Creating a shadow around a canvas drawn shape?

No need for a Bitmap, just needed to set the layer type to LAYER_TYPE_SOFTWARE the original approach worked.

public class TestShapeShadow extends View{    Paint paint;    public TestShapeShadow(Context context)    {       super(context);          paint = new Paint(Paint.ANTI_ALIAS_FLAG);        paint.setShadowLayer(12, 0, 0, Color.YELLOW);        // Important for certain APIs         setLayerType(LAYER_TYPE_SOFTWARE, paint);    }    @Override    protected void onDraw(Canvas canvas)    {           canvas.drawRect(20, 20, 100, 100, paint);    }}

1. create. a Path, add some elements to it

2. set BlurMaskFilter to a Paint

3. draw a path with dx, dy shadow offset

4. unset mask filter

5. draw a path again with no. offset

I followed the ideas of @pskink above and found a solution.I put the code snippet here for anyone in need.

If you wonder what shadow properties are, you can refer to this tester:https://okawa-h.github.io/box-shadow_tester/

public class MyViewWithShadow extends View {    Paint paint;    int mainColor;    int shadowColor;    // shadow properties    int offsetX = -25;    int offsetY = 30;    int blurRadius = 5;    public MyViewWithShadow(Context context)    {        super(context);        mainColor = Color.RED;        shadowColor = Color.BLACK; // this color can also have alpha        paint = new Paint(Paint.ANTI_ALIAS_FLAG);        paint.setStyle(Paint.Style.FILL);    }    @Override    protected void onDraw(Canvas canvas)    {           // Create paint for shadow        paint.setColor(shadowColor);        paint.setMaskFilter(new BlurMaskFilter(            blurRadius /* shadowRadius */,            BlurMaskFilter.Blur.NORMAL));        // Draw shadow before drawing object        canvas.drawRect(20 + offsetX, 20 + offsetY, 100 + offsetX, 100 + offsetY, paint);        // Create paint for main object        paint.setColor(mainColor);        paint.setMaskFilter(null);        // Draw main object         canvas.drawRect(20, 20, 100, 100, paint);    }}