CoreGraphicsGraident.m

// Macros for the top and bottom colors of the gradient
#define kGradientTopColor            {0.0f/255.0f, 0.0f/255.0f, 0.0f/255.0f, 1.0f}
#define kGradientBottomColor         {209.0f/255.0f, 209.0f/255.0f, 209.0f/255.0f, 1.0f}

// Macro for the area that should be covered by the gradient
#define kGradientBounds              self.bounds

// Customize your UIView (e.g., UIView, UILabel, UIButton, etc...) drawRect method
- (void)drawRect:(CGRect)rect
{
    CGContextRef context = UIGraphicsGetCurrentContext();
    
    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
    
    CGFloat colorLocations[] = { 0.0f, 1.0f };
    
    CGFloat topColorComponents[] = kGradientTopColor;
    CGFloat bottomColorComponents[] = kGradientBottomColor;
    CGColorRef topColor = CGColorCreate(colorSpace, topColorComponents);
    CGColorRef bottomColor = CGColorCreate(colorSpace, bottomColorComponents);
    
    CFMutableArrayRef colorArray = CFArrayCreateMutable(NULL, 2, &kCFTypeArrayCallBacks);
    CFArrayAppendValue(colorArray, bottomColor);
    CFArrayAppendValue(colorArray, topColor);
    CGGradientRef gradient = CGGradientCreateWithColors(colorSpace, colorArray, colorLocations);    
    
    // Define the area, and the start & end point of the gradient. The following three lines define a linear, top-down gradient.
    CGRect bounds = kGradientBounds;
    CGPoint startPoint = CGPointMake(CGRectGetMidX(bounds), CGRectGetMinY(bounds));
    CGPoint endPoint = CGPointMake(CGRectGetMidX(bounds), CGRectGetMaxY(bounds));
    
    CGContextSaveGState(context);
    CGContextAddRect(context, bounds);
    CGContextClip(context);
    CGContextDrawLinearGradient(context, gradient, startPoint, endPoint, 0);
    CGContextRestoreGState(context);
    
    CFRelease(topColor);
    CFRelease(bottomColor);
    CFRelease(colorArray);
    CGGradientRelease(gradient);
    CGColorSpaceRelease(colorSpace);
}