FlyoutMenuView.java 文件源码

Bitmap createMenuShadowBitmap() {
    menuShadowRadius = (int) flyoutMenuView.menuElevation * 2;
    menuShadowInset = menuShadowRadius / 2;
    int size = 2 * menuShadowRadius + 1;
    Bitmap shadowBitmap = Bitmap.createBitmap(size, size, Bitmap.Config.ARGB_8888);
    shadowBitmap.eraseColor(0x0); // clear

    Paint paint = new Paint();
    paint.setAntiAlias(true);
    paint.setShader(new RadialGradient(
            menuShadowRadius + 1,
            menuShadowRadius + 1,
            menuShadowRadius,
            ColorUtils.setAlphaComponent(SHADOW_COLOR, SHADOW_ALPHA),
            ColorUtils.setAlphaComponent(SHADOW_COLOR, 0),
            Shader.TileMode.CLAMP));

    Canvas canvas = new Canvas(shadowBitmap);
    canvas.drawRect(0, 0, size, size, paint);

    return shadowBitmap;
}