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:
The first is from this post on a basic camera application: http://msdn.microsoft.com/en-us/library/hh202956(v=VS.92).aspx It takes the jpeg from the camera and writes it to isolated storage directly.
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();
}
}
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):
// 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();
}
If there are any alternative methods you have also I'd be interested, thanks!
