Issues when making a screenshot

[Carlos]

I have the following extension method in my application. It captures previews of my usercontrols and allows the user to navigate them via a menu.

 

/// <summary>
/// Renders a framework element as a bitmap image.
/// </summary>
/// <param name="frameworkElement">The framework element to be rendered.</param>
/// <param name="background">The background to be applied to the element, in case the element has trasnparent background.</param>
/// <param name="scale">The scaling of the image, default should be 1.</param>
/// <returns>The image as a scaled bitmap.</returns>
public static BitmapImage RenderToBitmap(this FrameworkElement frameworkElement, Brush background, double scale = 1)
{
    Check.NotNull(frameworkElement, "frameworkElement");

    // as seen here: http://stackoverflow.com/questions/19395105/wpf-pngbitmapencoder-how-to-disable-background-transparency

    var renderWidth = (int)(frameworkElement.RenderSize.Width * scale);
    var renderHeight = (int)(frameworkElement.RenderSize.Height * scale);

    if (renderWidth > 0 && renderHeight > 0)
    {
        var renderTarget = new RenderTargetBitmap(renderWidth, renderHeight, 96, 96, PixelFormats.Default);

        var sourceBrush = new VisualBrush(frameworkElement);

        var drawingVisual = new DrawingVisual();

        var rect = new Rect(new Point(0, 0), new Point(frameworkElement.RenderSize.Width, frameworkElement.RenderSize.Height));

        using (var drawingContext = drawingVisual.RenderOpen())
        {
            drawingContext.PushTransform(new ScaleTransform(scale, scale));
            drawingContext.DrawRectangle(background, null, rect);
            drawingContext.DrawRectangle(sourceBrush, null, rect);
        }

        renderTarget.Render(drawingVisual);

        var image = new BitmapImage();

        using (MemoryStream memoryStream = new MemoryStream())
        {
            JpegBitmapEncoder encoder = new JpegBitmapEncoder();

            encoder.Frames.Add(BitmapFrame.Create(renderTarget));

            encoder.Save(memoryStream);

            image.BeginInit();
            image.StreamSource = new MemoryStream(memoryStream.ToArray());
            image.EndInit();
        }

        return image;
    }

    return null;
}

 

Lately we've started a new development with the radmap control and we started to have some issues. The app hanged whenever we entered the view containing the map. I profiled the app and the results tell me that there's an issue with the radmap control.

 

I've started trying stuff and I realized that the problem starts when I try to generate the visual before the image creation. If I instead do renderTarget.Render(frameworkElement) it seems to work, but then I can't apply the background transformation to the visual. The problem starts when I use the map to create a VisualBrush. Could this be a bug? 

 

Thanks for your time.

 

 

[Petar Mladenov]

Hello Carlos,

Please send us some more code showing the way you use this method with RadMap and especially what you use in RadMap:
- - which map provider - Bing /OopenStreet ?
- - which map layer - ItemInformationLayer / VisualizationLayer ?
- - do you add shapes - map shape data , framework elements, how many ?
We will then try to reproduce such error on our side.


Regards,
Petar Mladenov
Telerik