If Apple decides that having the screen temperature vary with time, lighting, whatever, I promise it is easier for them to write a few hundred lines of code than it is to engineer secure holes in the sandbox, develop policy around their use, and deal with f.lux.<p>Adjusting white point is a feature, a little one in a long bullet item list, not a business model.<p>␄<p>Appendix: If you are doing this yourself, you can get an approximation of the white point for a temperature kelvin much more easily than computing it accurately. You are probably not doing astrophysics. A 1% or two error is ok.  See: <a href="http:&#x2F;&#x2F;www.zombieprototypes.com&#x2F;?p=210" rel="nofollow">http:&#x2F;&#x2F;www.zombieprototypes.com&#x2F;?p=210</a><p>If you want to use it in your iOS app, you can get a UIColor.colorWithKelvin() function from this gist. <a href="https:&#x2F;&#x2F;gist.github.com&#x2F;jimstudt&#x2F;c5069349f305dd5bb6b2" rel="nofollow">https:&#x2F;&#x2F;gist.github.com&#x2F;jimstudt&#x2F;c5069349f305dd5bb6b2</a> Use the color multiply function, also in that gist and multiply all of your colors by your white point. Which of course is a lot of work compared to adjusting the display CLUT, but you can get in the Apple store and you don&#x27;t get the ability to screw up the user&#x27;s other apps. (Hint: Use the screen brightness to guess the ambient light. You aren&#x27;t allowed to use the ambient light sensor.) ((Also, I&#x27;m relatively certain multiplying is not perceptually correct, but it seems close enough for things I&#x27;ve done so I haven&#x27;t gone down that rat hole.))