Ability to add image/icon/static text/computed value next to the slider

[marekburiak]

If there's multiple sliders, it's hard to determine which one does what just by looking at it.

It would be nice if one could add an image/icon/static text or a computed value on the right and left-hand side of the slider. By icon I mean the likes of font-awesome and by computed value I mean a user defined function that can format the displayed value (e.g. if instead of showing values 0-255 for the red channel you want to show "R: 33%"). If user doesn't provide a function then it would just display the plain value.
It would be nice to also position the computed value relative to the slider's handle (so the text moves as the handle moves).
The text styling should be customizable and able to be set for each "text block" separately (font, color, size, maybe also text alignment).
One should be able to display for example a computed value on the right hand side of the slider and also on the top of the handle at the same time. With this I just want to say that you should be able to show computed value in multiple places at the same time and with potentially different formatting, e.g. the value would display as "33%" above the handle and as "R: 84" on the right-hand side of the slider.
Thank you for consideration :)