How do RippleDrawable draw outside view bounds

Question

1. create a ripple.xml

2. set the drawable to a ImageView

I found that the circle is draw outside current ImageView

How does this work

Answer 1

The reason is about hardware accelerate，see the function isProjected() in RippleDrawable.

If isProjected() return true, DislayList will hold this RenderNode (see http://androidxref.com/7.1.1_r6/xref/frameworks/base/libs/hwui/DisplayListCanvas.cpp#addRenderNodeOp)

Answer 2

Easiest way- put the ImageView inside a larger layout, and apply the ripple to the layout.