When rotating, a modifier key should cause the rotated edit box to snap to common angles like 30 degree, 60, 90 degrees, etc. I personally suggest to snap to every 15 degrees, which conveniently includes 30, 45, 60, 90 etc. already.
WISHGROUP: Small Usability Fixes
Should be fixed by: https://phabricator.kde.org/rKRITA76255392e01877055f6469f9debb3cc09c46a831
Git commit afb5428f5c8a307ce52c6e2a4c620009b4cb519f by Boudewijn Rempt, on behalf of Michael Abrahams. Committed on 24/06/2016 at 06:08. Pushed by rempt into branch 'krita/3.0'. Snap free transform with shift key M +13 -2 plugins/tools/tool_transform2/kis_free_transform_strategy.cpp M +19 -11 plugins/tools/tool_transform2/kis_tool_transform.h http://commits.kde.org/krita/afb5428f5c8a307ce52c6e2a4c620009b4cb519f