Add Icon for Spirit Level Tool in Horizon and Perspective

[lu-k]

Horizon and Perspective allows for a a very simple correction of the rotation of the image by right clicking and drawing a line to be horizontal or vertical.

I would like to suggest to add a tool icon similar to the existing pen and rectangle tool of Mark reference lines in the same module (or like picker icon in other modules)

Here is how another popular Raw editor implemented this:

What problems does it solve?

• discoverability of the tool (right click actions are a bag of surprises atm)
• make it usable on trackpad (Pen tool in Horizon and Perspective is working fine)
• reduce number of actions compared to Pen tool, which needs three steps (draw line 1, draw line 2, choose transform)
• provide a simple way of fixing "rotation only", which is currently ctrl+click action on a perspective transform action
• using the rotation slider feels like hit and miss (because of slow feedback)

Further thoughts
Finally, I think it would be useful to access this tool through a keyboard shortcut. I mention this, as Pen tool in Horizon and Perspective is currently not accessible through keyboard shortcuts.

[Jiyone]

Yes please.