How Can I restrict a date picker in a date field, to disable a list of specific days from the calendar widget? I need to let the user choose a day from a datepicker in a date field, but disabling a list of specific days from the calendar picker, so the user can't select a not available day.

(Just for explain my use case. I am using Date field and Form api. My Disabled days are in a field in several nodes, and I can get the list of disabled days easily from a View listing this date field. If it is needed it can be exported too as json, xml, plain text or any other format, to serve as entry in the calendar picker.)

(After the user choose an available Day, I will have to do the same to let him select an available Time from a time picker.
This will be an appointment for a Photography Session.)
Using this answer: https://stackoverflow.com/a/15400806/1475662 and a bit of custom coding to add the js and the list of available (or not available) dates to the page.