How to show the following n events with respect to the current date or the past events to always ensure n elements in the view? I have an agenda on my homepage, and I want to always ensure 5 events.

If there are 5 or more following events (including the current one), show the nearest 5 from the start date.

If there is less, show X past events in such a way that the following and the past are 5 in total.

Examples:

Today is March 12.

a) List of events (more than 5 futures):
- March 10th
- March 11th
- March 12
- March 13
- March 14
- March, 15th
- March 16
- March 17
- March 18th

Show in the view
March 12, 13, 14, 15 and 16.

b) List of events (mix, p past events, q future events):
- March 9
- March 10th
- March 11th
- March 13
- March 14
- March, 15th

Show in the view:
March 10, 11, 13, 14 and 15.

c) List of events (no future events, show recent events).
- March 1st
- March 2
- March 3rd
- March 8
- March 9
- March 10th
- March 11th

Show in the view:
March 3, 8, 9, 10 and 11.
You will need to develop a custom module with a custom views sort plugin as views don't have something for this.

Read the Custom Views Sort Plugin for Upcoming Events blog post that will help you.