Odd behavior with darken/lighten

[jimbojsb]

Hi,

I think there is either a bug with darken or I'm misunderstanding how to use it. Given an existing UIColor, if I lighten it by 0.15f, it lightens correctly (albeit slightly more than I might expect, but other color libraries, such as the one in less.js, behave identically). However, darkening by any amount results in a color that is not exactly black, but essentially black. What's odd is that lightening by a negative float gives exactly the results I'd expect.

searchInput.backgroundColor = [[Colors teal] lighten:-0.15f]; // perfect
searchInput.backgroundColor = [[Colors teal] darken:0.15f]; // black

[bennyguitar]

The way it works, is it takes the float you pass in and multiplies the brightness of the color (from the Hue, Saturation, Brightness color formulation) by that value. So a .15 will result in a color that is 15% as bright as it used to be.

This might be confusing, and I'll look at making it what seems the most common-sense way of doing it.

[jimbojsb]

Ah, I see. Darken by .85f gives me the result I was looking for. I think maybe just the method names are slightly confusing or even just updating the readme with with what you noted above is sufficient.

[allaire]

This is really confusing. I suggest we take inspiration from sass (http://sass-lang.com/documentation/Sass/Script/Functions.html#darken-instance_method)

darken(#ccc, 5%) makes #ccc 5% darker

[bennyguitar]

Ok, it makes sense now. If you do [[UIColor plumColor] darken:0.05] it makes a 5% darker color.

[allaire]

Works flawlessly @bennyguitar (currently using :head)