eye dropper

when using brush tool or any other tool that works with eyedropper it would be nice

if it was possible to go up and down color values of a picked color. pressing and holding alt (brush mode)

and go up or donw with the stylus to determine desired colour values of picked colour. 

It would be really useful when coloring and zoomed in to be able to choose colours and colour values

of a picked colour while in brush mode. The ability to change colours under the tip of the stylus just 

by going up and down the screen or pick a complementary set of swatches. all under the tip of the stylus.

Holding and going up lighter values, down darker etc.