Nrthugu

I have the below code where i am creating a ImageReader instance in xamarin android, how to change Image Format from ImageFormatType.Rgb565 to PixelFormat.RGBA_8888

i am unable to find the Library or a Enum class for it.

mImageReader = ImageReader.NewInstance(windowWidth, windowHeight, ImageFormatType.Rgb565, 2)

You need to pass an int value of 3 (Android.Graphics.Format.Rgb888) to ImageReader.NewInstance, but currently you can not.

That is a bug/issue in Xamarin.Android auto-generation API process as they do not create a overload that accepts an Android.Graphics.Format enum, or just a plain int as the Java API does.

You can do this the same way you would do it in Java via Xamarin.Android's binding to Android.Runtime.JNIEnv or Java.Lang.Reflect

Example using JNI:

Note: Using JNI requires that the assembly be allowed to use "unsafe" code ( on the plus side, JNI is faster execution than using reflection...)

public static class ImageReaderEx

{

    public unsafe static ImageReader NewInstance(int width, int height, Android.Graphics.Format format, int maxImages)

    {

        JniArgumentValue* ptr = stackalloc JniArgumentValue[4];

        *ptr = new JniArgumentValue(width);

        ptr[1] = new JniArgumentValue(height);

        ptr[2] = new JniArgumentValue((int)format);

        ptr[3] = new JniArgumentValue(maxImages);

        JniPeerMembers _members = new XAPeerMembers("android/media/ImageReader", typeof(ImageReader));

        return Java.Lang.Object.GetObject<ImageReader>(_members.StaticMethods.InvokeObjectMethod("newInstance.(IIII)Landroid/media/ImageReader;", ptr).Handle, JniHandleOwnership.TransferLocalRef);

    }



    public unsafe static ImageReader NewInstance(int width, int height, int format, int maxImages)

    {

        JniArgumentValue* ptr = stackalloc JniArgumentValue[4];

        *ptr = new JniArgumentValue(width);

        ptr[1] = new JniArgumentValue(height);

        ptr[2] = new JniArgumentValue(format);

        ptr[3] = new JniArgumentValue(maxImages);

        JniPeerMembers _members = new XAPeerMembers("android/media/ImageReader", typeof(ImageReader));

        return Java.Lang.Object.GetObject<ImageReader>(_members.StaticMethods.InvokeObjectMethod("newInstance.(IIII)Landroid/media/ImageReader;", ptr).Handle, JniHandleOwnership.TransferLocalRef);

    }

}

Usage:

var imageReader = ImageReaderEx.NewInstance(1, 1, 3, 1);

or

var ImageReader = ImageReaderEx.NewInstance(1, 1, Android.Graphics.Format.Rgb888, 1);

In Xamarin, its Format.Rgba8888 (lower case). the doc is here