UIImage+CustomColours.h

UIImage+CustomColours.h

@interface UIImage (CustomColours)

+ (UIImage *) imageWithLinearGradientOfSize:(CGSize)size start:(UIColor *)start end:(UIColor *)end;
+ (UIImage *) imageWithSolidColor:(UIColor *)color size:(CGSize)size;

@end

UIImage+CustomColours.m

#import "UIImage+CustomColours.h"

@implementation UIImage (CustomColours)

+ (UIImage *) imageWithLinearGradientOfSize:(CGSize)size start:(UIColor *)start end:(UIColor *)end
{
    // Initialise
    UIGraphicsBeginImageContextWithOptions(size, YES, 1);
    
    // Create the gradient's colours
    CGFloat locations[2] = { 0.0, 1.0 };
    CFArrayRef colors = (__bridge CFArrayRef) @[(id)start.CGColor, (id)end.CGColor];
    
    CGColorSpaceRef myColorspace = CGColorSpaceCreateDeviceRGB();
    CGGradientRef myGradient = CGGradientCreateWithColors (myColorspace, colors, locations);
    CGPoint startPoint = CGPointMake(size.width / 2.0f, 0.0f);
    CGPoint endPoint = CGPointMake(size.width / 2.0f, size.height);
    
    // Do actual drawing
    CGContextDrawLinearGradient(UIGraphicsGetCurrentContext(), myGradient, startPoint, endPoint, kCGGradientDrawsAfterEndLocation);
    
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    
    // Clean up
    CGColorSpaceRelease(myColorspace); // Necessary?
    CGGradientRelease(myGradient); // Necessary?
    UIGraphicsEndImageContext(); // Clean up
    
    return image;
}

+ (UIImage *) imageWithSolidColor:(UIColor *)color size:(CGSize)size
{
    // Initialise
    UIGraphicsBeginImageContextWithOptions(size, YES, 1);
    
    // Set colour
    CGContextSetFillColorWithColor(UIGraphicsGetCurrentContext(), color.CGColor);
    
    // Do actual drawing
    CGContextFillRect(UIGraphicsGetCurrentContext(), CGRectMake(0, 0, size.width, size.height));
    
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    
    UIGraphicsEndImageContext(); // Clean up
    
    return image;
}

@end