How to get color from Gradient?

I have created a custom seekbar by making some changes in valueBar using this project LarsWerkman’s HoloColorPicker. My seekbar uses three colors to create linear gradient. In this project he gets color using HSV. How can i get the color where the pointer is located at from my seekbar?

I have created linear gradient using these codes below

shader = new LinearGradient(mBarPointerHaloRadius, 0,
x1, y1,
new int[] { mStartColor, mCenterColor, mEndColor },
null, Shader.TileMode.CLAMP);