Show Cropping Editor immediately

[I Putu Yoga]

Hi, thanks for this awesome tool. I have a problem here, How can i prompt user to immediately crop the image then show the image editor after that ? Example like set as lockscreen image from photos, you'll be prompted by system to crop the image first to fit the ratio aspect.

...and this is my simple idea, first i use PhotoChooserTask, then i want crop before assign it to image editor

void task_Completed(object sender, PhotoResult e)
    {
    // Crop first in here to fit the ratio
    // .....

    //Assign to Image Editor
        BitmapImage gambar = new BitmapImage();
        gambar.SetSource(e.ChosenPhoto);
        KanvasEditor.Source = gambar;
    }

    private void Button_Click_1(object sender, RoutedEventArgs e)
    {
        PhotoChooserTask task = new PhotoChooserTask();
        task.Completed += task_Completed;
        task.Show();
    }

Can you give me a clue or maybe a lend hand to give example code ? Thank You, Telerik is the best.

[I Putu Yoga]

Aha, i've found the solution

just set the PixelHeight and  PixelWidth in PhotoChooserTask, like 

PhotoChooserTask task = new PhotoChooserTask();
task.PixelHeight = 800;

task.PixelWidth = 480;

and then let the system do the rest for crop