Extending the Windows Phone Pictures Hub
19 Aug
2012
This article explains how to extend the Windows Phone Pictures Hub with your application.
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Introduction
The Pictures Hub is the centre of all still-image activity on Windows Phone. This article shows how an application can extend the Pictures Hub, adding itself as an "imaging" app that can be launched from the hub, picture viewer, or share picker option.
Register your app as an "Imaging application"
The application can be registered in the manifest file as an Imaging application, it will then appear in the Pictures Hub "applications" section (as shown below in fourth-from-left image):
All that is required is to open the WMAppManifest.xml and add the following code fragment after the Tokens node:
<Extensions>
<Extension ExtensionName="Photos_Extra_Hub"
ConsumerID="{5B04B775-356B-4AA0-AAF8-6491FFEA5632}"
TaskID="_default" />
</Extensions>
Register application as an image viewer
The application can be registered as an Image viewer. This allows the user to choose the app from the Pictures Hub's menu to open a selected image.
To register your app, first add the following text after the Tokens node in WMAppManifest.xml:
<Extensions>
<Extension ExtensionName="Photos_Extra_Viewer"
ConsumerID="{5B04B775-356B-4AA0-AAF8-6491FFEA5632}"
TaskID="_default" />
</Extensions>
In your code, override OnNavigatedTo() function. When your application is launched from Pictures hub, token is added in NavigationContext.QueryString. This token is used to get a Picture instance
using Microsoft.Xna.Framework.Media;
using System.Windows.Navigation;
using System.IO;
//...
protected override void OnNavigatedTo(System.Windows.Navigation.NavigationEventArgs e)
{
IDictionary<string, string> queryStrings = this.NavigationContext.QueryString;
//check if a token is added
if (queryStrings.ContainsKey("token"))
{
MediaLibrary library = new MediaLibrary();
//Acces to Picture instance from token.
Picture picture = library.GetPictureFromToken(queryStrings["token"]);
//Get Image Stream
Stream imageStream = picture.GetImage()
/*Todo Code to open image and display it
...
*/
queryStrings.Remove("token");
}
base.OnNavigatedTo(e);
}
Ensuring correct orientation of loaded image
Of course it's not so simple. When BitmapImage load image, it doesn't check image orientation. On Lumia 800 (maybe all WP7 devices) a portrait image will be loaded like a landscape Image. So you must check orientation manually. To do it you can use ExifLib library which can read exif image data and so image orientation.
Now you can easily perform correction image display.
<Image x:Name="imageViewer" RenderTransformOrigin="0.5,0.5" HorizontalAlignment="Center" VerticalAlignment="Center" Margin="0,150,0,0">
<Image.RenderTransform>
<RotateTransform x:Name="imageOrientation" />
</Image.RenderTransform>
</Image>
// Load Image to a BitmapImage
BitmapImage bitmap = new BitmapImage();
bitmap.CreateOptions = BitmapCreateOptions.None;
bitmap.SetSource(imageStream);
//display loaded image
imageViewer.Source = bitmap;
imageOrientation.Angle = 0;
//reposition stream to the beginning
imageStream.Seek(0, SeekOrigin.Begin);
//read exif data
JpegInfo info = ExifLib.ExifReader.ReadJpeg(imageStream, "");
if ( info.Orientation == ExifOrientation.TopRight)
{
imageOrientation.Angle = 90;
}
if (info.Orientation == ExifOrientation.BottomRight)
{
imageOrientation.Angle = 180;
}
if (info.Orientation == ExifOrientation.BottomLeft)
{
imageOrientation.Angle = -90;
}
The application can be registered as an Image Sharer, allowing it to be selected as an option for sharing an image (for example to a web service).
Open WMAppManifest.xml and add the following text after the Tokens node.
<Extensions>
<Extension ExtensionName="Photos_Extra_Share"
ConsumerID="{5B04B775-356B-4AA0-AAF8-6491FFEA5632}"
TaskID="_default" />
</Extensions>
In your code, override OnNavigatedTo() function. When your application is launched from Picture hub, FileId is added in NavigationContext.QueryString. This token is used to get a Picture instance
using Microsoft.Xna.Framework.Media;
using System.Windows.Navigation;
using System.IO;
//...
protected override void OnNavigatedTo(System.Windows.Navigation.NavigationEventArgs e)
{
IDictionary<string, string> queryStrings = this.NavigationContext.QueryString;
//check if a token is added
if (queryStrings.ContainsKey("FileId"))
{
MediaLibrary library = new MediaLibrary();
//Acces to Picture instance from token.
Picture picture = library.GetPictureFromToken(queryStrings["FileId"]);
//Get Image Stream
Stream imageStream = picture.GetImage()
/*Todo your code
...
*/
queryStrings.Remove("FileId");
}
base.OnNavigatedTo(e);
}
