Is screen repair covered under the 1 year apple warranty ?

Only if the Apple technician will deem it as a manufacturing defect. Otherwise, as KiltedTim has already mentioned, any other form of damage will not be covered. Your only potential option would be if you also purchased an AppleCare+ plan, then it might be covered as one of the two accidental damages at a reduced cost.

A broken or cracked screen would not be covered, but a failed display might be assessed as a manufacturing defect which could be covered by warranty. Contact Support (link) for more details on your specific case.

No. Accidental damage is not covered by the warranty.

iPhone Service Pricing - Apple Support