picasso rounded corner transformation for xamarin android

RoundedCornerTransformation.cs

 public class RoundedCornersTransformation : Java.Lang.Object, ITransformation
    {
        public enum CornerType
        {
            All,
            TopLeft,
            TopRight,
            BottomLeft,
            BottomRight,
            Top,
            Bottom,
            Left,
            Right,
            OtherTopLeft,
            OtherTopRight,
            OtherBottomLeft,
            OtherBottomRight,
            DiagonalFromTopLeft,
            DiagonalFromTopRight
        }

        private int _mRadius;
        private int _mDiameter;
        private int _mMargin;
        private CornerType _mCornerType;


        public RoundedCornersTransformation(int radius, int margin) : this(radius, margin, CornerType.All)
        {
        }

        public RoundedCornersTransformation(int radius, int margin, CornerType cornerType)
        {
            _mRadius = radius;
            _mDiameter = radius*2;
            _mMargin = margin;
            _mCornerType = cornerType;
        }

        public Bitmap Transform(Bitmap source)
        {
            int width = source.Width;
            int height = source.Height;

            Bitmap bitmap = Bitmap.CreateBitmap(width, height, Bitmap.Config.Argb8888);

            Canvas canvas = new Canvas(bitmap);
            Paint paint = new Paint {AntiAlias = true};
            paint.SetShader(new BitmapShader(source, Shader.TileMode.Clamp, Shader.TileMode.Clamp));
            DrawRoundRect(canvas, paint, width, height);
           // source.Recycle();
            if (source != bitmap)
            {
                source.Recycle();
            }
            return bitmap;
        }


        private void DrawRoundRect(Canvas canvas, Paint paint, float width, float height)
        {
            float right = width - _mMargin;
            float bottom = height - _mMargin;

            switch (_mCornerType)
            {
                case CornerType.All:
                    canvas.DrawRoundRect(new RectF(_mMargin, _mMargin, right, bottom), _mRadius, _mRadius, paint);
                    break;
                case CornerType.TopLeft:
                    DrawTopLeftRoundRect(canvas, paint, right, bottom);
                    break;
                case CornerType.TopRight:
                    DrawTopRightRoundRect(canvas, paint, right, bottom);
                    break;
                case CornerType.BottomLeft:
                    DrawBottomLeftRoundRect(canvas, paint, right, bottom);
                    break;
                case CornerType.BottomRight:
                    DrawBottomRightRoundRect(canvas, paint, right, bottom);
                    break;
                case CornerType.Top:
                    DrawTopRoundRect(canvas, paint, right, bottom);
                    break;
                case CornerType.Bottom:
                    DrawBottomRoundRect(canvas, paint, right, bottom);
                    break;
                case CornerType.Left:
                    DrawLeftRoundRect(canvas, paint, right, bottom);
                    break;
                case CornerType.Right:
                    DrawRightRoundRect(canvas, paint, right, bottom);
                    break;
                case CornerType.OtherTopLeft:
                    DrawOtherTopLeftRoundRect(canvas, paint, right, bottom);
                    break;
                case CornerType.OtherTopRight:
                    DrawOtherTopRightRoundRect(canvas, paint, right, bottom);
                    break;
                case CornerType.OtherBottomLeft:
                    DrawOtherBottomLeftRoundRect(canvas, paint, right, bottom);
                    break;
                case CornerType.OtherBottomRight:
                    DrawOtherBottomRightRoundRect(canvas, paint, right, bottom);
                    break;
                case CornerType.DiagonalFromTopLeft:
                    DrawDiagonalFromTopLeftRoundRect(canvas, paint, right, bottom);
                    break;
                case CornerType.DiagonalFromTopRight:
                    DrawDiagonalFromTopRightRoundRect(canvas, paint, right, bottom);
                    break;
                default:
                    canvas.DrawRoundRect(new RectF(_mMargin, _mMargin, right, bottom), _mRadius, _mRadius, paint);
                    break;
            }
        }

        private void DrawTopLeftRoundRect(Canvas canvas, Paint paint, float right, float bottom)
        {
            canvas.DrawRoundRect(new RectF(_mMargin, _mMargin, _mMargin + _mDiameter, _mMargin + _mDiameter),
                _mRadius, _mRadius, paint);
            canvas.DrawRect(new RectF(_mMargin, _mMargin + _mRadius, _mMargin + _mRadius, bottom), paint);
            canvas.DrawRect(new RectF(_mMargin + _mRadius, _mMargin, right, bottom), paint);
        }

        private void DrawTopRightRoundRect(Canvas canvas, Paint paint, float right, float bottom)
        {
            canvas.DrawRoundRect(new RectF(right - _mDiameter, _mMargin, right, _mMargin + _mDiameter), _mRadius,
                _mRadius, paint);
            canvas.DrawRect(new RectF(_mMargin, _mMargin, right - _mRadius, bottom), paint);
            canvas.DrawRect(new RectF(right - _mRadius, _mMargin + _mRadius, right, bottom), paint);
        }

        private void DrawBottomLeftRoundRect(Canvas canvas, Paint paint, float right, float bottom)
        {
            canvas.DrawRoundRect(new RectF(_mMargin, bottom - _mDiameter, _mMargin + _mDiameter, bottom),
                _mRadius, _mRadius, paint);
            canvas.DrawRect(new RectF(_mMargin, _mMargin, _mMargin + _mDiameter, bottom - _mRadius), paint);
            canvas.DrawRect(new RectF(_mMargin + _mRadius, _mMargin, right, bottom), paint);
        }

        private void DrawBottomRightRoundRect(Canvas canvas, Paint paint, float right, float bottom)
        {
            canvas.DrawRoundRect(new RectF(right - _mDiameter, bottom - _mDiameter, right, bottom), _mRadius,
                _mRadius, paint);
            canvas.DrawRect(new RectF(_mMargin, _mMargin, right - _mRadius, bottom), paint);
            canvas.DrawRect(new RectF(right - _mRadius, _mMargin, right, bottom - _mRadius), paint);
        }

        private void DrawTopRoundRect(Canvas canvas, Paint paint, float right, float bottom)
        {
            canvas.DrawRoundRect(new RectF(_mMargin, _mMargin, right, _mMargin + _mDiameter), _mRadius, _mRadius,
                paint);
            canvas.DrawRect(new RectF(_mMargin, _mMargin + _mRadius, right, bottom), paint);
        }

        private void DrawBottomRoundRect(Canvas canvas, Paint paint, float right, float bottom)
        {
            canvas.DrawRoundRect(new RectF(_mMargin, bottom - _mDiameter, right, bottom), _mRadius, _mRadius,
                paint);
            canvas.DrawRect(new RectF(_mMargin, _mMargin, right, bottom - _mRadius), paint);
        }

        private void DrawLeftRoundRect(Canvas canvas, Paint paint, float right, float bottom)
        {
            canvas.DrawRoundRect(new RectF(_mMargin, _mMargin, _mMargin + _mDiameter, bottom), _mRadius, _mRadius,
                paint);
            canvas.DrawRect(new RectF(_mMargin + _mRadius, _mMargin, right, bottom), paint);
        }

        private void DrawRightRoundRect(Canvas canvas, Paint paint, float right, float bottom)
        {
            canvas.DrawRoundRect(new RectF(right - _mDiameter, _mMargin, right, bottom), _mRadius, _mRadius,
                paint);
            canvas.DrawRect(new RectF(_mMargin, _mMargin, right - _mRadius, bottom), paint);
        }

        private void DrawOtherTopLeftRoundRect(Canvas canvas, Paint paint, float right, float bottom)
        {
            canvas.DrawRoundRect(new RectF(_mMargin, bottom - _mDiameter, right, bottom), _mRadius, _mRadius,
                paint);
            canvas.DrawRoundRect(new RectF(right - _mDiameter, _mMargin, right, bottom), _mRadius, _mRadius,
                paint);
            canvas.DrawRect(new RectF(_mMargin, _mMargin, right - _mRadius, bottom - _mRadius), paint);
        }

        private void DrawOtherTopRightRoundRect(Canvas canvas, Paint paint, float right, float bottom)
        {
            canvas.DrawRoundRect(new RectF(_mMargin, _mMargin, _mMargin + _mDiameter, bottom), _mRadius, _mRadius,
                paint);
            canvas.DrawRoundRect(new RectF(_mMargin, bottom - _mDiameter, right, bottom), _mRadius, _mRadius,
                paint);
            canvas.DrawRect(new RectF(_mMargin + _mRadius, _mMargin, right, bottom - _mRadius), paint);
        }

        private void DrawOtherBottomLeftRoundRect(Canvas canvas, Paint paint, float right, float bottom)
        {
            canvas.DrawRoundRect(new RectF(_mMargin, _mMargin, right, _mMargin + _mDiameter), _mRadius, _mRadius,
                paint);
            canvas.DrawRoundRect(new RectF(right - _mDiameter, _mMargin, right, bottom), _mRadius, _mRadius,
                paint);
            canvas.DrawRect(new RectF(_mMargin, _mMargin + _mRadius, right - _mRadius, bottom), paint);
        }

        private void DrawOtherBottomRightRoundRect(Canvas canvas, Paint paint, float right,
            float bottom)
        {
            canvas.DrawRoundRect(new RectF(_mMargin, _mMargin, right, _mMargin + _mDiameter), _mRadius, _mRadius,
                paint);
            canvas.DrawRoundRect(new RectF(_mMargin, _mMargin, _mMargin + _mDiameter, bottom), _mRadius, _mRadius,
                paint);
            canvas.DrawRect(new RectF(_mMargin + _mRadius, _mMargin + _mRadius, right, bottom), paint);
        }

        private void DrawDiagonalFromTopLeftRoundRect(Canvas canvas, Paint paint, float right,
            float bottom)
        {
            canvas.DrawRoundRect(new RectF(_mMargin, _mMargin, _mMargin + _mDiameter, _mMargin + _mDiameter),
                _mRadius, _mRadius, paint);
            canvas.DrawRoundRect(new RectF(right - _mDiameter, bottom - _mDiameter, right, bottom), _mRadius,
                _mRadius, paint);
            canvas.DrawRect(new RectF(_mMargin, _mMargin + _mRadius, right - _mDiameter, bottom), paint);
            canvas.DrawRect(new RectF(_mMargin + _mDiameter, _mMargin, right, bottom - _mRadius), paint);
        }

        private void DrawDiagonalFromTopRightRoundRect(Canvas canvas, Paint paint, float right,
            float bottom)
        {
            canvas.DrawRoundRect(new RectF(right - _mDiameter, _mMargin, right, _mMargin + _mDiameter), _mRadius,
                _mRadius, paint);
            canvas.DrawRoundRect(new RectF(_mMargin, bottom - _mDiameter, _mMargin + _mDiameter, bottom),
                _mRadius, _mRadius, paint);
            canvas.DrawRect(new RectF(_mMargin, _mMargin, right - _mRadius, bottom - _mRadius), paint);
            canvas.DrawRect(new RectF(_mMargin + _mRadius, _mMargin + _mRadius, right, bottom), paint);
        }


        public string Key => "RoundedTransformation(radius=" + _mRadius + ", margin=" + _mMargin + ", diameter="
                             + _mDiameter + ", cornerType=" + _mCornerType.ToString() + ")";
    }