Lock crop ratio to current rect when holding Ctrl/Shift
Summary:
In many graphics apps, holding Ctrl and/or Shift locks the ratio of
the rectangle being resized, making it quicker than manually choosing
a ratio. This patch adds this functionality to the Crop tool.
When Ctrl or Shift is pressed, the current ratio of the crop rect
is saved, "locking it". When resizing, so long as Ctrl or Shift is
pressed, the ratio is enforced to this locked value. Otherwise it
behaves the same as before - enforcing ratio if one was chosen in
the GUI
Depends on D11379
Test Plan:
- Crop tool behaves normally when Ctrl/Shift not pressed
- Crop ratio locked when Ctrl/Shift is pressed
- Ctrl/Shift has no effect if ratio is already restricted by the Basic toggle or Advanced combobox
Reviewers: Gwenview, rkflx
Reviewed By: Gwenview, rkflx
Differential Revision: https://phabricator.kde.org/D11380