add Android version

Pixiview.Android/Renderers/CircleImageRenderer.cs

@@ -0,0 +1,66 @@
+using System;
+using Android.Content;
+using Android.Graphics;
+using Android.Graphics.Drawables;
+using Pixiview.Droid.Renderers;
+using Pixiview.UI;
+using Xamarin.Forms;
+
+[assembly: ExportRenderer(typeof(CircleImage), typeof(CircleImageRenderer))]
+namespace Pixiview.Droid.Renderers
+{
+    public class CircleImageRenderer : Xamarin.Forms.Platform.Android.FastRenderers.ImageRenderer
+    {
+        private Paint paint;
+        private int radius;
+        private float scale;
+
+        public CircleImageRenderer(Context context) : base(context)
+        {
+        }
+
+        protected override void OnMeasure(int widthMeasureSpec, int heightMeasureSpec)
+        {
+            base.OnMeasure(widthMeasureSpec, heightMeasureSpec);
+
+            int size = Math.Min(MeasuredWidth, MeasuredHeight);
+            radius = size / 2;
+            SetMeasuredDimension(size, size);
+        }
+
+        protected override void OnDraw(Canvas canvas)
+        {
+            paint = new Paint();
+            var bitmap = DrawableToBitmap(Drawable);
+            if (bitmap == null)
+            {
+                base.OnDraw(canvas);
+                return;
+            }
+            var bitmapShader = new BitmapShader(bitmap, Shader.TileMode.Clamp, Shader.TileMode.Clamp);
+            scale = radius * 2.0f / Math.Min(bitmap.Width, bitmap.Height);
+
+            var matrix = new Matrix();
+            matrix.SetScale(scale, scale);
+            bitmapShader.SetLocalMatrix(matrix);
+            paint.SetShader(bitmapShader);
+
+            canvas.DrawCircle(radius, radius, radius, paint);
+        }
+
+        private Bitmap DrawableToBitmap(Drawable drawable)
+        {
+            if (drawable is BitmapDrawable bd)
+            {
+                return bd.Bitmap;
+            }
+            int w = drawable.IntrinsicWidth;
+            int h = drawable.IntrinsicHeight;
+            var bitmap = Bitmap.CreateBitmap(w, h, Bitmap.Config.Argb8888);
+            var canvas = new Canvas(bitmap);
+            drawable.SetBounds(0, 0, w, h);
+            drawable.Draw(canvas);
+            return bitmap;
+        }
+    }
+}