iOs iPhone App Button Spacing – Golden Ratio Strikes Again

As is often the case, I needed to arrange a few round buttons evenly across a view, and wanted to set the width and spacing in a nice way. It occurred to me that though it is oversold, the golden ratio is at least a reasonable place to start. So I first set up the problem as so:

  1. The spacing + buttonWidth = 1.618*buttonWidth.
  2. the edge to Button Spacing is equal to the button to button spacing.

in other words:

Golden Button Setup.png

So, I derived this with some algebra…

buttonWidth = viewWidth/(1.303*numberOfButtons + 0.3083)
sp = 0.3083*w

For a 320 point wide view, that leads to the following table of values:

n width spacing between center postion
2 109.4 33.7 88.4
3 75.6 23.3 61.1
4 57.6 17 46.7
5 46.7 14.4 37.8

Drawing this with round buttons looks like this, which to my eyes and testing, seem like a good implementation with regards to Fitt’s Law

Later in the day, I got a phone call and noticed the button spacing on the Phone app. Huh, look at that:

Almost to the pixel for three buttons…

I have this posted as a gist

+ (NSArray *)evenlySpacedGoldenRatioButtonsWith:(NSInteger)numberOfButtons width:(CGFloat)spaceWidth yPos:(CGFloat)spaceHeight  {
    //this gives position in purely frame Math way
    //an autolayout method should be made -- trying to think how I want to implement that -- method that takes view and buttons -- block?

    CGFloat buttonWidth = spaceWidth/(1.303*(CGFloat)numberOfButtons + 0.3083);
    CGFloat buttonSpacing = 0.3083*buttonWidth;

    NSMutableArray *buttons = [NSMutableArray new];

    for (NSInteger i = 0; i < numberOfButtons; i++) {
        UIButton *aButton = [UIButton buttonWithType:UIButtonTypeCustom];
        CGFloat x = floor(buttonSpacing + (CGFloat)i*(buttonSpacing + buttonWidth));
        aButton.frame = CGRectMake(x, spaceHeight, buttonWidth, buttonWidth);

        //  Basic Default Colors
        aButton.backgroundColor = [UIColor darkGrayColor];
        [aButton setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal];
        [aButton setTitleColor:[[UIColor whiteColor] colorWithAlphaComponent:.65] forState:UIControlStateHighlighted];

        [buttons addObject:aButton];
    return [NSArray arrayWithArray:buttons];

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