Obj-C: stimulate the highlightBule

highlightBule.m

    + (UIImage *) imageForSelectedBlue {
        CGRect rect = CGRectMake(0, 0, 10, 10);
        UIGraphicsBeginImageContext(rect.size);
        CGContextRef context = UIGraphicsGetCurrentContext();
        
    	size_t num_locations = 2;
        CGFloat locations[2] = { 0.0, 1.0 };
        CGFloat components[8] = { 0.021, 0.548, 0.962, 1.000, 0.008, 0.364, 0.900, 1.000 };
        
        CGColorSpaceRef rgbColorspace = CGColorSpaceCreateDeviceRGB();
        CGGradientRef selectionGradient = CGGradientCreateWithColorComponents(rgbColorspace, components, locations, num_locations);
        
        CGPoint startPoint = CGPointMake(CGRectGetMidX(rect), CGRectGetMinY(rect));
        CGPoint endPoint = CGPointMake(CGRectGetMidX(rect), CGRectGetMaxY(rect));
        
        CGContextDrawLinearGradient(context, selectionGradient, startPoint, endPoint, 0);
        
        CGGradientRelease(selectionGradient);
        CGColorSpaceRelease(rgbColorspace);
        
        UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();
        return img;
    }