Android Rounded ImageView without modifying the original bitmap. Best used with ScaleType.CENTER_CROP or ScaleType.FIT_XY

RoundedImageView.java

package com.snepo.common.widgets;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.Path.Direction;
import android.graphics.Path.FillType;
import android.graphics.PorterDuff.Mode;
import android.graphics.PorterDuffXfermode;
import android.graphics.RectF;
import android.support.v4.view.ViewCompat;
import android.util.AttributeSet;
import android.widget.ImageView;

public class RoundedImageView extends ImageView {

	private Path mMaskPath;
	private Paint mMaskPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
	private int mCornerRadius = 10;

	public RoundedImageView(Context context) {
		super(context);

		init();
	}

	public RoundedImageView(Context context, AttributeSet attributeSet) {
		super(context, attributeSet);

		init();
	}

	public RoundedImageView(Context context, AttributeSet attrs, int defStyle) {
		super(context, attrs, defStyle);

		init();
	}

	private void init() {
		ViewCompat.setLayerType(this, ViewCompat.LAYER_TYPE_SOFTWARE, null);
		mMaskPaint.setXfermode(new PorterDuffXfermode(Mode.CLEAR));
	}

	/**
	 * Set the corner radius to use for the RoundedRectangle.
	 * 
	 * @param Primitive int - The corner radius of the rounded rectangle.
	 */
	public void setCornerRadius(int cornerRadius) {
		mCornerRadius = cornerRadius;
		generateMaskPath(getWidth(), getHeight());
		invalidate();
	}

	@Override
	protected void onSizeChanged(int w, int h, int oldW, int oldH) {
		super.onSizeChanged(w, h, oldW, oldH);

		if (w != oldW || h != oldH) {
			generateMaskPath(w, h);
		}
	}

	private void generateMaskPath(int w, int h) {
		mMaskPath = new Path();
		mMaskPath.addRoundRect(new RectF(0,0,w,h), mCornerRadius, mCornerRadius, Direction.CW);
		mMaskPath.setFillType(FillType.INVERSE_WINDING);
	}

	@Override
	protected void onDraw(Canvas canvas) {
		if(canvas.isOpaque()) { // If canvas is opaque, make it transparent
			canvas.saveLayerAlpha(0, 0, canvas.getWidth(), canvas.getHeight(), 255, Canvas.HAS_ALPHA_LAYER_SAVE_FLAG);
		}

		super.onDraw(canvas);

		if(mMaskPath != null) {
			canvas.drawPath(mMaskPath, mMaskPaint);
		}
	}
}