Step 3 of 4: Adding Code for Image Cropping

The code in this step will load the default image and allow the user to crop it. Follow these steps:

Open the MainPage.xaml.cs file and add the following using (Imports in Visual Basic) statements.

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using C1.Silverlight; using C1.Silverlight.Imaging; using System.IO;

Add the following code to load a default image and define cropping:

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public partial class MainPage : UserControl { C1Bitmap bitmap = new C1Bitmap(); Rect selection; public MainPage() { InitializeComponent(); LoadDefaultImage(); image.Source = bitmap.ImageSource; var mouseHelper = new C1MouseHelper(imageGrid); mouseHelper.MouseDragStart += OnDrag; mouseHelper.MouseDragMove += OnDrag; } void OnDrag(object sender, MouseDragEventArgs e) { var transform = Application.Current.RootVisual.TransformToVisual(image); var start = transform.Transform(e.StartPosition); var end = transform.Transform(e.CurrentPosition); start.X = Math.Min(Math.Max(start.X, 0), bitmap.Width); end.X = Math.Min(Math.Max(end.X, 0), bitmap.Width); start.Y = Math.Min(Math.Max(start.Y, 0), bitmap.Height); end.Y = Math.Min(Math.Max(end.Y, 0), bitmap.Height); selection = new Rect(new Point( Math.Round(Math.Min(start.X, end.X)), Math.Round(Math.Min(start.Y, end.Y))), new Size(Math.Round(Math.Abs(start.X - end.X)), Math.Round(Math.Abs(start.Y - end.Y)))); UpdateMask(); } void UpdateMask() { topMask.Height = selection.Top; bottomMask.Height = bitmap.Height - selection.Bottom; leftMask.Width = selection.Left; rightMask.Width = bitmap.Width - selection.Right; } void LoadDefaultImage() { LoadImageStream(Application.GetResourceStream(new Uri("/SilverlightApplication3;component/Lenna.jpg", UriKind.Relative)).Stream); } void LoadImageStream(Stream stream) { bitmap.SetStream(stream); imageGrid.Width = bitmap.Width; imageGrid.Height = bitmap.Height; selection = new Rect(0, 0, bitmap.Width, bitmap.Height); UpdateMask(); } }

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public partial class MainPage : UserControl
    {

        C1Bitmap bitmap = new C1Bitmap();
        Rect selection;


        public MainPage()
        {
            InitializeComponent();
            LoadDefaultImage();
            image.Source = bitmap.ImageSource;


            var mouseHelper = new C1MouseHelper(imageGrid);
            mouseHelper.MouseDragStart += OnDrag;
            mouseHelper.MouseDragMove += OnDrag;
        }

        void OnDrag(object sender, MouseDragEventArgs e)
        {
            var transform = Application.Current.RootVisual.TransformToVisual(image);
            var start = transform.Transform(e.StartPosition);
            var end = transform.Transform(e.CurrentPosition);
            start.X = Math.Min(Math.Max(start.X, 0), bitmap.Width);
            end.X = Math.Min(Math.Max(end.X, 0), bitmap.Width);
            start.Y = Math.Min(Math.Max(start.Y, 0), bitmap.Height);
            end.Y = Math.Min(Math.Max(end.Y, 0), bitmap.Height);

            selection = new Rect(new Point(
                Math.Round(Math.Min(start.X, end.X)),
                Math.Round(Math.Min(start.Y, end.Y))),
                new Size(Math.Round(Math.Abs(start.X - end.X)), Math.Round(Math.Abs(start.Y - end.Y))));

            UpdateMask();
        }

        void UpdateMask()
        {
            topMask.Height = selection.Top;
            bottomMask.Height = bitmap.Height - selection.Bottom;
            leftMask.Width = selection.Left;
            rightMask.Width = bitmap.Width - selection.Right;
        }
      
        void LoadDefaultImage()
        {
            LoadImageStream(Application.GetResourceStream(new Uri("/SilverlightApplication3;component/Lenna.jpg", UriKind.Relative)).Stream);
        }

       void LoadImageStream(Stream stream)
        {
            bitmap.SetStream(stream);

            imageGrid.Width = bitmap.Width;
            imageGrid.Height = bitmap.Height;

            selection = new Rect(0, 0, bitmap.Width, bitmap.Height);
            UpdateMask();
        }
    }

In the next step you will run the application.