CODEWITHSUNDEEP
xamarin.androidxamarin.forms
Naveen Bathina
Naveen Bathina

Reputation: 414

Convert StackLayout as Image in Xamarin

I'm working on Xmarin Forms(PCL) project, I want to convert the StackLayout to Image / buffer and send it to printer for hard print.

Can anyone suggest how to do it in (Xamarin.Android & Xamarin.iOS).

Upvotes: 2

Views: 1666

Answers (2)

hvaughan3
hvaughan3

Reputation: 11105

Taken from this link, which I have personally used, quite a while back though, the following code will take a screenshot of the entire page.

I ended up modifying the code to only take a screenshot of a specific view on the page and also changed a few other things but this example is what I based it off of, so let me know if you would rather see that code and/or if something below is not working for you.

First you create an interface in your Forms project, IScreenshotManager.cs for example:

public interface IScreenshotManager {
    Task<byte[]> CaptureAsync();
}

Now we need to implement our interface in Android, ScreenshotManager.cs for example:

public class ScreenshotManager : IScreenshotManager {

    public static Activity Activity { get; set; }

    public async System.Threading.Tasks.Task<byte[]> CaptureAsync() {

        if(Activity == null) {

            throw new Exception("You have to set ScreenshotManager.Activity in your Android project");
        }

        var view = Activity.Window.DecorView;
        view.DrawingCacheEnabled = true;

        Bitmap bitmap = view.GetDrawingCache(true);

        byte[] bitmapData;

        using (var stream = new MemoryStream()) {
            bitmap.Compress(Bitmap.CompressFormat.Png, 0, stream);
            bitmapData = stream.ToArray();
        }

        return bitmapData;
    }
}

Then set ScreenshotManager.Activity in MainActivity:

public class MainActivity : Xamarin.Forms.Platform.Android.FormsApplicationActivity {

    protected override async void OnCreate(Android.OS.Bundle bundle) {
        ...
        ScreenshotManager.Activity = this; //There are better ways to do this but this is what the example from the link suggests
        ...
    }
}

Finally we implement this on iOS, ScreenshotManager.cs:

public class ScreenshotManager : IScreenshotManager {
    public async System.Threading.Tasks.Task<byte[]> CaptureAsync() {
        var view = UIApplication.SharedApplication.KeyWindow.RootViewController.View;

        UIGraphics.BeginImageContext(view.Frame.Size);
        view.DrawViewHierarchy(view.Frame, true);
        var image = UIGraphics.GetImageFromCurrentImageContext();
        UIGraphics.EndImageContext();

        using(var imageData = image.AsPNG()) {
            var bytes = new byte[imageData.Length];
            System.Runtime.InteropServices.Marshal.Copy(imageData.Bytes, bytes, 0, Convert.ToInt32(imageData.Length));
            return bytes;
        }
    }
}

Upvotes: 1

eakgul
eakgul

Reputation: 3698

You can't. Xamarin does not have that kind of feature. You should write a Renderer for your UIComponent.

Fortunately there is an Objective-C iOS implementation, and an Android one as well. You can inspire from them.

Upvotes: 1

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