使用CAGradientLayer绘制渐变色

使用CAGradientLayer

self.centerline.backgroundColor = [UIColorclearColor];

CAGradientLayer *gradient = [CAGradientLayerlayer];

gradient.frame = self.centerline.bounds;

gradient.colors = [NSArrayarrayWithObjects:

                    (id)[UIColorwhiteColor].CGColor,

                    (id)[UIColorlightGrayColor].CGColor,

                    (id)[UIColorwhiteColor].CGColor,

                   nil];

gradient.startPoint = CGPointMake(0.0,0.0);

gradient.endPoint = CGPointMake(1.0,1.0);

[self.centerline.layerinsertSublayer:gradientatIndex:0];