我正在做一个Xamarin跨平台项目，无法在UI上显示uri图像。 我总是得到一个错误，说位图太大

Question

I am doing a Xamarin project for school and can't display any uri images on my user interface. I always get this error in the debug window:

java.lang.RuntimeException: Canvas: trying to draw too large(241238816bytes) bitmap.

This is cross platform so I can't just set a height and width request and Xamarin does the work for me. I can't just download picasso or FFImageLoading from Nuget and pass a few parameters because this is Android AND iOS. No UWP by the way. Just Android and iOS. I saw something on Github for resizing images but that's for image files, not uri's. Saving the uri image as a file first doesn't work because most of them are 200+ MB each! I need to pass the "Image" source to the ImageSource.FromUri(new Uri(myUriIWantToPass)); I understand I am probably going to have to write code to pass the uri string, height request, width request. Make a new Bitmap that's scaled down. Then load it and then set the Image source to the new scaled down bitmap somehow. I will copy and paste code for the backend of the page. It's called PlantProfilePage.xaml.cs and that code should be enough to go by for an answer.

protected override void OnAppearing()
        {
            base.OnAppearing();
            FamilyName.BindingContext = this;
            GenusName.BindingContext = this;
            ScientificName.BindingContext = this;
            //PlantPicture.Source = ImageSource.FromUri(new Uri(uriList[0].ToString()));
            string url = "https://collections.nmnh.si.edu/media/index.php?irn=11986034";
            //string encodedURL = Uri.EscapeDataString(url);
            try
            {
                WebRequest request = WebRequest.Create(url);
                request.BeginGetResponse((IAsyncResult arg) =>
                {
                    Stream stream = request.EndGetResponse(arg).GetResponseStream();
                    ImageSource imageSource = ImageSource.FromStream(() => stream);
                    Device.BeginInvokeOnMainThread(() => PlantPicture.Source = imageSource);
                }, null);

                //PlantPicture.Source = UriImageSource.FromUri(new Uri(url));
            }
            catch (UriFormatException ufe)
            {
                Debug.WriteLine("Uri didn't work: " + ufe);
            }

I need to resize these uri string's I'm using from hundreds of megabytes to something that won't cause the project to give me the error:

java.lang.RuntimeException: Canvas: trying to draw too large(241238816bytes) bitmap.

This should work for both Android and iOS both.

Answer 1

The FFImageLoading worked. It will show scaled down uri images for the Android and iPhone screen.