绘制图像时绘制外部阴影

I currently create a rounded version of an image in my app by drawing to a canvas. I would like to draw a faint outershadow around the image, but I cant quite get it right. I have 2 questions: 1. How can I draw an outer shadow (I can only seem to draw a shadow with a x or y offset) 2. How can I draw the shadow so that it does not have the artifacts shown in the attached image. Code:I currently create a rounded version of an imag