public void drawRadialsGradient() {
        Shader radialGradient = new RadialGradient(centerX, centerY,
                radius, mStartColor, mEndColor, Shader.TileMode.CLAMP);
        reDraw(radialGradient);
    }
author : engineer
e-mail : yingkongshi11@gmail.com
time   : 2017/12/10
desc   :
version: 1.0
app/src/main/java/home/smart/fly/animations/master/widget/MasterPaintView.java