "Picture has been saved to isolated storage."; }); } finally { // Close image stream e.ImageStream.Close(); } } </code></pre> <p>It seems to use a 4kb Buffer, is there any point in doing it this way? Seems a bit more complicated than this method which converts the image to a bitmap then uses the save as Jpeg method (http://www.windowsphonegeek.com/tips/All-about-WP7-Isolated-Storage---Read-and-Save-Images):</p> <pre><code> // Create a filename for JPEG file in isolated storage. String tempJPEG = "logo.jpg"; // Create virtual store and file stream. Check for duplicate tempJPEG files. using (IsolatedStorageFile myIsolatedStorage = IsolatedStorageFile.GetUserStoreForApplication()) { if (myIsolatedStorage.FileExists(tempJPEG)) { myIsolatedStorage.DeleteFile(tempJPEG); } IsolatedStorageFileStream fileStream = myIsolatedStorage.CreateFile(tempJPEG); StreamResourceInfo sri = null; Uri uri = new Uri(tempJPEG, UriKind.Relative); sri = Application.GetResourceStream(uri); BitmapImage bitmap = new BitmapImage(); bitmap.SetSource(sri.Stream); WriteableBitmap wb = new WriteableBitmap(bitmap); // Encode WriteableBitmap object to a JPEG stream. Extensions.SaveJpeg(wb, fileStream, wb.PixelWidth, wb.PixelHeight, 0, 85); //wb.SaveJpeg(fileStream, wb.PixelWidth, wb.PixelHeight, 0, 85); fileStream.Close(); } </code></pre> <p>If there are any alternative methods you have also I'd be interested, thanks!</p>

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