Toolkit DrawingView is giving AndroidRuntime] java.lang.RuntimeException: Canvas: trying to draw too large(216039040bytes) bitmap.

Question

Toolkit DrawingView is giving AndroidRuntime] java.lang.RuntimeException: Canvas: trying to draw too large(216039040bytes) bitmap when I draw a single horizontal line after reading from Memory stream

 await using var stream = await DrawingView.GetImageStream(512, 512);

 using var memoryStream = new MemoryStream();

 stream.CopyTo(memoryStream);

 stream.Position = 0;

 memoryStream.Position = 0;

 var imageBytes = memoryStream.ToArray();

 var SignatureBase64 = Convert.ToBase64String(imageBytes);

var SignatureImageSource = ImageSource.FromStream(() => new MemoryStream(Convert.FromBase64String(SignatureBase64)));

Answer 1

Hello,

This error is expected. The process of converting DrawingView to an image stream is actually very complicated, and you cannot directly assign it to an Image by reading the stream. You need to convert it through the API provided by DrawingView.

Please refer to the following documents and code examples.

• Saving the result out to an image

private async void DrawingView_DrawingLineCompleted(object sender, CommunityToolkit.Maui.Core.DrawingLineCompletedEventArgs e)
{
    var imgstream = await DrawingView.GetImageStream(desiredWidth: 400, desiredHeight: 300, imageOutputOption: DrawingViewOutputOption.FullCanvas);
    test_img.Source = ImageSource.FromStream(() => imgstream);
}

Best Regards,

Alec Liu.

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