Sort Colors (Objective-C)

Question

I\'m doing this sort of thing:

- (NSArray*)colors {
    float divisor = .3333;
    NSMutableArray *retVal = [NSMutableArray array];
    for (float one=0; one <         


        

Answer 1

I think using [UIColor colorWithHue:saturation: brightness: alpha:] is your best bet. If you fix saturation, brightness and alpha and just use Hue you'll get all the colours in order.

Check out the wiki for HSB for more information.

for (float hsb = 0; hsb <= 1.0f; hsb += divisor) {
             UIColor *color = [UIColor colorWithHue:hsb saturation:1.0f brightness:1.0f alpha:.5f];
            [retVal addObject:color];
}

Answer 2

This worked quite well. It will NOT help the fact that you have a lot of repeated colors. See below:

NSArray *sorted = [[dict allValues] sortedArrayUsingComparator:^NSComparisonResult(UIColor* obj1, UIColor* obj2) {
    float hue, saturation, brightness, alpha;
    [obj1 getHue:&hue saturation:&saturation brightness:&brightness alpha:&alpha];
    float hue2, saturation2, brightness2, alpha2;
    [obj2 getHue:&hue2 saturation:&saturation2 brightness:&brightness2 alpha:&alpha2];
    if (hue < hue2)
        return NSOrderedAscending;
    else if (hue > hue2)
        return NSOrderedDescending;

    if (saturation < saturation2)
        return NSOrderedAscending;
    else if (saturation > saturation2)
        return NSOrderedDescending;

    if (brightness < brightness2)
        return NSOrderedAscending;
    else if (brightness > brightness2)
        return NSOrderedDescending;

    return NSOrderedSame;
}];

You can access the components (HSBA) like this in iOS 4.x:

    CGFloat *components = (CGFloat *)CGColorGetComponents([color CGColor]);
    float hue = components[0];
    float saturation = components[1]; // etc. etc.

To avoid repeating colors: you can put the elements in an NSMutableDictionary, keyed on something like their hue-saturation-brightness (each rounded to the nearest .10)... then you get the array from THAT, and then sort.